Determination of the Antiprotozoal and Antibacterial Drug Metronidazole in Blood and Dosage Forms Using a Simple Spectrophotometric Method

A new, precise, and sensitive method for the determination of Metronidazole has been created. Metronidazole has been determined in both blood and dosage forms. The reaction is based on the reduction of the nitro group of metronidazole followed by coupling with the diazotized paminodiphenylamine to produce a soluble, colored complex measured at 515 nm. Beer-Lambert law is obeyed over the concentration range from 20 to 100 µg/mL, the molar absorptivity is 1397.88 L/mol.cm.The method has been used for the determination of metronidazole in the blood of the volunteer after 4, 6, 8, and 12 h from the administration of 500 mg tablet showing that the higher level of the drug was found after 6 h from swallowing the drug orally with excellent precision range (RSD% 0.0122-0.0387). The method has been also applied for the estimation of drug content in injection and tablet dosage forms with accuracy ranging from -4.1- to +4.0.