Stability of sodium valproate tablets repackaged into dose administration aids.

OBJECTIVES: Since sodium valproate, a commonly used antiepileptic drug, has been reported to be unstable in the presence of moisture, our objective was to investigate the effect of repackaging into dose administration aids. METHODS: Sodium valproate 100 mg immediate-release tablets were repackaged and stored for 56 days at accelerated conditions (40 degrees C/75% relative humidity), room temperature (25 degrees C) and under refrigeration (2-8 degrees C). Samples were analysed at 3, 7, 10, 14, 21, 35, 49 and 56 days to determine chemical stability using high-performance liquid chromatography, while physical testing included assessment of weight changes and dissolution behaviour. KEY FINDINGS: The results revealed that the sodium valproate content in the tablets remained within the acceptable range of 90-110% under all storage conditions for 56 days. Physical stability, however, was not maintained, with a total weight gain of 12.36% under accelerated conditions over the 56 days. Samples stored under all conditions showed variable dissolution compared to the controls, with the amount of sodium valproate in solution following 45 min of dissolution testing below 75% for half of all the intervals determined. CONCLUSIONS: Repackaging sodium valproate tablets into dose administration aids results in unacceptable weight variation and changes in the dissolution profiles.

Compliance aids and medicine stability: new evidence of quality assurance.

Although increasing use of compliance aids is resulting in improved clinical outcomes for patients, the stability of some drugs being repackaged into these aids is being questioned. This is due to the fact that despite their widespread use, there is limited availability of relevant stability data. This review presents clinical evidence for repackaging into Dose Administration Aids (DAAs), the Australian Pharmaceutical Advisory Committee and other guidelines on general stability issues related to repackaging and a summary of evidence for stability studies conducted in the practice. For frusemide and prochlorperazine chosen as candidates for study because of their light sensitivity, while discoloration on light exposure rendered them unacceptable for patient use, precautions in repackaging and patient counselling can easily overcome this problem. In the case of sodium valproate however, hygroscopicity results in these tablets being unusable after exposure to accelerated storage conditions. In the absence of specific data on the stability of drug products repackaged into compliance aids, the guidelines, practical recommendations for repackaging and the management of compliance aids put forward in this article provide the pharmacist with the tools to make an informed decision on this process.