BR102022001718A2 - CARIOSTATIC BASED ON SILVER NANOPARTICLES - Google Patents

Abstract

This invention reports the invention of a formulation containing silver particles of nanometric dimensions and metallic ions and fluorides, obtained by the reduction of silver ions in the presence of reducing agents. The manufacturing method is also described in this invention report.

Description

CARIOSTATIC BASED ON SILVER NANOPARTICLES FIELD OF INVENTION

[0001] The present invention finds its field of application among products designed to stop tooth injuries caused by caries. It is a suspension containing nanometric silver particles and metallic ions and fluorides, obtained by the reduction of silver ions in the presence of reducing agents. The manufacturing method is also described in this invention report.

BASICS OF THE INVENTION

[0002] Although there are no detailed statistics, it is believed that between 60 and 95% of humanity will have at least one cavity lesion during their lifetime.

[0003] The most traditional treatment methodology uses the removal of decayed tissue, using specific instruments (drills), which is followed by the application of a restoration that aims to prevent the injury from recurring. More recently, technologies have been developed that enable the removal of necrotic tissue through enzymatic action or the application of laser light. The traditional method, however, remains by far the most used treatment. It is an invasive procedure, which often requires the application of anesthesia, causing considerable discomfort to the patient.

[0004] The use of silver as an antimicrobial agent has been described since ancient times. At the beginning of the 20th century, the application of silver-based compounds was widespread, both to stop cavities and to create restorations, where it was combined with mercury, aiming to form metallic alloys. These materials were replaced in the second half of the 20th century by polymeric resins, the aesthetic result of which became a much more acceptable standard.

[0005] More recently, the World Health Organization (WHO) encouraged the use of atraumatic treatments and an efficient alternative is silver diamine fluoride (DFP). When applied at regular intervals, this product has proven action in stopping coronary cavities, which are located on chewing surfaces or between teeth. The product is sold in countries such as Brazil, Argentina, Japan and the USA, in the form of ammonia solutions containing fluorine and concentrations ranging between 12% and 38%.

[0006] Despite its efficient clinical effect, DFP stains teeth black or dark brown when in contact with lesions. This is not a desirable aspect, especially if the cavities are located in the frontal region. For this reason, many patients reject this type of treatment, as the aesthetic aspect is unacceptable. Another disadvantage is the fact that the product stains the skin and soft tissues in case of contact and these stains take up to two weeks to come out, making them impossible to wash.

[0007] Since the advent of nanoscience and nanotechnology, silver nanoparticles and their combinations with other antibacterial agents have been very well demonstrated in the scientific literature. There are also several requests for invention privileges combining silver, fluorine and other additives aimed at applications related to oral hygiene, treatment of infections or even treatment of cavities, always based on observations from in vitro studies, that is, in the laboratory. .

[0008] Particles of gold, copper, silver and other metallic compositions, including alloys, of nanometric dimensions also have proven antimicrobial action.

[0009] A wide range of applications for invention privileges related to the application of metallic nanoparticles with effects in combating infections, treatments against microorganisms, applications in the manufacture of prostheses, incorporation into polymeric materials aimed at various applications in the medical field have been filed around the world in the last 20 years. Some significant examples are described below.

[0010] Gels and liquid solutions containing silver nanoparticles (AgNPs) for combating skin infections caused by bacteria or fungi, infections in the respiratory system and genital and urinary infections are presented in document WO 2006074117. Gels containing AgNPs were also described in the document WO 2007017901, which claims to prove its antibacterial activity against P. aeruginosa, E. coli, and S. aureus. These formulations can be administered to skin and oral cavity infections.

[0011] The combination of calcium phosphate and nanometric silver is presented in document WO2010072882A1, which claims its wide disinfectant use in public spaces, clothing and packaging, dentistry in general, food and paints, due to its bactericidal and fungicidal power.

[0012] Chitosan is a cationic polysaccharide. It is obtained from the deacetylation of chitin, which is found in the exoskeleton of crustaceans and insects, as well as fungi. Lobsters and crabs contain 15 to 25% chitin in their shells. Chitosan also has antibacterial activity. It is biocompatible, biodegradable and non-toxic, as long as the person is not allergic to crustaceans and has already been used in the medical field.

[0013] Chitosan-based formulations are used as appetite suppressants. It is formed by the association of 2-amino-2-deoxy-bD-glucose units, providing its use in the hygiene and personal care, biotechnology, pharmacology and agriculture industries. Some types of products are listed below: facial lotions and additives, preservatives and antioxidants, emulsifiers and flocculants, membranes, soil modifiers and fungicides.

[0014] As they are both materials with antimicrobial properties proven in detailed scientific studies, the hypothesis of the combination of chitosan and AgNPs becomes a very reasonable and feasible hypothesis. Its synergy of action has been demonstrated in the inhibition of the in vitro growth of Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, and Acinetobacter baumannii.

[0015] The use of AgNPs in various applications in the dental field was extensively reviewed in the scientific literature by Noronha et al. (2017), in a work widely cited by other authors internationally.

[0016] Invention privileges reported for their use in restorations, such as kits for ceramic coverings (WO2011049719) and nanometric calcium phosphate dental composites (WO2012003290).

[0017] Bioadhesive polymers bonded to inorganic particles, such as silver, have also been proposed, as described in US8,119,162, which makes use of particles that disintegrate or prevent bacterial adhesion for oral hygiene, to inhibit the formation of films such as bacterial plaque .

[0018] The combination of silver with polysaccharides also appears in WO2006/026026, which combines these components in a solvent containing a stabilizing medium to be used in oral hygiene product formulations. A similar strategy, from a conceptual perspective, appears in US2008/0147019 and US2011/0129536 using the same components.

[0019] Applications in mouthwashes and dentifrices are described in US6,565,873, which proposes a controlled-release biodegradable system containing nanoparticles, while document US6,790,460 describes similar compositions for the mucous membrane and oral cavity.

[0020] DFP, which is currently marketed for the prevention and interruption of caries, turns the carious region dark and is a low-viscosity aqueous solution. The low viscosity makes it difficult to apply to the affected area and the product often runs into unwanted areas.

[0021] However, if we consider only the carisotactic effect, the performance of this compound is very satisfactory, considering the simplicity with which it can be used.

• (i) são numerosas as descrições de sistemas contendo prata iônica ou nanométrica cuja ação anitimicrobiana foi confirmada em estudos in vitro e;
• (ii) um produto que não mancha os dentes deve ter muito mais aceitação por razões estéticas.

[0022] For the context of this invention, two factors were considered:

• (i) there are numerous descriptions of systems containing ionic or nanometric silver whose antimicrobial action has been confirmed in in vitro studies and;
• (ii) a product that does not stain teeth should be much more accepted for aesthetic reasons.

SUMMARY OF THE INVENTION

[0023] This invention describes a cariostatic formulation, with the ability to stop the development of these lesions, without causing the darkening of the teeth and their manufacturing process.

[0024] The formulations contain metallic nanoparticles with dimensions ranging between 10 and 50 nanometers, organic acid, polysaccharides and fluoride, presented in liquid form.

[0025] The manufacturing method involves the steps of dissolving the precursors separately (ionic silver and reducing agent) and both in a polysaccharide solution in water in the presence of organic acid. The addition of the solutions leads to the formation of metallic nanoparticles. Fluoride is added to this formulation, as well as stabilizing or antioxidant agents.

DESCRIPTION OF THE INVENTION

[0026] This invention deals with a cariostatic formulation, whose action is to stop caries lesions, without staining the teeth and the description of its manufacturing process.

[0027] Manufacturing process of this formulation.

[0028] The formulation does not leave color or stains, unless it is used with many frequent applications.

[0029] The formulation is liquid, yellow in color, has bactericidal activity, specifically bacteriostatic and makes it possible to paralyze the caries lesion.

[0030] This formulation does not require an outpatient environment for its application, it is atraumatic and non-invasive. Therefore, it is particularly recommended for patients who experience anxiety, trauma or fear when undergoing traditional treatment methods.

• - 0,002 % a 0,250% em naopartículas metálicas selecionadas entre prata, ouro, cobre, e suas ligas;
• - As morfologias podem ser esférica, elíptica, prismática, bastões e placas e misturas entre estas, com dimensões entre 10 nm a 500 nm, são obtidas a partir de precursores dos metais por reações de redução controlada, onde os compostos precursores são escolhidos entre óxidos, acetatos, nitratos, acetil-acetonatos, carbonato, cloreto, citrato, fluoreto e iodato;
• - 0,025% a 3,0% de quitosana, com massa molar em uma faixa de valores que varia entre 20 kDa e 1000 kDa, seus derivados, os quais são escolhidos entre: carboximetil-quitosana, lactato de quitosana, acetato de quitosana, amilopectina e hidroxipropil-celulose;
• - 0,06 % a 3,0% de um sal fluoreto, obtido a partir de sais solúveis em água, a partir de soluções aquosas;
• - 0,07 % a 3,0% de um ácido orgânico, selecionado entre ácido acético, ácido oxálico, ácido ascórbico e outros ácidos orgânicos de estrutura geral RCOOH, onde R refere-se a um radical orgânico;
• - 0,01% a 2,0% de um dispersante líquido baseado em água, eventualmente acrescido de co-solvente, o qual é escolhido entre os glicóis como: propileno glicol, poli(etileno glicol), inclusive de diferentes massas molares, glicóis substituídos, co-solventes como etanol, isopropanol e polisorbatos e outros aditivos poliméricos para controle de viscosidade derivados da celulose como: hidróxi-propil metilcelulose, hidróxi-propil celulose, carbóxi-metil celulose e metilcelulose;

[0031] The composition of the formulation is described below:

• - 0.002% to 0.250% in metallic nanoparticles selected from silver, gold, copper, and their alloys;
• - The morphologies can be spherical, elliptical, prismatic, rods and plates and mixtures between these, with dimensions between 10 nm and 500 nm, are obtained from metal precursors by controlled reduction reactions, where the precursor compounds are chosen from oxides , acetates, nitrates, acetyl-acetonates, carbonate, chloride, citrate, fluoride and iodate;
• - 0.025% to 3.0% chitosan, with molar mass in a range of values that varies between 20 kDa and 1000 kDa, its derivatives, which are chosen from: carboxymethyl-chitosan, chitosan lactate, chitosan acetate, amylopectin and hydroxypropyl cellulose;
• - 0.06% to 3.0% of a fluoride salt, obtained from water-soluble salts, from aqueous solutions;
• - 0.07% to 3.0% of an organic acid, selected from acetic acid, oxalic acid, ascorbic acid and other organic acids with the general structure RCOOH, where R refers to an organic radical;
• - 0.01% to 2.0% of a liquid dispersant based on water, possibly added with a co-solvent, which is chosen from glycols such as: propylene glycol, poly(ethylene glycol), including those of different molar masses, glycols substituted, co-solvents such as ethanol, isopropanol and polysorbates and other polymeric additives for viscosity control derived from cellulose such as: hydroxy-propyl methyl cellulose, hydroxy-propyl cellulose, carboxy-methyl cellulose and methyl cellulose;

• - As diferentes formas do produto com suas opções individuais de componentes incluem a adição de polissacarídeos que desempenha ação e atividade antibacteriana sinérgica;
• - associação iônica;

[0032] The nanoparticles are preferably silver and the stoichiometric ratio of metal ion to reducing agent varies in the range of values between 0.15 and 11.0.

• - The different forms of the product with their individual component options include the addition of polysaccharides that perform synergistic antibacterial action and activity;
• - ionic association;

[0033] The presentation of the product is a liquid, whose color depends on the optical properties of the particles, which in turn depend on interactions with the medium in which it is dispersed and the wavelength of the incident light. They may also depend on their size, geometry and the distribution of size and geometric shape for each component option in the composition. For example, a gold-containing composition may be red or brownish, while another gold-containing composition may also be blue or purple, depending on the other components involved;

[0034] Application is topical, in cavities and tissue affected by a caries lesion for treatment.

• - Obtenção de solução aquosa de íons metálicos, com concentração em uma faixa de valores que varia entre 0,020 a 0,50 moles por litro;
• - Obtenção de solução, também aquosa do agente redutor, com concentração em uma faixa de valores que varia entre 0,018 a 1,700 moles por litro. Possíveis escolhas: hidrazina, borohidreto de sódio, albumina, LiAlH4 e boranos;
• - Obtenção de solução de quitosana 20 e 10000 kDa em água a partir da dissolução do polissacarídeo em uma solução aquosa de um ácido orgânico de adicionando-se entre 0,05 e 5,0 gramas em volumes de até 500mL;
• - Os procedimentos são todos realizados à temperatura ambiente;
• - As soluções são adicionadas colocando a primeira solução na terceira solução e, em seguida, adiciona-se a segunda solução à mistura;
• - Adicionar um sal de fluoreto à mistura de soluções de uma forma escolhida entre: dissolver diretamente o sal sólido na mistura e adicionar uma solução aquosa do sal de fluoreto na mistura;

[0035] The manufacturing methodology is described and comprises the following steps:

• - Obtaining an aqueous solution of metal ions, with concentrations in a range of values that vary between 0.020 and 0.50 moles per liter;
• - Obtaining a solution, also aqueous, of the reducing agent, with concentration in a range of values that varies between 0.018 and 1.700 moles per liter. Possible choices: hydrazine, sodium borohydride, albumin, LiAlH4 and boranes;
• - Obtaining a solution of chitosan 20 and 10000 kDa in water by dissolving the polysaccharide in an aqueous solution of an organic acid and adding between 0.05 and 5.0 grams in volumes of up to 500mL;
• - The procedures are all carried out at room temperature;
• - Solutions are added by placing the first solution in the third solution and then the second solution is added to the mixture;
• - Add a fluoride salt to the mixture of solutions in a way chosen between: directly dissolving the solid salt in the mixture and adding an aqueous solution of the fluoride salt to the mixture;

• - Ação cariostática;
• - nanopartículas metálicas conferem um aspecto visual aceitável, inexistente em tecnologias comparáveis; tem o mesmo efeito clínico que o DFP;
• - a formulação não requer a utilização a remoção do tecido necrosado;
• - aplicação simples.

[0036] The formulation described above has the characteristics:

• - Cariostatic action;
• - metallic nanoparticles provide an acceptable visual appearance, which does not exist in comparable technologies; has the same clinical effect as DFP;
• - the formulation does not require the use of removal of necrotic tissue;
• - simple application.

Examples of embodiments of the invention EXAMPLE 1

[0037] Chemical reduction of silver ions with silver borohydride, using silver nitrate, where 90 mg of this salt are dissolved in 500 mL of water and the solution was heated to boiling, under magnetic stirring. Then, 10 mL of 1% (m/V) sodium citrate solution is added and the system is allowed to rest. The nanoparticles synthesized by this method showed an absorption maximum at approximately 420 nm in the UV-visible absorption spectrum.

EXAMPLE 2

[0038] 100 mL of an aqueous solution of ascorbic acid (6 × 10-4 mol×L-1) was used and the pH was controlled in the range of 6.0 to 10.5, by adding HNO3 ( 0.2 mol/L) or NaOH (0.1 mol/L). The system was heated to a temperature of 39.5°C, under magnetic stirring and 1.0 mL of a 0.005 mol/L silver nitrate solution was added. The solution turned brown for the synthesis with pH = 10.5 and cloudy blue for those with pH < 10.5.

EXAMPLE 3

[0039] 4 × 10-4 mol/L silver acetate solution under magnetic stirring and room temperature, 1 mL of 0.055 mol/L NaBH4 was quickly added, making the solution yellow immediately after its addition.

EXAMPLE 4

[0040] Dissolving 1.0 gram of chitosan in 200 mL of 0.5% (v/v) acetic acid solution. Next, 4.0 mL of a 0.012 mol/L silver nitrate solution were added and then sodium borohydride was added. The ratio between AgNO3 and NaBH4 was maintained at 1:6 by mass. The reduction of Ag+ was started immediately, the color of the solution went from colorless to light yellow and finally reddish. After synthesis, wait around 45 minutes with the colloid under agitation to finish. optics. Immediately after synthesis, the samples were stored in a refrigerator.

[0041] The formulations described here are intended to stop the occurrence of injuries to teeth caused by caries and the process of obtaining them is preserved in terms of their innovative character. People versed in the approaches described in this document can develop variations, modifications, alterations, adaptations and equivalents that are applicable and compatible with the work environment. There is no need to depart from the spirit, scope and scope of the invention, as described in the claims.

Claims (7)

FORMULATION TO STOP CARIES LESIONS characterized by comprising the following components:

• - 0.002% to 0.250% in metallic nanoparticles selected from silver, gold, copper, and their alloys;
• - the morphologies can be spherical, elliptical, prisms, rods and plates and mixtures between these, with dimensions between 10 nm and 500 nm, are obtained from metal precursors by controlled reduction reactions, where the precursor compounds are chosen from oxides , acetates, nitrates, acetyl-acetonates, carbonate, chloride, citrate, fluoride and iodate;
• - 0.025% to 3.0% chitosan, with molar mass in a range of values that varies between 20 kDa and 1000 kDa, its derivatives, which are chosen from: carboxymethyl-chitosan, chitosan lactate, chitosan acetate, amylopectin and hydroxypropyl cellulose;
• - 0.06% to 3.0% of a fluoride salt, obtained from water-soluble salts, from aqueous solutions;
• - 0.07% to 3.0% of an organic acid, selected from acetic acid, oxalic acid, ascorbic acid and other organic acids with the general structure RCOOH, where R refers to an organic radical;
• - 0.01% to 2.0% of a liquid dispersant based on water, with a slightly acidic pH, possibly added with a co-solvent, which is chosen from glycols such as: propylene glycol, poly(ethylene glycol), including different molar masses, substituted glycols, co-solvents such as ethanol, isopropanol and polysorbates and other polymeric additives for viscosity control derived from cellulose such as: hydroxy-propyl methylcellulose, hydroxy-propyl cellulose, carboxy-methyl cellulose and methylcellulose.

PRODUCT FOR PARALYZING CARIES LESIONS according to claim 1, characterized in that the metallic nanoparticle is preferably silver and the stoichiometric ratio of metallic ion to reducing agent varies in the range of values between 0.10 and 10.0. PRODUCT FOR PARALYZING CARIES LESIONS according to claim 1, characterized in that the different forms of the product with their individual component options include the addition of polysaccharides that perform antibacterial activity and ionic association. CARIES LESION PARALYSIS PRODUCT according to claim 1, characterized in that the cationic character of chitosan and the anionic character of fluoride give them the property of forming associations of the type “chitosan fluorides” and soluble non-stoichiometric chitosan fluoride complexes. PRODUCT FOR PARALYZING CARIES LESIONS according to claim 1, characterized in that the presentation is a viscous liquid whose color depends on the optical properties of nanometric-sized particles and their interactions with the medium in which they are dispersed. PRODUCT FOR PARALYZING CARIES LESIONS according to claim 1, characterized by a final product whose application can be topical in cavities and tissue affected by a caries lesion for treatment and remineralization. PROCESS FOR OBTAINING A PRODUCT characterized by comprising the following steps:

• - obtaining an aqueous solution of metal ions, with concentrations in a range of values that vary between 0.020 and 0.50 moles per liter;
• - obtaining a solution, also aqueous, of the reducing agent, with a concentration in a range of values that varies between 0.018 and 1.700 moles per liter; possible choices: hydrazine, sodium borohydride, albumin, LiAlH4 and boranes;
• - obtaining a solution of chitosan 20 and 10000 kDa in water by dissolving the polysaccharide in an aqueous solution of an organic acid and adding between 0.05 and 5.0 grams in volumes of up to 500mL;
• - the procedures are all carried out at room temperature;
• - the solutions are added by placing the first solution in the third solution and then the second solution is added to the mixture;
• - add a fluoride salt to the mixture of solutions in a way chosen between: directly dissolving the solid salt in the mixture and adding an aqueous solution of the fluoride salt to the mixture.