Biodegradable Polymeric Systems Research Articles

Formulation and Evaluation of Lungs-Specific Doxorubicin-Loaded Chitosan-PLGA-Alginate Polymeric Nanoparticles

Background: An antibiotic called doxorubicin is produced by the Streptomyces peuce-tius bacterium, which is a member of the anthracycline drug class and is used in chemotherapy. Usually, doxorubicin is employed to cure solid tumors in children and adult patients. The physical and biological stability of the medicine can be increased by encasing it in nanoparticles, which increases the active pharmaceutical ingredient's bioavailability. Objective: This study aimed to create lungs targeting doxorubicin-loaded biodegradable polymer-ic nanoparticulate system by utilizing an appropriate method and conducting its evaluation. Methods: The polymeric nanoparticles using biodegradable polymers were prepared by the emul-sion polymerization method. Franz- diffusion cells were utilized to conduct in-vitro drug diffu-sion investigations. Results: Based on the outcomes of the experiments carried out for the research, polymeric nano-particles of doxorubicin were prepared utilizing different concentrations of chitosan, Sodium al-ginate, and PLGA. The visual appearance of doxorubicin polymeric nanoparticles shows homo-geneous dispersion with no phase separation form. The percentage yield, % entrapment efficien-cy, and drug content obtained for the final formulation were 93.43 ± 1.776, 87.31 ± 1.075, and 91.98 ± 0.493, respectively. A size dimension of 174.51 nm with a PDI of 0.242 and zeta poten-tial value of -36.1 mV of prepared nanoparticles demonstrate the stability of the formulation. The presentation of the PNPs of the optimized formulation having 310mg Tween 80 showed in vitro diffusion of 98.93% ± 0.296 % and an increased flux rate. Based on the determination coeffi-cients, the Higuchi model (K0 = 20.43 and R2= 0.982) was determined to have the best fit for the release data. Conclusion: Based on the trials conducted during the investigation, it was determined that the emulsion polymerization technique was best for the fabrication of the polymeric nanoparticles by utilizing different concentrations of chitosan, Sodium alginate, and PLGA. The formulation F6 containing 310mg Tween 80 suggested improved in vitro diffusion following the Higuchi model throughout all formulations. The findings suggest that a sustained process was responsible for the drug's release from the doxorubicin polymeric nanoparticles.

Assessing the properties of biodegradable magnesium alloy AZ31 protected by a polymer layer on a plasma electrolytic oxidized (PEO) surface

In the present work we consider the AZ31 Mg alloy for applications as medical implants with bone contact. The alloy has the advantages that it combines a high strength with light weight. Most importantly, it eventually dissolves in the body environment and there is therefore no need to remove implants by additional surgery. However, this dissolution should not happen too fast in order to guarantee mechanical integrity during the healing process. This requires the application of appropriate composite coatings. In a first step, an inorganic protective layer is formed by plasma electrolytic oxidation (PEO) using an electrolyte which contains calcium glycerophosphate (CaGP). Special emphasis is placed on the effect of varying CaGP concentrations in the electrolyte, considering molar concentrations between 0.01 and 0.03 mol/l. In a second step, polymer coatings were applied on composite layers to find out whether the system properties can be further improved. Two types of polymer layers were developed using a spin coating method, based on the biodegradable polymer systems polycaprolactone and polyethylene glycol. The results obtained in the present investigation suggest that introducing CaGP into the electrolyte of plasma electrolyte oxidation induces a composite layer consisting of MgO and CaP compounds. The coatings developed in 0.02 mol/l CaGP electrolyte exhibit superior adhesion strength. A significant tenfold increase in corrosion resistance and the highest cell viability are observed on coatings developed in 0.02 mol/l CaGP electrolyte and then superimposed with PCL. These results suggest that a coating on AZ31, after PEO in an electrolyte with 0.02 mol/l CaGP and then superimposed with PCL, represents a promising candidate for applications as bio-absorbable bone implant material. The coated material by far outperforms the material with no surface treatment.

Effect of MoS2 on Simple and Novel PEG/κ-Carrageenan Hydrogels for TNBC Cancer Drug Delivery

Molybdenum disulfide (MoS2), a two-dimensional inorganic molecule, has lately been studied in medical research with regard to carrying pharmaceuticals due to its distinctive characteristics. A biodegradable polymer system applicable in cancer drug delivery can be created with the addition of MoS2. In our research described in this paper, we investigated the influence of the amount of MoS2 on the characteristics and performance of our novel gel blend. It was aimed to prepare a new gel blend, which we thought would have the potential to be used as a stimulus-sensitive, polymeric hydrogel as a carrier in the triple negative breast cancer (TNBC) drug delivery system, with the MoS2 added to the polyethylene glycol (PEG)/κ-carrageenan combination. This 2D material (MoS2) impacted the hydrogel by improving the transmittance, swelling, and elasticity performance compared to the normal no MoS2 structure of the polymeric gel. The polymer blend characteristics were mainly tested using UV-VIS spectrophotometry and gravimetric analysis. The varied properties of these gel mixtures were investigated using five different mass ratios of MoS2. The 5 mg MoS2/(PEG)/κ-carrageenan gel was the best sample investigated in terms of the elasticity. The results of the study demonstrated that our gel system can be utilized for precisely targeted and regulated delivery of cancer drugs. To create preliminary data for this near future goal, the release mechanism of the Doxorubicin drug loaded into the produced gel were examined.

MAPLE deposition of hybrid PLGA-Fe3O4- Cypress-PEDOT: PSS coatings

We report on the Matrix Assisted Pulsed Laser Evaporation, laser technology for depositing biocompatible, antimicrobial, hydrophilic, and biodegradable complex hybrid polymeric system loaded with essential cypress-oil and magnetite nanoparticles as resorbable implants, capable of targeting possible hyperthermia applications, an anticancer moderate field heating therapy. Magnetite nanoparticles based on iron oxide (Fe3O4) coated with Cypress essential oil (denoted: Fe3O4- Cypress) and embedded in PLGA (poly(lactic-co-glycolic acid) (denoted: PLGA-Fe3O4- Cypress-) and PLGA - poly(3,4-ethylene dioxythiophene) doped with poly(styrene sulfonate) anions) (PEDOT: PSS) mixture (denoted: PLGA-Fe3O4- Cypress- PEDOT: PSS) were used as MAPLE targets. The controlled drug delivery of the active Cypress oil, an antimicrobial therapeutic agent from Fe3O4- Cypress nanoparticles could be possible by applying an external radio frequency (RF) magnetic field. The Fe3O4-Cypress-based powders as well as the final hybrid coatings have been characterized in terms of stoichiometry, morphology, magnetic, antimicrobial properties, biocompatibility, and response to external physical stimuli. FTIR analyses confirmed the quasi-stoichiometric laser transfer of organic compounds while the XRD evidenced the semicrystalline structure of deposited thin films. SEM and AFM images evidence that conductive polymer addition led to the films' relief flattening and a decrease in the coatings' thickness and roughness by changing the polymeric packaging. The samples containing conductive polymer exhibited 3 times higher current and corrosion rate values. All coatings are hydrophilic and revealed enhanced cellular viability when cultured with osteoblast-like MG-63 cells. The composite structures exhibited significant antimicrobial activity against Gram-positive (Staphylococcus aureus), and Gram-negative (Escherichia coli) bacteria, as well as to the opportunistic yeast Candida albicans.

Gelation upon the Mixing of Amphiphilic Graft and Triblock Copolymers Containing Enantiomeric Polylactide Segments through Stereocomplex Formation.

Biodegradable injectable polymer (IP) systems that form hydrogels in situ when injected into the body have considerable potential as medical materials. In this paper, we report a new two-solution mixed biodegradable IP system that utilizes the stereocomplex (SC) formation of poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA). We synthesized triblock copolymers of PLLA and poly(ethylene glycol), PLLA-b-PEG-b-PLLA (tri-L), and a graft copolymer of dextran (Dex) attached to a PDLA-b-PEG diblock copolymer, Dex-g-(PDLA-b-PEG) (gb-D). We found that a hydrogel can be obtained by mixing gb-D solution and tri-L solution via SC formation. Although it is already known that graft copolymers attached to enantiomeric PLLA and PDLA chains can form an SC hydrogel upon mixing, we revealed that hydrogels can also be formed by a combination of graft and triblock copolymers. In this system (graft vs. triblock), the gelation time was shorter, within 1 min, and the physical strength of the resulting hydrogel (G' > 100 Pa) was higher than when graft copolymers were mixed. Triblock copolymers form micelles (16 nm in diameter) in aqueous solutions and hydrophobic drugs can be easily encapsulated in micelles. In contrast, graft copolymers have the advantage that their molecular weight can be set high, contributing to improved mechanical strength of the obtained hydrogel. Various biologically active polymers can be used as the main chains of graft copolymers, and chemical modification using the remaining functional side chain groups is also easy. Therefore, the developed mixing system with a graft vs. triblock combination can be applied to medical materials as a highly convenient, physically cross-linked IP system.

Effect of pro‐oxidants on the aerobic biodegradation, disintegration, and physio‐mechanical properties of compostable polymers

AbstractBiodegradable polymers are gaining momentum to resolve the globally acknowledged plastic waste problem. Understanding, characterizing, and developing new generations of biodegradable plastics is crucial to provide industries with alternative green materials that can fully satisfy biodegradation rates and lifetime specifications. This study evaluates the influence of metal pro‐oxidant additives on the degradation properties of various biodegradable polymer systems. For this purpose, iron (III) stearate (FeSt3) and bismuth oxide (Bi2O3), as oxidant agents, were incorporated into poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV), poly(butylene adipate‐co‐terephthalate) (PBAT), cellulose acetate (CA), poly(lactic acid) (PLA), and thermoplastic starch (TPS) bioplastics. The material performances and biodegradability properties due to the additives on the resulting bioplastic formulations were investigated. A mechanism was proposed in which both pro‐oxidant additives can accelerate the thermo‐oxidation processes under composting conditions and cleave the polymer chains into smaller fragments to stimulate the biodegradation rate through microorganisms' activity. The study revealed that both pro‐oxidant additives, FeSt3 and Bi2O3, effectively improved the biodegradation process for all tested polymers except TPS, which already had a very high biodegradation rate. The observed change in the barrier and mechanical properties due to the additives were within tolerable limits of corresponding neat polymers.

Apoptosis-targeted gene therapy for non-small cell lung cancer using chitosan-poly-lactic-co-glycolic acid -based nano-delivery system and CASP8 and miRs 29A-B1 and 34A.

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related deaths worldwide, with resistance to apoptosis being a major driver of therapeutic resistance and aggressive phenotype. This study aimed to develop a novel gene therapy approach for NSCLC by targeting resistance to apoptosis. Loss of function mutations of caspase 8 (CASP8) and downregulation of microRNAs (miRs) 29A-B1 and 34A were identified as key contributors to resistance to apoptosis in NSCLC. A biodegradable polymeric nano-gene delivery system composed of chitosan-poly-lactic-co-glycolic acid was formulated to deliver initiator CASP8 and miRs 29A-B1 and 34A. The nano-formulation efficiently encapsulated the therapeutic genes effectively internalized into NSCLC cells and induced significant apoptosis. Evaluation of the nano-formulation in A549 tumor spheroids showed a significant increase in apoptosis within the core of the spheroids, suggesting effective penetration into the spheroid structures. We provide a novel nano-formulation that demonstrate therapeutic potential for suicidal gene therapy in NSCLC.

Quality by Design Enabled Systematic Optimization of Calcineurin Inhibitor loaded Polymeric Nanoparticles for Sustained Topical Delivery in Psoriasis

Background: The present work describes the systematic development and optimization of cyclosporine-A loaded biodegradable polymeric nanoparticulate system using quality by design paradigm, to achieve an effective and sustained release of the cyclosporine-A to the targeted lesion of plaque psoriasis. Methods: The polymeric nanoparticles were formulated using the solvent emulsification method using Polycaprolactone and Hyaluronic acid as polymers. An Ishikawa fishbone diagram was constructed for risk assessment and to describe various plausible product and process variables influencing the quality target product profile. Critical process and product parameters were further optimized by Response surface methodology using Central Composite Design by Minitab 19 Software. The development and optimization of cyclosporine-A loaded biodegradable polymeric nanoparticles were further carried out by developing the relationship of independent variables viz. amount of polymers polycaprolactone and hyaluronic acid on dependent variables viz. particle size, zeta potential, and entrapment efficiency and exploring their interactions. Validation of the model was done by checkpoint analysis method. Results: The particle size, zeta potential, and Entrapment efficiency of the optimized polymeric nanoparticles were found to be 317.2 ± 1.271, -0.249 ± 0.903 mV and 83.33 ± 1.124%, respectively. SEM images of the lyophilized nanoparticles showed spherical particles. In-vitro drug release study showed a slow and sustained release of 88.52 ± 1.10% of drugs up to 14 days. Conclusion: The nanoparticulate system would also help in overcoming the problem associated with poor water solubility and low permeability of the drug and will explore drug loaded biodegradable polymeric nanoparticles as a novel platform for effective therapy of psoriasis.

Multipolymer microsphere delivery of SARS-CoV-2 antigens.

Effective antigen delivery facilitates antiviral vaccine success defined by effective immune protective responses against viral exposures. To improve severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antigen delivery, a controlled biodegradable, stable, biocompatible, and nontoxic polymeric microsphere system was developed for chemically inactivated viral proteins. SARS-CoV-2 proteins encapsulated in polymeric microspheres induced robust antiviral immunity. The viral antigen-loaded microsphere system can preclude the need for repeat administrations, highlighting its potential as an effective vaccine. STATEMENT OF SIGNIFICANCE: Successful SARS-CoV-2 vaccines were developed and quickly approved by the US Food and Drug Administration (FDA). However, each of the vaccines requires boosting as new variants arise. We posit that injectable biodegradable polymers represent a means for the sustained release of emerging viral antigens. The approach offers a means to reduce immunization frequency by predicting viral genomic variability. This strategy could lead to longer-lasting antiviral protective immunity. The current proof-of-concept multipolymer study for SARS-CoV-2 achieve these metrics.

Copaiba essential oil loaded-nanocapsules film as a potential candidate for treating skin disorders: preparation, characterization, and antibacterial properties

Infections have emerged as a novel target in managing skin and mucosa diseases. Bacterial resistance to antimicrobials and biofilm elimination from surfaces remains a challenge. Because polymeric nanocapsules (NC) can increase antimicrobial activity, this study aimed to produce and characterize NC into chitosan films (CSF). Copaiba essential oil (CO) presents antimicrobial activity and was chosen to load NC. In addition, the antibacterial activity was evaluated to obtain a new biodegradable polymeric platform system with the potential to treat topical diseases associated with bacterial infections. The CO-NC produced by nanoprecipitation presented particle size lower than 250 nm, negative charge, and encapsulation efficiency higher than 70 %. Direct incorporation of CO into CSF (CO-CSF) by casting method worsened the film’s characteristics. However, incorporating CO-NC into CSF (CO-NC-CSF) avoided these drawbacks demonstrating improved physical, mechanical, morphological, and topographical properties. FTIR results demonstrated possible intermolecular interactions among the polymers and CO. The CO-NC-CSF and CO-CSF presented antibacterial properties against Staphylococcus aureus, and Pseudomonas aeruginosa, especially the formulation containing 1 % of CO. These results indicated that CO-NC-CSF is a promising candidate for treating skin disorders.

Late Catch-up In-Stent Restenosis and Stent Thrombosis for 2nd Generation Biodegradable Polymer Drug Eluting Stents

Second generation drug-eluting stents (DES) have reduced the rate of in-stent restenosis (ISR) to < 10% [1, 2] in patients undergoing PCI. However, late catch-up in-stent restenosis remains an issue despite the advent in drug-eluting stent technology from 1st to 2nd generation drug eluting stents. The late catch-up phenomenon has been associated with serious consequences and adverse events and remains an important issue in modern practice, despite medical advances with more biocompatible and biodegradable polymers, as well as new therapeutic agents and thinner scaffolds in the development of 2nd generation DES polymer systems. The idea behind biodegradable polymers has been to provide a more controlled elution profile for DES drugs, allowing for long-term therapeutic, but sub-toxic, drug levels in the arterial tissue to prevent ISR and stent thrombosis. However, the late catch-up phenomenon remains an issue resulting in 2ndary revascularization beyond the first year of primary PCI, as it is defined as ISR >1 year. Late stent thrombosis (<1 year) and very late stent thrombosis (>1 year) also remain an issue for biodegradable polymer systems. A long-term presence of the polymer can cause inflammation and thrombogenesis, which is dependent upon polymer degradation kinetics in case of biodegradable polymer DES systems. However, the cause of late catch-up restenosis and stent thrombosis is multi-factorial from a drug-in-polymer formulation perspective of drug release kinetics, e.g., drug elution profile, drug physiochemical properties, and polymer degradation kinetics. It appears that the focus should be on controlling burst release for both late catch-up restenosis and stent thrombosis phenomena.

Systemic biodistribution and hepatocyte-specific gene editing with CRISPR/Cas9 using hyaluronic acid-based nanoparticles

The goal of this study was to evaluate hepatocyte-specific gene editing, via systemic administration of hyaluronic acid (HA)-based nanoparticles in naïve CD-1 mice. Using HA-poly(ethylene imine) (HA-PEI) and HA-PEI-mannose nanoparticles with differential mannose density (1X and 2X), we have evaluated systemic biodistribution and hepatocyte-specific delivery using IVIS imaging and flow cytometry. Additionally, we have investigated hepatocyte-specific delivery and transfection of CRISPR/Cas9 gene editing plasmid and eGFP gene payload to integrate at the Rosa26 locus. IVIS imaging showed uptake of HA-PEI nanoparticles primarily by the liver, and with addition of mannose at different concentrations, the nanoparticles showed increased uptake in both the liver and spleen. HA-PEI-mannose nanoparticles showed 55–65% uptake by hepatocytes, along with uptake by resident macrophage regardless of the mannose concentration. One of two gRNA targets showed 15% genome editing and obtained similar results for all three nanoparticle formulations. Cells positive for our gene payload were greatest with HA-PEI-mannose-1X nanoparticles where 16.2% of cells were GFP positive. The results were encouraging as proof of concept for the development of a non-viral biodegradable and biocompatible polymeric delivery system for gene editing specifically targeting hepatocytes upon systemic administration.

Morphology, Thermo-Mechanical Properties and Biodegradibility of PCL/PLA Blends Reactively Compatibilized by Different Organic Peroxides.

Reactive blending is a promising approach for the sustainable development of bio-based polymer blends and composites, which currently is gaining more and more attention. In this paper, biodegradable blends based on poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) were prepared via reactive blending performed in an internal mixer. The PCL and PLA content varied in a ratio of 70/30 and 55/45. Reactive modification of PCL/PLA via liquid organic peroxides (OP) including 0.5 wt.% of tert-butyl cumyl peroxide (BU), 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane (HX), and tert-butyl peroxybenzoate (PB) is reported. The materials were characterized by rotational rheometer, atomic force microscopy (AFM), thermogravimetry (TGA), differential scanning calorimetry (DSC), tensile tests and biodegradability tests. It was found that the application of peroxides improves the miscibility between PCL and PLA resulted in enhanced mechanical properties and more uniform morphology. Moreover, it was observed that the biodegradation rate of PCL/PLA blends reactively compatibilized was lower comparing to unmodified samples and strongly dependent on the blend ratio and peroxide structure. The presented results confirmed that reactive blending supported by organic peroxide is a promising approach for tailoring novel biodegradable polymeric systems with controllable biodegradation rates.

Formoterol PLGA-PEG Nanoparticles Induce Mitochondrial Biogenesis in Renal Proximal Tubules.

Formoterol is a long-acting β2 agonist (LABA). Agonism of the β2-adrenergic receptor by formoterol is known to stimulate mitochondrial biogenesis (MB) in renal proximal tubules and recover kidney function. However, formoterol has a number of cardiovascular side effects that limits its usage. The goal of this study was to design and develop an intravenous biodegradable and biocompatible polymeric nanoparticle delivery system that targets formoterol to the kidney. Poly(ethylene glycol) methyl ether-block-poly(lactide-co-glycolide) nanoparticles containing encapsulated formoterol were synthesized by a modified single-emulsion solvent evaporation technique resulting in nanoparticles with a median hydrodynamic diameter of 442 + 17 nm. Using primary cell cultures of rabbit renal proximal tubular cells (RPTCs), free formoterol, encapsulated formoterol polymeric nanoparticles, and drug-free polymeric nanoparticles were biocompatible and not cytotoxic over a wide concentration range. In healthy male mice, polymeric nanoparticles were shown to localize in tubules of the renal cortex and improved the renal localization of encapsulated formoterol compared to the free formoterol. At a lower total formoterol dose, the nanoparticle localization resulted in increased expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), the master regulator of MB, and increased electron transport chain proteins, markers of MB. This was confirmed by direct visual quantification of mitochondria and occurred with both free formoterol and the encapsulated formoterol polymeric nanoparticles. At the same time, localization of nanoparticles to the kidneys resulted in reduced induction of MB markers in the heart. These new nanoparticles effectively target formoterol to the kidney and successfully produce MB in the kidney.

Cellular therapy for myocardial ischemia using a temperature-responsive biodegradable injectable polymer system with adipose-derived stem cells

ABSTRACT Adipose-derived stem cell (AdSC) has been attracting attention as a convenient stem cell source. Not only AdSC can differentiate into various tissue cells, but it can also accelerate cell proliferation, anti-inflammation, and angiogenesis by secreting paracrine factors. Studies have demonstrated AdSC treatment of ischemic heart. However, an improvement in the remaining live AdSCs administered at the injected site while maintaining paracrine factor secretion is desired to achieve effective regenerative medicine. We previously reported the ABA-type tri-block copolymer of poly(ɛ-caprolactone-co-glycolic acid) and poly(ethylene glycol) (tri-PCG), exhibiting temperature-responsive sol-to-gel transition as biodegradable injectable polymer (IP) systems. Moreover, we recently reported that the biodegradable temperature-triggered chemically cross-linked gelation systems exhibited longer gel state durations using tri-PCG attaching acryloyl groups and a polythiol derivative. In this study, we explored this IP-mediated AdSC delivery system. We investigated the cell viability, mRNA expression, and cytokine secretion of AdSCs cultured in the physical or chemical IP hydrogels. Both of these IP hydrogels retained a certain number of viable cells, and RT-PCR and ELISA analyses revealed that mRNA expression and secretion of vascular endothelial growth factor of the AdSCs cultured in the chemical hydrogel were higher than the physical hydrogel. Moreover, AdSCs injected with the chemical hydrogel into ischemic heart model mice showed longer retention of the cells at the injected site and recovery from the ischemic condition. The results mean that the IP system is a promising candidate for a stem cell delivery system that exhibits the recovery of cardiac function for myocardial infarction treatment.

Engineered resveratrol-loaded fibrous scaffolds promotes functional cardiac repair and regeneration through Thioredoxin-1 mediated VEGF pathway

Despite recent advancements, mortality due to coronary heart disease (CHD) remains high. Recently, the use of tissue-engineered grafts and scaffolds has emerged as a candidate for supporting the myocardium after an ischemic event. Resveratrol is a naturally occurring plant-based non-flavonoid polyphenolic compound found in many natural foods, including grapes and red wine. We embedded resveratrol in a polycaprolactone (PCL) scaffold and evaluated the cardio-therapeutic effects in a murine model of myocardial infarction (MI), with animals being grouped into Sham (S), Myocardial Infarction (MI), MI + PCL, and MI + PCL-Resveratrol (MI + PCL-R). After 4 and 8 weeks, echocardiography was performed to assess ejection fraction (EF) and fractional shortening (FS), which was followed by immunohistochemistry and immunofluorescence analysis at 8 weeks. The MI + PCL-R group showed a significant improvement in EF and FS compared with the MI + PCL group at 4 and 8-weeks post-surgery. PCL-R scaffolds treated hearts revealed decreased inflammatory cell infiltration, improved collagen extracellular matrix (ECM) secretion and blood vessel network formation following MI. The immunofluorescence analysis revealed resveratrol-loaded scaffolds promote increased expression of cTnT, Cx-43, Trx-1, and VEGF proteins. This study reports resveratrol-mediated rescue of ischemic myocardium when delivered through a biodegradable polymeric scaffold system after MI.

Biodegradable Polymers for the Production of Nets for Agricultural Product Packaging.

It is well known that the need for more environmentally friendly materials concerns, among other fields, the food packaging industry. This regards also, for instance, nets used for agricultural product (e.g., citrus fruits, potatoes) packaging. These nets are typically manufactured by film blowing technique, with subsequent slicing of the films and cold drawing of the obtained strips, made from traditional, non-biodegradable polymer systems. In this work, two biodegradable polymer systems were characterized from rheological, processability, and mechanical points of view, in order to evaluate their suitability to replace polyethylene-based polymer systems typically used for agricultural product net manufacturing. Furthermore, laboratory simulation of the above-mentioned processing operation paths was performed. The results indicated a good potential for biodegradable polymer systems to replace polyethylene-based systems for agricultural product packaging.

Engineering microenvironment of biodegradable polyester systems for drug stability and release control.

Polymeric systems made of poly(lactic acid) or poly(lactic-co-glycolic acid)are widely used for long-term delivery of small and large molecules. The advantages of poly(lactic acid)/poly(lactic-co-glycolic acid) systems include biodegradability, safety and a long history of use in US FDA-approved products. However, asdrugs delivered by the polymeric systems and their applications become more diverse, the significance of microenvironment change of degrading systems on long-term drug stability and release kinetics has gained renewed attention. In this review, we discuss various issues experienced with acidifying microenvironment of biodegradable polymer systems and approaches to overcome the detrimental effects of polymer degradation on drug stability and release control.

Clinically established biodegradable long acting injectables: An industry perspective.

Long acting injectable formulations have been developed to sustain the action of drugs in the body over desired periods of time. These delivery platforms have been utilized for both systemic and local drug delivery applications. This review gives an overview of long acting injectable systems that are currently in clinical use. These products are categorized in three different groups: biodegradable polymeric systems, including microparticles and implants; micro and nanocrystal suspensions and oil-based formulations. Furthermore, the applications of these drug delivery platforms for the management of various chronic diseases are summarized. Finally, this review addresses industrial challenges regarding the development of long acting injectable formulations.

Engineering at the Nanoscale: A Strategy for Developing High-Performance Functional Polymer Nanocomposites

The talk will concentrate on various approaches being used to engineer materials at the nanoscale for various applications in future technologies. In particular, the case of clay, carbon nanostructures (e.g., nanotubes, graphene), metal oxides, bionanomaterials (cellulose, starch, and chitin) will be used to highlight the challenges and progress. Several bio-degradable polymer systems will be considered, such as rubbers, thermoplastics, thermosets, and their blends for the fabrication of functional polymer nanocomposites. The interfacial activity of nanomaterials in compatibilism binary polymer blends will also be discussed. Various self-assembled architectures of hybrid nanostructures can be made using relatively simple processes. Some of these structures offer an excellent opportunity to probe novel nanoscale behavior and can impart unusual macroscopic end properties. I will talk about various applications of these materials, taking into account their multifunctional properties. Some of the promising applications of clay, metal oxides, nano cellulose, chitin, carbon nanomaterials, and their hybrids will be reviewed.