Preparation of polylactide-co-glycolide and chitosan hybrid microcapsules of amifostine using coaxial ultrasonic atomizer with solvent evaporation

Abstract

The objective of this study was to evaluate the effect of various processing and formulation factors on the characteristics of amifostine hybrid microcapsules. Amifostine-loaded hybrid microcapsules were prepared using PLGA and chitosan. In short, amifostine powder was dissolved in de-aerated water with or without chitosan. The amifostine solution was later emulsified into PLGA solution in dichloromethane containing phosphatidylcholine. The resultant emulsion was fed through the inner capillary of a coaxial ultrasonic atomizer. The liquid fed through the coaxial outer capillary was either water or chitosan solution. The atomized droplets were collected into PVA solution and the droplets formed microcapsules immediately. The hybrid microcapsules prepared with chitosan solution only as an outer layer liquid showed the maximum efficiency of encapsulation (30%). The median sizes of all three formulations were 33-44 microm. These formulations with chitosan showed positive zeta-potential and sustained drug release with 13-45% amifostine released in 24 h. When chitosan was incorporated into inner as well as outer liquid layers, the drug release increased significantly, 45% (compared with other formulations) released in 24 h and almost 100% released in 11 days. Hybrid microcapsules of amifostine showed moderately high efficiency of encapsulation. The cationic charge (due to the presence of chitosan) of these particles is expected to favour oral absorption and thus overall bioavailability of orally administered amifostine.

The Influence of Solvent Processing on Polyester Bioabsorbable Polymers

“…This change in T g is indicative of increased chain mobility induced by residual solvent, with chloroform showing a greater reduction in T g compared to DCM. This plasticizing effect has been previously reported to result from residual solvent [19,20]. After 14 days the glass transition temperature reverted back towards the ‘as-received’ state, samples prepared with DCM displaying a T g ∼21.6–29.7°C after 14 days.…”

Development, Characterization, and In Vitro Evaluation of Resveratrol-Loaded Poly-(ε-caprolactone) Microcapsules Prepared by Ultrasonic Atomization for Intra-Articular Administration

“…As a consequence of its simplicity and versatility, coaxial ultrasonic atomizers have been shown to produce microcapsules in mild conditions, rapidly leading to a uniform size distribution, a spherical population with desirable properties of drug release, and high loading efficiencies, depending on procedure configuration. Some of the experimental parameters that can be set to obtain a controlled size distribution are the flow rates of the inner and outer channel, the power input provided by an ultrasonic generator, or the polymer concentration [15,16,17,18,19,20,21,22]. Using this technique, microdrops are generated in air as a soft spray by the ultrasound vibrational energy and the polymer coating around the aqueous inner core is solidified in a collection bath, where the organic solvent is removed by evaporation.…”

Cellular delivery of PEGylated PLGA nanoparticles

“…By encapsulating target drugs into custom‐engineered particles, such as nanoparticles with a specific size, shape and surface characteristics, it has been possible to improve cancer drug safety and efficacy in various models. Since polylactide‐co‐glycolide (PLGA) is an FDA‐approved biodegradable polymer currently used in seventeen preparations on the market, our group has been exploring the use of PLGA‐based nanoparticles to encapsulate a variety of drugs, [1–3] including drugs used in cancer therapy. For nanoparticles to work as intended, they must be internalized by the target cells in significant quantity.…”