JP3892048B2 - Aqueous solution composition comprising a polymer hydrogel composition - Google Patents

Description

〔Ｒ¹は炭素原子７〜１８個のアルキルまたはアルケニル、
Ｒ²及びＲ³の各々は独立に、炭素原子１〜３個のアルキル、ヒドロキシアルキルまたはカルボキシアルキル、
ｍは２〜４、
ｎは０または１、
Ｘはヒドロキシルで任意に置換された炭素原子１〜３個のアルキレン、及び、
Ｙは−ＣＯ₂−または−ＳＯ₃−である〕
で示される双イオン性洗浄剤（界面活性剤）である。
上記一般式に含まれる双イオン性洗浄剤（界面活性剤）は、式：

の単純ベタイン、及び、式：

〔式中、ｍは２または３を表す〕
のアミドベタインを包含する。
双方の式中の、Ｒ¹、Ｒ²及びＲ³は前記と同義である。特にＲ¹は、基Ｒ¹の少なくとも半分、好ましくは少なくとも四分の三が１０〜１４個の炭素原子を有するようなココヤシから得られたＣ１２アルキル基とＣ１４アルキル基との混合物でよい。Ｒ²及びＲ³は好ましくはメチルである。
使用可能な別の界面活性剤は、式：

または

〔式中、ｍは２または３〕
のスルホベタインであるか、または、式中の−（ＣＨ₂）₃ＳＯ₃ ^-が

によって置換された変異体であり、これらの式のＲ¹、Ｒ²及びＲ³は前記と同義である。
本発明の組成物は、皮膚または毛髪の洗浄製品、例えば、浴用ジェル、シャワージェル、手洗い組成物、洗顔液、シャンプー、髭剃り前及び後の製品、濯ぎ落とし型、拭き取り型、擦り込み型の皮膚手入れ製品の形態に製造され得る。
本発明の組成物は一般に、注入可能な液体、半液体、例えばペーストであり、好ましくは、Ｈａａｋｅ回転粘度計ＲＶ２０で２５℃、１０ｓ^-1の剪断速度で測定した粘度は１，５００〜１００，０００ｍＰａｓの範囲である。
組成物のその他の典型成分としては、好ましくは０．２〜２．０重量％の乳白剤、好ましくは０．２〜２．０重量％の防腐剤、好ましくは０．５〜２．０重量％の香料がある。
発明の第二の実施態様によれば、本発明は、ヒドロゲル粒子を含む水溶液の調製方法に関する。このヒドロゲル粒子は以下の組成、即ち、
（ｉ）水溶液に入れられると不溶化する少なくとも１種類の水溶性ポリマーから成る０．１〜３０重量％のヒドロゲル組成物と、
（ｉｉ）水溶液に可溶性または分散性の水溶性ポリマーから成る０．２〜３０重量％のヒドロゲル組成物と、
（ｉｉｉ）（ｉ）と（ｉｉ）とから形成された網状構造に閉込められた１．０％〜６０％の水不溶性有効物質と、から成る組成を有しており、
有効物質（ｉｉｉ）の粒子は０．２〜２００マイクロメーターの粒度を有しており、
上記ヒドロゲルは２５マイクロメーターよりも大きく、ヒドロゲルの粒度は有効物質の粒度よりも大きい。
方法は以下の段階、即ち、
（ａ）ポリマー溶液を形成するためにポリマー（ｉ）と（ｉｉ）とを水に溶解させる段階と、
（ｂ）ヒドロゲル前駆体溶液を形成するために成分（ｉｉｉ）をポリマー溶液に分散させる段階と、
（ｃ）水溶液中で第一ポリマー（ｉ）が可溶性でなく第二ポリマー（ｉｉ）が可溶性または分散性になるように水溶液を配合する段階と、
（ｄ）上記ヒドロゲル前駆体溶液と水溶液とを混合して、ヒドロゲル前駆体が水溶液に接触したときに、有効物質を閉込めるために十分に剛性であるが基質に塗布されたときに容易に破壊するような十分に軟質の細長い軟質の麺状ヒドロゲルを形成させる段階と、
（ｅ）機械的ミキサーまたはインラインミキサーを用いて麺状ヒドロゲルをヒドロゲル粒子に破壊する段階とから成る。
以下の非限定例は本発明をより十分に理解するために示したものである。本発明の請求の範囲がこれらの実施例に限定されると考えてはならないことは理解されよう。
特に注釈がない限り、上記のパーセンテージはすべて重量％を意味する。
実施例
実施例１：直接混合法によるシリコーン油含有ヒドロゲル分散液（即ち、ヒドロゲル組成物）の調製
ヒドロゲルが不連続ドメインを形成するように水を基剤とする界面活性組成物に高分子ヒドロゲルを分散させ得る多くの方法が存在する。我々が有用であると知見した技術のすべては、ある種の水溶性ポリマーの場合に溶液環境、例えばｐＨ、イオン強度、温度、イオンの種類、架橋剤の存在、などが変化したときに生じる急速ゲル化または架橋を利用する。
この実施例は、慣用の機械的撹拌機を用いてヒドロゲル形成用ポリマー溶液（ヒドロゲル前駆体溶液と呼ぶ）と液体クレンザーとを直接混合することによって本発明に有用なヒドロゲル分散液を調製する方法を説明する。この場合、ヒドロゲル前駆体溶液を洗浄用組成物と混合したときに生じるｐＨ変化が相変化（ゲル化）を惹起するようにポリマー系を選択する。ゲル化は十分に急速なので、添加したそれ自体は水連続性のヒドロゲル前駆体溶液（（１）水性界面活性剤溶液に添加されたときに不溶化する第一ポリマーと（２）特性改質用第二ポリマーと（３）有効物質との溶液）は、最初から洗浄用組成物に溶解せず不連続な分散水相を形成する。
ヒドロゲル前駆体溶液の調製
オーバーヘッド撹拌機を使用して４０部のシリコーン油を、１重量％のキトサン（第一ポリマー）（Ｐｒｏｔａｎ社製のＳｅａ Ｃｕｒｅ ３４０（商標））と０．８重量％の酢酸と３重量％のヒドロキシエチルセルロース（第二ポリマー）（Ａｑｕａｌｏｎ社製のＮａｔｒｏｓｏｌ ２５０ ＭＲ（商標））とを含む６０部の水性ポリマー溶液に４００ｒｐｍで３０分間混合することによって、シリコーン油（６０，０００センチストークス、Ｄｏｗ Ｃｏｒｎｉｎｇ社製）の４０％エマルジョンを調製した。このようにして調製したエマルジョンは、ポリマー溶液に分散した約４μｍ〜５０μｍの範囲の広い粒度分布を有するシリコーン油滴を含んでいた。
直接混合によるヒドロゲル分散液の調製
上記の乳化シリコーン油を含有する１２．５部のヒドロゲル前駆体溶液を、表１に示す組成をもつ８７．５部の液体クレンザーに添加した。オーバーヘッド撹拌機（Ｔｅｋｍａｒ社製のモデルＲＷ２０ＤＺＭ）で混合した。等しい化学組成を有しているが分散液形成のために異なる撹拌速度を用いた２つの分散液を調製した。実施例１Ａでは、分散液を８０ＲＰＭで２５分間混合したが、実施例１Ｂでは混合速度を２００ＲＰＭにした。双方の実施例は、不規則な形状のヒドロゲルドメインを含んでおり、これらのドメイン自体がゲルマトリックスに閉込められた乳化シリコーン油滴を含んでいた。
実施例１Ａ及び１Ｂの組成をそれらの幾つかの物理的特性と共に表２に示す。

実施例２：直接混合によって調製されたシリコーン油含有ヒドロゲル分散液の別の例
実施例１に記載のヒドロゲル前駆体溶液と同様であるが異なるポリマー組成を有しているヒドロゲル前駆体溶液を以下の手順で調製した。６０，０００センチポアズを有する４０部のシリコーン油を、１重量％のキトサン（第一ポリマー）（Ｐｒｏｔａｎ社製のＳｅａ Ｃｕｒｅ ３４０）と０．８重量％の酢酸と３重量％のカチオン性グアーポリマー（第二ポリマー）（Ｒｈｏｎｅ−Ｐｏｕｌｅｎｃ社製のＪａｇｕｑｒ Ｃ１３Ｓ）とを含む６０部の水性ポリマーゲル溶液中でオーバーヘッド撹拌機を用いて４００ｒｐｍで３０分間乳化した。
乳化シリコーンを含有する１２．５部のこのヒドロゲル前駆体溶液を次に、８７．５部の表１に記載の液体クレンザーに添加し、８０ｒｐｍで２５分間混合した。この方法で、シリコーン油滴がゲルマトリックスに閉込められた不規則な形状のヒドロゲル粒子を含む分散液が得られた。この分散液の組成及び特性も表２にまとめられている。
実施例３：押出によって調製されたシリコーン油を含有するヒドロゲル分散液
この実施例は本発明の目的に有用なヒドロゲル分散液が同時押出法を使用しても調製できることを示す。特にこの実施例は、ヒドロゲル前駆体溶液（この場合には分散シリコーン油を含有している）と水性液体クレンザー組成物とを２流体ノズルで同時押出することによって調製した組成物を示す。この方法では、液体クレンザー組成物に懸濁した麺状粒子の形態で分散したヒドロゲル組成物が得られる。麺状ヒドロゲル分散液は、液体クレンザーに独特の外観を与える。あるいは、麺状ヒドロゲルを所望の範囲の大きさに細断または細分する任意の数の剪断技術によって更に処理してもよい。方法をシリコーン油含有ヒドロゲル組成物に関して説明するが、この方法は以後の実施例に示すような多様な材料に使用できる。
シリコーン油を分散したヒドロゲル前駆体溶液の調製
ｐＨ７〜７．５の範囲の水溶液中でシリコーン油と中和カルボン酸含有アクリルコポリマー（第二ポリマー）（Ｒｏｈｍ ＆ Ｈａａｓ社製のＡｃｕｌｙｎ−３３（商標））の水溶液とを機械的撹拌によって混合した。この場合には特性改質用ポリマーとしてＡｃｕｌｙｎ−３３を使用した。Ａｃｕｌｙｎ−３３の濃度及び撹拌速度によって油滴の粒度を直径５〜１５０μｍの範囲に調節した。濃度が高いほど及び撹拌速度が早いほど、油滴の粒度が低下する。６−カラゲナン（Ｇｅｌｃａｒｉｎ ＧＰ−９１１（商標），ＦＭＣ）溶液と第一ポリマー（網状構造形成ポリマー）とを、４５〜５０℃で穏やかに撹拌しながら（＜１００ｒｐｍ）混合物に添加した。この実施例では、異なる粒度のシリコーン油滴を含む２つのヒドロゲル前駆体分散液を調製した。１つの分散液では、シリコーン油滴の粒度は２〜３０μｍの範囲であり、第二の分散液では油滴の粒度が４０〜１００μｍの範囲であった。
同時押出によるヒドロゲル分散液の調製
上記の加温（４５〜５０℃）前駆体溶液を市販のノズル（Ｂｅｔｅ Ｆｏｇ Ｎｏｚｚｌｅ Ｉｎｃ．社製のシリーズＮｏ．１／４ ＸＡ ＳＲ４５０ Ａ）の中央オリフィスに高圧シリンジポンプ（Ｈａｒｖａｒｄ Ａｐｐａｒａｔｕｓ社製のシリンジポンプモデル４０）を用いて導入した。同時に、低温（室温〜２２℃）のシャワージェル配合物（表３に示す組成）をノズルの外側オリフィスに噴射し、“麺状”ヒドロゲル組成物粒子を含む最終製品を形成した。また、洗浄用組成物、この場合にはシャワージェルの輸送にも高圧シリンジポンプを使用した。最終分散液中のヒドロゲル及びシリコーンの含量を、ヒドロゲル前駆体及び界面活性組成物の流量比を調節することによって調節した。この比は、最終製品が確実に５重量％のシリコーン油を含有するように調節した。
実施例３Ａ及び実施例３Ｂの２つのヒドロゲル分散液の特性値を表４にまとめる。これらの分散液は、表３のシャワージェル組成物に懸濁した直径約１，０００μｍの麺状粒子から構成されていた。

実施例４：ヒドロゲルの特性に対するポリマー組成の効果
この実施例は、使用特性に影響を与えるヒドロゲルのレオロジー特性を網状構造形成（第一）ポリマーと特性改質用（第二ポリマー）との選択及び濃度によって操作する方法を示す。
網状構造形成ポリマーとしてカラゲナンを用い、架橋剤としてカリウムイオンを用いた架橋法によって一連のモデルヒドロゲル粒子を調製した。モデル洗浄用組成物としてＫＣｌの水溶液を用い実施例３に記載の押出方法の改良法で分散液を調製した。ヒドロゲル分散液の違いは、ヒドロゲル前駆体溶液中に使用したカラゲナンの濃度だけであり、濃度は１〜６重量％の範囲であった。形成された全部の粒子が約３０００μｍの粒径をもつほぼ球形の粒子であった。
Ｉｎｓｔｒｏｎ（モデル１１２２）は、上述の種々のゲル組成物の強度を識別する好適な手段であることが知見された。測定手順は以下の通りである。ヒドロゲル粒子をへら（スパチュラ）で分散液から慎重に取り出し、ｋｉｍｗｉｐｅに載せて余剰の液体を除去した。ヒドロゲルの直径の近似値をキャリパーで測定した。次に、ヒドロゲルをＩｎｓｔｒｏｎの金属基台に移し、１０ニュートンの荷重をヒドロゲル粒子に接触するまで下降させた。次いでＩｎｓｔｒｏｎを起動し、チャート記録計で力を距離の関数として測定した。チャート記録計をクロスヘッド速度１ｍｍ／分、チャート速度５０ｍｍ／分に設定した。
これによって２ニュートンの全規模荷重の読取りができる。力を０．５０ｍｍ、１．００ｍｍ及び１．５０ｍｍで記録した。力をヒドロゲルの断面積及び歪みによって除算することによってサンプルの弾性率を算出した。測定の進行中に粒子が水和状態に維持されていたことに注目されたい。
上記手順で測定した一連のヒドロゲル粒子のゲル強度を図１に示す。これらの結果は、ゲル強度が、カラゲナン濃度の増加に伴って有意に増加することを示した。ポリマー濃度が２重量％を上回る値であるとき、ゲルは極めて硬質の感触を与え、皮膚に滑らかに塗布できなかった。このような粒子は、有効物質を捕捉でき保存中に安定に維持されるであろうが、有効物質の分配が均一でなく、組成物がざらついた感触を与えるので洗浄という用途には最適でない。これらの結果はまた、ヒドロゲル粒子のゲル強度を低下させることが望ましい場合には、ゲル内のポリマー濃度を低下させるしかないことを示す。これは技術の応用性を大幅に制限する。以下に示すようにこの制限は、ヒドロゲルの特性、例えばそのゲル強度を改質するために第二ポリマーを使用することによって克服され得る。
上記と同じ手順によって別の一連のモデルヒドロゲル粒子を調製した。ヒドロゲル前駆体溶液の各々は、２重量％のカラゲナンと０〜２重量％のアクリルコポリマー即ちアクリゾールＡＳＥ−６０（Ｒｏｈｍ ＆ Ｈａａｓ）とを含有していた。これは特性改質用の第二ポリマーである。水和粒子の形状及び粒度はすべての粒子で極めて類似しており、また前述のカラゲナンのみから成るヒドロゲルにも類似していた。Ｋ＋で架橋させることによって形成したヒドロゲル粒子のゲル強度に対する添加アクリゾールＡＳＥ−６０の効果を図２に示す。この結果は、ポリマーの総濃度が増加した場合であってもアクリゾール濃度の増加に伴ってゲル強度が有意に低下したことを示す。３：１〜２：１の範囲の重量比でカラゲナンとアクリゾールとを含有するヒドロゲル（図２の矢印）は、シリコーン油のような乳化保湿油などの有効物質を効果的に捕捉でき、顕著なざらつきを伴うことなく皮膚に滑らかに塗布できる。
上記実施例の目的は、網状構造形成ポリマーと特性改質用ポリマーとから成るポリマー系の選択によってゲル強度を調節できることを示すことである。上記に引用したゲル強度の正確な値を過度に重視しないように注意すべきである。出願人らは、ヒドロゲル粒子の強度に対するヒドロゲル前駆体溶液中のポリマー組成の定量的効果が、前駆体溶液に分散させる有効物質の種類、粒度及び濃度に有意に依存することを知見した。この傾向は同じであるが正確な値は異なるであろう。複雑であるかもしれないが、当業者は、網状構造形成剤及び特性改質剤の広義の定義に包含されるポリマーの組合せを利用して各状況に応じたゲル強度の適正バランスを見出すことができるであろう。
実施例５：生体外皮膚に対するシリコーン油の付着
洗浄工程でシリコーン油を皮膚に付着させる種々の洗浄用組成物の能力をブタの皮膚に基づく生体外モデルを用いて測定した。
被検組成物の０．５ｍｌのアリコートを、最初に３７℃の水道水で湿らせた５．０８ｃｍ×５．０８ｃｍ（２″×２″）の方形のブタの皮膚切片に塗布した。組成物を１０秒間泡立たせ、次いで流温水で１０秒間濯いだ。皮膚を紙タオルで一回拭って余剰の水を除去し、２分間自然乾燥させた。次に、粘着テープ片を１０ｇ／ｃｍ²の荷重下で皮膚に３０秒間押し付けた。使用した粘着テープは、３ｃｍ幅のＪ−Ｌａｒ Ｓｕｐｅｒｃｌｅａｒ（商標）テープであった。この試験手順で、皮膚に付着していたシリコーンが幾つかの外側皮膚層と共にテープに転移した。
テープに付着しているシリコーン及び皮膚の量をＸ線分光蛍光法で測定した。テープの粘着面が計器のビームに向き合うようにテープ片をＸ線分光蛍光計に配置した。Ｘ線ビームで露光されたテープの中央に標準化領域を規定するためにテープをマスクで覆った。測定開始に先立って計器のサンプル室を真空下に配置し、次いで分光計を使用してシリコーン及びイオウの量を測定した。イオウは、テープに転移した皮膚の量を表す。
清潔な粘着テープ片で観察されたシリコーン及びイオウの量を実験測定値から減算した。連続的に試験したテープ片の実験測定値を加算し、シリコーン及びイオウのそれぞれの累積合計を皮膚の単位面積あたりのシリコーン対イオウの比として表した。高いＳｉ／Ｓ比は高い付着レベルに対応する。各測定に合計１０個のテープ片を使用した。
実施例２及び３に記載の組成物を上述の手順で測定し、ブタの皮膚切片に付着したシリコーンの量を表５に示す。これらの結果から、ヒドロゲル組成物がこれらの試験でシリコーン油を十分に皮膚に付着させたことが明らかである。

実施例６：種々のポリマーによって調製したヒドロゲル分散液
この実施例は、ポリマーが必要なヒドロゲル形成能力とゲル強度とを有している限り、種々のポリマーを用いてヒドロゲル分散液を調製できることを示す。以下に記載の組成物中では、カチオン性ポリマーであるキトサン（第一ポリマー）（Ｐｒｏｎｏｖａ Ｂｉｏｐｏｌｙｍｅｒ社製のＳｅａｃｕｒｅ ３４３）を網状構造形成ポリマーとして使用し、カチオン性改質グアー（Ｊａｇｕａｒ Ｃ−１３Ｓ，Ｃａｌｇｏｎ）と合成カチオン性ポリマーであるポリジメチルジアルキルアンモニウムクロリド（Ｍｅｒｑｕａｔ １００（商標），Ｃａｌｇｏｎ）を特性改質用の第二ポリマーとして使用した。ヒドロゲル前駆体溶液は、６０，０００ｃｐｓをもつ３５部のシリコーン油と、１．５重量％のＪａｇｕａｒ Ｃ１３Ｓと０．７５重量％のキトサンと０．１０重量％のＭｅｒｑｕａｔ １００と０．３５％の酢酸と０．０５重量％のココアミドプロピルベタインとを含有する６５部のポリマー溶液とをオーバーヘッド撹拌機を用いて３００ｒｐｍで１５分間混合することによって調製した。得られたエマルジョンは、ポリマー溶液中に分散した２〜６０μｍの範囲の粒度をもつシリコーン油滴を含んでいた。
実施例３に記載の押出プロセスを使用して、１４．３重量％ヒドロゲル分散液（全組成物を基準として５重量％のシリコーン油含有）を調製した。界面活性剤系は実施例３と同じもの（表３）を使用したが、配合成分のＡｎｔｉｌ １４１を０．９７％でなく０．３％にした。ヒドロゲル分散液は、液滴の平均粒度が２〜６０μｍの範囲である分散シリコーン油を含む麺状粒子分散液であった。
実施例６（本実施例）の組成物からのシリコーン油の付着を表６に示す。実施例５に記載の方法に従って付着試験を実施した。分散液は、同様の粒度のシリコーン液滴を含む他のヒドロゲルと同様の付着を示し、これは、使用されるポリマーの種類よりも分散液の種類及び特性値のほうが付着レベルの決定に重要であることを示唆する。

実施例７：ヒドロゲルによって生じた付着増進の例
本発明のヒドロゲル分散液の使用によって得られる有益な効果の１つは、構造の内部に取り込まれた有効物質の付着が、有効物質を単独で使用した場合に比べて増進されることである。この実施例は、シリコーン油の場合の効果を示す。特に、種々の皮膚洗浄用組成物からのシリコーン油の付着を実施例５に記載の付着試験で比較した。実施例３Ａ、３Ｂ及び６のヒドロゲル分散液に含まれている油滴と同じ粒度のシリコーン油滴を得るために６０，０００ｃｐｓのシリコーンを表３の洗浄用組成物に直接乳化することによって一連の組成物を調製した。
ヒドロゲル分散液対シリコーンエマルジョン単独の付着結果を表７にまとめる。分散ヒドロゲルドメインに有効物質を混入することによって実質的な付着増進が得られたことが証明されている。

実施例８：炭化水素油を含有するヒドロゲル分散液の調製
本発明のヒドロゲル分散液に多様な種類の成分を混入し得る。先行の実施例ではシリコーン油を用いるこれらの分散液のいくつかの普遍的特徴を示した。別のクラスの有用な材料は炭化水素油である。このクラスに包含される有効物質材料としてはペトロラタムのような湿潤剤、パルミチン酸イソプロピルのような皮膚緩和薬及びＲａｒｓｏｌ ＭＣＸ（商標、２−エチルヘキシル−Ｐ−メトキシシンナメート）のような日光遮断剤がある。これらの実施例は、このような炭化水素油を分配するためのヒドロゲルの使用を示す。
ヒドロゲル前駆体溶液の調製
１００％ペトロラタム、５０％パルミチン酸イソプロピルと５０％ペトロラタムとの混合物、５０％Ｐａｒｓｏｌ ＭＣＸと５０％ペトロラタムとの混合物のような種々の炭化水素油の４０％エマルジョンを調製するために、４０部の炭化水素油を、０．５重量％のキトサン（第一ポリマー）（Ｐｒｏｎｏｖａ Ｂｉｏｐｏｌｙｍｅｒ社製のＳｅａｃｕｒｅ ３４３）と１．９重量％のＪａｇｕａｒ Ｃ１３Ｓ（第二ポリマー）と０．４重量％のココアミドプロピルベタインと０．２５重量％の酢酸とを含む６０部の水性ポリマー溶液にオーバーヘッド撹拌機を用いて３００ｒｐｍで２０分間混合した。１００％ペトロラタムのサンプル以外は室温で混合した。１００％ペトロラタムのエマルジョンは、６０℃でペトロラタムを融解し、これを室温のポリマー溶液に添加し、室温で混合することによって調製した。
同時押出によるヒドロゲル分散液の調製
実施例３に記載の押出法を使用し、それぞれ実施例８Ａ、８Ｂ及び８Ｃの１００％ペトロラタム、５０％パルミチン酸イソプロピル／５０％ペトロラタム、５０％Ｐａｒｓｏｌ ＭＣＸ／５０％ペトロラタムを含むヒドロゲルの１２．５重量％分散液を調製した。界面活性剤系は、配合成分にＡｎｔｉｌ １４１を使用しなかった以外は実施例３と同じもの（表３）を使用した。これらのサンプルはいずれも直径約１，０００ｎｍの麺状ヒドロゲル分散液を含んでいた。
実施例９：固体脂肪酸を含むヒドロゲル分散液の調製
先行の実施例は、多様な種類の疎水性油を本発明のヒドロゲル分散液に混入できることを示した。別のクラスの有用な材料は分散疎水性固体またはワックス状粒子である。このクラスの材料に包含される有効物質の例としては、脂肪酸のような湿潤剤、皮膚緩和薬、Ｐヒドロキシ安息香酸のようないくつかの固体日光遮断剤、トリクロサンのような抗菌剤、サリチル酸のようなにきび防止薬がある。
この実施例では、このような固体状またはワックス状の疎水性固体の分配にヒドロゲルを使用できることを示すために固体脂肪酸の混合物を特定例として用いた。
ヒドロゲル前駆体溶液の調製
２２ｇの変性コーンスターチ（Ｎａｔｉｏｎａｌ Ｓｔａｒｃｈ ＆ Ｃｈｅｍｉｃａｌ社製のＣａｐｓｕｌ（商標））と４．４ｇのカラゲナン（ＦＭＣ社製のＧｅｌｃａｒｉｎ ＧＰ９１１（商標））と０．５５ｇのラウリル硫酸ナトリウム（ＢＤＨ社製）とを８３．０５ｇの脱イオン水に８０℃で溶解した。５０重量％のパルミチン酸と４８重量％のステアリン酸とを含有する２１０ｇの溶融脂肪酸混合物を上記ポリマー溶液に添加し、６０℃で乳化させて脂肪酸エマルジョンを形成した。次に、脂肪酸エマルジョンをＨｏｂａｒｔ Ｋｉｔｃｈｅｎ Ａｉｄミキサーに移し、冷却しながら混合して、粘性の混練生地状脂肪酸エマルジョンを形成した。エマルジョンは、直径１〜４０μｍの範囲の粒度の脂肪酸粒子を含んでいた。
次に、上記組成物を４％のＭｅｒｑｕａｔ １００（Ｃａｌｇｏｎ社製）と０．５％のキトサン（Ｐｒｏｔａｎ社製のＳｅａ Ｃｕｒｅ ３４０）と０．４％の酢酸とを含有する等量のポリマー溶液と混合して、分散脂肪酸を含有するヒドロゲル前駆体溶液を形成した。
押出によるヒドロゲルの調製
次に、実施例３に記載の方法を用い、１４部のヒドロゲル前駆体溶液を表３の８６部の液体クレンザーと同時押出して、ヒドロゲル分散液を形成した。この分散液は、界面活性組成物中に均一に分布した麺状ゲル粒子から構成されていた。
実施例１０：固体脂肪酸を含有するヒドロゲル分散液の別の例
この実施例は、異なるゲル形成ポリマーを使用した以外は実施例９とほぼ同様である。
ヒドロゲル前駆体溶液の調製
２２ｇの変性コーンスターチ（Ｎａｔｉｏｎａｌ Ｓｔａｒｃｈ ＆ Ｃｈｅｍｉｃａｌ社製のＣａｐｓｕｌ）と４．４ｇのカラゲナン（ＦＭＣ社製のＧｅｌｃａｒｉｎ ＧＰ９１１）と０．５５ｇのラウリル硫酸ナトリウム（ＢＤＨ社製）とを８３．０５ｇの脱イオン水に８０℃で溶解した。５０重量％のパルミチン酸と４８重量％のステアリン酸とを含有する２１０ｇの溶融脂肪酸混合物を上記ポリマー溶液に添加し、６０℃で乳化させて脂肪酸エマルジョンを形成した。次に、脂肪酸エマルジョンをＨｏｂａｒｔ Ｋｉｔｃｈｅｎ Ａｉｄミキサーに移し、冷却しながら混合して、粘性の混練生地状脂肪酸エマルジョンを形成した。エマルジョンは、直径１〜４０μｍの範囲の粒度の脂肪酸粒子を含んでいた。
次に、上記組成物を１０重量％の完全加水分解ポリビニルアルコール溶液（Ａｉｒ Ｐｒｏｄｕｃｔ社製のＡｉｒｖｏｌ ３５０（商標））を含有する等量のポリマー溶液と混合した。
押出によるヒドロゲルの調製
次に、実施例３に記載の方法を用い、１４部のヒドロゲル前駆体溶液を表３の８６部の液体クレンザーと同時押出して、ヒドロゲル分散液を形成した。この分散液は、界面活性組成物中に均一に分布した麺状ゲル粒子から構成されていた。
実施例１１：液体クレンザーからの脂肪酸の付着
ブタの皮膚に対する脂肪酸の付着をガスクロマトグラフ法によって測定した。５．０８ｃｍ×５．０８ｃｍ（２インチ×２インチ）のブタ皮膚片を先ず約０．３５ｇの液体クレンザーで１分間洗浄した。処理したブタ皮膚を５０秒間水洗した。皮膚を紙タオルで一回乾燥し、２分間風乾し、次いで１０ｇのヘプタンで３０分間抽出した。ヘプタン溶液のアリコートをＧＣに噴射して、皮膚に付着した脂肪酸の量を測定した。対照サンプルは７部の水と実施例９及び１０の分散液を調製するために使用した７部の脂肪酸エマルジョンと表３に示した８６部の界面活性組成物（実施例１０と１１を調製するためにも使用）とから構成されていた。実施例９及び１０から付着した脂肪酸の量を表８の対照に比較した。結果は、これらのヒドロゲル分散液から有意な脂肪酸付着が生じることを示す。更に、シリコーン油の場合と同様に、ヒドロゲルの配合成分に脂肪酸を加えると、付着が有意に増加する（実施例９及び１０と対照との比較）。

実施例１２：脂質を含有するヒドロゲル分散液の調製
３０部のグリセロールと１５部のコレステロール（Ｃｒｏｄａ Ｃｈｅｍｉｃａｌｓ ＬＴＤ社製のコレステロールＵＳＰ）と７．５部の糖エステル（Ｍｉｔｓｕｂｉｓｈｉ−Ｋａｓｅｉ Ｆｏｏｄｓ Ｃｏｒｐ．社製のＲｙｏｔｏ Ｓ２７０（商標））と７．５部のステアリン酸（Ｕｎｉｃｈｅｍａ Ｉｎｔｅｒｎａｔｉｏｎａｌ社製）とを１５０℃のホットプレートで加熱することによって溶融脂質溶液を調製した。次に、透明な溶融脂質溶液を約９８℃に冷却し、１０部の中和Ａｃｕｌｙｎ ３３（Ｒｏｈｍ ＆ Ｈａａｓ，２重量％，ｐＨ：７．５−８．０）溶液及び３０部のカラゲナンＧｅｌｃａｒｉｎ ＧＰ９１１（商標）溶液（２重量％）と混合して、コレステロールを含有するヒドロゲル分散前駆体を形成した。
実施例３に記載の押出法を使用して、１７重量％のヒドロゲル分散液（全組成物を基準として２．５５重量％のコレステロール含有）を調製した。実施例３（表３）と同じ界面活性剤系を調製に使用した。この洗浄用組成物からのコレステロールの付着を実施例１３で測定した。比較のために、液体クレンザー中に均一に分散した２．５重量％のコレステロールを含有する比較実施例を調製した。この比較実施例の組成及び調製方法を以下の表９に示す。

調製
グリセロールとスクロースエステルとステアリン酸とコレステロールとを一緒にしてホットプレートで溶融する。界面活性剤と過剰の水とをプレミックスする。界面活性剤を脂質／グリセロール混合物に添加し、次いでＪａｇｕａｒを添加する。系を保存しｐＨを５．３に調節する。ＮａＣｌを用いて１０ｓ^-1／２５℃の粘度を５，０００ｍＰａｓに調節する。
実施例１３：皮膚に対するコレステロールの付着
洗浄用組成物からブタの皮膚に付着したコレステロールの量を以下の方法によって測定した。水道水で予め湿らせた５×５ｃｍ²のブタ皮膚に０．２５ｇのクレンザーを５０回擦り込んだ。次に皮膚を脱イオン水で１０秒間濯ぎ、紙タオルで叩いて乾燥した。分析用に３ｍｌのエタノールを使用して皮膚からコレステロールを抽出した。
皮膚から抽出したコレステロールの量を分光光度法で測定した。エタノール抽出物を８０℃のオーブンで乾燥した。乾燥内容物に１００μｌのメタノールを添加した。１，０００μｌのＳｉｇｍａ社製の水性コレステロール試薬をサンプルに添加し、抽出コレステロールと５分間反応させた。次いで水性コレステロール溶液を５００μｌのクロロホルムと混合し、微量遠心管に注入した。管を１３，０００ｒｐｍで５分間遠心することによって水溶液からクロロホルムを分離した。遠心後、最上部の透明な水相をピペットにキュベットに注入し、分光光度計で５００ｎｍの吸光度を測定し、標準校正曲線を用いて皮膚から抽出されたコレステロールの量を測定した。
実施例１２で処理することによって皮膚から抽出されたコレステロールの量を表１０の２つの対照に比較する。データは、２つの対照に比べて実施例１２のヒドロゲルサンプルからコレステロールが有意に付着したことを示す。

実施例１４
１０重量％のシリコーンヒドロゲル（全組成物の５重量％のシリコーン油）とＡｎｔｉｌ １４１を０．９７％でなく０．３重量％含有する９０重量％の表３の界面活性組成物とから成る液体クレンザー組成物を実施例３に記載の方法を用いて調製した。６０，０００ｃｐｓの５０重量％のシリコーン油と０．４７重量％のカラゲナンＧＰ９１１と０．１５５重量％のＡｃｕｌｙｎ−３３と０．３１重量％のポリビニルアルコール（Ａｉｒ Ｐｒｏｄｕｃｔ社製のＡｉｒｖｏｌ ５４０）と２４．０６重量％の水とを含有するシリコーンヒドロゲル前駆体溶液を表３の記載と同様にして調製した。ヒドロゲル前駆体溶液は、５〜６０マイクロメーターの範囲の粒度のシリコーン油滴を含んでいる。
以下に記載のプロトコルを使用し、消費者の使用後の皮膚感触に対するシリコーンヒドロゲル含有クレンザーの効果を、シリコーンヒドロゲル分散液非含有の液体クレンザーとの比較によって評価した。この評価の試験部位は、前腕の掌側表面である。手及び前腕を水道の流水（３０℃）下に約１５秒間維持して予め湿らせ、手に３．５ｇのヒドロゲル含有液体クレンザーを分配し、指定された腕を２０秒間洗い、流水で１０秒間濯いだ。前腕を紙タオルで叩いて乾かした。シリコーンヒドロゲル非含有の同じクレンザーを用いて他方の腕で同様の手順を繰り返した。パネリスト全員に使用後の皮膚感触の判定を依頼した。８人中の７人のパネリストが使用後の皮膚感触の違いを意識し、これらの７人中の５人がシリコーンヒドロゲル含有液体クレンザーで処理した腕の皮膚感触のほうが好ましいと判断した。
実施例１５：スキンローションとなるヒドロゲル分散液の調製
この実施例は、皮膚手入れの用途に好適な水溶液組成物を用いてヒドロゲル分散液を調製できることを示す。この実施例では、ヒドロゲル調製のために、０．９重量％のＮｉｔｒｏｓｏｌ ２５０ ＨＨＲ（Ａｑｕａｌｏｎ社製のヒドロキシエチルセルロース）と０．０６重量％のＣａｒｂｏｐｏｌ Ｃ９８１（ＢＦ Ｇｏｏｄｒｉｃｈ社製）と０．４重量％のＮａ₃ＰＯ₄と０．０５重量％のＧＬｙｄａｎｔ Ｐｌｕｓとを含有し、界面活性剤非含有の水溶液組成物を調製した。
１０部のペトロラタム（Ｐｅｎｒｅｃｏ社製のＳｎｏｗ Ｗｈｉｔｅ（商標））と、０．６重量％のキトサン（Ｐｒｏｔａｎ社製Ｓｅａｃｕｒｅ ３４３）と０．４重量％の酢酸と１．８重量％のＪａｇｕａｒ Ｃ１３Ｓ（Ｒｈｏｎｅ−Ｐｏｕｌｅｎｃ）とを含有する９０部の水性ポリマー溶液とを、オーバーヘッド機械的撹拌機を使用して６０℃、３００ｒｐｍで１５分間撹拌することによってペトロラタムヒドロゲル前駆体溶液を形成した。このようにして調製したエマルジョンは、１〜３０μｍの範囲のサイズをもつペトロラタム液滴を含んでいた。２５部のペトロラタムヒドロゲル前駆体溶液を、＃１４ゲージのシリンジ針を用いて７５部の水溶液組成物に噴射して細長い麺状ヒドロゲルを形成した。次に、ペトロラタムの麺状ヒドロゲルを含有する水性組成物を、メッシュサイズ２００μｍを有するスクリーンに通して、ヒドロゲル分散液を形成した。このサンプルは、ペトロラタム液滴が濃縮した軟質の大粒ヒドロゲル粒子を含有し、皮膚手入れの用途に好適であった。
実施例１６：ヒドロゲル形成に対する処理条件の影響
この実施例は、ヒドロゲル粒子の形成が、ヒドロゲル前駆体溶液を水溶液組成物に混入するために使用される混合装置に左右されることを示す。好ましい方法である押出／低剪断混合法は、ヒドロゲル粒子の粒度の調節、及び、ヒドロゲル粒子内部の水不溶性有効物質の保持を改善する。
０．４重量％のＳｅａｃｕｒｅ ３４３と０．２重量％の酢酸と２．０重量％のＪａｇｕａｒ Ｃ１３Ｓとを含有する７０部のポリマー溶液と、６０，０００ｃｐｓの３０部のシリコーン油とを、オーバーヘッド機械的ミキサーを使用して６０ｒｐｍで７分間混合することによってシリコーンヒドロゲル前駆体溶液を調製した。このようにして調製したシリコーンエマルジョンは粒度約１３２μｍをもつ３０重量％のシリコーン油を含有していた。
ヒドロゲル加工のために異なる粘度をもつ２種類の水性液体クレンザーを調製した。表１１に示す組成をもつこれらの２種類の水溶液組成物はいずれも０．４重量％のＣａｒｂｏｐｏｌ ＥＴＤ２０２０と０．４重量％のＢｅｎｔｏｎｅとによって増粘した１７．５重量％の界面活性剤を含有していた。これらの２つのクレンザーの粘度はそれぞれ１５，０００ｃｐｓ及び３，５００ｃｐｓであり、約７．８のｐＨを有していた。バッチ法及び同時押出／インライン混合法の２つの方法を使用してこれらの２つの液体クレンザー中の大粒ヒドロゲル分散液を製造した。
バッチ法では、１５部の上記シリコーンヒドロゲル前駆体溶液を８５部の液体クレンザーに添加し、オーバーヘッドミキサーを使用して６０ｒｐｍで１５分間混合した。同時押出／インライン混合法には実施例３に記載の装置を使用した。２つの流体ノズルから１５部のシリコーン前駆体溶液と８５重量％の液体クレンザーとを同時押出して、細長い軟質の麺状ヒドロゲルを形成した。予め硬化させた麺状ヒドロゲルを次に、低剪断インライン混合装置に２０ｃｃ／分の流速で連続的に通して麺状ヒドロゲルをヒドロゲル粒子に破壊した。麺状ヒドロゲルを破壊するために異なる２つのインライン混合装置を使用した。一方は直径０．６４ｃｍ（１／４″）及び長さ１５．２ｃｍ（６″）の静止インラインミキサーである。他方は、メッシュサイズ約２００μｍの等しい２つのスクリーンを内蔵するインラインミキサーである。ヒドロゲル粒子の粒度及びヒドロゲルのゲル粒子の内部に保留されたシリコーン油の％の双方を表１２に示す。

Background of the Invention
Field of Invention
The present invention relates to novel large hydrogel particles suspended in an aqueous medium and to a continuous extrusion / mixing process for producing such hydrogel particles. Hydrogel particles consist of two different high molecular weight polymers. One polymer is insoluble in an aqueous medium and forms a network structure to maintain gel binding. The other polymer is soluble in an aqueous medium and swells the gel to adjust the strength of the gel. The water-insoluble material is confined and encapsulated in a network formed by these two types of polymers and is more efficiently distributed from an aqueous composition (eg, a liquid cleanser containing hydrogel particles). Gel particles with adjustable particle size and adjustable gel strength are prepared by first adding an aqueous solution containing two polymers and a water-insoluble material to an aqueous medium (eg, by spraying) to form an elongated soft noodle-like polymer gel. It can be easily produced by forming and then cutting / breaking the gel particles to the desired particle size (eg by mixing or mechanical agitation).
Background of the Invention
Liquid cleansers or other compositions that dispense skin active substances that have some beneficial effect on the skin are desired and known in the art. For example, the use of silicone oil droplets that provide an effect of enhancing moisture retention is known.
One way to enhance the delivery of active substances (eg silicone oils and vegetable oils) to the skin or hair is to use cationic properties such as Polymer JR® from Amerchol or Jaguar® from Rhone Poulenc. The hydrophilic polymer is used. This method is disclosed, for example, in European Patent EP 93,602, International Patents WO 94/03152 and WO 94/01351. In each of these references, both the adhering polymer and usually small silicone particles are evenly distributed throughout the liquid cleanser composition (ie, there are no concentrated “pockets” of active agent).
In another reference, the hydrophilic polymer itself is incorporated into a liquid cleanser or aqueous solution to provide various beneficial effects. For example, in U.S. Pat. Nos. 4,491,539, 4,556,510, 4,678,606 and 4,917,823, guar gum, polyacrylamide, polyacrylic acid and polymer JR (registered) Trademark) are disclosed as thickeners, foam modifiers or skin feel improvers. In either case, the polymer is uniformly mixed or distributed throughout the surfactant composition to provide the beneficial effects recited in the claims.
However, a type of inclusion or containment of active substances in concentrated form to enhance the adhesion of water-insoluble skin active substances from cleansers or aqueous media or to improve the use properties of cleansers with hydrophilic polymers. The use of individual hydrogel particles or dispersions that act as structures is not taught in any reference.
Applicants surprisingly would be typical if the active substance was incorporated into the liquid composition in the form of a unitary hydrogel carrier containing the active substance (ie, a discontinuous aqueous phase trapping the active substance). Significant levels of active substance adhesion to skin or other substrates compared to liquid gel compositions containing polymeric substances (eg, cationic adhesion substances such as cationic guar) that aid in the adhesion of liquids or active substances It was found that it was improved. In particular, when small particles are used, a higher deposition amount can be obtained than a composition in which oil droplets are dispersed throughout the composition without the presence of an adhesion aid. Applicants have also noted that individual hydrogel particles, in addition to adhesion enhancement, provide sensory characteristics during cleanser use (ie, smooth creamy feel) when applying a cleanser or aqueous composition generally to the skin. It has been found to improve.
Several proposals have been tested in the industry to distribute certain active substances as gel particles, but it is possible to retain the active substance in the composition and to easily distribute it during final use (eg, application). Never both sides succeeded.
For example, US Pat. No. 5,089,269 to Noda et al. Discloses an improved gelatin capsule-containing cosmetic composition that encapsulates a hydrophobic component covered by a gelatin film swollen with water. Earlier gelatin gels, or capsules coated with other hydrogels such as agar, alginate or carrageenan, required strong destructive forces to break the capsule and release the encapsulated components. In some cases, these capsules only slipped on the skin surface when applied to the skin. The patent proposed an improved gelatin capsule that overcomes the above undesirable properties. However, as described in that patent, the same problem occurred when the improved capsules were smaller than 100 μm or larger than 1,000 μm. That is, the improved gel-coated capsule becomes so hard that it cannot be broken or is easily removed from the finger or palm during application. Thus, neither the patent nor any other technique teach a hydrogel composition that retains an active substance and efficiently releases it as desired, such as the hydrogel composition of the present invention. Further, this reference does not teach how to form such hydrogel-containing aqueous compositions.
EP 0,355,908 A1 describes a process for the production of polysaccharide gel particles such as agar, carrageenan or gellan gel particles having a particle size of less than 100 μm for use in foods, skin lotions or cleansers. Is disclosed. The document also teaches that the gel particles contain a water insoluble material suitable for human body care products. These types of gel particles are still too hard and easy to break, leaving room for improvement because they do not provide smooth rubbing properties when the particle size is large.
Takizawa, U.S. Pat. Nos. 4,777,089 and 4,908,233, disclose hydrous compositions comprising microcapsules made by a simple coacervation process. In these patents, capsules are produced by a simple coacervation process using two different types of water-soluble polymers. When an organic or inorganic salt is added, the first polymer undergoes phase separation and the second polymer does not undergo phase separation. In the absence of the second polymer, the first polymer cannot surround the core material of the capsule, or when the capsule is formed, the capsule aggregates to form a coarse granular mass.
Thus, none of the references teaches that hydrogel particles can be formed using a combination of two different water soluble polymers. Nor is it taught how to make this type of hydrogel particles.
Summary of the Invention
The present invention relates to an aqueous composition comprising novel hydrogel particles formed by two different water-soluble polymers. The hydrogel particles “capture” the water-insoluble active substance in the network formed by these two types of polymers. The polymer network containing the active substance collapses smoothly when applied to a substrate such as the skin, giving the composition desirable use characteristics (eg, a smooth and rich creamy feel). More particularly, the aqueous composition of the present invention comprises:
(A) 300 centipoise (cps), preferably 1,000 cps, more preferably more than 3,000 cps, containing 0% to 60%, preferably 2% to 40% surfactant, 40-95% by weight aqueous solution such that when present, the surfactant is selected from anionic, nonionic, cationic, zwitterionic, zwitterionic surfactants and mixtures thereof When,
(B) (i) 0.1-30% by weight, preferably 0.3-15% hydrogel composition comprising at least one water-soluble polymer that is ideally insolubilized by thermal gelation when placed in the aqueous solution. When,
(Ii) 0.2-30%, preferably 0.5-10% by weight of a hydrogel composition comprising at least one water-soluble second polymer that is soluble or dispersible in the aqueous solution;
(Iii) 1.0 to 60% by weight, preferably 5 to 40% by weight of a water-insoluble active substance confined in the network formed by the polymers (i) and (ii);
5-60 wt% hydrogel composition consisting of
Consists of
The particles of the active substance preferably have a particle size of about 0.2 to 200 micrometers,
The hydrogel is preferably characterized by having a particle size of about 25 micrometers, preferably 100 micrometers, more preferably greater than 200 micrometers and not more than a few centimeters.
According to one embodiment, the gel-forming polymer is selected from the group consisting of gel-forming polysaccharides such as carrageenan or agar, gel-forming proteins and heat-gelling synthetic polymers.
Preferably, the gel-forming polymer comprises a homo- or copolymer containing N-acrylamide and a polyacrylate or methacrylate containing a branched or linear long chain alcohol acrylate or methacrylate. Is a synthetic polymer selected from
Ideally, the polymer of (i) is insolubilized upon contact with the aqueous solution of term (a), usually by precipitation or coacervation caused by pH changes. The polymer (i) in such a case will typically be polyglucosamine. Alternatively, precipitation or coacervation is caused by changes in electrolyte concentration. The polymer (i) in such a case is selected from the group consisting of polyvinyl alcohol and hydroxyalkyl cellulose having a molecular weight greater than 13,000 and a degree of hydrolysis of 78% to 100%.
Ideally, the polymer of (i) is insolubilized by being crosslinked with a crosslinking agent present in the aqueous solution (a). Therefore, when the polymer (i) is carrageenan, the crosslinking agent is potassium ion. Moreover, when polymer (i) is an alginate, a crosslinking agent is a calcium ion. When the polymer (i) is polyvinyl alcohol, the crosslinking agent is borax ion.
In another embodiment of the invention, the polymer (ii) is
(A) a carboxylic acid-containing acrylic polymer,
(B) a nonionic polymer selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, modified corn starch and hydroxyalkyl cellulose or hydroxyalkyl methyl cellulose; and
(C) a cationic polymer,
Selected from the group consisting of
According to yet another embodiment of the present invention, an aqueous composition containing novel hydrogel particles is prepared by first adding a polymer solution containing the above two types of polymers and a water-insoluble material to the aqueous medium (eg, jetting). In the form of elongated noodles (theoretically there is no limit on the particle size of the noodles since it can be extruded) and soft (i.e. sufficiently rigid to hold the active substance, but initially with smaller particles) It is prepared by forming a polymer gel (which is soft enough to break down and later enable the active substance to be distributed to the skin) and cut it into gel particles of the desired particle size. More specifically, the aqueous composition is prepared by the following procedure:
(A) dissolving the first and second polymers in water to form a polymer solution, and dispersing the water-insoluble material in the prepared polymer solution to form a hydrogel precursor solution;
(B) formulating the aqueous composition so that the first polymer becomes insoluble in the aqueous composition by chemical or physical interaction and the second polymer becomes soluble or dispersible;
(C) The hydrogel precursor solution (a) is jetted into the aqueous composition (b) to form an elongated soft noodle-like hydrogel, and the low-shear mixing device is used to break the elongated soft noodle-like hydrogel into hydrogel particles .
The one or more second polymers (2) (b) that form the hydrogel composition are (1) help to stabilize the active agent in the polymer hydrogel, and (2) are suitable for the entire hydrogel composition It is a polymer for property modification necessary for imparting gel strength.
The invention also relates to the use of the above aqueous composition in human body cleansing, especially skin care creams and products.
[Brief description of the drawings]
FIG. 1 shows the effect of the concentration of carrageenan (one of the materials that can be used as network-forming polymer (2) (a) insolubilized in aqueous medium) on the gel strength of hydrogel particles.
FIG. 2 shows the effect on gel strength when an acrylic polymer, acrylol (one of the materials that can be used as a property modifying polymer (2) (b) soluble in both water and aqueous media) is combined with carrageenan. Show.
Detailed Description of the Invention
According to one embodiment, the present invention relates to a hydrogel composition that is uniformly dispersed and stably suspended in an aqueous composition designed for human body washing or skin care. The hydrogel composition is a discrete polymer gel phase (ie, placed in the aqueous solution) that exists as a macroscopic domain (ie, having a particle size greater than 25 micrometers, preferably greater than 100 micrometers and less than or equal to several centimeters) in the aqueous solution. At least one polymer network-forming polymer is formed by insolubilization; one or more property-modifying second polymers that are soluble or dispersible in aqueous solution are also required). In addition, these domains are contained within the gel structure, ie, the web or network formed by the network-forming polymer (s) and the property-modifying polymer (s). In the following description, water-insoluble substances called “active substances” can be captured. The hydrogel composition maintains the integrity of the discontinuous domains and has sufficient gel strength (generally (generally (one)) to capture and retain the insoluble active substance (s) during processing and storage of the aqueous composition. One or more) provided by the first network-forming polymer). However, hydrogels are also smooth without any unpleasant feeling, such as a feeling of foreign body or roughness due to the destruction or components of the hydrogel particles when the composition is applied and rubbed onto a predetermined substrate such as the skin. It must be soft enough to collapse. The flexibility of the gel particles can be manipulated by the amount of property modifying polymer (s) and network-forming polymer (s) incorporated into the gel composition.
In the second embodiment of the present invention, in order to prepare a hydrogel dispersion or hydrogel structure, usually a water-insoluble active substance is first emulsified or dissolved in an aqueous polymer solution containing both a network-forming polymer and a property-modifying polymer. An emulsion or dispersion is formed by dispersing. This aqueous polymer containing the dispersed active substance is referred to hereinafter as a “hydrogel precursor solution”. The hydrogel precursor solution containing the dispersed active substance (and containing both the first polymer and the second polymer as defined in (2) (a) and (2) (b) above) is then subjected to hydrogel dispersion. Spherical, noodle-like or in some cases irregularly shaped hydrogel domains in which the liquid precursor is insoluble upon contact with the aqueous solution and becomes insoluble (due to the presence of component (2) (a)) Are added or jetted into a suitable aqueous solution and mixed under the conditions to form
The hydrogel dispersion may be prepared in a batch process or a continuous process depending on the method of mixing the hydrogel precursor solution and the aqueous composition. To prepare the hydrogel dispersion, batch methods such as overhead mixers or floaters or continuous methods such as two-fluid coextrusion nozzles or in-line injectors, in-line mixers or in-line screens can be used. The particle size of the hydrogel composition in the final composition can be manipulated by varying the mixing speed, mixing time, mixing apparatus and aqueous solution viscosity. In general, the particle size of the prepared hydrogel composition can be reduced by using a mixing device that reduces the mixing speed, shortens the mixing time, decreases the viscosity of the aqueous solution, or generates low shear forces during mixing. Can expand. In order for optimal transfer of the hydrogel to the substrate by application, the size of the hydrogel domain (eg, particles) must be greater than 25 μm, preferably greater than 100 μm, in at least one dimension (eg, diameter). A large particle size of several centimeters may be used. In order to form hydrogel particles, a jet / low shear mixing method is preferred. The hydrogel precursor solution is simultaneously jetted or coextruded to form an elongated soft noodle-like hydrogel. There is no theoretical upper limit on the size of the extruded noodle-like hydrogel. (As mentioned above, the mixed hydrogel particles must be at least 25 microns). The precured soft noodle-like hydrogel is then broken into irregularly shaped hydrogel particles using a low-speed floater or mechanical mixer for batch processes, or a low shear mixing device such as an inline static mixer or inline screen for continuous processes. To do. An in-line mixing method that excels in the ability to trap or hold the water-insoluble active substance inside the gel particles and adjust the particle size of the hydrogel particles is preferable. The pre-cured elongated noodle-like hydrogel must be sufficiently soft to be easily broken at low shear mixing conditions. When the pre-cured noodle-like hydrogel is too stiff, the noodle-like hydrogel can clog the in-line mixer or become entangled with the mechanical mixer, creating problems during processing. The rigidity of the pre-cured noodle-like hydrogel can be easily manipulated by the composition of the hydrogel precursor solution or the composition of the aqueous solution and the curing time of the noodle-like hydrogel in the aqueous solution. In general, to reduce the stiffness of the noodle-like hydrogel, the level of the network-forming polymer (2 (a)) in the hydrogel precursor solution or the property modifying polymer (2 (b)) is reduced. The noodle-like hydrogel in the aqueous solution may be shortened, or the concentration of the crosslinking agent in the aqueous solution may be reduced.
Aqueous hydrogel composition
The aqueous hydrogel composition stabilizes the active substance with three essential components: (i) a hydrogel-forming polymer system (a first polymer that is insolubilized upon contact with a suitable aqueous solution to form a gel network), and And / or (ii) a water-insoluble active substance (along with components (i) and (ii) in aqueous solution composition (iii)). And (iii) an aqueous solution composition capable of maintaining the binding property of the hydrogel by the first polymer in which the hydrogel is suspended and insolubilized. Each of these components is described in more detail below.
As mentioned above, the hydrogel structure or hydrogel composition consists of (i) a hydrogel-forming polymer system (including at least two types of polymers) and (ii) a water-insoluble active substance.
(I)Hydrogel-forming polymer system
The polymer system useful for forming a hydrogel having the desired properties (the component (i)) itself is (a) a water-soluble first polymer that is insolubilized when placed in an aqueous solution composition (component (iii)), b) A property modification that ensures that the final hydrogel composition has sufficient gel strength to retain the active substance during processing and storage, but not excessively strong enough that the hydrogel does not disintegrate smoothly when applied to a substrate, such as skin. And a second polymer for quality.
Polymers (a) and (b) together form a web or network that retains the active substance. Each of the polymers (a) and (b) and the mechanism by which the polymer (a) is insolubilized in the surfactant composition will be described in more detail below.
(A)First polymer
The first polymer is most broadly defined as any water-soluble polymer that becomes insoluble when placed in the aqueous solution composition (iii). This insolubilization is accomplished using one of the following insolubilization mechanisms.
(1)Thermal gelation
Suitable polymers that exhibit this type of gelation behavior (ie, insolubilization by thermal gelation) are those that are water soluble at temperatures above about 40-50 ° C. and form a gel when the polymer solution is cooled to room temperature. . Examples of such polymers are (i) gel-forming polysaccharides such as carrageenan or agar. A particularly preferred polymer of this kind is a carrageenan polymer. Particularly suitable carrageenans are products sold under the trademarks Gelcarin GP911 and Gelcarin 379 from FMC. Examples of such polymers are also (ii) gel-forming proteins. A particularly preferred gel-forming protein is gelatin. Suitable gelatins include gelatin G9372 ™ and G2625 ™ sold by Sigma Chemicals. Examples of such polymers are also (iii) synthetic polymers that undergo thermal gelation, such as poly (N-isopropylacrylamide), an acrylic acid ester or methacrylic acid, preferably a linear long chain alcohol as one of the monomer units. A homo- or copolymer of a polyacrylate or methacrylate-containing polymer incorporating an acid ester. The latter class of polymers is described, for example, in Landec Labs Inc. Sold under the trade name Intelliners.
(2)Precipitation and coacervation
Suitable polymers that exhibit this type of behavior are those that are water soluble at room temperature but are substantially insolubilized by changing the chemical or physical properties of the aqueous solution, such as pH or electrolyte concentration. One example of a particularly suitable pH sensitive polymer is chitosan (polyglucosamine) or various variants thereof that have been chemically modified. Particularly useful chitosan is sold under the trade names Seacure 343 and Seacure 443 from Pronov Biopolymers. These materials have a molecular weight in the range of 10,000 to 100,000. Chitosan is a network-forming polymer that is particularly useful in the hydrogel compositions of the present invention because it can be dissolved in an aqueous solution of less than pH 4.5 to form a uniform hydrogel precursor solution. When this solution is mixed with an aqueous solution such as a liquid cleanser having a typical pH range of 5.0 to 7.0, an insoluble polymer is readily formed.
Another class of polymers that form suitable hydrogel networks by precipitation / coacervation are electrolyte sensitive polymers. These polymers precipitate to form an insoluble network by adding the polymer solution to a liquid cleanser containing high levels of salt or ionic surfactant. Examples of such polymers include polyvinyl alcohol having a molecular weight greater than 13,000 daltons and a degree of hydrolysis ranging from 78% to 100%, and Aqualon Corp. There is hydroxyethyl cellulose as sold under the trade name Natrosol.
Depending on the other components present in the aqueous solution, the same polymer may be of class (2) (a) (ie a water soluble polymer that is insolubilized upon contact with an aqueous surfactant solution) or class (2) (b) (ie It should be understood that it acts as either soluble in both water and aqueous surfactant solutions. Thus, the electrolyte concentration sensitive polymer is a class (2) (b) polymer in an electrolyte-free composition, but in an aqueous surfactant solution containing sufficient electrolyte to insolubilize the polymer. (2) The polymer of (a). A similar theory holds when certain polymers become insoluble in the presence of certain crosslinking agents. When no crosslinker is present in the base formulation, the polymer will be (2) (b) polymer, but when present, the polymer will be (2) (a) polymer.
(3)Cross-linking
Suitable water-soluble polymers that exhibit this type of behavior are polymers that can form water-insoluble complexes with water-soluble monomeric or polymeric crosslinkers (eg salts or polyacrylates). The network of insoluble polymers can be formed by reacting the aqueous polymer solution with the crosslinker before or after the aqueous polymer solution is added to the aqueous solution composition. Examples of easily crosslinkable polymers include 6-carrageenan that can crosslink with potassium ions, alginate that can crosslink with calcium ions, or polyvinyl alcohol that can crosslink with borax ions.
(B) Second polymer for property modification
The aforementioned polymers are essential for forming a hydrogel because they provide a backbone network without which a hydrogel composition cannot exist. However, these polymers alone are usually difficult to give excessively stiff and smooth coating properties, and are not sufficiently surface active in hydrogel precursor solutions, so the type of water-insoluble active substances used in the present invention. It is difficult to effectively stabilize the emulsion or dispersion. It has been found that a more highly surface active second water soluble polymer is needed to form a dispersion with the desired stability.
The second function of the property modifying polymer is related to its effect on gel strength. As mentioned above, the hydrogel composition has sufficient strength to maintain the disperse domains / particles of the hydrogel discontinuously such that the disperse domains / particles of the hydrogel effectively trap the active substance within its structure. In addition, it is desirable that the hydrogel domains / particles be sufficiently soft (non-rigid) so that the hydrogel domains / particles can be smoothly applied to the skin during product use. This balance is obtained by optimizing the polymer composition of the hydrogel.
It has been found that some water soluble polymers, when incorporated into the hydrogel precursor solution with the first polymer, effectively modify the gel strength of the hydrogel composition to establish this balance. Accordingly, the strength and skin feel characteristics of the hydrogel can be easily manipulated by adjusting the amount of network-forming polymer (first polymer) and property modifying second polymer in the hydrogel precursor solution.
A variety of anionic, cationic, zwitterionic and nonionic hydrophilic polymers can be used for these purposes. These second polymers are soluble in aqueous compositions (in contrast, the first polymer is not soluble) and have a molecular weight greater than 5,000 daltons, preferably 10,000 daltons, and most preferably 50,000 daltons ing.
Examples of water-soluble polymers that have been found to be useful as property modifying polymers include (i) carboxylic acid-containing acrylics such as alkali-soluble polyacrylic latex sold under the trade name Acrisol or Acculyn from Rohm & Haas. Polymers and B.I. F. Crosslinked polyacrylic acid and copolymers sold under the trade name Carbopol from Goodrich, (ii) polyvinyl alcohol sold under the trade name Airvol from Air Products, ISP Technologies Inc. Polyvinylpyrrolidone sold under the trade name, National Starch & Chemicals under the trade name Capsule or Purity Gum Bee, modified corn starch sold under the trade name Natrosol, under the trade name Natrosol, and under the trade name Methocel from Dow Chemical Nonionic polymers such as hydroxypropylmethylcellulose, (iii) modified polysaccharides such as cationic guar sold under the trade name Jaguar C13S from Rhone Poulenc, and Amerchol sold under the trade name Ucare Polymer JR30 or JR40 Cationic Modified Cellulose, Product Name Merquat from Calgon 100, synthetic cationic polymers such as polydimethyldialkylammonium chloride homo- or copolymers sold under Merquat 550, and vinylpyrrolidone / dimethylaminoethyl methacrylate copolymers sold under the trade name Gafquat 755 from GAF Chemicals, etc. There are cationic polymers.
The second component of the “hydrogel” composition is the active substance (component (ii) above). This is described in more detail below.
(Ii)Active substance
The term active substance in this text means a material that has the ability to have a beneficial and often long lasting effect on the substrate to be cleaned, such as skin, hair or teeth. In the case of skin, active substances suitable for the present invention are water insoluble materials that can be applied from aqueous compositions such as liquid cleansing compositions to protect the skin, maintain moisture or condition the skin.
Preferred active substances are:
(A) linear and cyclic polydimethylsiloxanes, silicone oils such as amino, alkyl, alkylaryl and aryl silicone oils, gums and improved versions thereof,
(B) Jojoba oil, soybean oil, sunflower oil, rice bran oil, avocado oil, almond oil, olive oil, sesame oil, peanut oil, castor oil, coconut oil, mink oil; natural fats and oils such as cocoa butter, beef tallow and lard A hardened oil obtained by hydrogenation of the oil; oils and fats such as synthetic mono-, di- and triglycerides such as myristic acid glyceride and 2-ethylhexanoic acid glyceride;
(C) waxes such as carnauba wax, whale wax, beeswax, lanolin and derivatives thereof,
(D) a hydrophobic plant extract,
(E) hydrocarbons such as liquid paraffin, petrolatum, microcrystalline wax, ceresin, squalene, squalane, pristane and mineral oil;
(F) higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, linoleic acid, linolenic acid, lanolinic acid, isostearic acid and polyunsaturated fatty acids (PUFA);
(G) higher alcohols such as lauryl, cetyl, styrol, oleyl, behenyl, cholesterol and 2-hexadecanol alcohol;
(H) cetyl octanoate, myristyl lactate, cetyl lactate, isopropyl myristate, myristyl myristate, isopropyl palmitate, isopropyl adipate, butyl stearate, decyl oleate, cholesterol isostearate, glycerol monostearate, glycerol distearate, Glycerol tristearate, alkyl lactate, alkyl citrate and alkyl tartrate; esters such as sucrose ester, sorbitol ester,
(I) Fish oil, peppermint, jasmine, camphor, sandalwood, bitter orange peel, dragon brain, terpentine, meat katsura, bergamot, Wenzhou mandarin, ginger, pine, lavender, laurel, clove, hiba, eucalyptus, lemon, primrose, thyme, peppermint Essential oils such as rose, sage, menthol, cineole, eugenol, citral, citronell, borneol, linalool, geranitoles, evening primrose, camphor, thymol, spirantol, pinene, limonene and terpenoid oils,
(J) lipids and lipid-like substances such as cholesterol, cholesterol ester ceramide, sucrose ester and pseudoceramide described in EP 556,957;
(K) vitamins such as vitamins A and E, vitamin alkyl esters such as vitamin C alkyl esters,
(L) a sunscreen such as octylmethoxylcinnamate (Parsol MCX) and butylmethoxybenzoylmethane (Parsol 1789);
(M) a phospholipid such as lecithin,
(N) antibacterial agents such as 2-hydroxy-4,2 ', 4'-trichlorodiphenyl ether (DP300) and 3,4,4'-trichlorocarbanilide (TCC), and
There are mixtures of any of the above ingredients.
Another active substance considered is a water soluble material (eg, glycerin, enzyme, -hydroxy acid) confined in any of the above oils.
The active substance is mixed in an aqueous hydrogel precursor solution (solution containing the first polymer and the second polymer for property modification). To this end, the active substance can be mixed into the aqueous hydrogel precursor solution, or the active substance can be pre-emulsified in an aqueous solution and then mixed into the hydrogel precursor solution. In the direct mixing method, low levels of surfactant can be added to the hydrogel precursor solution to enhance the emulsification and stability of the skin active substance. The active substance is present in the aqueous polymer solution in an amount of 5 to 65%, preferably 10 to 40% by weight of the hydrogel composition. Depending on the mixing conditions, the composition of the polymer (ie the composition of the polymer forming the hydrogel) and the concentration, the particle size of the active substance particles is in the range of 0.2 micrometers to several hundred micrometers. In order to improve stability and adhesion efficiency, the particle size of the active substance particles is preferably in the range of 5 to 150 micrometers.
As mentioned above, the present invention includes an aqueous solution composition comprising a hydrogel composition as fully defined above. The liquid composition itself is described in more detail below.
(Iii)Aqueous composition
As described above, the present invention can be obtained by dispersing a hydrogel in which an active substance is mixed (that is, an active substance is contained in a web formed by the polymers (2) (a) and (2) (b)). The aqueous solution composition. Depending on the application, the aqueous solution composition comprises from about 0 to about 60% by weight, preferably from 2 to 40% by weight of surfactant selected from any known surfactant suitable for human care or cleaning applications. May be contained. Higher levels of surfactants, typically in the range of 5-50% by weight, are used for general human body wash applications. The surfactant is selected from anionic, nonionic, cationic, zwitterionic and zwitterionic surfactants and mixtures thereof. It should be noted that surfactants are not an essential component of the composition, for example, a surfactant-free skin lotion composition can be considered.
The aqueous solution composition must be formulated so that the water-soluble first polymer becomes insoluble upon contact with the aqueous solution composition. It is also most important that the aqueous composition has the ability to suspend the dispersed hydrogel phase for hydrogel processing and stable hydrogel suspension. Accordingly, the liquid composition needs to have a sufficiently high low shear viscosity to prevent sedimentation (or creaming) of the hydrogel composition under the action of gravity during processing and storage. This is 25 ° C, 10 sec^-1Obtained at a shear rate of at least 300 cps, preferably 1,000 cps, more preferably 3,000 cps. This viscosity is usually sufficient to stably suspend many hydrogel dispersions of the present invention without causing obvious gravitational phase separation. In order to obtain proper stability, liquids with higher viscosity are required as the size of the hydrogel dispersion particles increases.
The increase in viscosity of the aqueous composition can be obtained by mixing organic or inorganic polymeric thickeners in the composition or by careful selection and combination of surfactants. Both methods are known in the art. For example, U.S. Pat. Nos. 4,917,823, 4,491,539, 4,556,510, 4,678,606 and 5,002,680 disclose the viscosity of a liquid cleanser. Teaches the use of increasing polymeric thickeners, such as U.S. Pat. Nos. 5,236,619, 5,132,037, 5,284,603, 5,296,158 and No. 5,158,699 discloses a method of formulating a stable viscous liquid composition using an appropriate combination of surfactants.
When a surfactant is used, the surfactant can be selected from any known surfactant suitable for external application to the surface of the human body.
One preferred anionic detergent (surfactant) has the formula:
RCO₂CH₂CH₂SO_ThreeM
Wherein R represents an alkyl or alkenyl group having 7 to 21 carbon atoms, and M represents a solubilizing cation such as sodium, potassium, ammonium or substituted ammonium. Preferably, at least three quarters of the RCO groups have from 12 to 18 carbon atoms and are obtained from coconut palm, coconut palm / coconut palm blends.
Another preferred anionic detergent (surfactant) is of the formula:
RO (CH₂CH₂O)_nSO_ThreeM
[Wherein, R represents an alkyl group having 8 to 22 carbon atoms, n represents a range of 0.5 to 10, particularly 1.5 to 8, and M represents a solubilizing cation as described above] It is.
It should be understood that anionic surfactants also include fatty acid soaps.
The fatty acid soap is typically an alkali metal or alkanol ammonium salt of an aliphatic alkane or alkene monocarboxylic acid. Sodium, potassium, mono-, di- and tri-ethanolammonium cations or combinations thereof are suitable for the purposes of the present invention. Soap is a known alkali metal salt of a natural or synthetic fatty acid (alkanoic acid or alkenoic acid) having about 8 to 22 carbons, preferably 12 to about 18 carbons. These may be defined as alkali metal carboxylates of acrylic hydrocarbons having about 12-22 carbons.
Examples of soaps that can be used are described in Caswell et al. US Pat. Nos. 4,695,395 and 4,260,507 (Barrett). The contents of both patents are hereby incorporated by reference.
Other possible anionic surfactants include alkyl glyceryl ether sulfates, sulfosuccinates, taurates, sarcosinates, sulfoacetates, alkyl phosphates, alkyl phosphate esters and acyl lactates, alkyl glutamates and mixtures thereof.
Sulfosuccinate has the formula:
R^FiveO₂CCH₂CH (SOM) CO₂M;
May be a monoalkylsulfosuccinate having the formula:
R^FiveCONHCH₂CH₂O₂CCH₂CH (SO_ThreeM) CO₂M
Amide-MEA sulfosuccinate having
R in the formula^FiveIs C₈-C₂₀Alkyl, preferably C₁₂-C₁₆Represents alkyl, and M represents a soluble cation.
Sarcosinates generally have the formula:
R^FiveCON (CH_Three) CH₂CO₂M
[In the formula, R^FiveIs C₈-C₂₀Alkyl, preferably C₁₂-C₁₆Represents alkyl].
Taurate generally has the formula:
R^FiveCONR⁶CH₂CH₂SO_ThreeM
[In the formula, R^FiveIs C₈-C₂₀Alkyl, preferably C₁₂-C₁₅Alkyl, R⁶Is C₁-C_FourAlkyl, M represents a soluble cation].
Another useful surfactant is of the following formula:
R^Five(OCH₂CH₂)_nCOOM
[In the formula, R^FiveIs C₈-C₂₀Of alkyl, preferably C₁₂-C₁₆Alkyl, M represents a solubilizing cation].
Unpleasant surfactants such as primary alkane sulfonates or alkyl benzene sulfonates are generally not used.
Suitable nonionic surfactants include alkyl polysaccharides, aldobionamides (eg, lactobionamides taught in US Pat. No. 981,737 of Au et al., Which is incorporated herein by reference), ethylene glycol esters, Glycerol monoethers, polyhydroxyamides (glucamides) (eg fatty acid amides taught in Letton US Pat. No. 5,312,934, which is incorporated herein by reference), ethoxylates of primary and secondary alcohols, especially C ethoxylated with an average of 1 to 20 moles of ethylene oxide per mole of alcohol_8-20There are fatty alcohols.
The surfactant is preferably present at a level of 1-35% by weight, preferably 3-30% by weight.
Moreover, it is preferable that a composition contains the surface active adjuvant which has a skin relaxation effect in the quantity of 0.5-15 weight%. Suitable surface active aids have alkyl or alkenyl groups with 7 to 18 carbon atoms and have the overall structural formula:

[R¹Is an alkyl or alkenyl having 7 to 18 carbon atoms,
R²And R^ThreeEach independently is alkyl of 1 to 3 carbon atoms, hydroxyalkyl or carboxyalkyl,
m is 2-4,
n is 0 or 1,
X is an alkylene of 1 to 3 carbon atoms optionally substituted with hydroxyl, and
Y is -CO₂-Or -SO_Three-Is)
Is a zwitterionic detergent (surfactant).
The zwitterionic detergent (surfactant) included in the above general formula has the formula:

Simple betaine and the formula:

[Wherein m represents 2 or 3]
Of amide betaines.
R in both formulas¹, R²And R^ThreeIs as defined above. Especially R¹Is the group R¹Or a mixture of C12 and C14 alkyl groups obtained from coconut such that at least half, preferably at least three quarters, of 10-14 carbon atoms. R²And R^ThreeIs preferably methyl.
Another surfactant that can be used is the formula:

Or

[Where m is 2 or 3]
Or a — (CH₂)_ThreeSO_Three ^-But

Which are replaced by R in these formulas¹, R²And R^ThreeIs as defined above.
The composition of the present invention can be used for skin or hair cleansing products such as bath gels, shower gels, hand washing compositions, facial cleansers, shampoos, products before and after shaving, rinsing, wiping and rubbing skin. It can be manufactured in the form of a care product.
The compositions of the invention are generally injectable liquids, semi-liquids such as pastes, preferably at 25 ° C. for 10 s on a Haake rotational viscometer RV20.^-1Viscosity measured at a shear rate of 1,500 to 100,000 mPas.
Other typical ingredients of the composition are preferably 0.2-2.0 wt% opacifier, preferably 0.2-2.0 wt% preservative, preferably 0.5-2.0 wt%. % Fragrance.
According to a second embodiment of the invention, the present invention relates to a method for preparing an aqueous solution comprising hydrogel particles. The hydrogel particles have the following composition:
(I) 0.1-30% by weight of a hydrogel composition comprising at least one water-soluble polymer that becomes insoluble when placed in an aqueous solution;
(Ii) 0.2-30 wt% hydrogel composition comprising a water soluble polymer soluble or dispersible in aqueous solution;
(Iii) 1.0% to 60% of a water-insoluble active substance confined in a network formed from (i) and (ii),
The particles of active substance (iii) have a particle size of 0.2-200 micrometers;
The hydrogel is larger than 25 micrometers, and the particle size of the hydrogel is larger than the particle size of the active substance.
The method consists of the following steps:
(A) dissolving the polymers (i) and (ii) in water to form a polymer solution;
(B) dispersing component (iii) in the polymer solution to form a hydrogel precursor solution;
(C) blending the aqueous solution such that the first polymer (i) is not soluble and the second polymer (ii) is soluble or dispersible in the aqueous solution;
(D) When the hydrogel precursor solution is mixed with an aqueous solution, when the hydrogel precursor comes into contact with the aqueous solution, it is sufficiently rigid to contain the active substance but easily breaks when applied to the substrate Forming a sufficiently soft elongate soft noodle-like hydrogel,
(E) breaking the noodle-like hydrogel into hydrogel particles using a mechanical mixer or an in-line mixer.
The following non-limiting examples are presented for a better understanding of the present invention. It will be understood that the claims of this invention should not be considered as limited to these examples.
Unless otherwise noted, all the above percentages mean weight percent.
Example
Example 1:Preparation of silicone oil-containing hydrogel dispersion (ie, hydrogel composition) by direct mixing method
There are many ways in which a polymeric hydrogel can be dispersed in a water-based surfactant composition such that the hydrogel forms discontinuous domains. All of the techniques we have found useful are the rapidity that occurs in the case of certain water-soluble polymers when the solution environment changes, such as pH, ionic strength, temperature, ion type, presence of crosslinkers, etc. Use gelation or cross-linking.
This example describes how to prepare a hydrogel dispersion useful in the present invention by directly mixing a hydrogel-forming polymer solution (referred to as a hydrogel precursor solution) and a liquid cleanser using a conventional mechanical stirrer. explain. In this case, the polymer system is selected such that the pH change that occurs when the hydrogel precursor solution is mixed with the cleaning composition causes a phase change (gelation). Since gelation is sufficiently rapid, the addition itself is a water-continuous hydrogel precursor solution ((1) a first polymer that becomes insoluble when added to an aqueous surfactant solution and (2) a property modification step. The solution of the bipolymer and (3) the active substance) does not dissolve in the cleaning composition from the beginning and forms a discontinuous dispersed aqueous phase.
Preparation of hydrogel precursor solution
Using an overhead stirrer, 40 parts of silicone oil was mixed with 1% by weight chitosan (first polymer) (Sea Cure 340 ™ from Protan), 0.8% by weight acetic acid and 3% by weight hydroxy. Silicone oil (60,000 centistokes, Dow Corning) by mixing for 30 minutes at 400 rpm with 60 parts of an aqueous polymer solution containing ethylcellulose (second polymer) (Natrosol 250 MR ™ from Aqualon). ) 40% emulsion was prepared. The emulsion thus prepared contained silicone oil droplets having a broad particle size distribution ranging from about 4 μm to 50 μm dispersed in the polymer solution.
Preparation of hydrogel dispersion by direct mixing
12.5 parts hydrogel precursor solution containing the above emulsified silicone oil was added to 87.5 parts liquid cleanser having the composition shown in Table 1. The mixture was mixed with an overhead stirrer (Model RW20DZM manufactured by Tekmar). Two dispersions with equal chemical composition but with different stirring speeds for dispersion formation were prepared. In Example 1A, the dispersion was mixed at 80 RPM for 25 minutes, but in Example 1B, the mixing speed was 200 RPM. Both examples contained irregularly shaped hydrogel domains, which themselves contained emulsified silicone oil droplets confined to a gel matrix.
The compositions of Examples 1A and 1B are shown in Table 2 along with some of their physical properties.

Example 2: Another example of a hydrogel dispersion containing silicone oil prepared by direct mixing
A hydrogel precursor solution similar to the hydrogel precursor solution described in Example 1 but having a different polymer composition was prepared by the following procedure. 40 parts of silicone oil having 60,000 centipoise is mixed with 1 wt% chitosan (first polymer) (Sea Cure 340 from Protan), 0.8 wt% acetic acid and 3 wt% cationic guar polymer ( The mixture was emulsified with an overhead stirrer at 400 rpm for 30 minutes in 60 parts of an aqueous polymer gel solution containing (second polymer) (Jagucr C13S manufactured by Rhone-Poulenc).
12.5 parts of this hydrogel precursor solution containing emulsifying silicone was then added to 87.5 parts of the liquid cleanser described in Table 1 and mixed at 80 rpm for 25 minutes. In this way, a dispersion containing irregularly shaped hydrogel particles with silicone oil droplets confined in the gel matrix was obtained. The composition and properties of this dispersion are also summarized in Table 2.
Example 3: Hydrogel dispersion containing silicone oil prepared by extrusion
This example shows that hydrogel dispersions useful for the purposes of the present invention can also be prepared using a coextrusion method. In particular, this example shows a composition prepared by co-extruding a hydrogel precursor solution (containing a dispersed silicone oil in this case) and an aqueous liquid cleanser composition with a two-fluid nozzle. In this method, a hydrogel composition dispersed in the form of noodle-like particles suspended in the liquid cleanser composition is obtained. The noodle-like hydrogel dispersion gives the liquid cleanser a unique appearance. Alternatively, the noodle-like hydrogel may be further processed by any number of shearing techniques that shred or subdivide it into a desired range of sizes. Although the method will be described with reference to a silicone oil-containing hydrogel composition, the method can be used with a variety of materials as shown in the following examples.
Preparation of hydrogel precursor solution with dispersed silicone oil
Silicone oil and an aqueous solution of neutralized carboxylic acid-containing acrylic copolymer (second polymer) (Aculin-33 ™ from Rohm & Haas) were mixed by mechanical stirring in an aqueous solution in the pH range of 7-7.5. . In this case, Aculyn-33 was used as a polymer for property modification. The particle size of the oil droplets was adjusted to a range of 5 to 150 μm in diameter according to the concentration of Acculin-33 and the stirring speed. The higher the concentration and the faster the stirring speed, the lower the oil droplet size. 6-Carrageenan (Gelcarin GP-911 ™, FMC) solution and first polymer (network-forming polymer) were added to the mixture at 45-50 ° C. with gentle stirring (<100 rpm). In this example, two hydrogel precursor dispersions containing silicone oil droplets of different particle sizes were prepared. In one dispersion, the particle size of the silicone oil droplets was in the range of 2-30 μm, and in the second dispersion, the particle size of the oil droplets was in the range of 40-100 μm.
Preparation of hydrogel dispersions by coextrusion.
A high pressure syringe pump (Harvar Apparatus) syringe is placed in the central orifice of a commercially available nozzle (Series No. 1/4 XA SR450 A manufactured by Bete Fog Nozzle Inc.). It was introduced using a pump model 40). At the same time, a low temperature (room temperature to 22 ° C.) shower gel formulation (composition shown in Table 3) was injected into the outer orifice of the nozzle to form a final product containing “noodle-like” hydrogel composition particles. A high pressure syringe pump was also used to transport the cleaning composition, in this case the shower gel. The hydrogel and silicone content in the final dispersion was adjusted by adjusting the flow ratio of the hydrogel precursor and the surfactant composition. This ratio was adjusted to ensure that the final product contained 5% by weight silicone oil.
Table 4 summarizes the characteristic values of the two hydrogel dispersions of Example 3A and Example 3B. These dispersions were composed of noodle-like particles having a diameter of about 1,000 μm suspended in the shower gel composition shown in Table 3.

Example 4: Effect of polymer composition on hydrogel properties
This example shows how to manipulate the rheological properties of a hydrogel that affect the properties of use depending on the selection and concentration of the network-forming (first) polymer and the property-modifying (second polymer).
A series of model hydrogel particles were prepared by a crosslinking method using carrageenan as the network-forming polymer and potassium ions as the crosslinking agent. A dispersion was prepared by an improvement of the extrusion method described in Example 3 using an aqueous solution of KCl as the model cleaning composition. The only difference in the hydrogel dispersion was the concentration of carrageenan used in the hydrogel precursor solution, which ranged from 1 to 6% by weight. All the particles formed were approximately spherical particles having a particle size of about 3000 μm.
Instron (model 1122) has been found to be a suitable means of identifying the strength of the various gel compositions described above. The measurement procedure is as follows. Hydrogel particles were carefully removed from the dispersion with a spatula and placed on a Kimwipe to remove excess liquid. An approximate value for the diameter of the hydrogel was measured with a caliper. The hydrogel was then transferred to an Instron metal platform and a 10 Newton load was lowered until it contacted the hydrogel particles. The Instron was then activated and the force was measured as a function of distance with a chart recorder. The chart recorder was set to a crosshead speed of 1 mm / min and a chart speed of 50 mm / min.
This allows reading of a full scale load of 2 Newtons. The force was recorded at 0.50 mm, 1.00 mm and 1.50 mm. The elastic modulus of the sample was calculated by dividing the force by the cross-sectional area and strain of the hydrogel. Note that the particles remained hydrated during the measurement.
The gel strength of a series of hydrogel particles measured by the above procedure is shown in FIG. These results indicated that the gel strength increased significantly with increasing carrageenan concentration. When the polymer concentration was above 2% by weight, the gel gave a very hard feel and could not be applied smoothly to the skin. Such particles can capture the active substance and remain stable during storage, but are not optimal for cleaning applications because the distribution of the active substance is not uniform and the composition gives a rough feel. These results also show that if it is desired to reduce the gel strength of the hydrogel particles, the polymer concentration within the gel can only be reduced. This greatly limits the applicability of the technology. As shown below, this limitation can be overcome by using a second polymer to modify the properties of the hydrogel, such as its gel strength.
Another series of model hydrogel particles was prepared by the same procedure as above. Each of the hydrogel precursor solutions contained 2% by weight carrageenan and 0-2% by weight acrylic copolymer, ie, Acrisol ASE-60 (Rohm & Haas). This is a second polymer for property modification. The shape and particle size of the hydrated particles were very similar for all particles, and also similar to the hydrogel consisting only of the aforementioned carrageenan. The effect of added Acrisol ASE-60 on the gel strength of hydrogel particles formed by crosslinking with K + is shown in FIG. This result shows that the gel strength decreased significantly with increasing acrisol concentration even when the total polymer concentration increased. Hydrogels containing carrageenan and acrisol in a weight ratio in the range of 3: 1 to 2: 1 (arrows in FIG. 2) can effectively capture active substances such as emulsified moisturizing oils such as silicone oils, and are prominent It can be applied smoothly to the skin without being rough.
The purpose of the above examples is to show that gel strength can be adjusted by selecting a polymer system comprising a network-forming polymer and a property modifying polymer. Care should be taken not to overly emphasize the exact values of gel strength quoted above. Applicants have found that the quantitative effect of the polymer composition in the hydrogel precursor solution on the strength of the hydrogel particles depends significantly on the type, particle size and concentration of the active substance dispersed in the precursor solution. This trend will be the same but the exact values will be different. Although it may be complex, one skilled in the art can find the proper balance of gel strength for each situation using the combination of polymers included in the broad definition of network formers and property modifiers. It will be possible.
Example 5: Adhesion of silicone oil to in vitro skin
The ability of various cleaning compositions to attach silicone oil to the skin during the cleaning process was measured using an in vitro model based on pig skin.
A 0.5 ml aliquot of the test composition was applied to a 5.08 cm × 5.08 cm (2 ″ × 2 ″) square pig skin section initially moistened with 37 ° C. tap water. The composition was bubbled for 10 seconds and then rinsed with running water for 10 seconds. The skin was wiped once with a paper towel to remove excess water and allowed to air dry for 2 minutes. Next, 10 g / cm of the adhesive tape piece²And pressed against the skin for 30 seconds. The adhesive tape used was a 3 cm wide J-Lar Superclear ™ tape. In this test procedure, the silicone that had adhered to the skin transferred to the tape along with several outer skin layers.
The amount of silicone and skin adhering to the tape was measured by X-ray spectrofluorescence. The piece of tape was placed on an X-ray spectrofluorometer so that the adhesive surface of the tape was facing the instrument beam. The tape was covered with a mask to define a standardized area in the center of the tape exposed with the X-ray beam. Prior to the start of the measurement, the instrument sample chamber was placed under vacuum and then the spectrometer was used to measure the amount of silicone and sulfur. Sulfur represents the amount of skin transferred to the tape.
The amount of silicone and sulfur observed with a clean piece of adhesive tape was subtracted from the experimental measurements. The experimental measurements of continuously tested tape pieces were summed, and the cumulative total of silicone and sulfur was expressed as the ratio of silicone to sulfur per unit area of skin. A high Si / S ratio corresponds to a high adhesion level. A total of 10 pieces of tape were used for each measurement.
The compositions described in Examples 2 and 3 were measured according to the procedure described above and the amount of silicone attached to the pig skin section is shown in Table 5. From these results, it is clear that the hydrogel composition sufficiently adhered the silicone oil to the skin in these tests.

Example 6: Hydrogel dispersions prepared with various polymers
This example shows that various polymers can be used to prepare hydrogel dispersions as long as the polymer has the required hydrogel-forming ability and gel strength. In the composition described below, a cationic polymer chitosan (first polymer) (Seaure 343 manufactured by Pronova Biopolymer) is used as a network-forming polymer, and a cationic modified guar (Jaguar C-13S, Calgon) is used. ) And a synthetic cationic polymer, polydimethyldialkylammonium chloride (Merquat 100 ™, Calgon), was used as a second polymer for property modification. The hydrogel precursor solution consists of 35 parts silicone oil with 60,000 cps, 1.5% by weight Jaguar C13S, 0.75% by weight chitosan, 0.10% by weight Merquat 100 and 0.35% acetic acid. And 65 parts of a polymer solution containing 0.05% by weight cocoamidopropyl betaine were prepared by mixing for 15 minutes at 300 rpm using an overhead stirrer. The resulting emulsion contained silicone oil droplets having a particle size in the range of 2-60 μm dispersed in the polymer solution.
Using the extrusion process described in Example 3, a 14.3% wt hydrogel dispersion (containing 5 wt% silicone oil based on the total composition) was prepared. The same surfactant system as in Example 3 (Table 3) was used, but the compound component Antil 141 was 0.3% instead of 0.97%. The hydrogel dispersion was a noodle-like particle dispersion containing a dispersed silicone oil having an average droplet size in the range of 2 to 60 μm.
The adhesion of silicone oil from the composition of Example 6 (this example) is shown in Table 6. The adhesion test was performed according to the method described in Example 5. Dispersions exhibit similar adhesion to other hydrogels containing similar sized silicone droplets, because the type of dispersion and the characteristic values are more important for determining the adhesion level than the type of polymer used. Suggest that there is.

Example 7: Example of enhanced adhesion caused by hydrogel
One of the beneficial effects obtained by using the hydrogel dispersion of the present invention is that the adhesion of the active substance incorporated into the structure is enhanced compared to using the active substance alone. This example shows the effect of silicone oil. In particular, the adhesion of silicone oil from various skin cleansing compositions was compared in the adhesion test described in Example 5. A series of emulsions were prepared by directly emulsifying 60,000 cps of silicone into the cleaning composition of Table 3 to obtain silicone oil droplets of the same particle size as the oil droplets contained in the hydrogel dispersions of Examples 3A, 3B and 6. A composition was prepared.
The adhesion results for the hydrogel dispersion vs. the silicone emulsion alone are summarized in Table 7. It has been demonstrated that substantial adhesion enhancement was obtained by incorporating active substances into the dispersed hydrogel domains.

Example 8: Preparation of hydrogel dispersion containing hydrocarbon oil
Various kinds of components can be mixed in the hydrogel dispersion of the present invention. The previous examples showed some universal features of these dispersions using silicone oil. Another class of useful materials are hydrocarbon oils. Active substance materials included in this class include humectants such as petrolatum, emollients such as isopropyl palmitate, and sunscreens such as Rarsol MCX (trademark, 2-ethylhexyl-P-methoxycinnamate). is there. These examples illustrate the use of hydrogels to distribute such hydrocarbon oils.
Preparation of hydrogel precursor solution
To prepare a 40% emulsion of various hydrocarbon oils such as 100% petrolatum, a mixture of 50% isopropyl palmitate and 50% petrolatum, a mixture of 50% Parsol MCX and 50% petrolatum. Hydrogen oil was mixed with 0.5 wt% chitosan (first polymer) (Seacle 343 from Pronova Biopolymer), 1.9 wt% Jaguar C13S (second polymer) and 0.4 wt% cocoamidopropyl betaine. And 60 parts of an aqueous polymer solution containing 0.25% by weight acetic acid were mixed at 300 rpm for 20 minutes using an overhead stirrer. Except for the 100% petrolatum sample, it was mixed at room temperature. An emulsion of 100% petrolatum was prepared by melting petrolatum at 60 ° C., adding it to the room temperature polymer solution, and mixing at room temperature.
Preparation of hydrogel dispersions by coextrusion.
12.5 of a hydrogel containing 100% petrolatum, 50% isopropyl palmitate / 50% petrolatum, 50% Parsol MCX / 50% petrolatum of Examples 8A, 8B and 8C, respectively, using the extrusion method described in Example 3. A weight percent dispersion was prepared. The same surfactant system as in Example 3 (Table 3) was used except that Antil 141 was not used as a blending component. All of these samples contained a noodle-like hydrogel dispersion having a diameter of about 1,000 nm.
Example 9: Preparation of a hydrogel dispersion containing solid fatty acids
Previous examples have shown that various types of hydrophobic oils can be incorporated into the hydrogel dispersions of the present invention. Another class of useful materials are dispersed hydrophobic solids or waxy particles. Examples of active substances included in this class of materials include humectants such as fatty acids, emollients, some solid sunscreens such as P-hydroxybenzoic acid, antibacterial agents such as triclosan, salicylic acid There are anti-acne medications.
In this example, a mixture of solid fatty acids was used as a specific example to show that hydrogels can be used to distribute such solid or waxy hydrophobic solids.
Preparation of hydrogel precursor solution
83 g of 22 g of modified corn starch (Capsul ™ from National Starch & Chemical), 4.4 g carrageenan (Gelcarin GP911 ™ from FMC) and 0.55 g sodium lauryl sulfate (BDH) Dissolved in 0.05 g deionized water at 80 ° C. 210 g of a molten fatty acid mixture containing 50% by weight palmitic acid and 48% by weight stearic acid was added to the polymer solution and emulsified at 60 ° C. to form a fatty acid emulsion. The fatty acid emulsion was then transferred to a Hobart Kitchen Aid mixer and mixed with cooling to form a viscous kneaded dough-like fatty acid emulsion. The emulsion contained fatty acid particles with a particle size ranging from 1 to 40 μm in diameter.
Next, an equal amount of polymer solution containing 4% Merquat 100 (Calgon), 0.5% chitosan (Proa Corporation Sea Cure 340) and 0.4% acetic acid Mix to form a hydrogel precursor solution containing dispersed fatty acids.
Preparation of hydrogels by extrusion
Next, using the method described in Example 3, 14 parts of the hydrogel precursor solution was coextruded with 86 parts of the liquid cleanser of Table 3 to form a hydrogel dispersion. This dispersion was composed of noodle-like gel particles uniformly distributed in the surfactant composition.
Example 10: Another example of a hydrogel dispersion containing solid fatty acids
This example is similar to Example 9 except that a different gel-forming polymer was used.
Preparation of hydrogel precursor solution
22 g of modified corn starch (Capsul from National Starch & Chemical), 4.4 g carrageenan (Gelcarin GP911 from FMC) and 0.55 g sodium lauryl sulfate (from BDH), 83.05 g deionized water Was dissolved at 80 ° C. 210 g of a molten fatty acid mixture containing 50% by weight palmitic acid and 48% by weight stearic acid was added to the polymer solution and emulsified at 60 ° C. to form a fatty acid emulsion. The fatty acid emulsion was then transferred to a Hobart Kitchen Aid mixer and mixed with cooling to form a viscous kneaded dough-like fatty acid emulsion. The emulsion contained fatty acid particles with a particle size ranging from 1 to 40 μm in diameter.
The composition was then mixed with an equal amount of polymer solution containing 10% by weight fully hydrolyzed polyvinyl alcohol solution (Airvol 350 ™ from Air Products).
Preparation of hydrogels by extrusion
Next, using the method described in Example 3, 14 parts of the hydrogel precursor solution was coextruded with 86 parts of the liquid cleanser of Table 3 to form a hydrogel dispersion. This dispersion was composed of noodle-like gel particles uniformly distributed in the surfactant composition.
Example 11: Fatty acid deposition from a liquid cleanser
Fatty acid adhesion to pig skin was measured by gas chromatography. A 5.08 cm × 5.08 cm (2 inch × 2 inch) pig skin piece was first washed with about 0.35 g of liquid cleanser for 1 minute. The treated pig skin was washed with water for 50 seconds. The skin was dried once with a paper towel, air dried for 2 minutes and then extracted with 10 g heptane for 30 minutes. An aliquot of heptane solution was sprayed onto the GC to measure the amount of fatty acid attached to the skin. The control sample was prepared with 7 parts of water and 7 parts of the fatty acid emulsion used to prepare the dispersions of Examples 9 and 10 and 86 parts of the surfactant composition shown in Table 3 (Examples 10 and 11 were prepared. Also used for). The amount of fatty acid deposited from Examples 9 and 10 was compared to the control in Table 8. The results show that significant fatty acid deposition occurs from these hydrogel dispersions. Furthermore, as with silicone oils, the addition of fatty acids to the hydrogel formulation increases significantly the adhesion (comparing Examples 9 and 10 with the control).

Example 12: Preparation of a hydrogel dispersion containing lipids
30 parts glycerol, 15 parts cholesterol (cholesterol USP from Croda Chemicals LTD), 7.5 parts sugar ester (Ryoto S270 ™ from Mitsubishi-Kasei Foods Corp.) and 7.5 parts stearin. A molten lipid solution was prepared by heating an acid (Unichema International) with a hot plate at 150 ° C. The clear molten lipid solution was then cooled to about 98 ° C. and 10 parts neutralized Acculyn 33 (Rohm & Haas, 2 wt%, pH: 7.5-8.0) solution and 30 parts carrageenan Gelcarin GP911. Mixed with TM solution (2 wt%) to form a hydrogel dispersion precursor containing cholesterol.
Using the extrusion method described in Example 3, a 17 wt% hydrogel dispersion (containing 2.55 wt% cholesterol based on the total composition) was prepared. The same surfactant system as in Example 3 (Table 3) was used for the preparation. Cholesterol adhesion from this cleaning composition was measured in Example 13. For comparison, a comparative example was prepared containing 2.5% by weight cholesterol uniformly dispersed in a liquid cleanser. The composition and preparation method of this comparative example is shown in Table 9 below.

Preparation
Glycerol, sucrose ester, stearic acid and cholesterol are combined and melted on a hot plate. Premix surfactant with excess water. Surfactant is added to the lipid / glycerol mixture and then Jaguar is added. Store the system and adjust the pH to 5.3. 10s with NaCl^-1Adjust the viscosity at / 25 ° C. to 5,000 mPas.
Example 13: Adhesion of cholesterol to the skin
The amount of cholesterol adhering to the pig skin from the cleaning composition was measured by the following method. 5 x 5 cm pre-moistened with tap water²The swine skin was rubbed with 0.25 g of cleanser 50 times. The skin was then rinsed with deionized water for 10 seconds and patted dry with a paper towel. Cholesterol was extracted from the skin using 3 ml of ethanol for analysis.
The amount of cholesterol extracted from the skin was measured spectrophotometrically. The ethanol extract was dried in an oven at 80 ° C. 100 μl of methanol was added to the dried contents. 1,000 μl of Sigma aqueous cholesterol reagent was added to the sample and allowed to react with the extracted cholesterol for 5 minutes. The aqueous cholesterol solution was then mixed with 500 μl of chloroform and injected into a microcentrifuge tube. Chloroform was separated from the aqueous solution by centrifuging the tube at 13,000 rpm for 5 minutes. After centrifugation, the uppermost transparent aqueous phase was poured into a pipette into a cuvette, the absorbance at 500 nm was measured with a spectrophotometer, and the amount of cholesterol extracted from the skin was measured using a standard calibration curve.
The amount of cholesterol extracted from the skin by treatment in Example 12 is compared to the two controls in Table 10. The data shows that cholesterol was significantly attached from the hydrogel sample of Example 12 compared to the two controls.

Example 14
Liquid consisting of 10% by weight silicone hydrogel (5% by weight silicone oil of total composition) and 90% by weight of the surfactant composition of Table 3 containing 0.3% by weight of Antil 141 instead of 0.97% A cleanser composition was prepared using the method described in Example 3. 25. 60,000 cps 50 wt.% Silicone oil, 0.47 wt.% Carrageenan GP911, 0.155 wt.% Acculyn-33, 0.31 wt.% Polyvinyl alcohol (Airvol 540 from Air Products) and 24. A silicone hydrogel precursor solution containing 06 wt% water was prepared as described in Table 3. The hydrogel precursor solution contains silicone oil droplets with a particle size ranging from 5 to 60 micrometers.
Using the protocol described below, the effect of a silicone hydrogel-containing cleanser on skin feel after use by consumers was evaluated by comparison with a liquid cleanser containing no silicone hydrogel dispersion. The test site for this evaluation is the palmar surface of the forearm. Keep hands and forearms under running tap water (30 ° C.) for about 15 seconds to pre-wet, dispense 3.5 g hydrogel-containing liquid cleanser on hands, wash designated arms for 20 seconds, and run for 10 seconds with running water Rinse. The forearm was struck with a paper towel and dried. The same procedure was repeated with the other arm using the same cleanser without silicone hydrogel. All panelists were asked to determine skin feel after use. Seven out of eight panelists were aware of the difference in skin feel after use and five of these seven judged that the skin feel of the arms treated with a silicone hydrogel-containing liquid cleanser was preferred.
Example 15: Preparation of hydrogel dispersion as skin lotion
This example shows that a hydrogel dispersion can be prepared using an aqueous solution composition suitable for skin care applications. In this example, 0.9 wt% Nitrosol 250 HHR (Aqualon hydroxyethyl cellulose), 0.06 wt% Carbopol C981 (BF Goodrich) and 0.4 wt% were prepared for hydrogel preparation. Na_ThreePO_FourAnd 0.05% by weight of Glydant Plus, a surfactant-free aqueous solution composition was prepared.
10 parts petrolatum (Snow White ™ from Penreco), 0.6% by weight chitosan (Protan's Seacure 343), 0.4% by weight acetic acid and 1.8% by weight Jaguar C13S (Rhone) A petrolatum hydrogel precursor solution was formed by stirring 90 parts of an aqueous polymer solution containing -Poulenc) for 15 minutes at 60 ° C. and 300 rpm using an overhead mechanical stirrer. The emulsion thus prepared contained petrolatum droplets having a size in the range of 1-30 μm. 25 parts of the petrolatum hydrogel precursor solution was sprayed onto 75 parts of the aqueous composition using a # 14 gauge syringe needle to form an elongated noodle-like hydrogel. Next, the aqueous composition containing petrolatum noodle-like hydrogel was passed through a screen having a mesh size of 200 μm to form a hydrogel dispersion. This sample contained soft large hydrogel particles enriched with petrolatum droplets and was suitable for skin care applications.
Example 16: Effect of processing conditions on hydrogel formation
This example shows that the formation of hydrogel particles depends on the mixing device used to incorporate the hydrogel precursor solution into the aqueous solution composition. The preferred method, extrusion / low shear mixing, improves the control of the size of the hydrogel particles and the retention of the water-insoluble active substance inside the hydrogel particles.
70 parts of a polymer solution containing 0.4% by weight Seacure 343, 0.2% by weight acetic acid and 2.0% by weight Jaguar C13S and 60 parts by weight of 60,000 cps silicone oil A silicone hydrogel precursor solution was prepared by mixing for 7 minutes at 60 rpm using a mechanical mixer. The silicone emulsion thus prepared contained 30% by weight silicone oil having a particle size of about 132 μm.
Two aqueous liquid cleansers with different viscosities were prepared for hydrogel processing. These two aqueous compositions having the compositions shown in Table 11 both contain 17.5 wt% surfactant thickened with 0.4 wt% Carbopol ETD2020 and 0.4 wt% Bentone. Was. The viscosity of these two cleansers was 15,000 cps and 3,500 cps, respectively, and had a pH of about 7.8. Two methods of batch and coextrusion / in-line mixing were used to produce large hydrogel dispersions in these two liquid cleansers.
In the batch method, 15 parts of the silicone hydrogel precursor solution was added to 85 parts of a liquid cleanser and mixed for 15 minutes at 60 rpm using an overhead mixer. The apparatus described in Example 3 was used for the coextrusion / in-line mixing method. 15 parts of the silicone precursor solution and 85% by weight liquid cleanser were coextruded from two fluid nozzles to form an elongated soft noodle-like hydrogel. The precured noodle-like hydrogel was then continuously passed through a low shear in-line mixing device at a flow rate of 20 cc / min to break the noodle-like hydrogel into hydrogel particles. Two different in-line mixing devices were used to break the noodle-like hydrogel. One is a stationary in-line mixer with a diameter of 0.64 cm (1/4 ") and a length of 15.2 cm (6"). The other is an in-line mixer incorporating two equal screens with a mesh size of about 200 μm. Both the hydrogel particle size and the percent of silicone oil retained within the hydrogel gel particles are shown in Table 12.

Claims (12)

(A) a 40-95 wt% aqueous solution containing 5-50% surfactant and having a viscosity greater than 300 centipoise;
(B) (i) 0 comprising at least one water-soluble polymer selected from the group consisting of gel-forming polysaccharides, gel-forming proteins and heat-gelling synthetic polymers that are insolubilized when placed in the aqueous solution of (a). 1-30 wt% hydrogel composition;
(Ii) 0.2-30 wt% hydrogel composition comprising a water-soluble polymer that is soluble or dispersible in the aqueous solution of (a);
(Iii) consisting of 1.0 to 60% by weight of a water-insoluble active substance confined in the network formed by (i) and (ii), and 5 to 60% by weight of a hydrogel composition. ,
The particles of the active substance (iii) have a particle size of 0.2 to 200 micrometers,
The hydrogel particle size is greater than 25 micrometers,
The particle size of the hydrogel (b) is larger than the particle size of the active substance,
An aqueous composition wherein the composition comprising a hydrogel is formed by jetting a hydrogel precursor solution into an aqueous solution or coextruding the hydrogel precursor solution into an aqueous solution. The composition according to claim 1, wherein the polymer (i) is insolubilized by thermal gelation when contacted with the aqueous solution (a). The polymer of (i) is selected from the group consisting of homopolymers or copolymers of polyacrylates or methacrylate-containing polymers mixed with N-acrylamide, branched or linear long chain alcohol acrylates or methacrylates. a composition according to any one of claims 1 or 2, characterized in that a synthetic polymer. The composition according to claim 1 , wherein the polymer of (i) is insolubilized by precipitation or coacervation upon contact with the aqueous solution of (a). The composition according to claim 1, wherein precipitation or coacervation is caused by a change in electrolyte concentration. The composition of claim 1, wherein the polymer of (i) is insolubilized by crosslinking with a crosslinking agent present in the aqueous solution of (a). The property modifying polymer (ii)
(A) a carboxylic acid-containing acrylic polymer;
(B) a nonionic polymer selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, modified corn starch and hydroxyalkyl cellulose or hydroxyalkyl methyl cellulose;
2. The composition of claim 1 selected from the group consisting of (c) a cationic polymer. Use of a composition according to any one of claims 1 to 7 in a cream for human body washing or skin care or in a product. (A) 0.1 to 30% by weight comprising at least one water-soluble polymer selected from the group consisting of gel-forming polysaccharides, gel-forming proteins, and heat-gelling synthetic polymers, which are insolubilized when placed in the aqueous solution. A hydrogel composition of
(B) 0.2-30 wt% hydrogel composition comprising a water soluble polymer soluble or dispersible in the aqueous solution;
(C) comprising hydrogel particles having a composition consisting of 1.0 to 60% by weight of a water-insoluble active substance gel confined in the network formed by (a) and (b);
The particles of the active substance (c) have a particle size of 0.2 to 200 micrometers,
The hydrogel is larger than 25 micrometers,
A method for producing an aqueous composition wherein the hydrogel particle size is greater than the particle size of the active agent, the method comprising:
(I) dissolving the polymers (a) and (b) in water to form a polymer solution;
(Ii) dispersing component (c) in a polymer solution to form a hydrogel precursor solution;
(Iii) The first polymer (a) is soluble in an aqueous solution to form a 40 to 95 wt% aqueous solution containing 5 to 50% surfactant and having a viscosity exceeding 300 centipoise. And blending so that the second polymer (b) is soluble or dispersible,
(Iv) The hydrogel precursor solution and the aqueous solution are mixed by jetting the hydrogel precursor solution into the aqueous solution or by co-extrusion of the hydrogel precursor solution into the aqueous solution, the hydrogel precursor is brought into contact with the aqueous solution, and the active substance Forming an elongate noodle-like hydrogel that is sufficiently rigid to be confined and sufficiently soft to break when applied to a substrate;
(V) breaking the noodle-like hydrogel into particles by a mechanical mixer of an in-line mixer. The method according to claim 9 , wherein the insolubilization of the first polymer (a) is caused by thermal gelation, precipitation or coacervation, or crosslinking. 5. Composition according to claim 4 , characterized in that precipitation or coacervation is caused by a change in pH. The composition according to claim 4 , wherein the polymer (i) is insolubilized by precipitation or coacervation caused by pH change, and the polymer (i) is polyglucosamine.

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