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tio to form an intense yeltowish green complex (plausibfy 1!) showing A,,,, at 360 nm has been made basis of the method, 2C,,H,,N,0,S.Na+Co*" >[(C,,H,,N,O,5),CoJ(I+2 Na* for the sub-milligram level determination of the drug compound. Photometrio titration of the drug compound with cobait(II) are marked by a well-defined intersection at drug to reagent molar ratio of 2:1 in the form of an inverted L-shaped titra- tion curve. It may be mentioned that the formation o! above type of complex (15), as a result of the reaction of thiobarbituesic acid and related compounds such as thioureas with metal ¡ons like cobalt (11) and copper Qi) through coordination with sulphur atoms, is well known"%2, Further, these compounds as such are weak nucleophiles and their complexes with metal ions are not formed readily, triethylamine (a base) activates them by abstracting hydro- geri from thiol sulphur thus making them strong nucleophiles. With this method, thiopentone sodium in the range 0.1-0.5 mg could be determined with a maximum RSD of 0.7%. The Recoveries of active ingredient content from drug formuta- tion were in the range 99.0-99.6% with ASD's in the range 0.3-0.7% (Table Y). The proposed photometric titration methods besídes being simple, are more sensitive than pharmacopoeic method!, The excellent solution stability af the reagents and that of colour as well as well-established stoichiometries of the colour reactions involved are other attractive features of the proposed methods, REFERENCES 1. Pharmacopoeia of india, 3rd Edn., Vol. I!, Controller of Publica- tíons, Delhi, 1985, 517. 2. Connors, K.A., ln; Higuchi, T. and Hanssen, E.8. Eds., Pharma- ceutica) Analysis, 1st Indian Edn., CBS Publishers and Distribu- tors, Now Delhi, 1997, 232, 3. Atherden, L.M., in; Bentley and Drivers Text book of Pharma- ceutica! Chemistry, 11th Indian Edn., Oxford University Press, New Delhi, 1994, 670, 4. — Jogolankar, D.M., Kankute, S.D., Kamble, V.W.and Garad, M.V., y. Planar Chromatogr., 1997, 10, 133. 5. Ali, AM.M,, Farghaly, O.A, and Ghandour, M.A,, Anal. Chim, Acta., 2000, 412, 99. 6. — Sharma, D.K,, Sambra, B.5., Verma, N. and Verma, B.C., Col- lect. Czech. Chem. Commaun., 1997, 62, 42 7. Vogel, A.l, In; A Text book of Quantitative Inorganic Analysis, 3rd Edn., The ELBS and Longman, London, 1975, 443. 8. Verma, B.C., Sood, R.K. and Sidhu, H.S., Tatanta, 1983, 30, 787. 9. Reid, E.£., In; Organic Chemistry of Bivalent Sulphur, Vol, IV, Chemical Publishing Co., New York, 1970, 178, 10. Prabhakar, L.O., Umarani, C., Thanikachalam,V. and Palanivelu, C.B., Indian y, Chem., 1992, 31, 704. 11. Bailar, J.C., Emeleus, H.J., Nylohm, S.A. and Trotman-Dickenson, A.F., Eds., Comprehensive Inorganic ChemistryVol. 3, Pergaman Press, New York, 1973, 1083. 12. Karchmer, J.H., in; The Analytical Chemistry of Sulphur and its Compounds, Part 1I, Wiley Interscience, New York, 1970, 670. Simultaneous Spectrophotometric Estimation of Ibuprofen and Methocarbamal in Tablet Dosage Form 7. R. S. SATHEESHMANIKANDAN, DEEPA C. WALI, J. BARIWAL, S. S. KADAM AND S. R. DIANESHWAR* Bharati Vidyapeeth Deemed University, Poona College of Pharmacy, Erandwane, Pune-411 038 Accepted 24 November 2004 Revised 4 June 2004 Received 5 May 2003 Two simple economical procedures for simultaneous estimation of ibuprofen and methocarbamol in two-component tablet formulation have been developed, The method employs Q-analysis and two-wavelength method. Ibuproten has absorbance at 222 nm and-methocarbamo!l has absaor- *For correspondence E-mail: srdhaneswarO hotmail.com 810 Indian Journal of Pharmaceutica! Sciences bance maxima at 224 nm and 272 nm. The isoabsorptive point of ibuprofen and methocarbamol was tound to be 231,4 nm. Both November - December 2004 
