Drug release physiological factors

The degree of ionization under physiologic conditions Product formulation characteristics Disintegration and dissolution rates for solid dosages Drug release characteristics for timed-release preparations Patient factors... 

To obtain a predefined target release profile and robust formulation properties regarding influences of physiological factors (e.g., pH and food) on the drug release... 

Examples of applications of statistical designs for optimising correlations with in vivo data and for the testing of a formulation under different experimental conditions to elucidate the sensitivity of the drug release towards different physiological factors have also been published (Abrahamsson et al. 1999 Abuzarur-Aloul et al. 1997). 

Solvent-induced gelation could be obtained for a water-insoluble polymer, dissolved in a biocompatible solvent to create an injectable solution. When the solution is injected the solvent diffuses out and water from the physiological environment diffuses in. This diffusion process leads to a phase transition for the polymer as it goes from the solvent phase to a nonsolvent phase and forms a semisolid gel (44). Several factors such as polymer crystallinity, hydrophilicity, and water uptake govern the sol-gel transition and subsequently the drug release characteristics. 

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