Spectrophotometric Determination of Ertapenem in Bulk and Injection Formulations by P-dimethyl Amino Benzaldehyde (pdab)

A simple and cost effective spectrophotometric method was described for the determination of Ertapenem (ERP) in pure form and in pharmaceutical formulations. The method is based on the formation of dark yellow colored chromogen when the drug reacts with P-dimethyl amino benzaldehyde (PDAB) reagent. The method involves the condensation of the imino substitutes of the drug with PDAB at the λmax 528 nm, which was found to be the most suitable of several tests. This method was applied for the determination of drug contents in pharmaceutical formulations and enabled the determination of the drug in microgram quantities 0.5 to 3.0 mL for ERP. No interference is observed from excipients and the validity of the method was tested against reference method. The colored species has an absorption maximum at 528 nm and obeys beer’s law in the concentration range 0.02 – 0.12 mg/mL of the drugs. The apparent molar absorptivity is 0.0049, sandell’s sensitivitt is 6x10. The slope is 0.001255 and intercept of the equation of the regression line is 0.00095 ± 0.0008. The optimum experimental parameters for the reaction have been studied and the validity of the described procedure was assessed. Statistical analysis of the results has been carried out revealing high accuracy and good precision. The proposed method was successfully applied for the determination of ERP in pharmaceutical formulations.