Context: The oleo-gum-resin of Boswellia serrata Roxb. (Burseraceae) is widely used for the treatment of inflammatory diseases such as osteoarthritis, rheumatoid arthritis and cancer. Anti-inflammatory activity of 11-keto-β-boswellic acid (KBA) is impeded by poor oral bioavailability due to its high lipid solubility, rapid phase-1 metabolism and poor intestinal permeability.
Objective: This study developed a poly-dl-lactide-co-glycolide-based nanoparticle formulation of KBA to improve its oral bioavailability and in vivo anti-inflammatory activity.
Materials and methods: KBA was isolated from the oleo-gum resin of B. serrata, and its nanoparticle formulation (KBA-NPs) was prepared by the emulsion-diffusion-evaporation method. Oral bioavailability of KBA and KBA-NPs was studied at 50 mg/kg p.o. dose in Sprague-Dawley rats, and further evaluated for in vivo anti-inflammatory activity in carrageenan-induced rat paw oedema assay at the same dose level.
Results: The prepared KBA-NPs had a particle size of 152.6 nm with polydispersity index of 0.194, 79.7% entrapment efficiency and a cumulative 61.5% release of KBA from KBA-NPs, at 72 h. KBA-NPs showed 60.8% inhibition of rat paw oedema at 5 h as compared to 34.9% as that of KBA. The results of oral bioavailability study and in vivo anti-inflammatory activity showed 7- and 1.7-fold increase in bioavailability and anti-inflammatory activity, respectively, of KBA in KBA-NPs as compared to KBA alone.
Conclusion: The results of improved oral bioavailability and in vivo anti-inflammatory activity of KBA-NPs suggested successful development of KBA nanoparticle formulation.
Keywords: Boswellia serrata; PLGA-based nanoparticles; in vitro drug release; oral bioavailability.