Compounded gabapentin for neuropathic pain: Stability and beyond-use date (BUD) in some commonly used bases.
To investigate the stability and beyond-use date (BUD) of topical gabapentin in 3 commonly used bases. Lipoderm cream, Versabase gel, and Emollient cream were used to compound gabapentin (10%). The products were stored in Ecolojars, kept at 25°C, 4°C, and 40°C, and samples were collected on different days (days 0, 14, 28, and 90). Potency, stability, and organoleptic changes were monitored. At 25°C and 40°C, the potency of gabapentin in Lipoderm cream significantly increased (P < 0.05) after 28 and 90 days, respectively. In contrast, gabapentin degraded in Emollient cream (P < 0.05). At 25°C, the organoleptic properties of the drug compounded with Lipoderm cream (25°C) remained consistent for up to 28 days but showed signs of physical changes in other bases. Gabapentin recrystallized from Versabase gel and Emollient cream within 14 days. Gabapentin compounded with Lipoderm cream for topical use was stable in Ecolojars for 28 days at 25°C. Under the same conditions, the drug was not stable in Versabase gel and Emollient cream. Based on our stability and potency data, the beyond-use date of currently dispensed gabapentin (10%) formulations with Lipoderm cream should not be extended beyond the currently assigned 30-day mark, even when refrigerated. It is unclear whether the stability of these formulations is improved if stored in air-tight containers.