New spectrophotometric assay for pilocarpine.
A quick method for the determination of pilocarpine in eye drops in the presence of decomposition products is described. The method involves complexation of the alkaloid with bromocresol purple at pH 6. After treatment with 0.1N NaOH, the liberated dye is measured at 580 nm. The method has a relative standard deviation of 1.99%, and has been successfully applied to the analysis of 2 batches of pilocarpine eye drops. The recommended method was also used to monitor the stability of a pilocarpine nitrate solution in 0.05N NaOH at 65 degrees C. The BPC method failed to detect any significant decomposition after 2 h incubation, but the recommended method revealed 87.5% decomposition.
D007202:Indicators and Reagents; D009883:Ophthalmic Solutions / Q000032:analysis; D010862:Pilocarpine / Q000032:analysis*; D013053:Spectrophotometry / Q000379:methods
D007202:Indicators and Reagents; D009883:Ophthalmic Solutions; D010862:Pilocarpine