J. Pharm. BioTech Ind., Volume 2, Issue 2 (June 2025) – 2 articles

The main objective of this research was to correlate the equilibrium solubility of sodium sulfadiazine in several {ethanol (EtOH, 1) + water (2)} mixtures reported in mass/volume and mass/mass percentages at different temperatures. Aqueous solubility of sodium sulfadiazine decreases almost linearly with decreasing temperature, but it decreases non-linearly with the addition of EtOH to water. Logarithmic solubility was adequately correlated with a bivariate model involving temperature and mixture composition. These solubility results were also well correlated with the Jouyban–Acree-based models. Moreover, an adapted version of the Jouyban–Acree model was used to represent the density of the saturated solvent mixtures at different temperatures. Furthermore, the apparent specific volumes of this drug at saturation were also calculated from densities of saturated solutions and cosolvent mixtures free of drug as well as from the respective mixture compositions. These findings provide valuable insights into the solubility and volumetric behavior of sodium sulfadiazine, which could be useful for pharmaceutical formulation and process optimization. Full article

A selective inhibitor of cyclooxygenase-2 (COX-2), Celecoxib (CEB), known for its anti-inflammatory properties, can exhibit polymorphism, with Form III often emerging as an undesired crystalline impurity during the green manufacturing process of the preferred Form I. Controlling the Form III content in the drug product is crucial, as different crystalline forms can impact drug bioavailability and therapeutic efficacy. This study presents a method to quantify the weight percentage of Form III in the bulk of CEB Form I by employing powder X-ray diffraction (PXRD). Initially, pure Form I and III of CEB were characterized using DSC, FTIR, and PXRD, supporting the method’s development. Binary mixtures, with varying ratios of CEB polymorphs Form I and Form III, were prepared and analyzed using continuous scans over an angular (2θ) range of 2–40. The calibration curve was constructed using 2θ unique peaks for Form I and Form III, respectively. Linear regression analysis exhibited a strong linear relationship within the weight ratio range of 1–20%. The developed method was validated to assess recovery, precision, ruggedness, limits of detection, and quantitation. These findings indicate that the method exhibits repeatability, sensitivity, and accuracy. The newly developed and validated PXRD method is applicable for quality control of CEB Form I produced through the green melt crystallization process by detecting low levels of Form III polymorphic impurity. This research significantly contributes to ensuring the clinical efficacy and manufacturing quality of Celecoxib by providing a reliable method for controlling polymorphic impurities. Full article