Preparation of 3,4-diaminopyridine microparticles by solvent-evaporation methods

Microparticles prepared with poly(hydroxybutyrate-co-hydroxyvalerate) and poly(ε-caprolactone) blends to control the release of a drug model

The objective of this work was to verify the influence of the poly(epsilon-caprolactone) PCL concentration in poly(hydroxybutyrate-co-hydroxyvalerate) P(HBHV)/PCL microparticles, prepared by an emulsion/solvent evaporation process, on the release behavior of a drug. Differential Scanning Calorimetry analyses demonstrated that the preparation process increased the crystallite heterogeneity for the P(HBHV) in the particles. The drug caused an increase in the glass transition of the P(HBHV) in the microparticles. Dexamethasone acetate-loaded microparticles demonstrated drug sustained releases (up to 250 h), which profiles fit the biexponential model. The release of dexamethasone acetate caused an increase in the surface area of the microparticles. The kinetic constants of the sustained phase increased with the augmentation of the PCL content in the blend. The drug release mechanism was dependent on the presence of PCL in the microparticles. A Fickian release was determined for the microparticles prepared exclusively with P(HBHV), while non-Fickian release behaviors were found for the P(HBHV)/PCL microparticles.

Fast Ring-Shape Self-Assembling in Water-Based Ink-Jetted Droplets

We report on a phenomenon of ring pattern formation of nanoparticles in small ink-jetted droplets (30-60 microm diameter) of water-based suspensions on substrate, which occurs in several seconds, unlike 10 min and more in most previous works. The phenomenon may open the way for new applications connected with rapid creation of desired structures. In addition, we report here a method for the study of the relative motion of the solvent and pigments in suspension droplets by coloring the solvent with soluble dye and using spectral imaging techniques.

Poly-epsilon-caprolactone microspheres and nanospheres: an overview

Poly-epsilon-caprolactone (PCL) is a biodegradable, biocompatible and semicrystalline polymer having a very low glass transition temperature. Due to its slow degradation, PCL is ideally suitable for long-term delivery extending over a period of more than one year. This has led to its application in the preparation of different delivery systems in the form of microspheres, nanospheres and implants. Various categories of drugs have been encapsulated in PCL for targeted drug delivery and for controlled drug release. Microspheres of PCL either alone or of PCL copolymers have been prepared to obtain the drug release characteristics. This article reviews the advancements made in PCL-based microspheres and nanospheres with special reference to the method of preparation of these and their suitability in developing effective delivery systems.