Methodological advances in formulation and assay of herbal resources-based topical drug delivery systems.

Medicinal plants have been utilized for centuries as a source of healing compounds, which consist of thousands of known bioactive molecules with therapeutic potentials. This article aims to explore and emphasize the significance of medicinal plants and bioactive compounds in the development of topical pharmaceutical formulations. The journey from the extraction of phytochemicals to the development of topical pharmaceutical formulations is described with the aid of scientific evidence selected from PubMed, Google Scholar, ScienceDirect, and Web of Science. Articles published in English during 2018-2023 period were considered and selected randomly. The review discusses the extraction process of medicinal plants, solvent selection, and green synthesis of metal nanoparticles. Subsequently, various biological activities of plant extracts are elaborated especially focusing on antimicrobial, antioxidant, anti-inflammatory, and sun protection activities, along with the corresponding in vitro assays commonly employed for the evaluation. The article presents the process of compound isolation through bioactivity-guided fractionation and also the toxicity evaluation of isolated fractions. Finally, the formulation of medicinal plant extracts into topical pharmaceuticals is addressed, emphasizing the stability evaluation procedures necessary for ensuring product quality and efficacy.