Potential Roles of the Glass Transition Temperature of PLGA Microparticles in Drug Release Kinetics

Abstract

Poly­(lactic-co-glycolic acid) (PLGA) has been used for long-acting injectable drug delivery systems for more than 30 years. The factors affecting the properties of PLGA formulations are still not clearly understood. The drug release kinetics of PLGA microparticles are influenced by many parameters associated with the formulation composition, manufacturing process, and post-treatments. Since the drug release kinetics have not been explainable using the measurable properties, formulating PLGA microparticles with desired drug release kinetics has been extremely difficult. Of the various properties, the glass transition temperature, T g, of PLGA formulations is able to explain various aspects of drug release kinetics. This allows examination of parameters that affect the T g of PLGA formulations, and thus, affecting the drug release kinetics. The impacts of the terminal sterilization on the T g and drug release kinetics were also examined. The analysis of drug release kinetics in relation to the T g of PLGA formulations provides a basis for further understanding of the factors controlling drug release.

Poly(lactic-co-glycolic acid) microsphere production based on quality by design: a review

“…Water acts as a plasticizer, reducing the Tg. The moisture is then removed by vacuum drying or lyophilization (Bouissou et al, 2006;Park et al, 2021).…”

Engineering of stealth (maghemite/PLGA)/chitosan (core/shell)/shell nanocomposites with potential applications for combined MRI and hyperthermia against cancer

“…44,45 Furthermore, PLGA has been also proposed to formulate thermoresponsive delivery systems facilitating a heat-triggered drug release at the targeted site. [46][47][48] All these are the main reasons that could justified the inclusion of the polymer as the inner shell of a (core/shell)/shell nanostructure. As a result, the PLGA shell would provide pHand heat (hyperthermia)-responsive functionalities to this composite nanoplatform for the selective delivery of therapeutic molecules (drugs and/or genes) to malignant cells.…”

Optimization of Critical Parameters for Coating of Polymeric Nanoparticles With Plasma Membrane Vesicles

“…Sonication generates energy, and both PLGA NPs and membrane vesicles can exhibit changes in physical state in response to increased temperature. 21,32 Our sonicator was equipped with a recirculating chiller (Fig. S1) for temperature control, and initial experiments assessed the size and PDI of each component of our delivery platform after sonication at a range of temperatures.…”

“…0.55-0.75, T g ranges from 50-55°C (Lactel technical data). However, T g of PLGA nanoformulations can be much lower, 32 particularly when in aqueous solution (32.1°C) or encapsulated with increasing amounts of hydrophilic drugs (19.9-28.8°C). 33 While initial experiments on membrane vesicles and NPs alone indicated that sonication at temperatures below 30°C is su cient to avoid phase transition and aggregation (Fig.…”