Natural Bioenhancers: Current Outlook

Abstract

Pharmaceutical companies around the globe have always been in the urge of discovering innovative blockbuster drugs for various ailments by spending billions of dollars for the drug discovery programmes. Although identification of new chemical entities (NCEs) with alternate mode of actions for diseases is a primary concern for the pharmaceutical companies, application of innovative techniques and technologies to increase the bioavailability, efficacy and safety of the already existing drugs are of no less concern as well. In fact, enhancing bioavailability of therapeutically potent but poorly bioavailable molecules has always been a crucial aspect of drug development programmes, as it reduces the drug dosage and frequency resulting in reduced toxicity and cost for the patients [1]. Among the various factors responsible for poor bioavailability of drugs, physiochemical properties of the drug itself and biological barriers are two predominant factors [2]. While physicochemical properties of the drug include poor aqueous solubility, poor intestinal membrane permeability, and poor stability of drug in gastrointestinal tract (GIT), biological barrier constitutes hepatic and intestinal drug metabolizing enzymes (DMEs) and efflux drug transporters (EDTs). The metabolism of drugs by cytochrome P450 (CYP) DMEs in the gut wall and in the liver is the major contributors of reduced bioavailability of drugs that are substrate to these DMEs [3]. In addition to this, EDTs such as P-glycoprotein (P-gp), breast cancer resistant protein (BCRP), multidrug resistant-associated protein (MRP) are also responsible for reduced bioavailability of the therapeutically active drugs, especially anticancer drugs [3].