Synchronized Separation of Timolol from Some Prostaglandin Analogs (Bimatoprost, Latanoprost and Travoprost) for Determination in their Combined Pharmaceutical Formulations Using RP-HPLC

Abstract

A rapid, precise and selective RP-LC method was developed for the simultaneous determination of the well-known beta blocker, Timolol (TIM), along with some of the most commonly prescribed prostaglandin analogues, namely; Bimatoprost (BIM), Latanoprost (LAT) and Travoprost (TRV), in laboratory prepared mixtures and in their combined pharmaceutical formulations. The chromatographic separation was carried out using gradient elution mode with a mobile phase consisting of 25 mM phosphate buffer (pH 3 ± 0.1), acetonitrile and methanol at a flow rate of 1 mL/min on a stationary phase composed of Thermo Hypersil BDS C₁₈ (4.6×250 mm, 5 μm) column. UV detection was carried out at 295 nm and 210 nm wavelength gradient at 25°C. The method was validated according to ICH guidelines. Linearity, accuracy and precision results were satisfactory over the concentration ranges of 10.00-600.00 μg/ml for TIM and 1.00-60.00 μg/ml for BIM, LAT and TRV. The correlation coefficients (r² values) were 0.9965 for TIM, 0.99995 for BIM, 0.99998 for LAT and 0.99996 for TRV. The method was successfully applied for the determination of TIM in its synthetic mixture and co-formulated eye drops with each of the three prostaglandin analogues BIM, LAT or TRV. The developed method is specific and accurate for the quality control and routine analysis of the cited drugs in their pharmaceutical preparations. This method is considered global and can be applied to all prostaglandin analog combinations with TIM.

Keywords:

• Timolol
• Bimatoprost
• Latanoprost
• Travoprost
• HPLC