WO2018078412A1

WO2018078412A1 - Topical microemulsion of diosmetin and uses thereof

Info

Publication number: WO2018078412A1
Application number: PCT/IB2016/001724
Authority: WO
Inventors: Miryam Perez PALMA
Original assignee: Posi Visionary Solutions Llp
Priority date: 2016-10-31
Filing date: 2016-10-31
Publication date: 2018-05-03

Abstract

A pharmaceutical composition for topical delivery of diosmetin is in the form of a microemulsion of an oleous phase and an aqueous phase. The pharmaceutical composition is effective in the treatment of diminished circulatory system performance, ecchymosis, and/or tired legs syndrome. Various formulations of the pharmaceutical composition also comprise : an additional cosurfactant, and/or an agent for improving and promoting diosmetin permeation of the skin, and/or an antioxidant, and/or an antimicrobial preservative, and/or a solvent and/or an emollient or skin-conditioning agent. Also provided are methods for treating patients suffering from : diminished circulatory system performance, ecchymosis, and/or tired legs syndrome.

Description

TOPICAL MICROEMULSION OF DIOSMETIN AND USES THEREOF

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of pharmaceutical compositions for topical delivery of diosmetin and uses thereof.

BACKGROUND OF THE INVENTION

A notable characteristic of the skin is that it acts as an atypical "barrier", because it only allows some exogenous substances to enter the body. This property of the skin has provided the basis for an incalculable number of studies focused on the possibility of absorbing drugs, ushering in the development of exogenous compounds like estrogens, steroids, vitamins, flavonoids, and others, for the purpose of obtaining localized or systemic effects, the chemical structure of the drug and thus its

physiochemical properties and composition of its carrier being the determining factors for achieving effective therapeutic results.

Due to its composition and structure, the outermost layer of the skin, the corneous stratum, is considered to be the limiting step for percutaneous absorption. Because the lipid domains of the corneous stratum consist of multillamelar bilayers, the chemical substances to be delivered should be capable of repetitively traversing the interphases of the aqueous-lipid phases. In this way, particularly relevant considerations for percutaneous absorption are the physicochemical properties such as molecular weight, Log P, aqueous and lipid solubility, polarity and charge.

The majority of drugs under consideration for topical or transdermal delivery were originally designed with another way of delivery in mind. Therefore, their properties are not optimal for absorption through the skin. Nevertheless, there are some guidelines that can be used to select the ideal transdermal candidate exhibiting these properties: the molecules should be small (200-500 Da), should have a low melting point (good solubility), and should have a Log P of approximately 2 (Hadgraft J. "Feasibility

Assessment in Topical and Transdermal Delivery: Mathematical model and in-vitro studies" in "Transdermal Drug Delivery" Dekker 2003, pp 1-23).

Flavonoids is the generic name used to refer to a group of phenolic compounds produced by the secondary metabolism of vegetables, which can be bound to glucidic units (glycosidic flavonoids), or can be free aglycone flavonoids. Flavonoids are classified based on their structural variations. Of greater pharmacological relevance are flavones, flavonols, flavanones, and their corresponding glucosides. Flavonoids exhibit a wide range of biological functions, particularly their venotonic, antioxidant, and estrogenic properties. (Polifenoles de aplicacion en farmacia Ambito farmaceutico Fitoterapia 2005; 24: 85-94, Flavonoides Ambito farmaceutico Fitoterapia 2002; 21 : 108-113).

The permeation of the flavonoids through the skin has been insufficiently investigated; the available data indicate that this group of compounds enter the skin through the corneous stratum and can reach the viable layers of the epidermis and the dermis. The speed of absorption depends on the flavonoid structure, and on the composition of the carrier (Arct J . Flavonoids as components of biologically active cosmeceuticals Clinics in Dermatology 2008; 26: 347-357).

Diosmin is a flavonoid that has a wide range of biological functions, and it is frequently administered orally to treat chronic venous insufficiency, hemorrhoids, and related ailments. However, it requires high dosages due its low bioavailability, and must be administered over long periods of time, reducing the long-term effectiveness of the treatment, in addition to its low oral acceptance. After ingestion, intestinal bacteria converts the diosmin into its aglycone, diosmetin, and is absorbed as such into the body (Confirmation of diosmetin 3- O-glucoronide as major metabolite of diosmin in humans, using micro-liquid-chromatography-mass spectrometry and ion mobility mass spectrometry 2013, 405: 8295-8310); therefore, diosmetin is the active metabolite that enables the drug to work; likewise, diosmetin can be extracted from various natural sources such as the lemon peel. Diosmin, a prodrug that when converted into diosmetin, exhibits pharmacological functions associated with an improved circulatory system, including : improved venous tone, reduction of the synthesis of prostaglandins that are involved in the inflammatory response, protection against free radicals, promotion of complementary functions integral to the first phases of inflammation, and lymphatic drainage. These functions are important because they are associated with symptomatological relief of various illnesses such as in the case of ecchymosis following cosmetic or trauma surgery, or in the case of tired legs syndrome and its related symptoms, such as: heavy feeling in the legs, pain and burning sensation in the legs, rash and edema.

The prior art reports that the main problem observed in delivering drugs through the skin rests in the inability of absorbing them fast enough to ensure an effect-site concentration of the drug; diosmetin, active metabolite of the flavonoid diosmin, is no exception.

Key physicochemical factors that control the kinetics of absorption of exogenous drugs through the skin are: partition coefficient, solubility of lipid and aqueous compounds, molecular weight and charge. Further, it should be taken into

consideration that the drugs must be in solution to be bioavailable, and that the absorption takes place via passive diffusion. However, the aforementioned factors are not a guarantee that more of the drug enters the skin, which necessitates taking into consideration the selection and optimization of excipients to ensure optimal therapeutic effectiveness when developing these products.

Diosmetin has a smaller chemical structure than diosmin (300.263 Da < 608.545 Da), it is not very soluble in water (104.7 mg/L), with a partition coefficient of (3.10) relatively close to the key value for percutaneous permeation LogP « 2 (Beetge E. 2000. The influence of the physicochemical characteristics and pharmacokinetic properties of selected NSAID's on their transdermal absorption; International Journal of Pharmaceutics Vol. 193 No. 2 pp 261-264) (Goosen C, 1998. Correlation between physicochemical characteristics, pharmacokinetic properties and transdermal absorption of NSAID's; International Journal of Pharmaceutics Vol. 163 No. 1-2 pp 203- 209) and with fewer polar groups; whose molecule possesses greater probabilities of absorption than that of diosmin.

The table below is a comparative chart of diosmin and diosmetin; in addition, the table shows the desirable values in the active ingredients that make them ideal for formulation of topical use.

Table 1. Comparative chart: diosmin and diosmetin.

Ref.

(1) Beetge E. 2000. The influence of the physicochemical characteristics and pharmacokinetic properties of selected NSAID's on their transdermal absorption;

International Journal of Pharmaceutics Vol. 193, No. 2, pp 261-264; (2) Goosen C, 1998. Correlation between physicochemical cha racteristics, pharmacokinetic properties and transdermal absorption of NSAID's; International Journal of Pharmaceutics Vol . 163 No. 1-2 pp 203-209.

(3) Diosmin . PubChem - Open Chemistry Data base [Internet] Access : January 08 ENE 2014, available at

https ://pubchem. ncbi. nlm. nih. gov/ compound/5281613#section =Top

(4) Diosmetin ChemSpider [Internet] Access : Sept 15 2015, available at http ://www. chemspider.com/Chemical-Structure.4444931. html?rid = bbbf0854-c086- 49b8-9155- ld2762634d9b

(5) Diosmin . ChemSpider [Internet] ]Access : Jan 08 2014, available at:

http ://www. chemspider.com/Chemical-Structure.4642588. html?rid =42278293-0c4e- 482a-81 bf-f6ade004fl2a

Diosmetin has a partition coefficient that is closest to the optimum logP ~2 for percutaneous permeation compared to Diosmin . Nevertheless, to be formulated in a topical composition, diosmetin requires a topical system that permits it to permeate through the skin; therefore, it is necessary to create a formula that considerably improves the solubility characteristics of diosmetin in the carrier and that improves the permeability of diosmetin through the skin to achieve the desired pharmacological effects.

In pa rticular, the low solubility of polar and non-polar compounds impedes the formulation and optimization of a product with diosmetin, consequently limiting its permeability through the skin, and thereby impedes the desired pharmacological effectiveness of the product.

The prior art discloses several topical formulations that contain diosmetin. The most common among these are ointments and creams.

Furthermore, the formulation of diosmetin in microemulsions is desira ble, since this type of dosage takes advantage of local pharmacological effectiveness and also offers the advantage of thermodynamic stability. Nevertheless, it is difficult to formulate this active ingredient in microemulsion due to its physicochemical properties, in particular, its pa rtition coefficient and solubility (see Table 1) .

Currently, products that contain diosmetin in emulsions are cosmetics that are based on plant extracts containing flavonoids among other natural components. For insta nce, an herbal emulsion, Sulwhasoo Balancing Emulsion, made from herbal extracts, contains among its other ingredients Diosmetin. However, cosmetic emulsions containing herbal extracts do not compare in their therapeutic effectiveness with that of formulations containing diosmetin in controlled and adequate quantities, which underscores the necessity of overcoming the technical obstacles encountered in formulating diosmetin in microemulsions, since the latter consists of very stable topical pharmaceuticals that take advantage of its full pharmacological function.

The prior art reports flavonoid formulations structurally similar to diosmetin. Yi- Hung Tsai 2010, In vitro permeation and in vivo whitening effect of topical hesperetin microemulsion delivery system, International Journal of Pharmaceutics Vol. 388 No. 1-2 pp 257-262 discloses a hesperetin microemulsion. While hesperitin and diosmetin may be structurally similar flavonoid compounds, the structural differences between them directly impact their physicochemical properties, in that diosmetin (flavone) is more lipophylic than hesperitin (flavanone), the former being difficult to solubilize in non- polar compounds and even more difficult to solubilize in polar compounds(see Table 1). This represents a challenge in developing a composition that allows diosmetin to permeate the skin in therapeutically adequate concentrations.

The technical problem encountered in developing the present invention was to solve the problem associated with the low solubility and low permeability through the skin of diosmetin, characteristics that affect the development of a formulation and consequently the bioavailability of the drug.

There remains a need for topical diosmetin products for treating symptoms, for example, related to tired legs and ecchymosis. The present invention solves this problem, having obtained a pharmaceutical composition applicable for use on the skin and that enables the therapeutic activities previously mentioned.

SUMMARY OF THE INVENTION

The present invention refers to a composition for topical delivery in the form of a microemulsion comprising at least one component that comprises the oleous phase containing castor oil, at least one ingredient with surfactant properties of a

polyoxyethylenated castor oil derivative, at least one component with cosurfactant properties (diethylene glycol monoethyl ether), and a component which constitutes the aqueous phase (water). The microemulsion may also contain at least one additional cosurfactant, at least one agent for improving and promoting the permeability of the active ingredient through the skin, at least one antioxidant, at least one antimicrobial preservative, at least one solvent and at least one emollient or conditioning agent for the skin. Unless stated otherwise, all numbers in wt%, % by weight or g/100 ml. are relative to the total composition.

The microemulsion of the present invention is designed so that the specific combination of ingredients and proportions used can be used to solve the problem of the absorption of diosmetin through the skin, exhibiting an improved permeation coefficient (5.73 x 10^"6 cm/s) as compared to a diosmetin formula based on discrete hesperetin as cited in Yi-Hung Tsai 2010, (8.00 x 10^"7 cm/s) (see Example 1). In addition, the microemulsion of the present invention considerably increases the solubility of diosmetin as compared to the microemulsion based on the prior art (Tsai, 2010).

As such, the combined variables of components to proportion has a notable effect on the resulting solubility of diosmetin in the formulation, specifically in evaluating the solubility of diosmetin in the proposed formulation and in comparing the results with previously obtained results in formulations based on systems reported in the prior art, as previously mentioned (0.99 g/100 ml_). Thus, the invention improves the solubility and permeability of diosmetin through the skin.

In one embodiment, there is provided a topical composition for improving a circulatory system, treating ecchymosis or treating tired legs syndrome in a patient. The composition comprises a therapeutically effective amount of diosmetin, a surfactant, and a cosurfactant. The composition is a microemulsion comprising an oleous phase and an aqueous phase.

The topical composition of the present invention may have a diosmetin solubility in the range of about 1.45-3.73% by weight, for example, 2.46-3.08% by weight.

The topical composition of the present invention has a diosmetin skin permeability coefficiency in the range of about 1.0-2.0 x 10^"7 kp. Compositions comprising ethanol, menthol-ethanol or menthol-ethanol-polyethylene glycol have diosmetin skin permeability coefficiency from about 0.833 x 10^"06 kp to about 1.48 x 10^"06 kp.

Compositions effective for treating ecchymosis on the face or eyelids may have diosmetin skin permeability coefficiency at about 6.97 x 10^"07 kp. Compositions with and without menthol may have diosmetin skin permeability coefficiency from about 0.833 x 10^"06 kp to about 0.480 x 10^"06 kp.

In one embodiment, the composition has a range of about 0.05-5% by weight of diosmetin.

The composition may comprise about 4-45% by weight of oleous phase. The oleous phase may comprise castor oil, oleic acid, squalene, avocado oil, or a mixture thereof. In some embodiments, the oleous phase comprises castor oil.

The composition may comprise about 8-55% by weight surfactant. The surfactant may be selected from the group consisting of polyoxyl cetostearyl ether, polyoxyl cetyl ether, polyoxiethylenated castor oil derivatives and combinations thereof. In one embodiment, the surfactant is polyoxyl castor oil. In another embodiment, the surfactant is polyoxyl castor oil and polyoxyl cetostearyl ether. In yet another embodiment, the surfactant is polyoxyl castor oil and polyoxyl cetyl ether.

In one embodiment, the comprises about 15-55% by weight of cosurfactant.

The cosurfactant may comprise diethylene glycol monoethyl ether. The composition may comprise an additional cosurfactant. The additional cosurfactant may be selected from the group consisting of ethanol, isopropyl alcohol and a combination thereof. In one embodiment, the additional cosurfactant is ethanol.

In one embodiment, the composition comprises about 15-55% by weight of diethylene glycol monoethyl ether and ethanol.

The composition may comprise an additional agent in an amount effective for improving permeability of diosmetin through the skin of the patient. The additional agent may be selected from the group consisting of menthol, propylene glycol and a combination thereof. In one embodiment, the additional agent is menthol. The composition may comprise menthol at about 0.94-2.82% by weight. In another embodiment, the additional agent is propylene glycol.

The composition may further comprise an antioxidant. The antioxidant may be selected from the group consisting of butylhydroxyanisol, butyl hydroxytoluene and combinations thereof.

The composition may further comprise an antimicrobial preservative. The antimicrobial preservative may be selected from the group consisting of methyl paraben, propyl paraben, butyl paraben, phenoxyethanol and a combination thereof.

The composition may further comprise a solvent. The solvent may be selected from the group consisting of polyethylene glycol 400, polyethylene glycol 1000 and combinations thereof.

The composition may further comprise an emollient or skin-conditioning agent. The emollient or skin-conditioning agent may be selected from the group comprising medium-chain triglycerides, isopropyl myristate, octyldodecanol, propylene glycol dicaprylate, propylene glycol dicaprate, and a combination thereof.

The compositions of the present invention are useful in treating ecchymosis by injury or bruises on different parts of the body, as well as post-surgical ecchymosis on the body, face or eyelids.

In addition, the compositions of the invention prolong the venetonic effect of diosmetin, as well as prove useful, for instance, in the treatment of tired legs syndrome and its related symptoms, including heavy sensation in the legs, pain, burning, rash and edema.

According to another aspect of the invention, a method for treating a diminished circulatory system in a patient, comprising topically administering to such patient a therapeutically effective amount of the pharmaceutical composition of the present invention. Improved venous tone, reduction of the synthesis of prostaglandins involved in an inflammatory response, protection against a free radical, promotion of a complementary function integral to a first phase of inflammation, or lymphatic drainage may be achieved in the patient.

According to yet another aspect of the invention, a method for treating ecchymosis in a patient following surgery is provided. The method comprises administering to the patient a therapeutically effective amount of the instant topical compositions in a therapeutically effective amount. The surgery may be a cosmetic or trauma surgery. The ecchymosis may be on the body, face or eyelid of the patient. The ecchymosis may be associated with pregnancy, e.g., striae gravidarum (i.e., a stretch mark).

In yet another embodiment, a method for treating tired legs syndrome of a patient is provided, comprising administering to the patient a therapeutically effective amount of the instant topical compositions. The patient may be suffering from a malady selected from the group consisting of: heavy feeling in the legs, pain and burning sensation in the legs, rash, and edema.

For each medicament or composition described herein, a method for preparing the medicament or composition is provided. The preparation method comprises mixing diosmetin, a surfactant and a cosurfactant to make a microemulsion. The

microemulsion comprises an oleous phase and an aqueous phase.

BRIEF DESCRIPTON OF THE DRAWINGS

Figure 1 shows a permeability graph of diosmetin in microemulsion compositions 527 (with menthol) and 528 (without menthol). Composition 527 shows an increase in permeability of diosmetin compared to Composition 528.

Figure 2 shows a permeability graph of diosmetin of different microemulsion compositions with menthol. Comparison of permeability profiles of composition of diosmetin with menthol (Composition 527), menthol-ethanol (Composition 350), or menthol-ethanol- polyethylene glycol 400 (Composition 351).

Figure 3 shows local and dermatocosmetic tolerability graph of tired leg sensation for a diosmetin composition.

Figure 4 shows results of topical application of a diosmetin composition for relief of injuries or ecchymosis of patients who had undergone plastic surgery.

DETAILED DESCRIPTION OF THE INVENTION

Considering the foregoing, a first embodiment of the present invention refers to a composition for topical delivery of a microemulsion comprising at least one component comprising the oleous phase of castor oil, at least one component having surfactant properties that is a polyoxyethylene castor oil derivative, at least one component having cosurfactant properties which is diethylene glycol monoethyl ether, and one component constituting the aqueous phase that is water. The microemulsion may additionally contain at least one additional cosurfactant, at least one agent for improving or promoting absorption of the active ingredient through the skin, at least one antioxidant, at least one antimicrobial preservative, at least one solvent and at least one emollient or skin-conditioning agent.

In accordance with the invention, the oleous phase comprises at least castor oil. The at least one component with surfactant properties is a polyoxyethylene castor oil derivative selected from the group comprising at least polyoxyl 40 hydrogenated castor oil, polyoxyl 60 hydrogenated castor oil, or polyoxyl 35 castor oil, and can be selected from the alkyl polyoxyethylene group of ethers, which includes at least Polyoxyl cetostearyl ether, polyoxyl cetyl ether. Preferably, the surfactant is polyoxyethylene castor oil.

The at least one component having cosurfactant properties is diethylene glycol monoethyl ether.

The at least one additional cosurfactant component is selected at least from the following group comprising ethanol and isopropyl alcohol.

The component constituting the aqueous phase is water.

The at least one agent that promotes the permeability of the drugs is selected from the group comprising menthol and propylene glycol.

The at least one antioxidant is selected from the group comprising

butylhydroxyanisol and butylhydroxytoluene.

The at least one antimicrobial preservative is selected from the group comprising at least methyl paraben, propyl paraben, butylparaben and phenoxyethanol.

The at least one emollient or skin-conditioning agent is selected from the group which comprises at least medium-chain triglycerides, isopropyl myristate,

octyldodecanol and propylene glycol dicaprylate/dica prate.

The at least one solvent is selected from the group comprising hydrophilic polymers, for example polyethylene glycol 400, polyethylene glycol 1000.

In one embodiment of the invention, the at least one surfactant selected is polyoxyl 40 hydrogenated castor oil and polyoxyl 20 cetostearyl and polyoxyl 20 cetyl ether.

In another embodiment of the invention, the at least one surfactant selected is polyoxyl 40 hydrogenated castor oil.

In another embodiment of the invention, the cosurfactant is diethylene glycol monoethyl ether and the at least one additional cosurfactant is ethanol.

In one embodiment of the invention, one of the agents or components that promote permeability of the active ingredient or drug used is menthol.

In yet another embodiment of the invention, the at least one agent or component for promoting permeability is menthol, and the cosurfactant is ethanol. In another embodiment of the invention, one agent used to promote permeability is propylene glycol.

In yet another embodiment of the invention, the agent used to promote

permeability is menthol, and the additional cosurfactant used is ethanol and the solvent used is polyethylene glycol 400.

In another embodiment of the invention, the at least one surfactant selected is polyoxyl 40 hydrogenated castor oil and polyoxyl 20 cetostearyl ether, the cosurfactant is diethylene glycol monoethyl ether and the permeability promoter is propylene glycol.

The combination of factors components to proportion as such impact the results of solubility of diosmetin in the formulation, specifically in evaluating the solubility of Diosmetin in the proposed formulation and comparing the result with those obtain in formulations based on compositions of the prior art that were described in the above (0.99 g/ 100 ml_). Along these lines, the invention improves the solubility and permeability of Diosmetin through the skin.

The compositions of the present invention are useful in treating or reducing ecchymosis by injury or on the body in treating post-surgical ecchymosis in the face and eyelids.

In addition, the compositions of the invention are useful for treating tired leg feelings in patients who suffer peripheral venous insufficiency.

EXAMPLE 1

Formulation based on the prior art

Formulations with components described in Yi-Hung Tsai (2010) were evaluated, substituting hesperitin with diosmetin to determine the effect on solubility and permeability in this system (Yi-Hung Tsai 2010, In vitro permeation and in vivo whitening effect of topical hesperetin microemulsion delivery system, Int. J.

Pharmaceutics Vol. 388 No. 1-2 pp 257-262). Hesperitin is a flavonoid with structure very similar to diosmetin, leading to the decision to manufacture compositions with the same release system and to incorporate diosmetin instead of hespertin in these systems. The excipient proportions and the results obtained in terms of their solubility and permeability are shown below. Table 2. Microemulsions with diosmetin formulated in accordance with the prior art, Tsai, 2010.

Composition 065 exhibits the greatest diosmetin solubility, 0.99 g/100 mL and its corresponding permeability coefficient is 3.90 x 10^"7 indicating that formulations based on the prior art, Tsai, 2010 are inefficient in obtaining effect-site therapeutic

concentrations.

EXAMPLE 2

Formulation in accordance with the present invention

Formulations that differed from the excipients described in Tsai, 2010 were used in several proportions. The diosmetin solubility results obtained were as follows: Table 3. Solubility of diosmetin in microemulsions formulated in accordance with the present invention

The solubility corresponding to compositions 237 and 238 is 3.08 g/ 100 ml_; being the largest quantity possible that can be solubilized in this system. The diosmetin solubility in the proposed formulation is greater than the solubility of the composition based on the disclosure in Tsai, 2010, which achieved the best result of 0.99 g/ 100 ml_. The present invention, however, optimizes the Diosmetin composition in microemulsion, increasing its permeability through the skin and allowing it to reach the effect site as described below (in Tables 5 and 6).

EXAMPLE 3

Embodiments with menthol

In accordance with other embodiments of the present invention, menthol was added to promote penetration of the main ingredient. It was observed that the diosmetin solubility in the formulation was greater than in the prior art, which was 0.99 g/ 100 ml_. The various excipient proportions and the solubility results obtained are shown below: Table 4. Compositions in accordance with the invention with menthol

The incorporation of other excipients such as menthol is optional but further improves the absorption of the drug through the skin in contrast to the formulation based on the prior art (Tsai, 2010). In contrast to the composition without menthol (see Figure 1), the present invention composition allows the patient to benefit from menthol's soothing effect on the skin and improves permeability profile of diosmetin, leading to greater concentrations on the effect site.

The compositions evaluated in Figure 1 are shown below:

Table 5. Compositions in accordance with the invention with and without menthol

EXAMPLE 4

Example of embodiments with ethanol, menthol-ethanol and menthol-ethanol- polyethylene glycol In accordance with other embodiments of the present invention, one or more agents may be added to promote active ingredient penetration, as well as an additional cosurfactant. In this example, menthol, along with one or more additional

cosurfactants, is used as at least one promoting agent in the penetration of the active ingredient.

In addition, in another embodiment of the invention, an agent promoting absorption of the active ingredient, an additional cosurfactant, and a solvent may be added. In this example, menthol is used as the agent for promoting active ingredient absorption, ethanol as an additional cosurfactant, and polyethylene glycol 400 as a solvent.

Table 6 shows the permeability coefficient of diosmetin in modes with ethanol, menthol-ethanol and menthol-ethanol-polyethylene glycol. It is noteworthy that in all cases, the permeability coefficient is greater than that of any of the compositions presented in Example 1 that were based on the formulation of the prior art. Figure 2 shows improved diosmetin levels permeated by way of compositions containing ethanol, menthol-ethanol and menthol-ethanol-polyethylene glycol, the latter two showing better results than ethanol. Specifically, the compositions of the formulations in this example are listed in the following :

Table 6. Examples of composition embodiments with ethanol, menthol-ethanol and menthol-ethanol-polyethylene glycol

EXAMPLE 5

Embodiments of the invention with polyoxyl cetyl ether The diosmetin formulation in the present invention also can be applied to more delicate parts of the body like face and eyelids. Embodiments containing the at least one surfactant agent, polyoxyl castor oil and polyoxyl cetyl ether, are the preferred methods of application to more delicate skin and/or on persons sensitive to menthol and/or ethanol. In accordance with the foregoing, Table 7 below shows the solubility coefficients of various compositions using polyoxyl cetyl ether as surfactant.

Table 7. Examples of compositions with polyoxyl cetyl ether as surfactant

This embodiment shows that compositions containing the additional ingredient polyoxyl cetyl ether as surfactant provide better diosmetin solubility results than the composition 065 based on the prior art (0.99 g/ 100 mL). Particularly, the composition 022 shown in this example exhibits a greater diosmetin solubility of 3.73 g/ 100 mL. Corresponding to the previous examples, the present invention allows greater solubility of a larger quantity of diosmetin, which is one of the indispensable characteristics for optimal formulations of diosmetin in microemulsions, and which likewise allows the composition to provide its therapeutic effect.

EXAMPLE 6

Embodiments of the invention for ecchymosis in the face and eyelids

The effect of diosmetin on permeability was evaluated in different compositions using an alkyl polyoxyethylene ether, polyoxyl cetostearyl ether as surfactant, as well its proportions, described in the following : Table 8. Example of a composition for ecchymosis on the face and eyelids

Based on the permeability coefficient results shown in Table 8, it can be observed that composition 212, which contains an additional surfactant other than hydrogenated polyoxyl castor oil, polyoxyl cetostearyl ether, and an agent for improving the drug's absorption, propylene glycol, has a greater permeability coefficient, 6.97 x 10^"07, than the composition 065 based on the prior art that exhibited a permeability coefficient of 3.90 x 10^"7. This allows greater concentrations of diosmetin to be permeated through the skin and to achieve successful therapeutic effects (Table 8).

EXAMPLE 7

Drug trials

The composition of the present invention allows a greater quantity of diosmetin to be solubilized and improves its permeability through the skin. Likewise, the composition of the present invention and its pharmacological activities corresponds with the results of the following trials.

In an initial test of the pharmacological effect of the topical microemulsion containing 1.5 wt% diosmetin, 12.75 wt% castor oil, 19.89 wt% polyoxyl 40

hydrogenated castor oil, 39.70 wt% diethylene glycol monoethyl ether, 9.00 wt% ethanol, 2.29 wt% polyethylene glycol 400, 6.00 wt% menthol, 2.00 wt% Propylene glycol dicaprylate/dica prate, 0.02 wt% butyl para ben and 0.06 wt%

butylhydroxyanisole, the composition was applied to the legs of trial patients with peripheral venous insufficiency for treating and reducing symptoms of tired leg sensation. To this end, a trial was conducted with 25 voluntary female participants to study the diosmetin composition. A basal exam evaluated the presence of tired leg feelings using a visual analog scale (VAE) where 0 represented the absence of tired leg sensation and 10, the maximum tired leg sensation. The initial levels of tired leg sensation were recorded during the first visit (the beginning of the study). Following the initial evaluation, the composition of the present invention was applied and the patients were instructed to apply it topically to their legs on a daily basis, and to come back once week to report their perception of a tired leg sensation for 7 visits (a period of 49 days), where a complete disappearance of the sensation was reported in the last, or seventh, visit. The results of this trial are shown in Figure 3.

In a second evaluation of the pharmacological effect of the topical microemulsion containing 1.5 wt% diosmetin, 12.75 wt% castor oil, 19.89 wt% polyoxyl 40 hydrogenated castor oil, 39.70 wt% diethylene glycol monoethyl ether, 9.00 wt% ethanol, 2.29 wt% polyethylene glycol 400, 6.00 wt% menthol, 2.00 wt% propylene glycol dicaprylate/dica prate, 0.02 wt% butyl para ben and 0.06 wt%

butylhydroxyanisole, the diosmetin exhibited a venotonic effect in the treatment of bruising or ecchymosis on various parts of the body. To this end, the composition of the present invention was applied to patients who had undergone cosmetic surgery and who exhibited considerable and visible ecchymosis. For example, on one of the patients with extensive ecchymosis (See Figure 4), the ecchymosis reached its maximum point 48 hours after surgery but after applying the diosmetin of the present invention, the ecchymosis disappeared 10 days later, or 12 days after the surgery. The diosmetin microemulsion of the present invention was applied for 15 days, 3 times a day, and the disappearance of the ecchymosis was visually confirmed. In comparison, the time it would naturally take for ecchymosis as extensive as exhibited by the patient in Figure 4 to vanish would have been between 3 to 4 weeks.

Furthermore, the ecchymosis was eliminated in even lesser time periods (less than 7 days) in cases of less extensive ecchymosis, as compared to the 2 or 3 weeks it would normally take to vanish without applying any product (data not shown).

Claims

I . A pharmaceutical composition comprising a therapeutica lly effective a mount of diosmetin, a surfactant, and a cosurfactant, and wherein the composition is a microemulsion of an oleous phase and an aqueous phase.

2. The composition of claim 1, comprising 0.05-5% by weight diosmetin .

3. The composition of claim 1, comprising 4-45% by weight oleous phase, which phase comprises castor oil .

4. The composition of claim 1, comprising 8-55% by weight surfactant, and wherein the surfactant is selected from the group consisting of polyoxyl cetostearyl ether, polyoxyl cetyl ether, polyoxiethylenated castor oil derivatives, and combinations thereof.

5. The composition of claim 4, wherein the surfactant is polyoxyl castor oil .

6. The composition of claim 4, wherein the surfactant is a mixture of polyoxyl castor oil and polyoxyl cetostea ryl ether.

7. The composition of claim 4, wherein the surfactant is a combination of polyoxyl castor oil and polyoxyl cetyl ether.

8. The composition of claim 1, comprising 15-55% by weight cosurfactant, and wherein the cosurfactant comprises diethylene glycol monoethyl ether.

9. The composition of claim 8, further comprising an additional cosurfactant.

10. The composition of claim 9, wherein the additional cosurfactant is selected from the g roup consisting of ethanol, isopropyl alcohol and combinations thereof.

I I . The composition of claim 9, wherein the additional cosurfactant is ethanol .

12. The composition of claim 1, further comprising an additional agent in an amount effective for improving transdermal permeation of diosmetin.

13. The composition of claim 12, wherein the additional agent is selected from the group consisting of menthol, propylene glycol, and combinations thereof.

14. The composition of claim 12, wherein the additional agent is menthol .

15. The composition of claim 12, wherein the additional agent is propylene glycol .

16. The composition of claim 1, further comprising an antioxidant.

17. The composition of claim 16, wherein the antioxidant is selected from the group consisting of butylhydroxyanisol, butylhydroxytoluene and combinations thereof.

18. The composition of claim 1, further comprising an antimicrobial preservative.

19. The composition of claim 18, wherein the antimicrobial preservative is selected from the g roup consisting of methyl paraben, propyl paraben, butyl paraben, phenoxyethanol, and combinations thereof.

20. The composition of claim 1, further comprising a solvent.

21. The composition of claim 20, wherein the solvent is selected from the group consisting of polyethylene glycol 400, polyethylene glycol 1000, and

combinations thereof.

22. The composition of claim 1, further comprising an emollient and/or a skin-conditioning agent.

23. The composition of claim 22, wherein the emollient and/or skin- conditioning agent is selected from the group consisting of medium-chain triglycerides, isopropyl myristate, octyldodecanol, propylene glycol dicaprylate, propylene glycol dicaprate, and combinations thereof.

24. A method for treating a diminished circulatory system in a patient, comprising topically administering to such patient a therapeutically effective amount of the pharmaceutical composition of claim 1.

25. The method of claim 24, whereby improved venous tone, reduction of the synthesis of prostaglandins involved in an inflammatory response, protection against a free radical, promotion of a complementary function integral to a first phase of inflammation, or lymphatic drainage is achieved in the patient.

26. A method for treating a patient suffering from ecchymosis following surgery, comprising topically administering to the patient an effective a mount of the pha rmaceutical composition of claim 1.

27. The method of claim 26, wherein the surgery is a cosmetic or trauma surgery.

28. The method of claim 26, wherein the ecchymosis is on the body, face or eyelid of the patient.

29. The method of claim 26, wherein the ecchymosis is striae gravidarum.

30. A method for treating a patient suffering from tired legs syndrome, comprising administering to the patient an effective amount of the topical composition of claim 1.

31. The method of claim 30, wherein the tired legs syndrome is selected from the group consisting of heavy feeling in the legs, pa in and burning sensation in the legs, rash and edema .

32. A method for preparing a medicament useful for improving a circulatory system, treating ecchymosis or treating tired legs in a patient, comprising making the composition of claim 1.