Solubility enhancement of Boswellia serrata Roxb. ex Colebr. extract through a self dispersible lipidic formulation approach

Abstract

Boswellic acids (BAs) are isolated from oleo gum resin of Boswellia serrata Roxb. ex Colebr. and are reported to have anti-inflammatory, immunomodulatory and anti-tumor activity with better tolerance and lesser side effects compared to NSAIDs. Pharmacokinetic studies of BAs revealed its poor absorption through oral route due to poor solubility. The present study was aimed to develop and characterize a lipid based drug delivery system of Boswellia serrata extract (BSE) to enhance the solubility and in turn, the oral absorption of BAs. Suitable compositions for lipidic formulation were screened via solubility and compatibility studies. Pseudoternary phase diagrams were used to evaluate the microemulsion existence area. The self microemulsifying drug delivery system (SMEDDS) was characterized by solubility, clarity, drug precipitation, globule size, emulsification time and drug release profile. The optimal formulation of SMEDDS comprised of 37.5 % Tween-80, 12.5 % PEG-400 and 50 % oil (Caprylic/capric triglycerides). The dissolution study in hydrochloric acid buffer pH 1.2 showed significantly improved dissolution of BSE-SMEDDS (>90 %) compared to Plain BSE (practically no release) in 120 minutes. BSE-SMEDDS showed better anti-inflammatory activity than plain BSE in a carrageenan-induced rat paw edema model. The developed formulation was found to have better solubility and can be used as a possible alternative to traditional oral formulations of BSE with potential applications.