Solidified Reverse Micellar Solution (SRMS)-Based Indomethacin Sustained-Release Tablets: Formulation and In vitro Evaluation

Purpose: To formulate and evaluate sustained-release indomethacin tablets based on solidified reverse micellar solution (SRMS). Methods: SRMS consisting of mixtures of phospholipid (Phospholipon (R) 90H) and triglyceride (Softisan (R) 154) were prepared in the ratios of 1: 1, 2: 1 and 1: 2, respectively. SRMS-based tablets containing 75 mg of indomethacin each were prepared using a validated plastic mould. The physicochemical properties of the tablet formulations were studied. In vitro release study was carried out in simulated intestinal fluid (SIF, pH 7.5). Results: The results showed that the physicochemical properties of the tablet formulations were significantly affected by the composition/ratio of the lipid matrix used (p < 0.05). Tablet hardness ranged from 5.00 +/- 0.39 to 5.60 +/- 0.36 kgf for tablets formulated with SRMS 1: 2 and 2: 1 (N-3 and N-2), respectively. The tablets exhibited friability of < 1 % (p < 0.05). Erosion time in SIF ranged from 124.0 +/- 0.5 to 180.0 +/- 1.1 min while drug release from the tablets reached a maximum in 8 - 11 h for all the batches. Conclusion: Indomethacin tablets based on SRMS exhibited good sustained-release properties and can be further developed to achieve once daily administration for improved patient adherence to therapy.