Stability of reconstituted parecoxib for injection with commonly used diluents

The purpose of this study was to evaluate the effect of diluent type, storage conditions and the nature of package on the stability of reconstituted Parecoxib sodium for injection (PSI).

Parecoxib sodium for injection is a lyophilized product for single use. It is intended for the management of acute pain. Six diluent types were initially evaluated for physical compatibility with PSI. Reconstituted PSI was visually inspected at 8, 24 and 48 h after reconstitution with 0.9% sodium chloride injection (NS), lactated ringers injection (LR), bacteriostatic 0.9% NaCl injection (BNS), lactated ringers and 5% dextrose injection (LR + D5W), 5% dextrose injection (D5W), and 5% dextrose + 0.45% NaCl injection (D5W + 1/2NS). Reconstituted PSI, stored in glass vials and glass or plastic syringes at 5 degrees and 25 degrees C, under 500 lx light intensity for 48 h or subjected to freeze-thaw cycles, were tested for chemical stability by high-performance liquid chromatography (HPLC).

The PSI reconstituted with NS, BNS, D5W, and D5W + 1/2NS met visual acceptance criteria and showed almost no (<0.5% total) degradation under all storage conditions. No significant differences were seen between storage in glass vials or polypropylene/glass syringes. PSI reconstituted with LR and LR + D5W showed visual precipitation in many vials which was confirmed by the decrease in the HPLC assay values at all time points. The needlelike crystals (precipitate), analyzed by Infrared Spectroscopy and Scanning Electron Microscopy-Energy Dispersive Spectrometry (SEM-EDS) analyses, were identified as the free acid form of the active drug.

PSI is stable after reconstitution, with NS, BNS, D5W, and D5W + 1/2NS, when stored at room temperature in glass vials or glass/plastic syringes for up to 48 h* LR and LR + D5W are not recommended for reconstitution because of crystallization of the drug (free acid).