Diffusion During Swelling of Matrix – When water-soluble drugs are entrapped in glassy hydrogels, the release of the drugs engages simultaneously the absorption of water and desorption of drug while the hydrogels swell slowly. Drug release kinetics is governed by […]
DRUG RELEASE FROM POLYMER MATRICES: When the conventional dosage forms (i.e. tablets, capsules, ointment or creams) are administered orally or topically, the active drug in the dosage form is immediately released and absorbed into the systemic circulation. The release of […]
APPLICATIONS OF DIFFUSION PRINCIPLES: Drug Absorption by Passive Diffusion – Passive diffusion is the major trans-membrane transport process for most drugs. The driving force for passive diffusion is the difference in drug concentrations on either side of the cell membrane. […]
IN VITRO–IN VIVO CORRELATION: IVIVC refers to a relationship between a physicochemical characteristic of the dosage form, as determined by in vitro dissolution and biological property and as determined by in vivo pharmacokinetics. The objectives of IVIVC are to use […]
Any dissolution test method involves immersing the dosage form in a suitable dissolution medium, which is kept in motion at a constant speed and requires determining the rate at which the drug substance is released from the dosage form and […]
Systems of solids in liquids include the most frequently encountered and probably the most important type of pharmaceutical solutions. Many important drugs belong to the class of weak acids and bases. They react with strong acids and bases and, within […]
Effect of Ionic Dissociation and Molecular Association on Partition: The solute can exist partly or wholly as associated molecules in one of the phases or it may dissociate into ions in either of the liquid phases. The distribution law applies […]