Drug-excipient interactions and their affect on absorption.

Stability of Solids and Solid Dosage Forms

Drug-excipient interactions in solid dosage forms can affect drug product stability in physical aspects such as organoleptic changes and dissolution slowdown, or chemically by causing drug degradation. Recent research has allowed the distinction in chemical instability resulting from direct drug-excipient interactions and from drug interactions with excipient impurities. A review of chemical instability in solid dosage forms highlights common mechanistic themes applicable to multiple degradation pathways. These common themes include the role of water and microenvironmental pH. In addition, special aspects of solid-state reactions with excipients and/or excipient impurities add to the complexity in understanding and modeling reaction pathways. This paper discusses mechanistic basis of known drug-excipient interactions with case studies and provides an overview of common underlying themes. Recent developments in the understanding of degradation pathways further impact methodologies used in the pharmaceutical industry for prospective stability assessment. This paper discusses these emerging aspects in terms of limitations of drug-excipient compatibility studies, emerging paradigms in accelerated stability testing, and application of mathematical modeling for prediction of drug product stability.

Impact of excipient interactions on solid dosage form stability.

Vitamins in Pharmaceutical Formulations

Novel salts of omeprazole with Li + , Na + , K + , Mg 2+ , Ca 2+ , Ti 4+ , N + (R 1 ) 4 or ##STR1## as cation; processes for their preparation thereof, pharmaceutical compositions containing such salts and their use in medicine.

L. Magid

Papers

Effect of silica gel on stability and biological availability of ascorbic acid