Development and characterization of aloe vera–based herbal transdermal therapeutic systems for enhanced skin delivery

Transdermal drug delivery systems have become one of the new methods of enhancing the bioavailability and compliance of drugs in patients. The current research is dedicated to creating and testing herbal transdermal patches with Aloe vera extract by the solvent casting technique. Different polymers, such as hydroxypropyl methylcellulose (HPMC), polyvinyl alcohol (PVA), and chitosan were used to prepare various formulations with the help of appropriate plasticizers and permeation enhancers. The patches that were prepared were tested in terms of physicochemical parameters, i.e. thickness (0.21-0.29 mm), weight change (109-118 mg), folding strength (>250), surface pH (6.2-6.8), moisture content (3.8-5.1%), and uniform drug content (96.2-98.7%). The in vitro drug release test showed sustained release properties of up to 12 hours, with the highest release of the HPMC+PVA formulation (92.3%). The release kinetics was based on Higuchi diffusion model, which implies a controlled release of drugs. These findings indicate that the transdermal patches made of Aloe vera are a good platform of long-term drug delivery with a high degree of stability and adherence. The optimized formulation exhibited better performance of mechanical strength and drug release, which indicate its potentials in pharmaceutical use.