[18] Literature survey revealed that there are many developed methods on UV,[19�C23] HPTLC,[24,25] HPLC,[26�C31] for estimation of METO single as well as in combination. However, there have been no reports check this concerning the simultaneous determination of (Figure 1) and (Figure 2) TELMI by absorbance correction method. These method was developed and validated as per International Conference on Harmonization (ICH) guidelines.[32]. Figure 1 Chemical structure of Metoprolol succinate (METO) Figure 2 Chemical Structure of Telmisartan (TELM) MATERIALS AND METHODS Apparatus A shimadzu model 1800 (SHIMADZU CORPORATION, International Marketing Division, Japan) double beam UV/Visible spectrophotometer with spectral width of 2 nm, wavelength accuracy of 0.5 nm and a pair of 10 mm matched quartz cell was used to measure absorbance of all the solutions.

Spectra were automatically obtained by UV-Probe system software (UV Probe version 2.31). Digital balance Acculab (ALC 210.4) and Sonicator Eneritech (Ultra Sonicator) was used in the study. Material Active pharmaceutical ingredient of TELM and METO were supplied by Zydus Cadila Healthcare Ltd., Ahmedabad, Gujarat, India. Marketed formulation TELSAR BETA (UNICHEM LABORATORIES, India) contains TELM IP 40 mg and METO USP 50 mg. Other formulation Telmaxx 50 (GLENMARK pharmaceutical Ltd., Mumbai) was purchased from an open market for this study which contains TELM IP 40 mg and METO USP 50 mg [Table 3]. Table 3 Analysis of TELM and METO by proposed method Reagent and chemical Methanol was used as a solvent which was procured from Finar Chemicals Ltd.

, Ahmedabad, India. Double distilled water was used throughout the analysis. Preparation of standard stock solution An accurately weighed quantity of TELM (10 mg) and METO (10 mg) were transferred to a separate 100 ml volumetric flask and dissolved and diluted to the mark with methanol to obtain standard solution having concentration of TELM (100 ��g/ml) and METO (100 ��g/ml). Absorbance correction method The value of ��max of was determined by scanning the drug solution in the range 200-400nm at 0.5 band width and 600 nm/min scan speed and was found to be at 296 nm and 223 nm, respectively. TELM also showed absorbance at 223 nm, while METO did not show any interference at 296 nm. [Figure 3] To construct Beer’s plot for TELM and METO, stock solutions of both the drugs were prepared in methanol [100 ��g/ml]. Also Beer’s plot was constructed for TELM and METO in solution mixture at different concentration. Both the drugs followed linearity individually in TELM (2, 4, 6, 8, 10, 12, 14, 16 ��g/ml) and METO (3, 6, 9, 12, 15, 18, 21, 24 ��g/ml) and in mixture with the concentration range TELM:METO are (1:1.25, 2:2.5, 3:3.75, 4:5, 5:6.25, GSK-3 6:7.5, 7:8.75 ��g/ml).