Content area
Full Text
Abstract
The stability of diclofenac sodium injection was studied by means of a stability-indicating high-performance liquid chromatography assay method that was developed in our laboratory. There was a direct relationship between the peak heights and the concentrations. The percent relative standard deviation based on five injections was 0.9. The products of decomposition and the excipients present in the dosage form did not interfere with the developed assay method. The injection was stable for at least 23 days when stored in clear glass vials at room temperature. Contrary to the recommendation in the literature, the injection may not be stored at the refrigerated temperature. The physical appearance and the pH value of the injection did not change during the study period.
Introduction
Diclofenac sodium (Figure 1) is a popular nonsteroidal anti-inflammatory agent. It is used extensively for relief of inflammation and body pains. A formula for compounding a solution of diclofenac sodium for injection has been reported.1 The beyond-use date for this formulation was established at 1 day at room temperature and 3 days at the refrigerated temperature on the basis of guidelines reported in the United States Pharmacopeia-National Formulary (USP-NF).2
The purposes of these investigations were (1) to develop a stability-indicating high-performance liquid chromatographic (HPLC) assay method for the quantisation of diclofenac sodium, and (2) to study the chemical stability of diclofenac sodium 25-mg/mL injection.
Materials and Methods
Chemicals and Reagents
All the chemicals and reagents were USP-NF or American Chemical Society grade and were used without further purification. Diclofenac sodium powder (Lot C102451) was generously supplied by Professional Compounding Centers of America, Houston, Texas.
Equipment
An HPLC system (ALC 202 pump and model 484 multiple wavelength detector; Waters Corporation, Milford, Massachusetts) equipped with an injector (Model 7125; Rheodyne, Cotati, California) and a recorder (Ornniscribe 5213-12; Houston Instruments, Austin, Texas) were used. The column used (pBondapak CN, 150 × 4.6 mm, 5 µm) is available from Waters Corporation. All pH...