Development of a prolonged-release system for the association of nonsteroidal anti-inflammatory drugs (NSAIDs)

Pain is a response to cellular injury caused by accidental or intentional tissue damage. Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most prescribed medications worldwide for pain management, including postoperative pain. However, due to the high frequency of doses required during therapy, gastric injuries can develop. Tromethamine ketorolac and sodium diclofenac are two widely used NSAIDs for pain relief as anti-inflammatory and antipyretic agents (especially sodium diclofenac), but there are no formulations combining both drugs that provide sustained release. This drug release model is extremely useful in reducing the number of doses, increasing the dosing interval, and ensuring long-term effects. Microencapsulated systems are extensively used to better protect the drug from climatic conditions, gastric fluids, and to ensure greater stability, as well as being a great tool for modulating drug release according to the desired action and intended pharmacotherapy. Thus, in this study, using the most modern rational approach for the design of new drugs and evaluation of critical quality attributes, multivariate studies, in silico and in vitro prediction, a controlled release system for the combination of tromethamine ketorolac and sodium diclofenac was developed through microencapsulation in a lipid blend with beeswax and ethyl oleate using a cooling-induced emulsification method for the dispersed phase. Different concentrations of beeswax, ethyl oleate, and drugs were tested, and in experiments with lower percentages of ethyl oleate (wax-to-drug ratio of 6:1), it was possible to obtain matrix lipid solid system, with higher efficiency in modulating the release of both drugs for up to 12 hours. The drug content was quantified, ranging from 4 to 13 mg/mg for KT and 12 to 39 mg/mg for DS, and the release profile was analyzed using phosphate buffer pH 6.8 in USP apparatus 2. The formulations demonstrated a controlled release profile compared to free drug, indicating that drug release occurred through modulation of the lipid matrix system.