Boswellic Acid Loaded Nanoemulsion Gel For Arthritis: Formulation, Characterization And In Vivo Evaluation
Boswellic acid (BA) is resinous gum exudate from Boswellia serrata which is chemically triterpenoic acid responsible for anti-inflammatory activity and is listed in Indian Ayurvedic medicine . Traditionally it is used in conditions like pulmonary disease, diarrhea, dysentery and arthritis. More pronounced anti-inflammatory activity has been reported in 11-keto-β-boswellic acid (KBA) and 3-acetyl-11-keto-β-boswellic acid (AKBA). They are non-competitive, non-redox and selective inhibitors of 5-lipoxygenase, which is the key enzyme of leukotriene biosynthesis in arachidonic acid metabolism.
Chemical structure of a) 11-keto-β-Boswellic acid b) 3-Acetyl-11-keto-β-boswellic acid.
The present study aimed to investigate the anti-arthritic potential of boswellic acid loaded nanoemulsion gel topically. An o/w nanoemulsion (NE) was formulated by water titration method comprising boswellic acid (BA) as drug dissolved in isopropyl myristate (oil phase), Tween 80 as surfactant and labrasol as cosurfactant. The formulation with maximum physical and thermodynamic stability was selected and characterized for particle size, zeta potential and surface morphology using Malvern zeta sizer and Transmission electron microscopy (TEM). The formulation (BA-NE) with an average particle size of 22.93 ± 1.12nm and zeta potential of -32.4 ± 1.20mV, was converted to nanoemulsion gel (BA-NEG) using carbopol 980 (1% w/v) and subjected to in vivo evaluation on Freund's complete adjuvant induced arthritic rat model. The Arthritic index of BA-NEG treated group on day 28 was 55.29 ± 2.81and Inhibition rate on day 28 was 76.46 ± 5.48%, which were significantly higher than both standard (P < 0.05) and boswellic acid crude gel (P < 0.01) treatments. The reduction in cytokines in BA-NEG treated group was significant as compared control (P < 0.05). Thus causing a substantial reversal of arthritic symptoms.
References:  K.R. Kirtikar, B.D. Basu, (1935) Indian Medicinal Plants, M/s Periodical Experts, Delhi, India.