Voltammetric and HPLC determination of dorzolamide hydrochloride in eye drops.

The behaviour of dorzolamide hydrochloride (DOR) was investigated at a glassy carbon electrode in different buffer systems using cyclic (CV), linear sweep (LSV) and differential pulse voltammetry (DPV). The oxidation process was found to be irreversible over the pH range studied (2.0-8.0) and was shown to be diffusion controlled. An analytical method with adequate precision and accuracy was developed for the determination of DOR in Britton-Robinson buffer (BRb) at pH = 3.06 containing 10% methanol as supporting electrolyte. The peak current varied linearly with DOR concentration in the range 4.0 x 10(-5)-6.0 x 10(-4) M. Furthermore, a HPLC method with diode array detection was developed. A calibration graph was established for 1.1 x 10(-6)-1.9 x 10(-4) M of DOR. The procedures were successfully applied for the determination of the drug in eye drops.