Studies in dissolution enhancement of atenolol. Part I

The objective of this study was to design atenolol tablets with fast in vitro release rates. Different polymers were screened as possible carriers to enhance atenolol dissolution. Binary systems using povidone (PVP), crospovidone (PVP-CL), polyvinilpyrrolidone/vinylacetate (PVP/VA), and Eudragit(R)E were prepared. The physical properties of solid dispersions, compared to physical mixtures, were analysed using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The solubility and the release rate of atenolol from solid dispersions were compared to the drug alone. The influence of various parameters (type of polymer, drug to polymer ratio, pH) on the solubility and dissolution rate of the drug was also evaluated. The results of DSC and X-ray analyses of solid dispersions attested that the drug was always present in a crystalline form in the PVP-CL and Eudragit(R)E systems, while with the high content of PVP and PVP/VA an amorphisation of the atenolol was detectable. On the other hand, the diffraction patterns and the DSC thermograms of the physical mixtures revealed that to some extent the drug was always present in a crystalline form. An improvement in solubility and dissolution rate of atenolol with PVP and PVP-CL was obtained. (C) 1998 Published by Elsevier Science B.V. All rights reserved.