Role of PLGA Variability in Controlled Drug Release from Dexamethasone Intravitreal Implants

Peptide-Based Strategies in PLGA-Enhanced Tumor Therapy

Peptide-based therapeutics have gained attention in cancer treatment because of their good specificity, low toxicity, and ability to modulate immune responses. However, challenges such as enzymatic degradation and poor bioavailability limit their clinical application. Peptide-functionalized poly(lactic-co-glycolic acid) (PLGA) systems have emerged as a transformative platform in cancer therapy that offers unique advantages, including enhanced stability, sustained release, and precise delivery of therapeutic agents. This review highlights the synergistic integration of peptides with PLGA and addresses key challenges of peptide-based therapeutics. The application of peptide-functionalized PLGA systems encompasses a diverse range of strategies for cancer therapy. In chemotherapy, peptides disrupt critical tumor pathways, induce apoptosis, and inhibit angiogenesis, demonstrating their versatility in targeting various aspects of tumor progression. In immunotherapy, peptides act as antigens to stimulate robust immune responses or as immune checkpoint inhibitors to restore T cell activity, overcoming tumor immune evasion. These systems also harness the enhanced permeability and retention effect, facilitating preferential accumulation in tumor tissues while leveraging tumor microenvironment (TME)-responsive mechanisms, such as pH-sensitive or enzyme-triggered drug release, to achieve controlled, localized delivery. Collectively, peptide-functionalized PLGA systems represent a promising, versatile approach for precise cancer therapy that integrates innovative delivery strategies with highly specific, potent therapeutic agents.

Aging-induced microstructural evolution in risperidone loaded PLGA microspheres

This study demonstrates the application of innovative imaging-based characterization techniques to quantify structural changes as a function of ageing for poly (lactic-co glycolic acid) (PLGA) microspheres. Aging of polymers can potentially alter the performance of polymer-based therapeutics and therefore an understanding of the impact of aging on microsphere structure is important. Correlative focused ion beam scanning electron microscopy (FIB-SEM) and X-ray microscopy (XRM) were used to quantify the change in structural critical quality attributes (CQAs) of risperidone loaded microspheres at the single microsphere scale and overall batch scale. One batch of microspheres was aged one year beyond its shelf life while the other batch was within its shelf life, providing a robust comparison between an aged and fresh sample. Comparison of the aged and fresh microspheres revealed an increase in porosity and pore size following aging at the nanoscale, anticipated with physical relaxation of the PLGA. A novel XRM-based method to determine the material density of the microsphere batches was employed to assess the batch level changes induced by aging. A decrease in density in the aged microsphere batch was observed, that was consistent with the porosity increase seen in the FIB-SEM study. These results reveal aging produces an increase in porosity through polymer relaxation that widens the existing pores within the microspheres. The increased porosity was correlated to the in vitro release performance of the two microsphere batches, providing a novel method to assess the impact of polymer aging on the downstream performance of PLGA microsphere systems.

PLGA Implants for Controlled Drug Delivery and Regenerative Medicine: Advances, Challenges, and Clinical Potential

Poly(lactide-co-glycolide) (PLGA) implants have become a cornerstone in drug delivery and regenerative medicine due to their biocompatibility, tunable degradation, and capacity for sustained, localized therapeutic release. Recent innovations in polymer design, fabrication methods, and functional modifications have expanded their utility across diverse clinical domains, including oncology, neurology, orthopedics, and ophthalmology. This review provides a comprehensive analysis of PLGA implant properties, fabrication strategies, and biomedical applications, while addressing key challenges such as burst release, incomplete drug release, manufacturing complexity, and inflammatory responses. Emerging solutions-such as 3D printing, in situ forming systems, predictive modeling, and patient-specific customization-are improving implant performance and clinical translation. Emphasis is placed on scalable production, long-term biocompatibility, and personalized design to support the next generation of precision therapeutics.

Development of poly (lactic-co-glycolic acid) (PLGA) based implants using hot melt extrusion (HME) for sustained release of drugs: The impacts of PLGA's material characteristics

Hot melt extrusion (HME) processed Poly (lactic-co-glycolic acid) (PLGA) implant is one of the commercialized drug delivery products, which has solid, well-designed shape and rigid structures that afford efficient locoregional drug delivery on the spot of interest for months. In general, there are a variety of material, processing, and physiological factors that impact the degradation rates of PLGA-based implants and concurrent drug release kinetics. The objective of this study was to investigate the impacts of PLGA's material characteristics on PLGA degradation and subsequent drug release behavior from the implants. Three model drugs (Dexamethasone, Carbamazepine, and Metformin hydrochloride) with different water solubility and property were formulated with different grades of PLGAs possessing distinct co-polymer ratios, molecular weights, end groups, and levels of residual monomer (high/ViatelTM and low/ ViatelTM Ultrapure). Physicochemical characterizations revealed that the plasticity of PLGA was inversely proportional to its molecular weight; moreover, the residual monomer could impose a plasticizing effect on PLGA, which increased its thermal plasticity and enhanced its thermal processability. Although the morphology and microstructure of the implants were affected by many factors, such as processing parameters, polymer and drug particle size and distribution, polymer properties and polymer-drug interactions, implants prepared with ViatelTM PLGA showed a smoother surface and a stronger PLGA-drug intimacy than the implants with ViatelTM Ultrapure PLGA, due to the higher plasticity of the ViatelTM PLGA. Subsequently, the implants with ViatelTM PLGA exhibited less burst release than implants with ViatelTM Ultrapure PLGA, however, their onset and progress of the lag and substantial release phases were shorter and faster than the ViatelTM Ultrapure PLGA-based implants, owing to the residual monomer accelerated the water diffusion and autocatalyzed PLGA hydrolysis. Even though the drug release profiles were also influenced by other factors, such as composition, drug properties and polymer-drug interaction, all three cases revealed that the residual monomer accelerated the swelling and degradation of PLGA and impaired the implant's integrity, which could negatively affect the subsequent drug release behavior and performance of the implants. These results provided insights to formulators on rational PLGA implant design and polymer selection.

In-situ forming PLGA implants: Towards less toxic solvents

In-situ forming poly(lactic-co-glycolic acid) (PLGA) implants offer a great potential for controlled drug delivery for a variety of applications, e.g. periodontitis treatment. The polymer is dissolved in a water-miscible solvent. The drug is dissolved or dispersed in this solution. Upon contact with aqueous body fluids, the solvent diffuses into the surrounding tissue and water penetrates into the formulation. Consequently, PLGA precipitates, trapping the drug. Often, N-methyl-2-pyrrolidine (NMP) is used as a water-miscible solvent. However, parenteral administration of NMP raises toxicity concerns. The aim of this study was to identify less toxic alternative solvent systems for in-situ forming PLGA implants. Various blends of polyethylene glycol 400 (PEG 400), triethyl citrate (TEC) and ethanol were used to prepare liquid formulations containing PLGA, ibuprofen (as an anti-inflammatory drug) and/or chlorhexidine dihydrochloride (as an antiseptic agent). Implant formation and drug release kinetics were monitored upon exposure to phosphate buffer pH 6.8 at 37 °C. Furthermore, the syringeability of the liquids, antimicrobial activity of the implants, and dynamic changes in the latter's wet mass and pH of the release medium were studied. Importantly, 85:10:5 and 60:30:10 PEG 400:TEC:ethanol blends provided good syringeability and allowed for rapid implant formation. The latter controlled ibuprofen and chlorhexidine release over several weeks and assured efficient antimicrobial activity. Interestingly, fundamental differences were observed concerning the underlying release mechanisms of the two drugs: Ibuprofen was dissolved in the solvent mixtures and partially leached out together with the solvents during implant formation, resulting in relatively pronounced burst effects. In contrast, chlorhexidine dihydrochloride was dispersed in the liquids in the form of tiny particles, which were effectively trapped by precipitating PLGA during implant formation, leading to initial lag-phases for drug release.