Development of an Analytical Method for Spectrophotometric Estimation of Ketoprofen Using Mixed Co Solvency Approach

The present study demonstrates the use of mixed co solvency in the enhancement of solubility and estimation of ketoprofen, practically water insoluble dug and thus precludes the use of organic solvents. The selected solubilizers were sodium citrate (15%), PEG 400 (8%) and polyvinyl pyrolidine (7%). Beer’s law was obeyed in the concentration range of 2-20μg/ml at wavelength of 256nm. The solubility of ketoprofen was increased by 30 folds in the mixed cos-solvents as compared to distilled water. The recovery study revealed that any small change in the drug concentration in the solution could be accurately determined by the proposed method. The low values of LOD and LOQ indicated good sensitivity of proposed method. The study proved that mixed co-solvency phenomenon is an effective technique in enhancement of aqueous solubility of poorly water soluble drugs and can be successfully employed for estimation of drugs in routine analysis of tablets. INTRODUCTION: In the pharmaceutical formulation development most of the newly developed drug molecules are lipophilic in nature and poor aqueous solubility is one of the most difficult problems of this drugs . The analysis of these poorly water soluble drugs and insoluble drugs were carried out by spectrophotometric estimation using organic solvents like methanol, chloroform, ethanol, benzene, acetone, toluene, carbon tetrachloride, diethyl ether and acetonitrile . But the disadvantage of these organic solvents mentioned include costly, toxic and volatile in nature which would provide inaccuracy with the results . Several approaches have been proposed in literature to improve the aqueous solubility and hydrotropic solubilization is one of them . Various works have been reported on use of hydrotropic solvents in estimation of various lipophilic drugs . Hydrotropy is another type of co solvency and this gave a new concept a mixed-solvency concept that may be tried to observe the effect on solubility of poorly water soluble drugs. Few works based on this mixed co-solvency technique was reported to study the improvement in solubility by titrimetric estimation 13, . This mixed cosolvency technique is based on the principle that instead of using one solubilizer in large concentration for a desired level of solubility, several solubilizers like hydrotropes (sodium ascorbate, urea, sodium benzoate), co-solvents (propylene glycol, PEG 200, 300, 400) and water soluble solids (PEG 4000, 6000, cyclodextrins) in varying concentrations may be used that may show additive or synergistic enhancement in solubility. These solubilizers do not cause any toxicity and are non-volatile. Ketoprofen a propionic acid derivative that posses anti-inflammatory activity and hence used in the treatment of inflammation and pain associated with arthritis. Its molecular formula is C16H14O3. It is chemically (RS) 2-(3-benzoylphenyl)-propionic acid. It is practically insoluble in water, freely soluble in alcohol,