Drug release permeability

Fan LF, He W, Bai M, Du Q, Xiang B, Chang YZ, Gao DY. Biphasic drug release Permeability and swelling of pectin/ethylcellulose films, and in vitro and in vivo correlation of film-coated pellets in dogs. Chem Pharm Bull (Tokyo). 56 (8) 1118-1125,2008. 

The release data from various formulations using the cellulose membrane as the diffusion barrier were used to calculate the values for the diffusion coefficient (Z)), the permeability coefficient (P) and the partition coefficient (P0) (Table 9). From this, it is observed that the sample with maximum drug release (Methocel matrix formulation) has the highest diffusion... 

Zatz, J.L., Drug Release from Semisolids Effect of Membrane Permeability on Sensitivity to Product Parameters." Pharmaceutical Research 2 787-789, 1995. 

The use of siloxane polymers in applications such as separation membranes, drug release systems, and blood oxygenators requires extensive permeability studies. This, of course, also involves measurements of diffusivity and solubility.16... 

In the second experiment, the drug-loaded microspheres were posttreated with NaOH. The purpose of this experiment was to determine whether the surface of the microspheres can be altered by NaOH. Any such modification of the polymeric surface would increase its permeability. This would then account for the enhanced drug release effect. For this experiment, a sample of drug-loaded microspheres was prepared without NaOH in the usual manner. It was then posttreated with 0.14 mole NaOH/mole lactic acid. The conditions for the posttreatment were the same as for the solvent evaporation step. 

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