ABSTRACT
OBJECTIVE: To optimize the formulation of aspirin ointment. METHODS: With cumulative permeation quantity within 6 h and shin irritation as indexes, the method of central composite design was used to optimize the formulation of aspirin ointment, taking the most important three ingredients including sodium lauryl sulfale(X1), sodium citrate (X2) and triethanolamine (X3) as the study subjects. RESULTS: The optimized formulation of aspirin ointment was composed of 1.41% sodium lauryl sulfate, 3.5% sodium citrate and 3.0% triethanolamine. Three batches of aspirin ointment were prepared using the optimized formulation, for which the average cumulative permeation quantity within 6 h was 990.18 μg · cm-2, and no obvious shin irritation was observed. CONCLUSION: Central composite design is successfully used lo optimize the formulation of aspirin ointment.