Combined site-specific release retardant mini-matrix tablets (C-SSRRMT) for extended oral delivery of dexketoprofen trometamol: in vitro evaluation and single versus multiple doses pharmacokinetic study in human volunteers.

Development of extended release oral formulations of dexketoprofen trometamol (DT), a rapidly eliminated drug with high solubility, poses a great challenge especially when a portion of the dose is to be absorbed from the colon. In this study, site-specific release-retardant mini-matrix tablets (SSRRMTs) were developed and functionally coated with pH-responsive materials to achieve a site-specific delivery of DT at the duodenojejunal (DSRRMT) and ileocecal (ISRRMT) regions. Stomach-specific coated mini-tablets (SSCMTs) were manufactured for immediate release of about 16% of the daily dose of DT in the stomach. The SSCMT, DSRRMT, and ISRRMT were combined into a solid dosage form (C-SSRRMT tablets or capsules) to achieve the required linear release profile for once daily administration of DT. The SSRRMT and C-SSRRMT formulations were evaluated for the physical properties, in vitro -disintegration and in vitro dissolution and proved to be consistent with the pharmacopeial specifications. The in vitro release profiles of both C-SSRRMT tablets and capsules showed a constant release rate of about 6 mg/h and were similar to that of the theoretical target linear release profile. The pharmacokinetic study using human volunteers showed the bioequivalence of a single oral dose of C-SSRRMT capsules compared to three-successive oral doses of the immediate release market tablets with less ups and downs in the drug levels. The C-SSRRMT capsules formulation, may therefore, constitute an advance in the extended oral delivery of DT without the lack of efficacy and the adverse events frequently encountered in multiple daily dosing of the immediate release tablets.