A Novel Rp-Hplc Method for Simultaneous Estimation of Dorzolamide and Timolol Maleate in Ophthalmic Products

This research introduces an RP-HPLC method to estimate dorzolamide and timolol maleate quantitatively in the simultaneous mode. The stationary phase has consisted of A phenomenix^® C18 column which gave satisfactory separation of these drugs when subjected to analysis, where in the mobile phase is composed of Acetonitrile:Buffer (20:80,v/v). The instrument was set up as such that the pump draws mobile phase at a flow rate of 1.0 mL/min and monitored at 290nm wavelength. Linear relationship of concentration of drugs vs. peak area was ascertained to assess linearity parameters and a correlation coefficient of more than 0.9995 for all the drugs was achieved when studied in a range of 10 to 1000 ug/mL. The newly developed method showed high accuracy and precision with a percent recovery of 98.85% – 101.23% and a percent relief standard deviation of 0.5 – 1.7 %. The optimized method was validated according to the guideline laid down by ICH and was successfully applied to quantitate both the drugs in bulk, raw material, eye drops formulation and in physiological fluids.