Formulation and evaluation of topical gels containing Phyllanthus muellerianus leaf extract using various gelling agents

Introduction: The high expense of current pharmaceuticals used to treat wounds, as well as some of their adverse effects, has spurred the quest for alternatives, particularly those derived from natural sources that have minimum side effects, less microbial susceptibility and are less expensive. Phyllanthus muellerianus leaf extract incorporated in creams and ointments greatly decreased wound closure time and increased epithelialization at the wound site. This study aims to formulate and evaluate a gel made from P. muellerianus. Methods: Leaves of P. muellerianus were extracted using water. Phytochemical screening for tannins, flavonoids, alkaloids and reducing sugars was performed on the extract. The water extract was used to formulate twenty gels with varying gelling agents. Physicochemical analysis, toxicity, wound healing and stability studies were performed on the gels. Results: The extraction of P. muellerianus leaves yielded 13.1 %w/w. Only tannins, glycosides, saponins, sterols and triterpenoids were present. P. muellerianus gels (1 %w/v) were formulated with five different concentrations of each of four different gelling agents. The gels had satisfactory physicochemical properties, and the microbial load and drug content were within the acceptable range for herbal formulations. There was no indication of chemical interactions between the extract, polymer, and other excipients in Fourier transform infrared spectroscopy investigations. There were no significant changes in the pH, spreadability, viscosity and drug content of the gels throughout the stability assay period. Dermal toxicity studies revealed that the P. muellerianus gels were not toxic to the skin (acute and repeated dose dermal toxicity tests). Wounds treated with formulations A4 and C5 showed significantly decreased wound area from the fifth day to day 15 post-injury compared to the positive and negative control groups, with an increased rate of re-epithelialization, fibroblast proliferation, collagen deposition and neovascularization. Conclusion: Ultimately, P. muellerianus gels (A4 and C5) showed tremendous wound healing activity, stability and safety.