Technical field of the invention
The present invention relates to a topical composition comprising ajowan oil derived from the plant Trachyspermum ammi as the active ingredient and one or more of suitable additives. It also relates to the process for the preparation of the same.
Background of the invention
Most of the common skin infections in humans are caused by fungal and/or bacterial pathogens. Topical application of the drugs to the skin surface has been used since antiquity to treat such skin diseases and infections. The present line of treatment involves the use of synthetic antibacterial and antifungal compounds. An increasing problem with such treatment is the development of resistance that necessitates the use of antimicrobial drugs with more serious side effects. Natural medicines are known to be comparatively safe with less deleterious side effects than corresponding synthetic drugs. Therefore, there is an increasing use of natural medicines for the manufacture of compositions to overcome the problems of microbial resistance and adverse effects associated with the use of synthetic antimicrobials.
The ajowan, Trachyspermum ammi, belonging to the family Apiaceae (Umbellifereae) is an important fruit spice. Ajowan fruits contain about 2-5% percent essential oil. Ajowan oil is a colorless or brownish yellow liquid possessing a characteristic odor of thymol and a sharp taste. The principal constituent of the oil is thymol (35-60%). Others include carvacrol, p-cymene, y-terpinene, a- and p- pinenes and dipentene. Ajowan oil is reported to possess numerous medicinal actions such as antibacterial, antifungal, antiflatulent, antispasmodic, antirheumatic, diuretic, stimulant, carminative and expectorant properties. Use of ajowan oil and thymol per se as a component of grandma's household recipes to treat a range of common ailments is also well known.
US Patent No. 6,514,541 discloses a formulation useful in the treatment of drug resistant bacterial infection comprising an effective amount of thymol obtained form the plant Trachyspermum ammi and mint oil containing an effective amount of monoterpenes obtained from a hybrid of Mentha spicata and Mentha arvensis and
additives. The said formulation is a tablet, syrup, powder or injection and is administered through oral route or as subcutaneous injection.
The antimicrobial activities of carvacrol and thymol are well known and have been developed for use in birds and animals. US Patent No. 5,990,178 discloses pharmaceutical compositions containing carvacrol and/or thymol for treating a disease in poultry induced by hemoflagellates. US Patent No. 6,322,825 discloses pharmaceutical compositions for treating gastrointestinal infections in animals consisting essentially of an active agent and a pharmaceutically acceptable carrier wherein the active agent is an oil consisting essentially of a combination of thymol and carvacrol, said oil being extracted from Origanum vulgaris plant. US Patent No. 6,414,036 discloses compositions of carvacrol and thymol combined with group I salts or organic acids and a pharmaceutically acceptable carrier for the treatment of microbial infections in animals.
While antimicrobial properties of ajowan oil are well known, there is no suggestion regarding the development of a topical composition of ajowan oil and its use in the treatment against drug resistant bacterial or fungal pathogens. We have now developed a topical composition comprising ajowan oil as the active ingredient and one or more of suitable additives. The said composition has been found to exhibit a strong activity against skin inhabitant filamentous and non-filamentous fungi as well as gram positive and gram negative bacteria including multi-drug resistant fungal and bacterial pathogens. The composition described herein is therefore useful in the treatment of medical conditions that result from fungal and/or bacterial infections on the skin like itching, scaling, keratinization, excoriation, fissuring and other symptoms present in dermatological conditions, including but not limited to, various xerotic and pruritic dermatological disorders like atopic dermatitis, senile pruritus, ichthyosis, scabies, intertrigo, psoriasis etc., superficial dermatophytic infections like tinea corporis (ringworm of the skin), tinea pedis (athlete's foot), tinea curis (jock itch), tinea unguum (nail infection), tinea capitis (ring worm of scalp), cutaneous candidiasis like skin bright red inflammation, blister like superficial lesions and skin wound infection etc.
Summary of the invention
In one general aspect, it relates to a topical composition of ajowan oil comprising an effective amount of ajowan oil derived from the plant Trachyspermum ammi and one or more of suitable additives.
In another general aspect, it relates to a topical composition of ajowan oil comprising an effective amount of ajowan oil and one or more of suitable additives, wherein the ajowan oil is present in a concentration of from about 0.5% to about 10% by weight of the total weight of the composition.
In another general aspect, it relates to a topical composition of ajowan oil comprising an effective amount of ajowan oil and one or more of suitable additives; wherein the additives are selected from bases, emulsifying/solubilizing agents, humectants or preservatives.
In another general aspect, it relates to a topical composition of ajowan oil comprising an effective amount of ajowan oil and one or more of suitable additives selected from bases, emulsifying/solubilizing agents, humectants or preservatives, wherein the composition is in the form of a cream.
In another general aspect, it relates to a topical composition of ajowan oil comprising an effective amount of ajowan oil and as additives karanj oil, sesame oil, arlacel®165, cetostearyl alcohol, cetyl alcohol, arlamol, emulsifying wax, light liquid paraffin, propylene glycol, polyethylene glycol, glycerin, methyl paraben, propyl paraben, imidurea, boric oxide, zinc oxide, menthol and fragrance.
In another general aspect, it relates to a process for the preparation of a topical composition of ajowan oil comprising an effective amount of ajowan oil and one or more of suitable additives; wherein the process comprises the steps of:
- forming the first phase by heating the blend comprising of oily bases and emulsifying/solubilizing agents under constant homogenization;
- forming the aqueous phase by heating the blend comprising of water soluble additives with water by heating under constant homogenization;
- adding the first oil containing phase to the aqueous phase at a temperature of 50-80°C under constant homogenization;
- blending ajowan oil and one or more additives selected from preservatives, humectants, cooling agents and fragrances in one or more steps to obtain the final composition.
In another general aspect, it relates to a process for the preparation of a topical composition of ajowan oil comprising an effective amount of ajowan oil and one or more of suitable additives; wherein the process comprises the steps of:
- heating the blend of karanj oil, sesame oil, arlacel®165, light liquid paraffin, cetostearyl alcohol, cetyl alcohol, arlamol, emulsifying wax and polyethylene glycol upto 80°C under constant homogenization;
- forming an aqueous phase by heating the blend of glycerin and water upto 80°C under constant homogenization;
- adding the above oil containing phase to the above aqueous phase and cooling the resultant blend to 55-6CTC under constant homogenization;
- adding a thoroughly dissolved mixture of imidurea in water to the above mixture under continuous homogenization;
- adding the blend of ajowan oil, boric oxide and zinc oxide to the above mixture at a temperature below 40°C under continuous homogenization;
- adding the blend of methyl paraben, propyl paraben, glycerin, propylene glycol and menthol to the above mixture under continuous homogenization;
- mixing the fragrance with the above mixture to obtain the final composition.
Detailed Description of the invention
Treatment of fungal and bacterial skin infections involves the use of synthetic antimicrobial drugs. However, the development of resistance and emergence of multiple drug resistant strains is a serious problem resulting in treatment failure. To counter this problem, we have developed a topical composition comprising ajowan oil with minimal or no side effects for the treatment of skin infections caused by skin inhabitant filamentous and non-filamentous fungi as well as gram positive and gram negative bacteria including multi-drug resistant fungal and bacterial pathogens.
The term "Ajowan oil", refers to the oil extracted from the fruits of Trachyspermum ammi or Bishop's weed. Ajowan oil is present in a concentration of from about 0.5% to about 10% by weight of the total weight of the composition, preferably in a concentration of about 3%.
As used herein, the term "effective amount" means the amount of a compound or composition that, when administered to a mammal for treating a state, disorder or condition, is sufficient to effect such treatment. The "effective amount" of the composition may be administered as repeated applications.
The topical compositions may contain one or more additives to aid processing during manufacturing and to improve the consistency, homogeneity, spreadability, texture and appearance of the composition. Suitable additives may comprise ingredients selected from, but not limited to bases, emulsifying/solubilizing agents, humectants and preservatives. Some of these ingredients are overlapping and individual compounds may possess one or more of these activities in different degrees.
Suitable bases may include, without limitation, water, water miscible bases such as alcohols or macrogols, oil bases such as vegetable oils like sesame oil, karanj oil, peanut oil, almond oil, olive oil, mineral oils like paraffin, synthetic oils like silicones, fatty acids like stearic acid or palmitic acid, fatty alcohols like cetyl alcohol, stearyl alcohol or their combinations.
Suitable emulsifying/solubilizing agents may be anionic, cationic or non-ionic type substances. Examples include, without limitation, arlacel®165, cetostearyl alcohol, cetyl alcohol, arlamol, emulsifying wax, glyceryl monostearate, methylcellulose, sodium carboxymethylcellulose, other cellulose derivatives, acacia, gelatin, lecithin, potassium laurate, triethanolamine stearate, sodium lauryl sulfate, alkyl polyoxyethylene sulfates, dioctyl sodium sulfosuccinate, polyethylene glycols, (polyols e.g. ethylene glycol, propylene glycol, butylene glycol, polyol ethers, sorbitan esters, polyoxyethylene alkyl ethers (e.g., macrogol ethers such as cetomacrogol 1000), polyoxyethylene castor oil derivatives, polyoxyethylene sorbitan fatty acid esters, (e.g. Tween™), polyoxyethylene stearates or their combinations.
Suitable humectants may include, without limitation, glycerin, sorbitol, propylene glycol, low molecular weight polyethylene glycol or their combinations.
Suitable preservatives may include, without limitation, methyl paraben, propyl paraben, ethyl paraben, butyl paraben, chlorocresol, thiomerosal, sorbic acid, potassium sorbate, imidurea or their combinations.
The compositions may, optionally, contain other additives such as cooling agents, fragrances, antioxidants etc.
Suitable cooling agents may include menthol, menthol-based or acyclic carboximides and menthol-based or acyclic ketals (acetals).
Suitable fragrances may include any of the fragrances approved by Food and Drug Administration.
Suitable antioxidants may include butylated hydroxyanisole, butylated hydroxytoluene or propyl gallate.
The compositions of the invention are provided in a form intended to be applied topically, such as, for example, cream, lotion, thickened lotion, gel, milk, sticks, sprays, pastes, ointment or vesicular dispersion. A particularly preferred composition is a cream.
The compositions as described herein may be prepared by conventional processes known in the art for making topical compositions using easily available additives and conventional equipments. Such methods typically involve separately forming the oil phase and the aqueous phase with or without heating, cooling or application of vacuum. Solid materials may be dissolved in liquid materials or dispersed using high shear, or melted to facilitate incorporation into the base. The two phases are then mixed together either by simultaneous blending or by addition of one phase to the other phase at a specified temperature. This is followed by mixing of other ingredients in one or more steps at a specified temperature under continuous homogenization to obtain a uniform composition.
In one embodiment, the topical composition of the present invention comprises an effective amount of ajowan oil and as additives karanj oil, sesame oil, arlacel®165, cetostearyl alcohol, cetyl alcohol, arlamol, emulsifying wax, light liquid paraffin, propylene glycol, polyethylene glycol, glycerin, methyl paraben, propyl paraben, imidurea, menthol and fragrance.
Additional additives such as boric oxide, zinc oxide, for example, may be incorporated in the above embodiment for their antiseptic and/or antimicrobial properties.
In one embodiment, it relates to a process for the preparation of a topical composition of ajowan oil comprising an effective amount of ajowan oil and one or more of suitable additives; wherein the process comprises the steps of:
- forming the first phase by heating the blend comprising of oily bases and emulsifying/solubilizing agents under constant homogenization;
- forming the aqueous phase by heating the blend comprising of water soluble additives with water by heating under constant homogenization;
- adding the first oil containing phase to the aqueous phase at a temperature of 50-80°C under constant homogenization;
- blending ajowan oil and one or more additives selected from preservatives, humectants, cooling agents and fragrances in one or more steps to obtain the final composition.
In a further embodiment, it relates to a process for the preparation of a topical composition of ajowan oil comprising an effective amount of ajowan oil and one or more of suitable additives; wherein the process comprises the steps of:
- heating the blend of karanj oil, sesame oil, arlacel®165, light liquid paraffin, cetostearyl alcohol, cetyl alcohol, arlamol, emulsifying wax and polyethylene glycol upto 80°C under constant homogenization;
- forming an aqueous phase by heating the blend of glycerin and water upto 80°C under constant homogenization;
- adding the above oil containing phase to the above aqueous phase and cooling the resultant blend to 55-60/C under constant homogenization;
- adding a thoroughly dissolved mixture of imidurea in water to the above mixture under constant homogenization;
- adding the blend of ajowan oil, boric oxide and zinc oxide to the above mixture at a temperature below 40°C under constant homogenization;
- adding the blend of methyl paraben, propyl paraben, glycerin, propylene glycol and menthol to the above mixture under constant homogenization;
- mixing the fragrance with the above mixture to obtain the final composition.
The topical compositions of ajowan oil disclosed herein are further illustrated by the following examples but it should not be construed as limiting the scope of the invention.
EXAMPLES A-C
(Table Removed)

Procedure for Examples A-C:
- Part A ingredients were heated upto 80°C under constant homogenization;
- aqueous phase was formed by heating the Part E ingredients upto 80°C under constant homogenization;
- oil containing phase (Part A) was added to the aqueous phase (Part E) and resultant blend was cooled to 55-60/C under constant homogenization;
- a thoroughly dissolved mixture of imidurea in water (Part B) was added to the above mixture under constant homogenization;
- Part D ingredients were added to the above mixture at a temperature below 40°C under constant homogenization;
- Part C ingredients were added to the above mixture under constant homogenization;
- fragrance (Part F) was added to obtain the final composition.
Antimicrobial susceptibility test for the in vitro determination of antibacterial
and antifungal activity of the composition prepared in accordance with
Example A above as determined by agar well diffusion assay method
Evaluation of antibacterial and antifungal activity was comparatively performed with topical composition (200mg) comprising ajowan oil (representing 6mg/well of active ingredient) and topical composition (200mg) comprising only additives without ajowan oil.
Table 1 Determination of antibacterial activity of topical compositions: Zone of inhibition was recorded against superficial targeted bacterial pathogens after one day of incubation at 35±2'C by agar well diffusion assay method.

(Table Removed)
*Values are mean of three replicates ± standard error. ** Methicillin resistant Staphylococcus aureus.
Experiment protocol: Moist heat sterilized (121°C for 15 minutes) Muller Hinton agar medium was cooled to reach 40-45°C, thereafter 0.1% size of bacterial inoculum previously prepared in saline solution was added to each conical flask individually. After proper mixing of the contents, 25 ml of medium was poured into the pre dry heat sterilized (180°C for 1 hour) petri plates (100 mm diameter) and were held for 20 minutes for solidification. Two wells of 8 mm radius were punched in each of these plates. The compositions taken in sterilized syringe were added into the agar well gently. One well contained ajowan oil composition and the other well contained the additive only composition. The experiment was performed in triplicates. All petri plates were incubated in bacteriological incubator at 35±2°C for one day. Controls containing only Muller Hinton agar plates and Muller Hinton agar plates with
inoculum were run in parallel. After incubation, zones of inhibition were recorded with the help of calipers.
Table 2 Determination of antifungal activity of topical compositions: Zone of inhibition was recorded against superficial targeted fungal pathogens after three to five days of incubation at 25±2°C by agar well diffusion assay method.

(Table Removed)
*Values are mean of three replicates ± standard error. "Miconazole and Fluconazole resistant Candida species.
Experiment protocol: Moist heat sterilized (121°C for 15 minutes) Sabaroud dextrose agar medium was cooled to reach 40-45°C and thereafter 1% size of filamentous fungal inoculum and 0.1% size of non-filamentous fungal inoculum previously prepared in saline solutions were added to each conical flask individually. After proper mixing of the contents, 25 ml of medium was poured in to the pre dry heat sterilized (180°C for 1 hrs) petri plates (100 mm diameter) and were held for 20 minutes for solidification. Two wells of 8 mm radius were punched in each of these plates. The compositions taken in sterilized syringe were added into the agar well gently. One well contained ajowan oil composition and the other well contained the additive only composition. The experiments were performed in triplicates. All petri plates were incubated in incubator at 25±2°C for three to five days. Control containing only Sabaroud dextrose agar plates and Sabaroud dextrose agar plates with inoculum were run in parallel. After incubation, zones of inhibition were recorded with the help of calipers.
Result: Topical composition comprising ajowan oil showed strong zone of inhibition against all targeted bacterial and fungal pathogens in comparison to the additives containing composition without ajowan oil. Control plates containing only media did not show any microbial growth. Positive control plates containing media and inoculum showed luxuriant growth of respective pathogens. Therefore, on the basis of the present study, we can conclude that topical composition of ajowan oil has strong antibacterial and antifungal activity based on the zones of inhibition as evidenced from the above antimicrobial susceptibility tests.

WE CLAIM:
1) A topical composition comprising an effective amount of ajowan oil derived from the plant Trachyspermum ammi and one or more of suitable additives.
2) The topical composition according to Claim 1, wherein ajowan oil is present in a concentration of from about 0.5% to about 10% by weight of the total weight of the composition.
3) The topical composition according to Claim 1, wherein one or more of suitable additives are selected from bases, emulsifying/solubilizing agents, humectants, preservatives, cooling agents, fragrances and antioxidants as herein described.
4) The topical composition according to Claim 3, further comprising other antiseptic or antimicrobial agents.
5) The topical composition according to Claim 1, wherein the composition is in the form of a cream.
6) The topical composition according to Claim 1, comprising an effective amount of ajowan oil and as additives karanj oil, sesame oil, arlacel®165, cetostearyl alcohol, cetyl alcohol, arlamol, emulsifying wax, light liquid paraffin, propylene glycol, polyethylene glycol, glycerin, methyl paraben, propyl paraben, imidurea, boric oxide, zinc oxide, menthol and fragrance.
7) A process for the preparation of topical composition according to Claim 1;
wherein the process comprises the steps of:
- forming the first phase by heating the blend comprising of oily bases and emulsifying/solubilizing agents under constant homogenization;
- forming the aqueous phase by heating the blend comprising of water soluble additives with water by heating under constant homogenization;
- adding the first oil containing phase to the aqueous phase at a temperature of 50-80°C under constant homogenization;
- blending ajowan oil and one or more additives selected from preservatives, humectants, cooling agents and fragrances in one or more steps to obtain the final composition.
8) The topical composition and process for the preparation thereof substantially
as described and illustrated by the examples herein.