Topical antimicrobial gel with anacyclus pyrethrum ethanol extract

Abstract

A topical antimicrobial gel composition consisting of an ethanolic extract of Anacyclus pyrethrum roots dispersed in a Carbopol 940 hydrogel, propylene glycol, glycerin, methylparaben, triethanolamine and distilled water, wherein the composition is adjusted to a skin-compatible pH and configured to provide spreadable, homogeneous gel properties.

Description

AREA OF INVENTION

[0001] The invention relates to dermatological antimicrobial gel compositions containing plant ethanolic extracts embedded in Carbopol 940 gel matrices with humectants and preservatives, and intended for topical application against gram-positive and gram-negative bacteria. BACKGROUND OF THE INVENTION

[0002] Root extracts of Anacyclus pyrethrum (A. pyrethrum) contain bioactive components (e.g., alkylamides, sesquiterpenes) with proven antibacterial properties, although efficacy varies depending on the solvent, concentration, and strain tested. Several studies indicate inhibition of Staphylococcus aureus and other organisms at sufficient doses in agar diffusion and dilution tests. Topical gels based on Carbopol 940 are widely used due to their favorable rheology, spreadability, skin-friendly pH after neutralization with triethanolamine, and their ability to solubilize or disperse active ingredients with co-solvents such as propylene glycol and glycerin, while methylparaben or similar preservatives stabilize aqueous systems against microbial growth.Published reviews of gel formulations describe in detail pH adjustment, spreadability measurement, homogeneity, and stability at various storage temperatures as standard quality characteristics for dermatological gels, thus supporting robust product development and evaluation of herbal active ingredients. A defined composition combining ethanolic A. pyrethrum root extract with a Carbopol 940 base and excipients, exhibiting antimicrobial inhibition zones in agar-well diffusion against S. aureus and Salmonella species, as well as stable physicochemical properties, offers a cost-effective, user-friendly, natural topical option. SUMMARY OF THE INVENTION

[0003] The invention relates to a topical antimicrobial gel composition consisting of an ethanolic extract of A. pyrethrum roots dispersed in a Carbopol 940 hydrogel with propylene glycol, glycerin, methylparaben, triethanolamine, and purified water. The pH of the composition is adjusted for skin compatibility and optimized for spreadability and homogeneity. The composition exhibits antimicrobial activity in vitro, including the inhibition of Staphylococcus aureus and Salmonella typhi by agar-well diffusion test, and retains its stability (pH, viscosity, appearance) under ambient conditions and accelerated storage.In preferred embodiments, the concentration of the ethanolic extract, the ratio of the co-solvents, and the gel polymer content are adjusted to maximize the bioavailability of the phytochemicals while maintaining gel clarity and sensory properties for the user. The preservation system ensures product integrity throughout the entire expected shelf life. DETAILED DESCRIPTION

[0004] The active ingredient is an ethanolic extract from Anacyclus pyrethrum roots, produced by maceration or Soxhlet extraction with ethanol and subsequent concentration under reduced pressure to achieve a defined phytochemical profile. The literature reports antibacterial effects of Anacyclus extracts, with solvent and concentration influencing the zones of inhibition, particularly against Staphylococcus aureus in diffusion tests. The gel base consists of approximately 0.5–2.0% (w / w) Carbopol 940, hydrated in distilled water and neutralized with triethanolamine for gelation and adjustment to a skin-compatible pH (approximately 4.5–6.5). The pH affects the viscosity, spreadability, and stability of Carbopol gels. Propylene glycol and glycerin serve as co-solvents and humectants to improve the solubility and skin feel of the plant extract and to promote the distribution of hydrophobic and hydrophilic components in the gel matrix.Methylparaben provides antimicrobial preservation compatible with topical gel applications. The ethanolic extract is incorporated by pre-dissolving it in a portion of the propylene glycol and gradually adding it to the neutralized gel while stirring to ensure uniform dispersion without phase separation. The finished gel is degassed, filled into containers, and sealed. Quality characteristics include pH (skin compatibility), viscosity (application stability), spreadability (ease of application, measured using the glass slide method), and homogeneity (absence of particles / phase separation), according to established evaluation protocols for Carbopol gels. Antimicrobial activity is investigated in vitro using an agar well diffusion test against test strains. Previous studies have shown that extracts from A. pyrethrum produce zones of inhibition against S. aureus, with the MIC / MBC depending on the concentration and solvent.This aids in selecting the extract quantity to achieve measurable activity. Complementary studies have demonstrated antibacterial activity in other extracts and formulations. Stability studies evaluate appearance, pH, viscosity, and retention of activity at room temperature and elevated temperatures to confirm robustness. Studies on plant-based gels demonstrate formulation strategies that ensure stability and release properties over extended periods. The formulation avoids sensitizing excipients that exceed typical topical thresholds and aims for favorable sensory properties (non-greasy, rapid absorption). The packaging protects against light and evaporation; chelating agents or antioxidants can be added optionally to protect labile phytochemicals. The gel is applied to affected skin areas for antimicrobial action.While in vitro tests guide the development, further clinical studies will determine the therapeutic indications and labeling according to the usual translation pathways for natural products.

Claims

[1] A topical antimicrobial gel composition consisting of an ethanolic extract of Anacyclus pyrethrum roots dispersed in a Carbopol 940 hydrogel, propylene glycol, glycerin, methylparaben, triethanolamine and distilled water, wherein the composition is adjusted to a skin-compatible pH and configured to provide spreadable, homogeneous gel properties. [2] Composition according to claim 1, wherein the concentration of the ethanolic extract and the co-solvent propylene glycol are selected such that in vitro inhibition of Staphylococcus aureus and Salmonella strains in agar well diffusion is achieved, while maintaining gel stability and clarity during storage. [3] Composition according to claim 1 or 2, wherein the Carbopol 940 content is between about 0.5% and 2.0% (w / w) and the triethanolamine neutralization results in a pH between about 4.5 and 6.5 to balance viscosity, spreadability and drug release properties. [4] Composition according to any of the preceding claims, wherein the gel has a stable pH, a stable viscosity and a stable homogeneity under ambient conditions and during accelerated storage, and contains the preservative methylparaben in an amount that is effective to maintain the microbiological quality throughout the entire shelf life.