Stability of gabapentin 300-mg capsules repackaged in unit dose containers

Abstract

PURPOSE: The stability of a gabapentin 300-mg capsule product in the original bulk containers and repackaged in unit dose blister strips was studied. METHODS: Both products were stored for one year under long-term storage conditions (25 degrees C and 60% relative humidity [RH]) and for three months under accelerated storage conditions (40 degrees C and 75% RH) and tested for weight change, potency, and dissolution using validated analytical method. RESULTS: The capsules in the original containers showed no change in weight during the study period. However, the repackaged drug product stored under long-term storage conditions and under accelerated storage conditions showed significant weight increases (p < 0.001) during the study period. No significant differences in potency between the original and repackaged drug products were detected. Potency exceeded 97% for the products stored under the long-term storage conditions and exceeded 95% for the products stored under the accelerated storage conditions. At 13 weeks, samples from the original container and the blister strips stored under the accelerated storage conditions showed quantitative levels of the lactam degradation product; however, these levels were within acceptable limits. No other difference was observed between the original and the repackaged drug products, and both products remained stable throughout the study period. CONCLUSION: Gabapentin 300-mg capsules in the original containers and repackaged in blister strips were stable up to one year under long-term storage conditions and up to three months under accelerated storage conditions.