European Journal of Biomedical and Pharmaceutical Sciences

BCS CLASSIFICATION AND SOLUBILITY ENHANCEMENT TECHNIQUES FOR BCS CLASS II AND BCS CLASS IV DRUGS

Dr. Hitesh D. Karen, Dr. P. H. Prajapti and Jignesh I. Chaudhary*

ABSTRACT

The BCS is a scientific system for classifying drug substance based upon their aqueous solubility as related to dose and permeability. The BCS is guiding for prediction of in vivo performance of the drug substance in new drug discovery and lead optimization due to the dependence of drug absorption and pharmacokinetics properties. The solubility behavior of drugs remains one of the most challenging in formulation development. Due to poor aqueous solubility of BCS Class II result in the poor oral bioavailability makes drug formulation development more difficult. Hence, various approaches have been developed with a focus on enhancement of the solubility, dissolution rate, and oral bioavailability of poorly water-soluble drugs. Present article overviews the concept of Biopharmaceutical classification systems (BCS), Biopharmaceutical Drug Disposition Classification System (BDDCS) & recent classification for solubility enhancement of poorly water soluble drugs. The article also reviews various efforts taken for solubility enhancement using various techniques. Solubility, the phenomenon of dissolution of solute in solvent to give a homogenous system, is one of the important parameters to achieve desired concentration of drug in systemic circulation for desired (anticipated) pharmacological response. Low aqueous solubility is the major problem encountered with formulation development of new chemical entities as well as for the generic development. More than 40% NCEs (new chemical entities) developed in pharmaceutical industry are practically insoluble in water. Solubility is a major challenge for formulation scientist. Any drug to be absorbed must be present in the form of solution at the site of absorption. Various techniques are used for the enhancement of the solubility of poorly soluble drugs which include physical and chemical modifications of drug and other methods like particle size reduction, crystal engineering, salt formation, and solid dispersion, use of surfactant, complexation, and so forth. Selection of solubility improving method depends on drug property, site of absorption, and required dosage form characteristics.

Keywords: Poor solubility; bioavailability Formulation Development, solid dispersion, BCS Class II Drug, BCS Class IV Drug, Amorphous solid dispersion, Freeze-drying; Solid phospholipid nanoparticles; Solubility; Spray-drying.