Effect of aging on the release of salbutamol sulfate from lipid matrices

The aim of the present work was to evaluate the influence of aging that mig ht condition the release of salbutamol sulfate from oral formulations (lipi d matrices) using Gelucire(R) as lipid excipients. Gelucires are essentiall y characterized by their melting point and their hydrophilic-lipophilic bal ance. The release profiles of salbutamol sulfate from the capsules elaborat ed were dependent on the type of Gelucires, fast release, in the case of Ge lucire(R) 35/10, a slower release for Gelucire(R) 48/09 and a slow release for Gelucire(R) 46/07. Differential scanning calorimetry was used to study the physical state of drugs in the matrices. Gelucires may exhibit aging ef fects, whereby a range of physical properties may change upon storage. In t he case of Gelucire(R) 35/10, which presents a fast release of salbutamol s ulfate, storage produces a decrease in the values of dissolution constant f or all capsule sizes. Gelucire 48/09 showed a slower release rate than Gelu cire(R) 35/10, and after 1 year of storage, a decrease in the salbutamol di ssolution rate for capsule number 3 and 4 was observed. Gelucire(R) 46/07 p resented the slowest dissolution rate, but there were not statistically sig nificant differences. These results show that the faster the dissolution ra te, and the larger the capsule size, the higher is the influence of storage . (C) 2000 Elsevier Science B.V. All rights reserved.