Chromium picolinate loaded superporous hydrogel and superporous hydrogel composite as a controlled release device: in vitro and in vivo evaluation

The aim of this work was to develop chromium picolinate (CP) loaded gastroretentive device using superporous hydrogel (SPH) and superporous hydrogel composite (SPHC). The drug was considered as good candidate for such systems owing to its narrow absorption window. Swelling ratio, apparent density, scanning electron microscopy (SEM), drug content and drug release in pH 1.2 were evaluated for hydrogels. SEM of hydrogels showed interconnected pores with extensive capillary insertion. Swelling ratio for CP-SPH was higher than that of SPHC while apparent densities were lower. Both SPH and SPHC retarded drug release as values of half-life attained 3.64 and 2.94 h, respectively, while plain drug 0.22 h. The mechanical strength of SPHC was higher than SPH, so it was selected for in vivo studies in dogs. Radiographic examination in dogs showed that gastric retention persisted for 24 h. Percentage relative bioavailability was 298.8 %. SPHC could be thus considered as good gastroretentive device for CP.