Determination of Sodium Carboxymethyl Cellulose in Diluent of Risperidone Injectable Suspension via Dische Reaction

Sodium carboxymethyl cellulose (NaCMC) is a commonly used pharmaceutical excipient; however, no analytical method has been specifically reported for its determination in the diluent of risperidone injectable suspension. In this study, a simple and cost-effective spectrophotometric method based on the Dische reaction was developed and validated for the quantification of NaCMC. Critical reaction parameters were investigated and optimized using a design of experiments (DoE) approach. The method was validated according to ICH guidelines and demonstrated satisfactory specificity, linearity, accuracy, and precision over the concentration range of 25–150 μg/mL. Recovery values ranged between 98.5 and 101.3%, while repeatability and intermediate precision (expressed as %RSD) was less than 0.7%. The robustness of the derivatization procedure was examined using Monte Carlo simulations and capability analysis. The environmental performance of the proposed method was assessed using the environmental performance and practicality index and analytical green star area tools. The method was successfully applied to the analysis of commercial batches of risperidone injectable suspension diluent. The proposed assay offers a reliable, economical, and straightforward alternative to more complex analytical techniques and is suitable for routine quality control determination of NaCMC in pharmaceutical formulations.