Stability-indicating RP-HPLC method for analysis of telmisartan in the bulk drug and in formulations

A sensitive and reproducible HPLC method has been developed for quantitative analysis of telmisartan. The drug was separated from its degradation products on a C 18 column at ambient temperature with methanol-water 80:20 ( v / v ), pH 4.0 (adjusted by addition of orthophosphoric acid), as mobile phase at a flow rate of 1.0 mL min -1. Under these conditions the retention time of telmisartan was 4.85 ± 0.05 min. Quantification on the basis of peak area was achieved by UV detection at 225 nm; calibration plots were linear in the concentration range 10–60 μg mL -1 When the method was applied to a pharmaceutical formulation there was no chromatographic interference from tablet excipients. The method was validated for precision, robustness, recovery, and limits of detection and quantification. The drug was subjected to acidic and alkaline hydrolysis, and oxidising, dry heat, wet heat, and photodegrading conditions. Because the method could effectively separate the drug from its degradation products, it can be regarded as stability indicating.