Bioavailability enhancement of poorly water-soluble drugs (BCS Class II and IV Drugs) using hot-melt extrusion (HME): The cost-effective approach
Enhancement of solubility of BCS class II and IV drugs is significantaly important to achieve their desired concentration in systemic circulation for pharmacological response. Solubility enhancement can be achieved by converting the poorly water-soluble crystalline form into a more soluble amorphous form within the polymeric blends. Among several methods, Hot Melt Extrusion (HME) is well accepted and extensively used in the pharmaceutical industry as a means of improving the bioavailability of drugs due to its wide applications, simple process and low costs. During the melt extrusion process, the dispersion of APIs into the polymer matrix is accelerated under the influence of shear and heat. Marketed formulations Norvir®, Kaletra®, Venclexta® and Onmel® which are prepared by HME technology, are the classical examples of bioavailability enhancement.
Poorly water-soluble drugs (BCS class II and IV) are usually characterized by a low bioavailability, which is a major concern of formulation scientist worldwide (1). The BCS classification is explained in figure 1.
Bioavailability of these drugs can be significantly improved by converting crystalline drugs into amorphous form using solid dispersions approach. Among the approaches of solid dispersion, hot melt extrusion (HME) has gained popularity in the pharmaceutical industry as a means of improving the bioavailability of drugs due to its wide applications, simple process and low costs (2). It is an excellent alternative to other conventionally available techniques such as roll spinning and spray drying as no solvents are required thereby reducing the number of processing steps and eliminating time-consuming drying steps. In particular this review article will describe HME technology for improvement of bioavailability of BCS class II and IV drugs by enhancing solubility.
OVERVIEW OF THE LITERATURE
Multiple publications are available for solubility and bioavailability enhancement of poorly w ...