PMID: 8999434Jan 1, 1996Paper

Improvement of some pharmaceutical properties of drugs by cyclodextrin complexation. 5. Theophylline

Die Pharmazie
H O AmmarMamdouh M Ghorab

Abstract

The interaction of theophylline (TPH) with beta-cyclodextrin (beta-CD) was investigated by spectrophotometry, vapour pressure osmometry and DSC. The results revealed a molecular interaction between TPH and beta-CD. The continuous variation method was used to elucidate the stoichiometry of such an interaction by spectrophotometric as well as vapour pressure measurements. Both types of data revealed the formation of two-to-one TPH/beta-CD complex. The stability constant of the complex was determined at different temperatures by the vapour pressure osmometric method. The enthalpy and entropy of the interaction were evaluated and the results indicate the liberation of little heat during complexation and the disorder of the guest molecule upon complexation. The effect of beta-CD on the solubility of TPH indicates that beta-CD exhibits a definite solubilizing effect towards the drug with a typical Bs isotherm. The stability constant of the complex and the amount of drug solubilized in the form of complex reveal that complex-formation is the only factor governing the solubilizing effect of beta-CD towards the drug. The dissolution rates of TPH, TPH/beta-CD physical mixture as well as the prepared complex were determined according to U...Continue Reading

Related Concepts

Related Feeds

Birth Defects

Birth defects encompass structural and functional alterations that occur during embryonic or fetal development and are present since birth. The cause may be genetic, environmental or unknown and can result in physical and/or mental impairment. Here is the latest research on birth defects.