PLA/PLGA-Based Drug Delivery Systems Produced with Supercritical CO2-A Green Future for Particle Formulation?

Assessment of Solubility Behavior of a Copolymer in Supercritical CO2 and Organic Solvents: Neural Network Prediction and Statistical Analysis

In the industrial sector, understanding the behavior of block copolymers in supercritical solvents is crucial. While qualitative agreement with polymer solubility curves has been evaluated using complex theoretical models in many cases, quantitative predictions remain challenging. This study aimed to create a rapid and accurate artificial neural network (ANN) model to predict the lower critical solubility and upper critical solubility space of an atypical block copolymer, poly(styrene-co-octafluoropentyl methacrylate) (PSOM), in different supercritical solvent systems over a wide range of temperatures (51.75-182.05 °C) and high pressure (3.28-200.86 MPa). The experimental data set used in this study included one copolymer, five supercritical solvents, one cosolvent, and one initiator. It consisted of seven unique copolymer-solvent combinations (252 cloud point pressures) used to predict the model quantitatively and qualitatively. To predict the PSOM-solvent interactions, the study considered two different input systems: a six-variable system, a five-variable system, and one target output. Initially, we used a three-layer feed-forward neural network to select the best learning algorithm (Levenberg-Marquardt) from 14 different algorithms, considering one sample PSOM-solvent system. Then, the network topology was optimized by varying hidden neuron numbers from 2 to 80 for all seven PSOM-solvent combination systems. The predicted cloud point pressures were in excellent agreement with the experimental cloud point pressures, confirming the model's accuracy. It is clear from the results of a minimum mean square error (≤1.90 × 10-27) and maximum linear regression R 2 (≥0.99) during training, validation, and testing of all the data sets. Further, the ANN model accuracy was tested by statistical analysis, confirming the model's ability to accurately capture the miscibility regions of polymers, enabling efficient processing of various polymer materials. This data-driven approach facilitates the prediction of coexistence curves for other polymers and complex macromolecular systems.

Biodegradable composites with antibiotics and growth factors for dual release kinetics

Bone infections are still a major problem in surgery. To avoid severe side effects of systemically administered antibiotics, local antibiotic therapy is increasingly being considered. Using a pressure-based method developed in our group, microporous β-TCP ceramics, which had previously been characterized, were loaded with 2% w/v alginate containing 50 mg/mL clindamycin and 10 µg/mL rhBMP-2. Release experiments were then carried out over 28 days with changes of liquid at defined times (1, 2, 3, 6, 9, 14, 21 and 28d). The released concentrations of clindamycin were determined by HPLC and those of rhBMP-2 by ELISA. Continuous release (anomalous transport) of clindamycin and uniform release (Fick's diffusion) of BMP-2 were determined. The composites were biocompatible (live/dead, WST-I and LDH) and the released concentrations were all antimicrobially active against Staph. aureus. The results were very promising and clindamycin was detected in concentrations above the MIC as well as a constant rhBMP-2 release over the entire study period. Biocompatibility was also not impaired by either the antibiotic or the BMP-2. This promising approach can therefore be seen as an alternative to the common treatment with PMMA chains containing gentamycin, as the new composite is completely biodegradable and no second operation is necessary for removal or replacement.

Unveiling the potentials of hydrophilic and hydrophobic polymers in microparticle systems: Opportunities and challenges in processing techniques

Conventional drug delivery systems are associated with various shortcomings, including low bioavailability and limited control over release. Biodegradable polymeric microparticles have emerged as versatile carriers in drug delivery systems addressing all these challenges. This comprehensive review explores the dynamic landscape of microparticles, considering the role of hydrophilic and hydrophobic materials. Within the continuously evolving domain of microparticle preparation methods, this review offers valuable insights into the latest advancements and addresses the factors influencing microencapsulation, which is pivotal for harnessing the full potential of microparticles. Exploration of the latest research in this dynamic field unlocks the possibilities of optimizing microencapsulation techniques to produce microparticles of desired characteristics and properties for different applications, which can help contribute to the ongoing evolution in the field of pharmaceutical science.

In Vivo Toxicological Analysis of the ZnFe2O4@poly(tBGE-alt-PA) Nanocomposite: A Study on Fruit Fly

Recently, the use of hybrid nanomaterials (NMs)/nanocomposites has widely increased for the health, energy, and environment sectors due to their improved physicochemical properties and reduced aggregation behavior. However, prior to their use in such sectors, it is mandatory to study their toxicological behavior in detail. In the present study, a ZnFe2O4@poly(tBGE-alt-PA) nanocomposite is tested to study its toxicological effects on a fruit fly model. This nanocomposite was synthesized earlier by our group and physicochemically characterized using different techniques. In this study, various neurological, developmental, genotoxic, and morphological tests were carried out to investigate the toxic effects of nanocomposite on Drosophila melanogaster. As a result, an abnormal crawling speed of third instar larvae and a change in the climbing behavior of treated flies were observed, suggesting a neurological disorder in the fruit flies. DAPI and DCFH-DA dyes analyzed the abnormalities in the larva's gut of fruit flies. Furthermore, the deformities were also seen in the wings and eyes of the treated flies. These obtained results suggested that the ZnFe2O4@poly(tBGE-alt-PA) nanocomposite is toxic to fruit flies. Moreover, this is essential to analyze the toxicity of this hybrid NM again in a rodent model in the future.

Synthesis of Poly-Lactic Acid by Ring Open Polymerization from Beer Spent Grain for Drug Delivery

Poly-lactic acid (PLA) is a synthetic polymer that has gained popularity as a scaffold due to well-established manufacturing processes, predictable biomaterial properties, and sustained therapeutic release rates. However, its drawbacks include weak mechanical parameters and reduced medicinal delivery efficacy after PLA degradation. The development of synthetic polymers that can release antibiotics and other medicines remains a top research priority. This study proposes a novel approach to produce PLA by converting Brewer's spent grain (BSG) into lactic acid by bacterial fermentation followed by lactide ring polymerization with a metal catalyst. The elution properties of the PLA polymer are evaluated using modified Kirby-Bauer assays involving the antimicrobial chemotherapeutical, trimethoprim (TMP). Molded PLA polymer disks are impregnated with a known killing concentration of TMP, and the PLA is evaluated as a drug vehicle against TMP-sensitive Escherichia coli. This approach provides a practical means of assessing the polymer's ability to release antimicrobials, which could be beneficial in exploring new drug-eluting synthetic polymer strategies. Overall, this study highlights the potential of using BSG waste materials to produce valuable biomaterials of medical value with the promise of expanded versatility of synthetic PLA polymers in the field of drug-impregnated tissue grafts.

Degradable Polymeric Bio(nano)materials and Their Biomedical Applications: A Comprehensive Overview and Recent Updates

Degradable polymers (both biomacromolecules and several synthetic polymers) for biomedical applications have been promising very much in the recent past due to their low cost, biocompatibility, flexibility, and minimal side effects. Here, we present an overview with updated information on natural and synthetic degradable polymers where a brief account on different polysaccharides, proteins, and synthetic polymers viz. polyesters/polyamino acids/polyanhydrides/polyphosphazenes/polyurethanes relevant to biomedical applications has been provided. The various approaches for the transformation of these polymers by physical/chemical means viz. cross-linking, as polyblends, nanocomposites/hybrid composites, interpenetrating complexes, interpolymer/polyion complexes, functionalization, polymer conjugates, and block and graft copolymers, are described. The degradation mechanism, drug loading profiles, and toxicological aspects of polymeric nanoparticles formed are also defined. Biomedical applications of these degradable polymer-based biomaterials in and as wound dressing/healing, biosensors, drug delivery systems, tissue engineering, and regenerative medicine, etc., are highlighted. In addition, the use of such nano systems to solve current drug delivery problems is briefly reviewed.

Research Progress on Immunomodulatory Effects of Poly (Lactic-co- Glycolic Acid) Nanoparticles Loaded with Traditional Chinese Medicine Monomers

Immunomodulatory mechanisms are indispensable and key factors in maintaining the balance of the environment in humans. When the immune function of the immune system is impaired, autoimmune diseases occur. Excessive body fatigue, natural aging of the human body, malnutrition, genetic factors and other reasons cause low immune function, due to which the body is prone to being infected by bacteria or cancer. Clinically, the existing therapeutic drugs still have problems such as high toxicity, long treatment cycle, drug resistance and high price, so we still need to explore and develop a high efficiency and low toxicity drug. Poly(lactic-co-glycolic acid) (PLGA) refers to a nontoxic polymer compound that exhibits excellent biocompatibility. Traditional Chinese medicine (TCM) monomers come from natural plants, and have the characteristics of high efficiency and low toxicity. Applying PLGA to TCM monomers can make up for the defects of traditional dosage forms, improve bioavailability, reduce the frequency and dosage of drug use, and reduce toxicity and side effects, thus having the characteristics of sustained release and targeting. Accordingly, PLGA nanoparticles loaded with TCM monomers have been the focus of development. The previous research on drug loading advantages, preparation methods, and immune regulation of TCM PLGA nanoparticles is summarized in the following sections.

Intravitreal implants manufactured by supercritical foaming for treating retinal diseases

Chronic retinal diseases, such as age-related macular degeneration (AMD), are a major cause of global visual impairment. However, current treatment methods involving repetitive intravitreal injections pose financial and health burdens for patients. The development of controlled drug release systems, particularly for biological drugs, is still an unmet need in prolonging drug release within the vitreous chamber. To address this, green supercritical carbon dioxide (scCO2) foaming technology was employed to manufacture porous poly(lactic-co-glycolic acid) (PLGA)-based intravitreal implants loaded with dexamethasone. The desired implant dimensions were achieved through 3D printing of customised moulds. By varying the depressurisation rates during the foaming process, implants with different porosities and dexamethasone release rates were successfully obtained. These implants demonstrated controlled drug release for up to four months, surpassing the performance of previously developed implants. In view of the positive results obtained, a pilot study was conducted using the monoclonal antibody bevacizumab to explore the feasibility of this technology for preparing intraocular implants loaded with biologic drug molecules. Overall, this study presents a greener and more sustainable alternative to conventional implant manufacturing techniques, particularly suited for drugs that are susceptible to degradation under harsh conditions.

Biomimetic nanoparticles targeting atherosclerosis for diagnosis and therapy

Atherosclerosis is a typical chronic inflammatory vascular disease that seriously endangers human health. At present, oral lipid-lowering or anti-inflammatory drugs are clinically used to inhibit the development of atherosclerosis. However, traditional oral drug treatments have problems such as low utilization, slow response, and serious side effects. Traditional nanodrug delivery systems are difficult to interactively recognize by normal biological organisms, and it is difficult to target the delivery of drugs to target lesions. Therefore, building a biomimetic nanodrug delivery system with targeted drug delivery based on the pathological characteristics of atherosclerosis is the key to achieving efficient and safe treatment of atherosclerosis. In this review, various nanodrug delivery systems that can target atherosclerosis are summarized and discussed. In addition, the future prospects and challenges of its clinical translation are also discussed.

In Vitro Release and In Vivo Pharmacokinetics of Praziquantel Loaded in Different Polymer Particles

Approximately 1 billion people are affected by neglected diseases around the world. Among these diseases, schistosomiasis constitutes one of the most important public health problems, being caused by Schistosoma mansoni and treated through the oral administration of praziquantel (PZQ). Despite being a common disease in children, the medication is delivered in the form of large, bitter-tasting tablets, which makes it difficult for patients to comply with the treatment. In order to mask the taste of the drug, allow more appropriate doses for children, and enhance the absorption by the body, different polymer matrices based on poly(methyl methacrylate) (PMMA) were developed and used to encapsulate PZQ. Polymer matrices included PMMA nano- and microparticles, PMMA-co-DEAEMA (2-(diethylamino)ethyl methacrylate), and PMMA-co-DMAEMA (2-(dimethylamino)ethyl methacrylate) microparticles. The performances of the drug-loaded particles were characterized in vitro through dissolution tests and in vivo through pharmacokinetic analyses in rats for the first time. The in vitro dissolution studies were carried out in accordance with the Brazilian Pharmacopeia and revealed a good PZQ release profile in an acidic medium for the PMMA-DEAEMA copolymer, reaching values close to 100 % in less than 3 h. The in vivo pharmacokinetic analyses were conducted using free PZQ as the control group that was compared with the investigated matrices. The drug was administered orally at doses of 60 mg/kg, and the PMMA-co-DEAEMA copolymer microparticles were found to be the most efficient release system among the investigated ones, reaching a Cmax value of 1007 ± 83 ng/mL, even higher than that observed for free PZQ, which displayed a Cmax value of 432 ± 98 ng/mL.

Green Processing of Neat Poly(lactic acid) Using Carbon Dioxide under Elevated Pressure for Preparation of Advanced Materials: A Review (2012-2022)

This review provides a concise overview of up-to-date developments in the processing of neat poly(lactic acid) (PLA), improvement in its properties, and preparation of advanced materials using a green medium (CO₂ under elevated pressure). Pressurized CO₂ in the dense and supercritical state is a superior alternative medium to organic solvents, as it is easily available, fully recyclable, has easily tunable properties, and can be completely removed from the final material without post-processing steps. This review summarizes the state of the art on PLA drying, impregnation, foaming, and particle generation by the employment of dense and supercritical CO₂ for the development of new materials. An analysis of the effect of processing methods on the final material properties was focused on neat PLA and PLA with an addition of natural bioactive components. It was demonstrated that CO₂-assisted processes enable the control of PLA properties, reduce operating times, and require less energy compared to conventional ones. The described environmentally friendly processing techniques and the versatility of PLA were employed for the preparation of foams, aerogels, scaffolds, microparticles, and nanoparticles, as well as bioactive materials. These PLA-based materials can find application in tissue engineering, drug delivery, active food packaging, compostable packaging, wastewater treatment, or thermal insulation, among others.

Construction of nano slow-release systems for antibacterial active substances and its applications: A comprehensive review

At present, nano-carrier materials with antibacterial activity are of great significance. Due to the widespread resistance of many pathogenic microorganisms, it has seriously threatened human health. The natural antimicrobial substances extracted from fruits and vegetables can significantly improve their stability combined with nano-carrier materials. The resistance of pathogenic microorganisms will be substantially reduced, greatly enhancing the effect of active antimicrobial substances. Nanotechnology has excellent research prospects in the food industry, antibacterial preservation, food additives, food packaging, and other fields. This paper introduces nano-carrier materials and preparation techniques for loading and encapsulating active antibacterial substances in detail by constructing a nano-release system for active antibacterial substances. The antibacterial effect can be achieved by protecting them from adverse external conditions and destroying the membrane of pathogenic microorganisms. The mechanism of the slow release of the bacteriostatic active substance is also described. The mechanism of carrier loading and release is mainly through non-covalent forces between the bacteriostatic active substance and the carrier material, such as hydrogen bonding, π-π stacking, van der Waals forces, electrostatic interactions, etc., as well as the loading and adsorption of the bacteriostatic active substance by the chemical assembly. Finally, its wide application in food and medicine is introduced. It is hoped to provide a theoretical basis and technical support for the efficient utilization and product development of bacteriostatic active substances.

Nanomaterials to combat SARS-CoV-2: Strategies to prevent, diagnose and treat COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the associated coronavirus disease 2019 (COVID-19), which severely affect the respiratory system and several organs and tissues, and may lead to death, have shown how science can respond when challenged by a global emergency, offering as a response a myriad of rapid technological developments. Development of vaccines at lightning speed is one of them. SARS-CoV-2 outbreaks have stressed healthcare systems, questioning patients care by using standard non-adapted therapies and diagnostic tools. In this scenario, nanotechnology has offered new tools, techniques and opportunities for prevention, for rapid, accurate and sensitive diagnosis and treatment of COVID-19. In this review, we focus on the nanotechnological applications and nano-based materials (i.e., personal protective equipment) to combat SARS-CoV-2 transmission, infection, organ damage and for the development of new tools for virosurveillance, diagnose and immune protection by mRNA and other nano-based vaccines. All the nano-based developed tools have allowed a historical, unprecedented, real time epidemiological surveillance and diagnosis of SARS-CoV-2 infection, at community and international levels. The nano-based technology has help to predict and detect how this Sarbecovirus is mutating and the severity of the associated COVID-19 disease, thereby assisting the administration and public health services to make decisions and measures for preparedness against the emerging variants of SARS-CoV-2 and severe or lethal COVID-19.

Salicylic Acid Co-Precipitation with Alginate via Supercritical Atomization for Cosmetic Applications

Alginate-based microparticles were produced via supercritical assisted atomization (SAA) with the aim of obtaining a biocompatible and low-cost carrier for the delivery of active compounds in cosmetic applications. Salicylic acid was selected as an active model compound, and it was co-precipitated with alginate via SAA, operating at 82 bar and 80 °C. In particular, the drug-to-polymer weight ratio was fixed at 1/4, whereas polymer concentration was varied from 5 to 20 mg/mL in the starting aqueous solution. Operating in this way, alginate-salicylic acid microparticles were characterized by a mean diameter of 0.72 ± 0.25 µm, and the active compound became amorphous after processing. A salicylic acid encapsulation efficiency close to 100% was reached, and the drug release time from the biopolymeric microparticles was prolonged up to nine times with respect to untreated salicylic acid powder.

Supercritical Fluid Technologies for the Incorporation of Synthetic and Natural Active Compounds into Materials for Drug Formulation and Delivery

Various active compounds isolated from natural sources exhibit remarkable benefits, making them attractive for pharmaceutical and biomedical applications, such as antioxidant, antimicrobial, and anti-inflammatory activities, which contribute to the treatment of cardiovascular diseases, neurodegenerative disorders, various types of cancer, diabetes, and obesity. However, their major drawbacks are their reactivity, instability, relatively poor water solubility, and consequently low bioavailability. Synthetic drugs often face similar challenges associated with inadequate solubility or burst release in gastrointestinal media, despite being otherwise a safe and effective option for the treatment of numerous diseases. Therefore, drug-eluting pharmaceutical formulations have been of great importance over the years in efforts to improve the bioavailability of active compounds by increasing their solubility and achieving their controlled release in body media. This review highlights the success of the fabrication of micro- and nanoformulations using environmentally friendly supercritical fluid technologies for the processing and incorporation of active compounds. Several novel approaches, namely micronization to produce micro- and nano-sized particles, supercritical drying to produce aerogels, supercritical foaming, and supercritical solvent impregnation, are described in detail, along with the currently available drug delivery data for these formulations.

In Vitro Cell Behavior and Antibiotic Activity under Sustained Release of Doxycycline-Loaded Poly(lactic-co-glycolic acid) Microspheres

The state-of-the-art sustained drug delivery systems are related to features to improve pharmacological transport through a controlled ratio between drug release and the desired therapeutic effect. Microspheres of biodegradable polymers, such as poly(lactic-co-glycolic acid) (PLGA), play an important role in these approaches, directing the release in a specific region of interest. In this way, the encapsulation of doxycycline (DOX) as a microbial agent turns the PLGA microspheres into a potential device for the treatment of topic oral diseases. Thus, this work aimed to produce DOX-loaded PLGA microspheres and see how they interfered with mesenchymal stem cell viability and in the sustained release in antimicrobial assays. Scanning electron microscopy showed the spherical microstructured pattern, revealing assorted sized distribution, with major diameters ranging 1–3 µm. The encapsulation efficiency presented a mean of 80% in both methods to obtain the microspheres (sonication and magnetic rotation). The DOX release test revealed a gradual and continuous profile of 30–40% between 120 and 168 h. Mesenchymal stem cells cultured in PLGA with or without DOX at several concentrations revealed no effect on the cell metabolic activity. Striking morphology changes were observed by confocal microscopy after 1 to 3 days under culture. The live/dead assay indicated that when microsphere densities were increased (from 10 to 100 µg/mL) cultured cells presented an internalized pattern of microspheres in both groups of PLGA containing DOX or not, while slight cell death signals were identified nearby microsphere clusters. Microbiological assays performed by the agar diffusion test pointed out that an inhibition zone was identified in Staphylococcus aureus (S. aureus) cultures at earlier times of DOX release. Despite the well-known use of PLGA as a drug delivery vehicle, when synthesized with DOX, it presents both characteristics of the desired treatment to prevent healthy tissue damage while avoiding bacterial growth in a microenvironment with anatomical features, such as grooves, projections, and other tough conditions that favor the development of oral diseases.

Tailorable 3DP Flexible Scaffolds with Porosification of Filaments Facilitate Cell Ingrowth and Biomineralized Deposition

Facilitating cell ingrowth and biomineralized deposition inside filaments of 3DP scaffolds are an ideal bone repair strategy. Here, 3D printed PLGA/HA scaffolds with hydroxyapatite content of 50% (P5H5) and 70% (P3H7) were prepared by optimizing 3D printing inks, which exhibited good tailorability and foldability to meet clinical maneuverability. The supercritical CO2 foaming technology further endowed the filaments of P5H5 with a richer interconnected pore structure (P5H5-C). The finite element and computational fluid dynamics simulation analysis indicated that the porosification could effectively reduce the stress concentration at the filament junction and improved the overall permeability of the scaffold. The results of in vitro experiments confirmed that P5H5-C promoted the adsorption of proteins on the surface and inside of filaments, accelerated the release of Ca and P ions, and significantly upregulated osteogenesis (Col I, ALP, and OPN)- and angiogenesis (VEGF)-related gene expression. Subcutaneous ectopic osteogenesis experiments in nude mice further verified that P5H5-C facilitated cell growth inside filaments and biomineralized deposition, as well as significantly upregulated the expression of osteogenesis- and angiogenesis-related genes (Col I, ALP, OCN, and VEGF) and protein secretion (ALP, RUNX2, and VEGF). The porosification of filaments by supercritical CO2 foaming provided a new strategy for accelerating osteogenesis of 3DP implants.

Miniemulsion polymerization at low temperature: A strategy for one-pot encapsulation of hydrophobic anti-inflammatory drugs into polyester-containing nanoparticles

HYPOTHESIS

Conventional synthesis methods of polymeric nanoparticles as drug delivery systems are based on the use of large amounts of organic solvents, hence requiring several steps for the obtaining of waterborne dispersions. In view of the need for new environmentally friendly methods, emulsion polymerization and their related techniques are a good alternative for the production of monodispersed waterborne dispersions of biodegradable nanoparticles in a cleaner, reproducible and faster manner.

EXPERIMENTS

Herein, the miniemulsion polymerization technique at low temperature using poly(2-ethyl-2-oxazoline) as surfactant has been developed for poly(hydroxyethyl methacrylate-lactic acid) and poly(hydroxyethyl methacrylate-lactic-co-glycolic acid) nanoparticles. Additionally, the anti-inflammatory drug BRP-187 was used to proof the potential of this technique in the encapsulation of hydrophobic drugs. The effect of the oligomer composition on the miniemulsion and the final dispersion stability, the final oligomer conversion, the polymer particle size and the drug encapsulation efficiency has been studied.

FINDINGS

Monodisperse spherical particles ranging between 170 and 250 nm in diameter in long term non-toxic stable waterborne dispersions were obtained with drug encapsulation efficiencies up to 66%. In contrast with conventional synthesis techniques, residual organic solvents are completely removed and, thus, the potential of redox initiated miniemulsion polymerization to obtain stable drug loaded poly(hydroxyethyl methacrylate-lactic acid) and poly(hydroxyethyl methacrylate-lactic-co-glycolic acid) nanoparticles in an efficient and fast manner is shown.

Poly(Lactic Acid)-Based Microparticles for Drug Delivery Applications: An Overview of Recent Advances

The sustained release of pharmaceutical substances remains the most convenient way of drug delivery. Hence, a great variety of reports can be traced in the open literature associated with drug delivery systems (DDS). Specifically, the use of microparticle systems has received special attention during the past two decades. Polymeric microparticles (MPs) are acknowledged as very prevalent carriers toward an enhanced bio-distribution and bioavailability of both hydrophilic and lipophilic drug substances. Poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA), and their copolymers are among the most frequently used biodegradable polymers for encapsulated drugs. This review describes the current state-of-the-art research in the study of poly(lactic acid)/poly(lactic-co-glycolic acid) microparticles and PLA-copolymers with other aliphatic acids as drug delivery devices for increasing the efficiency of drug delivery, enhancing the release profile, and drug targeting of active pharmaceutical ingredients (API). Potential advances in generics and the constant discovery of therapeutic peptides will hopefully promote the success of microsphere technology.

Industrial Scale Manufacturing and Downstream Processing of PLGA-Based Nanomedicines Suitable for Fully Continuous Operation

Despite the efficacy and potential therapeutic benefits that poly(lactic-co-glycolic acid) (PLGA) nanomedicine formulations can offer, challenges related to large-scale processing hamper their clinical and commercial development. Major hurdles for the launch of a polymeric nanocarrier product on the market are batch-to-batch variations and lack of product consistency in scale-up manufacturing. Therefore, a scalable and robust manufacturing technique that allows for the transfer of nanomedicine production from the benchtop to an industrial scale is highly desirable. Downstream processes for purification, concentration, and storage of the nanomedicine formulations are equally indispensable. Here, we develop an inline sonication process for the production of polymeric PLGA nanomedicines at the industrial scale. The process and formulation parameters are optimized to obtain PLGA nanoparticles with a mean diameter of 150 ± 50 nm and a small polydispersity index (PDI < 0.2). Downstream processes based on tangential flow filtration (TFF) technology and lyophilization for the washing, concentration, and storage of formulations are also established and discussed. Using the developed manufacturing and downstream processing technologies, production of two PLGA nanoformulations encasing ritonavir and celecoxib was achieved at 84 g/h rate. As a measure of actual drug content, encapsulation efficiencies of 49.5 ± 3.2% and 80.3 ± 0.9% were achieved for ritonavir and celecoxib, respectively. When operated in-series, inline sonication and TFF can be adapted for fully continuous, industrial-scale processing of PLGA-based nanomedicines.

Platelet-Tumor Cell Hybrid Membrane-Camouflaged Nanoparticles for Enhancing Therapy Efficacy in Glioma

Purpose

Cell membrane-camouflaged nanoparticles (NPs) are drawing increasing attention because their surfaces acquire some characteristics of the cell membranes, making them a unique class of biomimetic materials for diverse applications. Modification of cell membrane or combination of different types of membranes can enhance their functionality.

Methods

We prepared platelet and tumor cell membrane camouflaged β-mangostin-loaded NPs, which were synthesized with platelet–C6 hybrid biomimetic coating, poly(lactic-co-glycolic acid), and β-mangostin (β-PCNPs). Then, we evaluated their targeting ability and anticancer activity against glioma in vitro and in vivo.

Results

Biomimetic coating enhanced active drug targeting and immune escape properties of nanocarrier in C6 and THP-1 cells, respectively, which improved their cytotoxicity. β-PCNPs were characterized to study the inherent properties of both source cells. Compared with bare β-NPs, β-PCNPs exhibited high tumor-targeting capability and induced apoptosis of C6 cells in vitro. Similarly, intravenous administration of drug through β-PCNPs resulted in enhanced tumor-targeting and exhibited excellent rate of inhibition of glioma tumor growth in mice. Moreover, the blood circulation time of drug in mice in the β-PCNP group was markedly prolonged and these mice exhibited better outcome than those in the β-NP group.

Conclusion

These results provide a new strategy of utilizing PCNPs as carriers for drug delivery, which improves the targeting efficiency and therapeutic efficacy of chemotherapeutic agents for glioma therapy.

Local Delivery of Pirfenidone by PLA Implants Modifies Foreign Body Reaction and Prevents Fibrosis

Peri-implant fibrosis (PIF) increases the postsurgical risks after implantation and limits the efficacy of the implantable drug delivery systems (IDDS). Pirfenidone (PF) is an oral anti-fibrotic drug with a short (<3 h) circulation half-life and strong adverse side effects. In the current study, disk-shaped IDDS prototype combining polylactic acid (PLA) and PF, PLA@PF, with prolonged (~3 days) PF release (in vitro) was prepared. The effects of the PLA@PF implants on PIF were examined in the rabbit ear skin pocket model on postoperative days (POD) 30 and 60. Matching blank PLA implants (PLA⁰) and PLA⁰ with an equivalent single-dose PF injection performed on POD0 (PLA⁰+injPF) served as control. On POD30, the intergroup differences were observed in α-SMA, iNOS and arginase-1 expressions in PLA@PF and PLA⁰+injPF groups vs. PLA⁰. On POD60, PIF was significantly reduced in PLA@PF group. The peri-implant tissue thickness decreased (532 ± 98 μm vs. >1100 μm in control groups) approaching the intact derma thickness value (302 ± 15 μm). In PLA@PF group, the implant biodegradation developed faster, while arginase-1 expression was suppressed in comparison with other groups. This study proves the feasibility of the local control of fibrotic response on implants via modulation of foreign body reaction with slowly biodegradable PF-loaded IDDS.

PLGA-based nanomedicines manufacturing: Technologies overview and challenges in industrial scale-up

Nanomedicines based on poly(lactic-co-glycolic acid) (PLGA) carriers offer tremendous opportunities for biomedical research. Although several PLGA-based systems have already been approved by both the Food and Drug Administration (FDA) and the European Medicine Agency (EMA), and are widely used in the clinics for the treatment or diagnosis of diseases, no PLGA nanomedicine formulation is currently available on the global market. One of the most impeding barriers is the development of a manufacturing technique that allows for the transfer of nanomedicine production from the laboratory to an industrial scale with proper characterization and quality control methods. This review provides a comprehensive overview of the technologies currently available for the manufacturing and analysis of polymeric nanomedicines based on PLGA nanoparticles, the scale-up challenges that hinder their industrial applicability, and the issues associated with their successful translation into clinical practice.

The Preparation of a Novel Poly(Lactic Acid)-Based Sustained H2S Releasing Microsphere for Rheumatoid Arthritis Alleviation

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease that mainly erodes joints and surrounding tissues, and if it is not treated in time, it can cause joint deformities and loss of function. S-propargyl-cysteine (SPRC) is an excellent endogenous hydrogen sulfide donor which can relieve the symptoms of RA through the promotion of H2S release via the CSE/H2S pathway in vivo. However, the instant release of H2S in vivo could potentially limit its further clinical use. To solve this problem, in this study, a SPRC-loaded poly(lactic acid) (PLA) microsphere (SPRC@PLA) was prepared, which could release SPRC in vitro in a sustained manner, and further promote sustained in vivo H2S release. Furthermore, its therapeutical effect on RA in rats was also studied. A spherical-like SPRC@PLA was successfully prepared with a diameter of approximately 31.61 μm, yielding rate of 50.66%, loading efficiency of 6.10% and encapsulation efficiency of 52.71%. The SPRC@PLA showed significant prolonged in vitro SPRC release, to 4 days, and additionally, an in vivo H2S release around 3 days could also be observed. In addition, a better therapeutical effect and prolonged administration interval toward RA rats was also observed in the SPRC@PLA group.

Drug Carriers: Classification, Administration, Release Profiles, and Industrial Approach

This work is aimed at providing a description of the complex world of drug carriers, starting from the description of this particular market in terms of revenue. Then, a brief overview of several types of conventional and innovative drug carrier systems has been included. The types of administration routes were also analyzed, with a critical and qualitative comment on drug release kinetics and drug profile shapes. Carriers were classified according to their ability to provide a prolonged and targeted release. The concept of the therapeutic window has been presented, providing advantages of having pulsed drug release to avoid side effects to target tissues. A critical comment on the use of conventional and innovative techniques for the production of drug carriers by large industrial companies has been proposed. As a final attempt for this work, an overall unique schematization of a drug carrier production process has been added, highlighting the necessity to create a strong double link among world-requested versatility of drug carriers for human applications and the newly developed industrial processes.