Validation of an HPLC method for analysis of nifedipine residues on stainless-steel surfaces in the manufacture of pharmaceuticals

Summary

A simple, sensitive, and convenient HPLC method has been developed, validated, and applied to analysis of nifedipine residues on the stainless-steel surfaces of equipment used in drug manufacture. Cotton swabs moistened with methanol were used to remove residues of the drug from the surfaces; recoveries were 82.26, 86.88, and 88.95% for 25, 125, and 250 μg per swab. The precision of the results, as relative standard deviation (RSD), was <5%. The method was validated over the concentration range 3–50 μg mL ^–1. Small quantities of residues of the drug and its main impurities were determined by HPLC on an ODS column with methanol-water-phosphate buffer (pH 3; 0.05 m)-sodium heptanesulfonate 65:35:3:0.13 ( v/v/v/w) as mobile phase at a flow rate of 0.8 mL min ^–1. Detection was at 235 nm.