Development and Validation of a Simple and Sensitive Spectrometric Method for Estimation of Cisplatin Hydrochloride in Tablet Dosage Forms: Application to Dissolution Studies

Cisplatin hydrochloride is an important chemotherapeutic drug for cancer treatment. It has a low molar absorptivity in the UV region and has no fluorescence. Therefore, a selective derivatizing reaction is required for its detection in bulk and pharmaceutical dosage form if detection by UV spectrophotometry is sought. In view of this, a simple, accurate, rapid, and cost-effective spectrophotometric method for its estimation has been developed by the complexation of the drug with ortho-phenylene diamine and monitoring the absorbance of formed green color at 706？nm. The method has been validated and successfully applied for the assay and dissolution studies of cisplatin hydrochloride tablets. The method demonstrated good linearity over the range from 0.4 to 1.4？μg/mL with a correlation coefficient of 0.9999. The accuracy of the method was 99.98%. The precision demonstrated relative standard deviation of less than 2.5%. The developed method was successfully applied for dissolution studies of sustained release tablets of cisplatin with a cumulative release of 86.7% in 12 hours. The proposed method can be applied in routine quality control in the pharmaceutical industries since it is precise, accurate, simple, and economic. 1. Introduction Cisplatin is an important chemotherapeutic drug for cancer treatment since 1978. It is one of the complexes responsible for cell division inhibition phenomenon [1]. In order to evaluate the drug in pharmaceutical dosage forms and in clinical situations and to optimize therapeutic regimens, analytical methods capable of separating the drug from its excipients or from its individual biotransformation products and detecting these species at therapeutically relevant levels are required [2]. Several efforts have been made so far that include derivative spectrophotometry [3–6], detection by phosphorescence of cisplatin in urine and plasma [7], atomic absorption spectrometry [8–10], electroanalytical methods [11], and high-performance liquid chromatography methods [12–21]. The structure of cisplatin hydrochloride is shown in Figure 1. Figure 1: Chemical structure of cisplatin. Cisplatin has a low molar absorptivity in the UV region and has no fluorescence. Therefore, a selective derivatizing reaction is required for the detection of drug in biological samples if the optical detection is sought. In view of this several derivatization methods have been developed but suffered from some limitations. Johnson et al. determined cisplatin in urine using derivative spectrophotometry. This method has some disadvantages as the derivatizing