INTRODUCTION- The mixed solvency concept can serve as a milestone for solubility enhancement and therefore deserves an urgent attention of the scientic community to assess its efciency and applicability. According to Maheshwari, each and every substance present on earth possesses solubilizing power be it a solid, liquid or gas. Some substances are good solvent for some and at the same time bad solvent for others. OBJECTIVE- The main objective of present research is to show that solids also possess solubilizing power. In the present research, melted dimethyl urea (at 135�C) was employed for dissolution of indomethacin without using any organic solvents (therefore eco-friendly method). MATERIALS AND METHOD- Indomethacin API was generous gift from M/S Alkem Laboratories Ltd.,Mumbai. Indomethacin tablets were procured from the local market. All other chemicals were of analytical grade.The instrument used was Shimadzu UV- Visible spectrophotometer (model UV-160A) with 1 cm matched silica cells. EXPERIMENTAL METHODS- SOLUBILITY STUDIES- The solubility of indomethacin at roomtemperature was found to be 0.36 mg/ml. Using approximate method of solubility determination, it was found that more than 800 mg indomethacin was dissolved by one gram of melted dimethyl urea(at 104 °C). CALIBRATION CURVE- 10gm dimethyl urea was taken in a 500ml volumetric ask and it was heated carefully on heating mantle. As soon as dimethyl urea was melted, 50 mg of standard sample of indomethacin was added and the ask was shaken to dissolve the drug. Intermittent heating and shaking was done for complete dissolution of drug. Then, 400 ml of hot distilled water (90� C) was transferred carefully (little at a time) to the volumetric ask and the contents are shaken for about 5 minutes. Then, the ask was allowed to cool to attain the room temperature. Then, the volume was made up 500ml with distilled water. This was the stock solution of drug (100µg/ml),by appropriate dilution of this stock solution with distilled water, standard solutions of the drug (5,10,15,20,25µg/ml) were prepared and their absorbance were noted at 265 nm against the respective reagent blanks and using these values, the calibration curve was obtained. PROPOSED METHOD- 20 tablets of nalidixic acid, formulation I were weighed and crushed to get a ne powder. 10gms of dimethyl urea was kept in a 500ml volumetric ask and the ask was carefully heated on heating mantle to melt the dimethyl urea. After complete melting of dimethyl urea, tablet powderequivalent to 50mg of drug was transferred to the ask and the ask was shaken for 10 minutes with intermittent heating and shaking. Then, 400ml of hot (90� C) distilled water was carefully (little at a time) added to the ask and the ask was shaken for about 5 minutes. Then, the ask was allowed to cool to attain room temperature and the volume was made up to mark with distilled water. After ltration through Whatmanlter paper no.41, 5ml ltrate was diluted to 50ml with distilled water and the absorbance was noted at 265 nm against reagent blank. Using calibration curve the drug content was computed. Similar treatment was done for formulation II. All analyses were performed thrice. RECOVERY STUDIES- Recovery studies taking 15 mg and 30 mg of pure drug as spiked drug together with pre-analysed tablet powder (equivalent to 50 mg) were performed using the same proposed method. RESULTS AND DISCUSSION- The aqueous solubility of indomethacin at room temperature was 0.36 mg/ml whereas the solubility of indomethacin in melted dimethyl urea was found to be 83.33mg per gram of melted dimethyl urea at 104 °C. It is evident from Table I that the percent drug estimated in formulation I and II were 99.33 ± 1.112 and 98.07 ± 1.843, respectively. The values are very close to 100, indicating accuracy and precision of the proposed method. Further, Table II shows that the range of percent recoveries varied from 98.96 ± 0.854 to 100.95 ± 1.557which are again very close to 100, indicating the accuracy of the proposed method. Proposed analytical technique is supported signicantly by small values of SOLID AS SOLVENT - MELTED DIMETHYL UREA AS SOLVENT TO ANALYSE INDOMETHACIN CAPSULES SPECTROPHOTOMETRICALLY AT 265 NM (MIXED SOLVENCY CONCEPT) Original Research Paper Maheshwari R. K Department Of Pharmacy, Shri G.S Institute Of Technology And Science, Indore, India- 452003 Engineering In the current attempt of research, novel method for spectrophotometric estimation of indomethacin in capsules using melted dimethyl urea as solvent was developed. The main objective behind research is to show “SOLIDS ALSO POSSESS SOLUBILIZING POWER”. The current study deals with novel spectrophotometric analytical technique for quantitative estimation of indomethacin in capsules using melted dimethyl urea as solvent. According to the theory proposed byMaheshwari, each& every substance possessessolubilising power, susbstance may be a gas, solid or liquid. Dimethyl ureaimbibes large solubilizing power to indomethacin and having approximate solubility more than 800 mg per gm of melted dimethyl urea whereas aqueous solubility of indomethacin is 0.36 mg/ml at room temperature. Calibration curve of indomethacin was plotted by recording the absorbances of standard solutions of drug. The absorbances were observed at 265 nm against respective reagent blanks.The percent label claims were found very close to 100 (99.33 ± 1.112 and 98.07 ± 1.843) indicating accuracy of the proposed method.Percent recoveries estimated by the proposed method are close to 100 with signicant low values of percentage deviation and standard error.Thus, it may be concluded that proposed method is simple, safe and precise and excludes use of toxic organic solvents. ABSTRACT KEYWORDS : Mixed Solvency, Solubilizing Power, Spectrophotometric Analysis, Niacinamide, Nalidixic Acid. Padiyar. A* Department Of Pharmacy, Shri G.S Institute Of Technology And Science, Indore, India- 452003 *Corresponding Author VOLUME-8, ISSUE-12, DECEMBER-2019 • PRINT ISSN No. 2277 - 8160 • DOI : 10.36106/gjra 20 X GJRA - GLOBAL JOURNAL FOR RESEARCH ANALYSIS CONCLUSION- The mixed solvency concept can be successfully employed in analytical estimation of various drugs. 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