Fabrication of mesoporous hydroxycarbonate apatite for oral delivery of poorly water-soluble drug carvedilol

The main aim of this study was to prepare nanosized hydroxycarbonate apatite (HCA) as a drug carrier to improve the dissolution rate and increase the bioavailability of poorly soluble drugs, intended to be administered orally. In the present study, uniform mesoporous HCA nanoparticles were synthesized using CaCO3 as a sacrificial template by the hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB) as a surfactant. The prepared HCA was used as a drug carrier to investigate the drug uptake and release properties employing carvedilol (CAR) as a model drug. The structure and morphology of mesoporous HCA, and the successful storage/release of CAR were systematically studied by N-2 adsorption, scanning electron microscopy (SEM), powder X-Ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, Fourier transform infrared (FT-IR) spectroscopy, and UV-VIS spectrophotometry. In vitro drug dissolution tests showed that mesoporous HCA produced burst release of CAR in comparison with micronized CAR in simulated gastric fluid and intestinal fluid. Stability test result indicated that amorphous state of CAR loaded in HCA nanoparticles had a good physical stability after room storage for 6 months. Hence, mesoporous HCA nanoparticles are excellent drug carriers for the oral delivery of poorly soluble drugs. (C) 2011 Elsevier B.V. All rights reserved.