Chitosan-grafted microspherical loaded In-situ gels for enhanced transdermal delivery of roxithromycin: In-vitro/Ex-vivo assessment

In a day-to--to-day life, everyone faces different kinds of dermal diseases, the only cure by conventional dosage forms having a high rate of side effects. This is a better and alternative approach in case of patients’ compliance and sustained drug release. To prepare solid dispersion for enhancement of solubility of roxithromycin and encapsulate solid dispersion into microspheres to decrease dose frequency and sustained release and incorporation of microspheres in situ gel for easy to utilize and adhere over the skin in microbial infection. Solid dispersion roxithromycin and HPMC at a ratio of 1:1 was prepared by melting method, and solubility was measured by in vitro dissolution rate. On the basis of 3² factorial design, 9 different formulations were evaluated by % drug release, particle size, and % entrapment efficiency. Lastly in situ gel was prepared by a cold method which evaluated through gelling time and temperature; in vitro gelation method. The solid dispersion found 1.3 times higher solubility than pure roxithromycin proved by in vitro drug release. Whereas, microsphere MF-9 selected as the best formulation via drug release (87.81%), entrapment efficiency (91.223%), % yield (86.681), and particle size (110µm). In-situ gel MIG-5 selected as the best formulation on the basis of drug content (89.326±0.564), viscosity (9551.666±6.233), and gelling time (25.333±2.054). Solid dispersion was prepared successfully with higher solubility than the pure drug. Microspheres have shown sustained drug release and in situ gels have a good adhesive property and MIG-5 further enhances the sustained drug release behaviour.