Biodegradable Copolymer Research Articles

Oral insulin delivery by epithelium microenvironment-adaptive nanoparticles

Oral protein drug delivery using nano-based systems remains challenging, as contradictory surface properties are required for efficient navigation through the intestinal mucus and epithelium barriers. Therefore, new nanoplatforms with tunable surface properties in vivo are urgently needed. Inspired by the slightly acidic microclimate of the jejunal epithelial surface, we report a novel epithelium microenvironment-adaptive nanoplatform that undergoes a hydrophilicity-hydrophobicity transition at the epithelial surface. First, we synthesized and characterized a biodegradable copolymer consisting of PEG and PLGA building blocks linked by a hydrazone bond (PLGA-Hyd-PEG) to fabricate the pH-sensitive core-shell architecture of an oral insulin system. Then we loaded the system as a freeze-dried powder into enteric-coated capsules. PLGA-Hyd-PEG nanoparticles showed excellent drug protection and rapid mucus penetration owing to the high stability of the PEG coating in jejunal fluid. In the acidic microenvironment of the jejunal epithelial surface (pH ~5.5), PEG was rapidly cleaved and the hydrazone bond was hydrolyzed, converting the nanoparticle surface from hydrophilic to hydrophobic, thereby facilitating internalization into cells. Pharmacodynamic studies showed that PLGA-Hyd-PEG nanoparticles resulted in significant decrease in blood glucose level after intrajejunal administration in both normal and diabetic rats relative to control nanoparticles. In addition, enteric-coated capsules containing PLGA-Hyd-PEG nanoparticles reduced blood glucose by 35% for up to 10 h after oral administration to diabetic rats. Our findings provide a new strategy for regulating the surface properties of nanoparticles for efficient oral drug delivery.

Therapeutic Stomatocytes with Aggregation Induced Emission for Intracellular Delivery.

Bowl-shaped biodegradable polymersomes, or stomatocytes, have much potential as drug delivery systems, due to their intriguing properties, such as controllable size, programmable morphology, and versatile cargo encapsulation capability. In this contribution, we developed well-defined therapeutically active stomatocytes with aggregation-induced emission (AIE) features by self-assembly of biodegradable amphiphilic block copolymers, comprising poly(ethylene glycol) (PEG) and AIEgenic poly(trimethylene carbonate) (PTMC) moieties. The presence of the AIEgens endowed the as-prepared stomatocytes with intrinsic fluorescence, which was employed for imaging of cellular uptake of the particles. It simultaneously enabled the photo-mediated generation of reactive oxygen species (ROS) for photodynamic therapy. The potential of the therapeutic stomatocytes as cargo carriers was demonstrated by loading enzymes (catalase and glucose oxidase) in the nanocavity, followed by a cross-linking reaction to achieve stable encapsulation. This provided the particles with a robust motile function, which further strengthened their therapeutic effect. With these unique features, enzyme-loaded AIEgenic stomatocytes are an attractive platform to be exploited in the field of nanomedicine.

Comparison of triblock copolymeric micelles based on \u03b1- and \u03b5-poly(L-lysine): a Cornelian choice

Due to the lack of safe carriers for the delivery of small interfering RNA (siRNA), clinical applications of nucleotide-based therapeutics have been limited. In this study, biodegradable amphiphilic triblock copolymers with tailored molecular weights for each block composed of methoxy poly(ethylene glycol) (2000 g/mol), poly(L-lysine) (1300 g/mol) and poly(D,L-lactic acid) (1800 g/mol) (mPEG45-α-PLL10-PLA25) were synthesized and fully characterized. The peptide synthesis was carried out on a solid phase to limit the presence of cationic charges. The arrangement and availability of cationic amino groups within a micellar vector were investigated to determine the colloidal stability as well as the predisposition of these systems to vectorize siRNAs in addition to their already known ability to improve the solubility of hydrophobic compounds. For this purpose, a triblock copolymer containing an epsilon poly(L-lysine) was synthesized similarly. Accordingly, the arrangement of the cationic segment modifies the rigidity involving a complexation constraint due to limited cationic charges available on the surface, which can compromise the efficiency of delivery into cells. In addition, the two vectors were biocompatible in different human cell lines.

Highly Efficient Modular Construction of Functional Drug Delivery Platform Based on Amphiphilic Biodegradable Polymers via Click Chemistry.

Amphiphilic copolymers with pendant functional groups in polyester segments are widely used in nanomedicine. These enriched functionalities are designed to form covalent conjugates with payloads or provide additional stabilization effects for encapsulated drugs. A general method is successfully developed for the efficient preparation of functional biodegradable PEG-polyester copolymers via click chemistry. Firstly, in the presence of mPEG as initiator, Sn(Oct)2-catalyzed ring-opening polymerization of the α-alkynyl functionalized lactone with D,L-lactide or ε-caprolactone afforded linear mPEG-polyesters bearing multiple pendant alkynyl groups. Kinetic studies indicated the formation of random copolymers. Through copper-catalyzed azide-alkyne cycloaddition reaction, various small azido molecules with different functionalities to polyester segments are efficiently grafted. The molecular weights, polydispersities and grafting efficiencies of azido molecules of these copolymers were investigated by NMR and GPC. Secondly, it is demonstrated that the resulting amphiphilic functional copolymers with low CMC values could self-assemble to form nanoparticles in aqueous media. In addition, the in vitro degradation study and cytotoxicity assays indicated the excellent biodegradability and low cytotoxicity of these copolymers. This work provides a general approach toward the preparation of functional PEG-polyester copolymers in a quite efficient way, which may further facilitate the application of functional PEG-polyesters as drug delivery materials.

Synthesis and characterization of poly(p-dioxanone)-based degradable copolymers with enhanced thermal and hydrolytic stabilities

Herein, we presented a novel biodegradable copolymer via the chain extending reaction of poly(p-dioxanone)-co-poly(2-(2-hydroxyethoxy) benzoate) (PPDO-co-PDHB) prepolymer with hexamethylene diisocyanate (HDI) as a chain extender. The structures and molecular weight of PPDO-co-PDHB prepolymer and PPDO-co-PDHB-PU chain-extended copolymer are characterized via hydrogen nuclear magnetic resonance spectroscopy (1H NMR) and viscosity test. The relationship between the molecular structures and properties of the chain-extended copolymers is established. The PPDO-co-PDHB-PU copolymers possess a better thermal stability comparing with the PPDO homopolymer. The study of mechanical properties shows that the elongation-at-break of PPDO-co-PDHB-PU is much higher than that of PPDO. The investigation of hydrolytic degradation behaviors indicates the degradation rate of PPDO can be controlled by adjusting the PDHB compositions, and proves that chain-extended copolymers exhibit an excellent hydrolytic stability being better than that of PPDO.

The Development of Design and Manufacture Techniques for Bioresorbable Coronary Artery Stents.

Coronary artery disease (CAD) is the leading killer of humans worldwide. Bioresorbable polymeric stents have attracted a great deal of interest because they can treat CAD without producing long-term complications. Bioresorbable polymeric stents (BMSs) have undergone a sustainable revolution in terms of material processing, mechanical performance, biodegradability and manufacture techniques. Biodegradable polymers and copolymers have been widely studied as potential material candidates for bioresorbable stents. It is a great challenge to find a reasonable balance between the mechanical properties and degradation behavior of bioresorbable polymeric stents. Surface modification and drug-coating methods are generally used to improve biocompatibility and drug loading performance, which are decisive factors for the safety and efficacy of bioresorbable stents. Traditional stent manufacture techniques include etching, micro-electro discharge machining, electroforming, die-casting and laser cutting. The rapid development of 3D printing has brought continuous innovation and the wide application of biodegradable materials, which provides a novel technique for the additive manufacture of bioresorbable stents. This review aims to describe the problems regarding and the achievements of biodegradable stents from their birth to the present and discuss potential difficulties and challenges in the future.

Place of intravitreal dexamethasone implant in the treatment armamentarium of diabetic macular edema.

Diabetic macular edema (DME) is a very important and well-known cause of visual loss in diabetics. Blood–retina barrier disruption and consequent intraretinal fluid accumulation may lead to retinal thickening at the posterior pole namely DME. Even though it is not clearly understood, current evidence suggests that chronic low-grade inflammation characterized with various cytokines has a major role in the occurrence of DME. Clinical trials are continuously shaping our treatment approaches for the eyes with DME. Today, vascular endothelial growth factor (VEGF) inhibitor and steroid administrations are the main alternatives in DME treatment. Dexamethasone (DEX) implant (Ozurdex®; Allergan, Inc., Irvine, CA, United States) was approved by the United States Food & Drug Administration in 2014 for DME treatment. The implant is made up of a biodegradable solid copolymer that is broken down by releasing its active ingredient into the vitreous cavity over time. Biphasic release feature of this sustained-release drug delivery system ensures its efficacy for up to 6 mo with an acceptable and manageable safety profile. DEX implant provides a favorable anatomical and functional outcome in DME as shown in several randomized-controlled studies but has a relatively higher ocular side-effect profile such as increased risk of cataract formation and raised intraocular pressure when compared to the gold standard anti-VEGF agents. Thus, DEX implant becomes the second-line treatment option demonstrating inadequate clinical response to anti-VEGF therapy. However, it can be preferred as the first-line treatment in vitrectomized and pseudophakic eyes. Even in some selected conditions DEX implant is favored over anti-VEGF agents where the use of VEGF-inhibitors is either inappropriate or contraindicated such as the patients with a recent history of a major cardiovascular or cerebrovascular event, pregnancy and noncompliant to frequent visits. This mini-review briefly overviews the efficacy, safety profile and complications of DEX implant and summarizes the outcome of DEX implant administration in major clinical studies on DME treatment.

Synthesis and Characterization of New Biodegradable Injectable Thermosensitive Smart Hydrogels for 5-Fluorouracil Delivery.

In this paper, injectable, thermosensitive smart hydrogel local drug delivery systems (LDDSs) releasing the model antitumour drug 5-fluorouracil (5-FU) were developed. The systems were based on biodegradable triblock copolymers synthesized via ring opening polymerization (ROP) of ε-caprolactone (CL) in the presence of poly(ethylene glycol) (PEG) and zirconium(IV) acetylacetonate (Zr(acac)4), as co-initiator and catalyst, respectively. The structure, molecular weight (Mn) and molecular weight distribution (Đ) of the synthesized materials was studied in detail using nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) techniques; the optimal synthesis conditions were determined. The structure corresponded well to the theoretical assumptions. The produced hydrogels demonstrated a sharp sol–gel transition at temperature close to physiological value, forming a stable gel with good mechanical properties at 37 °C. The kinetics and mechanism of in vitro 5-FU release were characterized by zero order, first order, Higuchi and Korsmeyer–Peppas mathematical models. The obtained results indicate good release control; the kinetics were generally defined as first order according to the predominant diffusion mechanism; and the total drug release time was approximately 12 h. The copolymers were considered to be biodegradable and non-toxic; the resulting hydrogels appear to be promising as short-term LDDSs, potentially useful in antitumor therapy.

Recent developments in biodegradable block copolymers

AbstractBlock copolymers consist of two or more segments of polymer chains in a typical arrangement through connected covalent bonds. Biodegradable block copolymers have emerged as useful carriers for controlled drug release, tissue engineering, and other biomedical applications due to their ability to form colloidal systems and tunable properties. This review focuses on recent advancements in the synthesis, characterization, and biomedical applications of biodegradable block copolymers.

Biodegradable, Tissue Adhesive Polyester Blends for Safe, Complete Wound Healing.

Pressure-sensitive adhesives typically used for bandages are nonbiodegradable, inhibiting healing, and may cause an allergic reaction. Here, we investigated the effect of biodegradable copolymers with promising thermomechanical properties on wound healing for their eventual use as biodegradable, biocompatible adhesives. Blends of low molecular weight (LMW) and high molecular weight (HMW) poly(lactide-co-caprolactone) (PLCL) are investigated as tissue adhesives in comparison to a clinical control. Wounds treated with PLCL blend adhesives heal completely with similar vascularization, scarring, and inflammation indicators, yet require fewer dressing changes due to integration of the PLCL adhesive into the wound. A blend of LMW and HMW PLCL produces an adhesive material with significantly higher adhesive strength than either neat polymer. Wound adhesion is comparable to a polyurethane bandage, utilizing conventional nonbiodegradable adhesives designed for extremely strong adhesion.

Biodegradable polyacrylate copolymer coating for bio-functional magnesium alloy

The clinical applications of magnesium (Mg) alloys remain a challenge due to their corrosion rate and toxicity problems. Herein, we report a biodegradable polyacrylate copolymer coating for enhancement of Mg alloy's anticorrosion performance and biocompatibility. Specifically, the biodegradable polyacrylate copolymer was first synthesized through the free-radical ring-opening copolymerization of 2-methylene-1,3-dioxepane (MDO), vinyl acetate (VAc), 7-(2-methacryloyloxyethoxy)-4-methylcoumarin (CMA), and dopamine methacrylamide (DMA). The poly(MDO-co-VAc-co-CMA-co-DMA) (PMVCD) coating was then applied on the surface of Mg alloy using electrophoretic deposition (EPD) and crosslinked under UV irradiation. The photo-crosslinking ability and biodegradability of PMVCD coating was provided by the CMA and MDO moieties, respectively. Potentiodynamic polarization, electrochemical impedance spectroscopy and in vitro degradation test demonstrated that the corrosion rate of PMVCD-coated Mg alloy was significantly decreased. Additionally, the enhanced cytocompatibility of PMVCD-coated Mg alloy was confirmed by in vitro cytotoxicity test.

Loading and release of\xa0cancer chemotherapy drugs utilizing simultaneous temperature and pH-responsive nanohybrid

BackgroundRecently, the development of nanocarriers and the improvement of their biochemical properties have became of great importance. Single-walled carbon nanotubes (SWCNT) have many applications in drug delivery systems (DDS) as a common carbon-based structure. In the current work, the penetration, co-loading, and co-release of Doxorubicin (DOX) and Paclitaxel (PAX), as two cancer chemotherapy agents, were investigated using a novel modified copolymer with functionalized SWCNT.ResultsThis study proposes a dual-responsive smart carrier that is sensitive to pH and temperature. The carrier consists of functionalized SWNT and Dimethyl acrylamide-trimethyl chitosan (DMAA-TMC) grafting on SWCNT. This suggested carrier was investigated by utilizing molecular simulations. Interaction energies between DOX, PAX, and carrier as well as the affinity of drugs to the nanocarrier were studied. The energy analysis of drug release and adsorption presented that DOX and PAX delivery using this carrier is selective and sensitive at healthy and cancerous conditions. The attraction of DMAA-TMC, as a biodegradable and biocompatible copolymer, with SWCNT showed that degradation mechanism in acidic environment deformed the copolymer. This leads to a smart release mechanism in an acidic cancerous tissue. Additionally, it improves hydrophilicity, optimum nano-particle size, and cell cytotoxicity concerns.ConclusionsThe simulation results manifested a significant contribution of DMAA-TMC in the adsorption and release of cancer chemotherapy drugs in normal and neoplastic tissues. The interaction of copolymer also improves the biocompatibility and biodegradability of the SWCNT. Smart drug delivery carrier can be a valuable nanohybrid for loading, transporting, and releasing of cancer chemotherapy drugs.Graphical abstract

A rapid quantitation of cell attachment and spreading based on digital image analysis: Application for cell affinity and compatibility assessment of synthetic polymers

Accurate and rapid quantitation of cell attachment, spreading, and growth on a polymer thin film coated glass cover slide was developed by analyzing the digital images of cells stained with dyes. A biodegradable block copolymer poly(ethylene glycol)-block-poly(l-lactide-co-2-methyl-2-carboxyl-propylene carbonate) [PEG-b-P(LA-co-MCC)] was synthesized as model polymer with poly(L-lactic acid) [PLLA] as a control polymer. Only a small quantity of polymer (~5 mg) was needed in this method through dissolving in a solvent and casting on cover slides which were previously modified with dimethyl dichlorosilane (DMDC). Then it was seeded with cells and taken pictures with a digital camera under an optical microscope and analyzed with ImageJ software. Cell number and a series of morphological data were obtained, including cell area, circularity, perimeter and Feret's diameter, etc. The quantitative analysis results indicated that cells preferred to attach and spread on the surface of the copolymer PEG-b-P(LA-co-MCC) compared to PLLA during 24 h of cell culture. This efficient procedure provides a series of convincing statistical data to evaluate the direct interaction between cells and polymers with only an optical microscope, a digital camera and ImageJ software. It's a rapid, economic way for assessing cell affinity and compatibility of novel synthetic polymers by cell culture in vitro.

Polymeric micelle mediated follicular delivery of spironolactone: Targeting the mineralocorticoid receptor to prevent glucocorticoid-induced activation and delayed cutaneous wound healing

Impaired wound healing in patients receiving glucocorticoid therapy is a serious clinical concern: mineralocorticoid receptor (MR) antagonists can counter glucocorticoid-induced off-target activation of MR receptors. The aim of this study was to investigate the cutaneous delivery of the potent MR antagonist, spironolactone (SPL), from polymeric micelle nanocarriers, prepared using a biodegradable copolymer, methoxy-poly(ethylene glycol)-di-hexyl-substituted-poly(lactic acid). Immunofluorescent labelling of the MR showed that it was principally located in the pilosebaceous unit (PSU), justifying the study rationale since polymeric micelles accumulate preferentially in appendageal structures. Cutaneous biodistribution studies under infinite and finite dose conditions, demonstrated delivery of pharmacologically relevant amounts of SPL to the epidermis and upper dermis. Preferential PSU targeting was confirmed by comparing amounts of SPL in PSU-containing and PSU-free skin biopsies: SPL nanomicelles showed 5-fold higher delivery of SPL in the PSU-containing biopsies, 0.54 ± 0.18 ng/mm2vs. 0.10 ± 0.03 ng/mm2, after application of a hydrogel in finite conditions. Canrenone, an active metabolite of SPL, was also quantified in skin samples. In addition to being used for the treatment of delayed cutaneous wound healing by site-specific antagonism of the MR, the formulation might also be used to treat pilosebaceous androgen-related skin diseases, e.g. acne vulgaris, since SPL is a potent androgen receptor antagonist.

Self-Assembled PEGylated Amphiphilic Polypeptides for Gene Transfection

In the present study, three biodegradable block copolymers composed of a poly(ethylene glycole) block and a copolypeptide block with varying compositions of cationic L-lysine (L-Lys) and hydrophobic benzyl-L-glutamate (Bzl- L-Glu) were designed for gene delivery applications. The polypeptides were synthesized by ring opening polymerization (ROP) and after orthogonal deprotection of Boc-L-Lys side chains, the polymer exhibited an amphiphilic character. To bind or encapsulate plasmid DNA (pDNA), various formulations were investigated: Nanoprecipitation and emulsion technique using various organic solvents as well as an aqueous pH-controlled formulation method. The complex and nanoparticle (NP) formations were monitored by dynamic light scattering (DLS), and pDNA interaction was shown by gel electrophoresis and subsequent controlled release with heparin. The polypeptides were further tested for their cytotoxicity as well as biodegradability. The complexes and NPs presenting the most promising size distributions and DNA binding ability were subsequently evaluated for their transfection efficiency in HEK293T cells. The highest transfection efficiencies were obtained with an aqueous formulation of the polypeptide containing the highest L-Lys content and lowest proportion of hydrophobic, helical structures (P1* ), which is therefore a promising candidate for efficient gene delivery by biodegradable gene delivery vectors.

Developing Novel Poly(Lactic-Co-Glycolic Acid) (PLGA) Films with Enhanced Adhesion Capacity by Biomimetic Mushroom-Shaped Microstructures

The adhesion strength of biomimetic mushroom-shaped microstructures made of a biocompatible and biodegradable copolymer, PLGA, is experimentally studied. The adhesive microstructures were successfully produced using a two-step molding technique. The adhesive experiments were performed on a flat and smooth glass substrate using different normal preloads and under both dry (in air) and wet (underwater) contact conditions. Regardless of contact conditions, mushroom-shaped microstructures generate much higher adhesion strength compared to a flat smooth reference sample made of the same PLGA material. Furthermore, PLGA mushroom-shaped microstructures exhibited superior adhesion strength using agar substrate as a representative material for biological tissue. Surface texturing indicates a good approach to modify adhesive properties PLGA without additional excipients. The effect of surface texturing is more pronounced under wet contact condition. The concept of using biomimetic adhesive surfaces made of biocompatible and biodegradable polymers is very promising for potential applications in drug delivery, tissue engineering and biomedical field.

Design and Development of D‒α‒Tocopheryl Polyethylene Glycol Succinate‒block‒Poly(ε-Caprolactone) (TPGS-b-PCL) Nanocarriers for Solubilization and Controlled Release of Paclitaxel.

The objective of this study was to synthesize and characterize a set of biodegradable block copolymers based on TPGS-block-poly(ε-caprolactone) (TPGS-b-PCL) and to assess their self-assembled structures as a nanodelivery system for paclitaxel (PAX). The conjugation of PCL to TPGS was hypothesized to increase the stability and the drug solubilization characteristics of TPGS micelles. TPGS-b-PCL copolymer with various PCL/TPGS ratios were synthesized via ring opening bulk polymerization of ε-caprolactone using TPGS, with different molecular weights of PEG (1–5 kDa), as initiators and stannous octoate as a catalyst. The synthesized copolymers were characterized using 1H NMR, GPC, FTIR, XRD, and DSC. Assembly of block copolymers was achieved via the cosolvent evaporation method. The self-assembled structures were characterized for their size, polydispersity, and CMC using dynamic light scattering (DLS) technique. The results from the spectroscopic and thermal analyses confirmed the successful synthesis of the copolymers. Only copolymers that consisted of TPGS with PEG molecular weights ≥ 2000 Da were able to self-assemble and form nanocarriers of ≤200 nm in diameter. Moreover, TPGS2000-b-PCL4000, TPGS3500-b-PCL7000, and TPGS5000-b-PCL15000 micelles enhanced the aqueous solubility of PAX from 0.3 µg/mL up to 88.4 ug/mL in TPGS5000-b-PCL15000. Of the abovementioned micellar formulations, TPGS5000-b-PCL15000 showed the slowest in vitro release of PAX. Specifically, the PAX-loaded TPGS5000-b-PCL15000 micellar formulation showed less than 10% drug release within the first 12 h, and around 36% cumulative drug release within 72 h compared to 61% and 100% PAX release, respectively, from the commercially available formulation (Ebetaxel®) at the same time points. Our results point to a great potential for TPGS-b-PCL micelles to efficiently solubilize and control the release of PAX.

Ceric-ions redox initiating technique for Zirconium and Niobium separation through graft copolymerization of natural polysaccharides

ABSTRACT The modification of the polysaccharides as a significant route to alter the physical and chemical properties via Ceric-initiated graft copolymerization of Acrylonitrile (AN) onto Carboxymethyl cellulose (CMC) was performed under inert atmosphere using ceric ammonium nitrate (CAN) as an initiator to prepare CMC-g-PAN copolymers. In this respect, NaOH solution hydrolyzed the graft copolymer, CMC-g-PAN, to obtain hydrolyzed CMC-g-PAN hydrogel, in which the CMC-g-PAN nitrile groups were totally transformed into a combination of hydrophilic carboxamide and carboxylate groups (H-CMC-g-PAN). Pure CMC and grafted copolymers structure were identified by an analyzation of FTIR spectral data, TGA, SEM and XRD. These biodegradable and low-cost graft copolymers, with improved features could really be utilized as promising adsorbents for separation and recovery of some metal values from different media. H-CMC-g-PAN was implanted for the effective separation of Zr(IV) and Nb(V) from nitric acid solution and the batch experimental results indicate that the extraction percentage by adsorbent gradually decreased by raising the HNO3 molarity. The calculated maximum capacity of H-CMC-g-PAN is 10.56 mg.g−1 Zr(IV) and 14.07 mg.g−1 Nb(V) under the used experimental conditions. Desorption investigation shows that the maximum desorption of Zr(IV) and Nb(V) was achieved with 1 M HCl, while selective stripping of Niobium was carried out using 1 M sodium hydroxide.

Brain-invasive meningiomas: molecular mechanisms and potential therapeutic options

Meningiomas are the most commonly diagnosed benign intracranial adult tumors. Subsets of meningiomas that present with extensive invasion into surrounding brain areas have high recurrence rates, resulting in difficulties for complete resection, substantially increased mortality of patients, and are therapeutically challenging for neurosurgeons. Exciting new data have provided insights into the understanding of the molecular machinery of invasion. Moreover, clinical trials for several novel approaches have been launched. Here, we will highlight the mechanisms which govern brain invasion and new promising therapeutic approaches for brain-invasive meningiomas, including pharmacological approaches targeting three major aspects of tumor cell invasion: extracellular matrix degradation, cell adhesion, and growth factors, as well as other innovative treatments such as immunotherapy, hormone therapy, Tumor Treating Fields, and biodegradable copolymers (wafers), impregnated chemotherapy. Those ongoing studies can offer more diversified possibilities of potential treatments for brain-invasive meningiomas, and help to increase the survival benefits for patients.

Minocycline hydrochloride loaded mPEG-PCLA membranes: Preparation and in vitro evaluation for periodontitis therapy

This study was aimed at alleviating shortcomings in the treatment of periodontitis by preparation of a biopolymer membrane loaded with minocycline hydrochloride (MH) inserted into periodontal pockets to treat infections. Monomethoxy-poly (ethylene glycol)-poly (ε-caprolactone-co-L-lactide) (mPEG-PCLA) is a biocompatible and biodegradable amphiphilic block copolymer. It, therefore, has attracted considerable attention in drug delivery systems and periodontal treatment. We chose it as a membrane material for MH-drug loading. The MH-loaded membranes were prepared by the solvent casting technique with the content of 5, 8 and 10 wt.%, respectively. Fourier transform infrared spectra (FTIR) revealed no interaction between MH and polymer. The drug-loaded membrane surface morphology was investigated by scanning electron microscopy (SEM). In vitro release studies showed that the initial drug release exceeded 40% within 24 h, followed by a sustained release for up to 2 weeks, which would enable the therapeutic level to maintain over a longer time. The antibacterial activity studies in vitro demonstrated a positive effect on the periodontal pathogen. MH drug-loaded membranes have no adverse effect on the growth of periodontal ligament fibroblasts in the MTT test. The study suggests that mPEG-PCLA membranes containing MH are a potential antibacterial drug delivery system for local treatment of periodontitis.