Biodegradable Polymeric Capsules Obtained via Room Temperature Spray Drying: Preparation and Characterization

Abstract

The aim of this contribution is to determine the relationship existent between the chemistry and/or viscosity of some biodegradable polymer solutions and the morphology of micro- and nanospheres resulted after spray drying the solutions at room conditions either in the presence or in the absence of an encapsulated aqueous material. Using dichloromethane as solvent, the following polyesters were used to prepare 2 wt% solutions: polyhydroxybutyrate (PHB), polylactic acid (PLA), poly(lactic-co-glycolic acid) (PLGA) and Eastar Bio GP (GP). A comprehensive thermal characterization was also performed on all polymers to verify the relationships existent between the structure of polyesters and certain important parameters, such as T(g), T(m), T(d). It was observed that a decrease in the solution viscosity triggers the formation of smoother microspheres. When the viscosity becomes low enough the sprayed solution can lead to the development of well defined nanospheres instead of microspheres. Additionally, it was found that in the presence of an aqueous core the micro- and/or nanocapsules coalesce into larger micrometric aggregates, due to the plasticizing effects of water on the polyester.

Oxygen‐Delivery Materials: Synthesis of an Open‐Cage Fullerene Derivative Suitable for Encapsulation of H2O2 and O2

“…Hydrogen peroxide H 2 O 2 encapsulated into biocompatible microcavities has been well studied as potential oxygen delivery materials for tissue engineering. Various polymer microspheres have been shown to encapsulate hydrogen peroxide for sustained release of oxygen, including polylactic acid and poly(methyl methacrylate) . Catalase has been incorporated into the system to catalyze the decomposition of the released H 2 O 2 into oxygen and water.…”

Effect of potassium ion on the stability and release rate of hydrogen peroxide encapsulated in silica hydrogels

“…Urea and other decomposition products, however, are contaminants that limit use of the product as a source of H 2 O 2 . Other researchers have tried encapsulating H 2 O 2 in various polymer matrices, such as polylactic‐co‐glycolic acid, polylactic acid, and polymethylmethacrylate, to increase its stability. The results showed low encapsulation efficiencies of H 2 O 2 because of its high diffusivity.…”

Hydrogen peroxide filled poly(methyl methacrylate) microcapsules: Potential oxygen delivery materials

“…Although research has been reported on the preparation of oil-filled polymer microcapsules by various techniques (Berkland et al, 2007;Dowding et al, 2004Dowding et al, , 2005Yow and Routh, 2006), there is limited research on the preparation of water-filled polymer microcapsules Bean et al, 2012). A few research groups have reported on the encapsulation of H 2 O 2 in polymers Stefanescu et al, 2011), however the microcapsules synthesized in these studies have very small amounts of encapsulated H 2 O 2 and quantitative H 2 O 2 release data are not presented in these studies.…”