Varshney, H. M. , Chatterjee, A.
ABSTRACT
Therapeutic effectiveness of a drug depends upon the bioavailability and ultimately upon the solubility of drug molecules. In case of the oral administration solubility is one of the important parameter for achieving desired concentration of drug in systemic circulation for pharmacological response to be shown. Currently, 40% of the drugs are poorly water soluble which produce side effects such as gastric irritation, peptic ulceration etc. whereas only 8% of new drug candidates have shown both high solubility and permeability. Dissolution rate, absorption, distribution and excretion of a moiety depend upon its solubility characteristics. On the basis of solubility, drugs are classified into four classes of the BCS classification. Solubility challenges are faced in the Class II and Class IV of the BCS system (where dissolution becomes the rate limiting step for the absorption of drug) which comprises of newer generation of NSAIDs like Zaltoprofen, Aceclofenac, Flurbiprofen, their older congeners like Indomethacin, Ibuprofen, Ketoprofen and Diclofenac; anti-diabetics Gliclazide, Glipizide ; newer calcium channel blockers (CCBs) like Nimodipine, Felodipine. Till date various methods of ameliorating the solubility has been suggested, current write up is devoted to the novel methods introduced in recent times wiz. hydrotropy, sono crystallization, hot melt extrusion technique, steam aided granulation, floating granulation, dried nano suspensions, spherical agglomeration, liquisolid technology, cryo techniques .
Keywords: Bioavailability, Solubility enhancement, Novel methods, Dissolution Characteristics.