Enhancement of Solubility of Poorly Water Soluble Drugs Diclofenac Sodium by Mixed Solvency Approach

Enhancement of solubility is one of the difficult tasks which become challenges in formulation development of orally administered drug with poor aqueous solubility. Poor water solubility of drugs often causes significant problems in producing formulations of sufficiently high bioavailability, preventing effective use of the drugs. 'Mixed-solvency ' concept is the phenomenon to increase the solubility of poorly water-soluble drugs in the aqueous solution containing blends of hydrotropic agents, co-solvents and water soluble solutes which may give synergistic enhancement effect on solubility of such drugs. In the present investigation , mixed solvency approach has been applied for the enhancement of aqueous solubility of a poorly watersoluble drugs diclofenec sodium (selected as a model drug), by making blends of randomly selected water-soluble substances from among the hydrotropic (urea, sodium acetate); water soluble solutes (PEG4000, PEG6000); and co-solvents (PEG200, PEG400). The aqueous solubility of diclofenac sodium was observed at room temperature in the randomly selected blends of solubilizers containing different combinations keeping total concentration 50%w/v constant. Diclofenec sodium have λmax 276 nm and obeys Beers Law in concentration range of 10-60 μg/ml. The results suggest that solubility of the diclofenac sodium containing blends of varying combinations was enhanced significantly using mixed solvency approach.