Compartmental modeling of skin transport.

The primary objective of this study is to introduce a simple and flexible mathematical approach which models transport processes in skin using compartments. The main feature of the presented approach is that the rate constants for exchange between compartments are derived from physiologically relevant diffusional transport parameters. This allows for better physical interpretation of the rate constants, and limits the number of parameters for the compartmental model. The resulting compartmental solution is in good agreement with previously published solutions for the diffusion model of skin when ten or more compartments are used. It was found that the new compartmental model with three compartments provided a better fit of the previously publish water penetration data than the diffusion model. Two special cases for which it is difficult to implement the diffusion model were considered using our compartmental approach. In both cases the compartmental model predictions agreed well with the diffusion model.

Plasma treatment as an efficient tool for controlled drug release from polymeric materials: A review.

One of the most actively developing fields in modern medicine is controlled drug delivery, an ability to keep optimal concentration of a drug at the desired body location. In particular, the most attention for potential use as drug delivery vehicles is drawn towards biodegradable polymeric materials. This is due to the versatility of tools for their fabrication, as well as due to the need to extract them after implantation being eliminated. In order to enhance polymer characteristics in terms of biocompatibility their surface can be functionalized. Plasma treatment is a method for the modification of material surface properties, which spans a wide range of applications in tissue engineering and regenerative medicine. The main advantage of this method is its ability to modify a polymeric surface without altering the bulk properties of materials, thus preserving original mechanical characteristics. Moreover, plasma modification is well-known for its speed, excluded need for solvents, and scalability. Recently, this approach has been gaining popularity for drug delivery applications. The applications of plasma treatment during the fabrication of drug delivery vehicles include surface activation, enhanced wettability, the fabrication of hydrophobic barrier layer, induced cross-linking and improved drug loading. This review covers the variety of approaches, applied to different polymeric biomaterials, including non-woven meshes, films, microparticles, microneedles and tablets, in order to achieve a controlled drug release. The applications of drug delivery devices with an implemented plasma treatment modification are also described.

A fiber distribution model for predicting drug release rates.

Sustained drug release can be achieved by loading a drug into polymer material. The drug release can then be controlled for potential use in various biomedical applications. A model for drug release from a polymeric fibrous scaffold, which takes into account the distribution of fiber diameters within its structure, is developed here. It is demonstrated that the fiber diameter distribution significantly affects the drug release profile from electrospun scaffolds. The developed model indicates that altering the fiber distribution can be used as an additional tool to achieve an appropriate drug release profile. Using published data, it was demonstrated that an application of the model allows a more precise calculation of the drug diffusion coefficient within the polymer, which is important for predicting drug release rates from fabricated materials.