Preparation and characterisation of atorvastatin calcium loaded nanogel as topical gel-based formulation

Abstract

Atorvastatin calcium suffers from poor bioavailability due to its low water solubility and extensive first-pass metabolism. To overcome these limitations, Atorvastatin calcium nanogels were developed to enhance solubility, promote controlled drug release, and improve wound-healing efficacy through localized delivery. Nanocrystals were prepared using a 2³ factorial design via the solvent–antisolvent precipitation method, optimizing factors such as stabilizer (Pluronic F-127), solvent–antisolvent ratio, and stirring time. The optimized nanosuspension (F8) was incorporated into an aloe vera–carbopol gel to form a nanogel, which was evaluated for physicochemical and rheological properties, pH, moisture content, spreadability, stability, and permeability in an ex vivo model. The formulated nanogel exhibited clear appearance, smooth texture, and a pH of 6.5, ensuring skin compatibility without irritation. It demonstrated high viscosity (8500 cp), ensuring good adherence at the application site. Compared to the pure drug and conventional gel, the nanogel showed significantly higher saturation solubility and enhanced drug permeation, releasing 400 ± 18 µg/cm² over 24 hours versus 50 ± 8 µg/cm² for the control. Stability studies confirmed no notable changes after 90 days of storage. Overall, the Atorvastatin calcium nanogel exhibited sustained drug release, improved therapeutic performance, and superior patient compliance due to its non-greasy, transparent, and easily applicable nature.