DEVELOPMENT, CHARACTERISATION, AND IN-VITRO RELEASE OF ARJUNA BARK EXTRACT LOADED MICROEMULSION FOR POTENTIAL BIOMEDICAL APPLICATIONS

ABSTRACTThe study focuses on the formulation and characterization of a microemulsion system using Arjuna bark extractas the active pharmaceutical ingredient. The extract, known for its medicinal properties, was obtained throughmaceration, yielding 11% w/w. Pre-formulation studies revealed that Arjuna bark extract is reddish-brown with amelting point of 270-300°C, UV absorption maxima at 276 nm, and solubility properties indicating highersolubility in methanol compared to other solvents. The partition coefficient showed hydrophilic tendencies. Toconstruct a microemulsion system, castor oil was utilized as the oil phase, Span-60 as the surfactant, and Tween-80 as the co-surfactant.Particle size, drug entrapment efficiency, oil concentration, and surfactant concentrationwere among the characteristics used to optimize the formulation. Castor oil at 2.5% concentration yielded the bestresults, achieving high drug entrapment efficiency (58±0.03%) and an optimal particle size (115±0.04 nm). Theuse of Span-60 at 3% concentration ensured better stability and minimized droplet agglomeration.Characterization studies, including FTIR analysis, confirmed the stability of the drug-excipient mixture. TEMimages showed that the microemulsions had discrete, spherical particles. Drug release experiments conducted invitro showed biphasic release behavior. Formulation F5 had the best drug release profile, with a cumulativerelease of 87.29±0.23% over 12 hours. Drug release kinetics followed zero-order release with super case IItransport, indicating that drug release was regulated by concentration of lipid used. Studies of stability conductedover a period of 60 days demonstrated that the optimized formulation F5 was stable at different temperatures withnegligible variations in particle size and entrapment efficiency. The microemulsion showed potential as aneffective drug delivery system for Arjuna bark extract, providing controlled release and ensuring the stability ofthe drug. This formulation can be further explored for therapeutic applications.