Formulation, in vitro and in vivo Characterisation of Diclofenac Potassium Sustained Release Tablets Based on Solidified Reverse Micellar Solution (SRMS)

Aims: To formulate sustained release diclofenac potassium tablets based on solidified reverse micellar solution (SRMS) and to evaluate the in vitro and in vivo properties of the tablets. Study Design: Formulation, in vitro and in vivo evaluation of sustained release diclofenac potassium. Place and Duration of Study: Department of Pharmaceutical Technology and Industrial Pharmacy, University of Nigeria, Nsukka and Department of Pharmaceutics, University of Nigeria, Nsukka 410001, Nigeria. Methodology: SRMS, consisting of mixtures of phospholipid and triglyceride were prepared in the ratios of 1: 1, 2: 1 and 1: 2 (Phospholipon (R) 90H: Softisan (R) 154) respectively. SRMS-based tablets containing 100 mg of diclofenac potassium each were prepared using validated plastic mould. The physicochemical properties of the tablet formulations were studied and compared with the market brands of the drug for sustained release properties. In vitro release was carried out in simulated intestinal fluid (SIF, pH 7.5) using the USP paddle method. Anti-inflammatory, analgesic/anti-nociceptive and ulcerogenic properties of the formulated tablets were studied using adult Wistar rats. Results: The results showed that the physicochemical properties of the tablet formulations were significantly affected by the composition/ratio of the lipid matrix (LM) used (p < 0.05). The hardness of the tablets ranged from 4.55 +/- 0.50 to 5.10 +/- 0.39 kgf for tablets formulated with LM 1: 2 and 1: 1 (M-3 and M-1) respectively. Friability results indicated that all the SRMs tablets exhibited friability values less than 1 %. The erosion time ranged from 35.8 +/- 1.10 to 120.3 +/- 0.32 min. The release profile of the tablets showed maximum release between 8 - 11 h for all the batches. Diclofenac potassium tablets based on SRMS had good anti-inflammatory and analgesic properties and also inhibited the ulcerogenicity of the NSAID by up to 85 %. Conclusion: Diclofenac potassium tablets based on SRMS could be used for once daily administration.