Progress in controlled ocular anti-VEGF drug release delivery system / 中华实验眼科杂志

Neovascularization is the hallmark of many fundus diseases, including diabetic retinopathy, retinal vein occlusion and neovascular age-related macular degeneration.More and more evidence suggests that vascular endothelial growth factor (VEGF) plays a critical role in neovascularization.Anti-VEGF drugs are the first-line treatment for neovascular fundus diseases and have achieved significant results.However, there are drawbacks such as short drug half-lives and the need for long-term administration to maintain effective concentrations, which increases the economic burden and medical risk for patients and reduces compliance.Therefore, finding a new method for intraocular drug delivery is of great clinical importance.Based on the principle that diabetes patients use insulin pumps to gradually release drugs, the ocular anti-VEGF drug delivery system can continuously release anti-VEGF drugs over a period of time, significantly reducing the injection frequency and improving patient compliance.At present, the research on ocular anti-VEGF drug delivery systems is still immature, and various systems are in different stages of clinical trials.According to different design principles, they can be divided into three categories with their characteristics, micropump (extraocular storage delivery systems), biodegradable implants, and non-biodegradable implants.This article summarized and analyzed the controlled ocular anti-VEGF drug release delivery systems currently in clinical trials.

Research progress of intelligent reversible drug delivery system / 药学学报

In the research on cancer theranostics, most environment-sensitive drug delivery systems can only achieve unidirectional and irreversible responsive changes under pathological conditions, thereby improving the targeting effect and drug release performance of the delivery system. However, such irreversible changes pose potential safety hazards when the dynamically distributed delivery system returns to the blood circulation or transports to the normal physiological environment. Intelligent reversible drug delivery systems can respond to normal physiological and pathological microenvironments to achieve bidirectional and reversible structural changes. This feature will help to precisely control the drug release of the delivery system, prolong the blood circulation time, improve the targeting efficiency, and avoid the potential safety hazards of the irreversible drug delivery system. In this review, we describe the research progress of intelligent reversible drug delivery system from two main aspects: controlled drug release and prolonged blood circulation time/enhanced cellular internalization of drug.

Application of organic nanocarriers for intraocular drug delivery / 浙江大学学报·医学版

The application of intraocular drug delivery is usually limited due to special anatomical and physiological barriers, and the elimination mechanisms in the eye. Organic nano-drug delivery carriers exhibit excellent adhesion, permeability, targeted modification and controlled release abilities to overcome the obstacles and improve the efficiency of drug delivery and bioavailability. Solid lipid nanoparticles can entrap the active components in the lipid structure to improve the stability of drugs and reduce the production cost. Liposomes can transport hydrophobic or hydrophilic molecules, including small molecules, proteins and nucleic acids. Compared with linear macromolecules, dendrimers have a regular structure and well-defined molecular mass and size, which can precisely control the molecular shape and functional groups. Degradable polymer materials endow nano-delivery systems a variety of size, potential, morphology and other characteristics, which enable controlled release of drugs and are easy to modify with a variety of ligands and functional molecules. Organic biomimetic nanocarriers are highly optimized through evolution of natural particles, showing better biocompatibility and lower toxicity. In this article, we summarize the advantages of organic nanocarriers in overcoming multiple barriers and improving the bioavailability of drugs, and highlight the latest research progresses on the application of organic nanocarriers for treatment of ocular diseases.

Preparation of azithromycin-ion exchange resin complexes for taste-masking and controlled drug release / 中国药科大学学报

@#In order to mask the bitterness of azithromycin (AZI) and individually regulate the drug release rate to reduce gastrointestinal irritation, immediate-release AZI-AmberliteTM IRP64/HPC and delayed-release AZI-AmberliteTM IRP69/RS100 were prepared by modifying with hydroxypropyl cellulose (HPC) and Eudragit RS100, respectively, and further combined to achieve controlled release.The drug loading and drug utilization rate of AZI-ion exchange resin complexes were measured; the structure of AZI-ion exchange resin complexes was characterized by differential scanning calorimetry and X-ray diffraction; and the wetting humidity, odor masking effects, in vitro dissolution and release behaviors were determined.The results showed that the formation of AZI-ion exchange resin complexes changed the original crystallization state of the drug, that the 2.5% HPC-modified AZI-AmberliteTM IRP64/HPC and the 0.5% RS100-modified AZI-AmberliteTM IRP69/RS100 demonstrated good taste masking effect, and that their combination in the drug content ratio of 13∶67 achieved the expected drug release behavior, i.e.rapid release of AZI in the first 10 min and smooth release in the later 6 h.These results indicated that the AZI-ion exchange resin complexes prepared by surface modification and their composites could mask the bitterness of AZI and realize the flexible adjustment of drug release rate, which lays the foundation for the research and development of new AZI preparations.

In vivo pharmacokinetics and in vitro-in vivo correlation of silymarin phospholipid complex microporous osmotic pump controlled-release tablets in beagle dogs / 药学实践杂志

Objective To evaluate the release characteristics in vitro, pharmacokinetics in rabbits and in vivo-in vitro correlation of silymarin phospholipid complex microporous osmotic pump controlled release tablets（SM-PC MPOP）. Methods The release characteristics of SM-PC MPOP in vitro were detected by HPLC in the artificial gastric fluid. Six beagle dogs were subjected to double cycle cross control, which were given SM-PC MPOP and Legalon（30 mg/kg）. The concentration of silybin in plasma was determined by HPLC and the data were processed by software. Results The cumulative release rate of SM-PC MPOP in vitro was over 85% in 12 h. The pharmacokinetics in beagle dogs showed that SM-PC MPOP and legalon conformed to double compartment first-order absorption model and the pharmacokinetic parameters were obtained: tmax:（3.2±0.4）and（0.9±0.1）h, Cmax:（0.298 6±0.068 9）and（0.629 9±0.076 5）μg/ml, AUC0→24:（2.996 8±0.583 3）and（2.268 9±0.432 8）h·μg /ml. The relative bioavailability of SM-PC MPOP was（162.21 ± 30.82）%. Conclusion SM-PC MPOP could release slowly, which could increase the relative bioavailability significantly. The correlation between the absorption in vivo and release in vitro was fine（r = 0.839 0）.

Optimization and Quest of HPMC loaded Stavudine Controlled Release Dosage Development by Central Composite Design utilizing Reduced Factorial Screening Technique

Abstract The current research focused on screening and finding the significant independent variables in stavudine loaded tablet, followed by optimizing the best formulation using central composite design. The objective of the study to develop stavudine loaded controlled release tablet utilizing reduced factorial design, followed by optimization technique as well as characterization of prepared tablets. Preliminary trial batches were prepared using different grades of hydroxypropyl methylcellulose. The resolution-IV reduced factorial design was selected to screen the significant independent variables in the dosage form design. A total number of eight runs were prepared and responses were recorded. The signified factors identified by half-normal and Pareto chart. The prepared tablets are evaluated for various physiochemical characterizations. Three dependent responses such as hardness, dissolution at 6 hour and 12 hours are considered in optimization process. Later on, drug-polymer interaction study was carried out. The principal of the study design based on finding the best formulation with prefixed set parameter values utilizing the concept of screening technique. It observed that HPMC K15M (57.18 %), HPMC K100 (66.32 %) and PVP K30 (7.97 %) as best composition in a formulation batch would fulfill the predetermined parameter with specific values.

Polymeric Material With Controlled Release of Antimicrobial Agents for Medical Application

@#Introduction: Nowadays the use of synthetic polymers has become an integral part of modern medicine. Poly(2-hydroxyethyl methacrylate) has attracted special attention for therapeutic use. The objective of this study was to develop novel polymeric material based on poly(2-hydroxyethyl methacrylate) by addition of water as pore-forming agent and antimicrobial components, which would differ from similar materials by controlled release of active substances. Methods: The antimicrobial release kinetics study materials were immersed into distilled water followed by sampling and measuring their concentration. Concentration of chlorhexidine bigluconate and metronidazole was determined using spectrophotometric method and decamethoxine by photocolorimetric method based on reaction with eosin. The swelling rate was determined by gravimetric method. Results: Conventional dressing materials, after being soaked with antiseptic solutions, have demonstrated limited abilities in releasing active substances. Gauze pads were found to release antimicrobials during a short period of time reaching 50–80 % for decamethoxine containing samples and almost 100 % for those with metronidazole and chlorhexidine bigluconate at 2 h of observation. No study active substances were released from activated charcoal dressings. Similar results were obtained with porcine xenografts. Unlike the above mentioned dressing materials, modified polymer matrix based on poly(2-hydroxyethyl methacrylate) showed the controlled release of antimicrobial substances into water medium. Study material containing 3.0 % of decamethoxine and 76.3 % of water demonstrated optimal efficiency in the rate and duration of release, exerting high physical and mechanical properties. Conclusion: The synthesized polymers are similar to conventional dressings in antimicrobial release kinetics, but in some characteristics they are better for practical application.

Controlled release and cytobiology of recombinant human parathyroid hormone 1-34 mediated by hyaluronic acid thermo-sensitive hydrogels / 药学学报

The bone formation promoter recombinant human parathyroid hormone 1-34 [PTH (1-34)] has a short half-life and low bioavailability. In this study, we prepared a biodegradable and temperature-sensitive hyaluronic acid-poly-N-isopropyl acrylamide (AHA-g-PNIPAAm), and further investigated its effects of PTH (1-34) release and cell behavior as drug carrier. The structure of AHA-g-PNIPAAM was confirmed by hydrogen nuclear magnetic resonance spectroscopy and infrared spectroscopy. Next, PTH (1-34) loaded thermo-sensitive hydrogels were prepared by physical swelling method and their stability was investigated. The morphology of hydrogel was observed by scanning electron microscope. The minimum critical transition temperature and drug release behavior of hydrogels were investigated by ultraviolet spectrophotometry. The tetrazolium-based colorimetric assay (MTT assay) was used to investigate the toxicity and proliferation effects of PTH (1-34)-loaded thermo-sensitive hydrogel on mouse mononuclear macrophage RAW264.7 and mouse precranial osteoblasts MC3T3-E1. The effect of PTH (1-34)-loaded thermo-sensitive hydrogel on the differentiation of RAW264.7 was investigated by the tartrate-resistant acid phosphatase assay. The results showed that the PTH (1-34)-loaded thermo-sensitive hydrogel prepared in this study displayed regular three-dimensional honeycomb structure, and had good stability, thermo-sensitivity and sustained and controlled release properties, which could promote the proliferation of MC3T3-E1 cells more effectively and inhibit the differentiation of RAW264.7 into osteoclasts.

Fighting type 2 diabetes: Formulation strategies for peptide-based therapeutics

Diabetes mellitus is a major health problem with increasing prevalence at a global level. The discovery of insulin in the early 1900s represented a major breakthrough in diabetes management, with further milestones being subsequently achieved with the identification of glucagon-like peptide-1 (GLP-1) and the introduction of GLP-1 receptor agonists (GLP-1 RAs) in clinical practice. Moreover, the subcutaneous delivery of biotherapeutics is a well-established route of administration generally preferred over the intravenous route due to better patient compliance and prolonged drug absorption. However, current subcutaneous formulations of GLP-1 RAs present pharmacokinetic problems that lead to adverse reactions and treatment discontinuation. In this review, we discuss the current challenges of subcutaneous administration of peptide-based therapeutics and provide an overview of the formulations available for the different routes of administration with improved bioavailability and reduced frequency of administration.

Gene expression and apoptosis response in hepatocellular carcinoma cells induced by biocompatible polymer/magnetic nanoparticles containing 5-fluorouracil

BACKGROUND: Super-paramagnetic iron oxide nanoparticles (SPION) contain a chemotherapeutic drug and are regarded as a promising technique for improving targeted delivery into cancer cells. RESULTS: In this study, the fabrication of 5-fluorouracil (5-FU) was investigated with loaded Dextran (DEXSPION) using the co-precipitation technique and conjugated by folate (FA). These nanoparticles (NPs) were employed as carriers and anticancer compounds against liver cancer cells in vitro. Structural, magnetic, morphological characterization, size, and drug loading activities of the obtained FA-DEX-5-FUSPION NPs were checked using FTIR, VSM, FESEM, TEM, DLS, and zeta potential techniques. The cellular toxicity effect of FA-DEX-5-FU-SPION NPs was evaluated using the MTT test on liver cancer (SNU-423) and healthy cells (LO2). Furthermore, the apoptosis measurement and the expression levels of NF-1, Her-2/neu, c-Raf-1, and Wnt-1 genes were evaluated post-treatment using flow cytometry and RT-PCR, respectively. The obtained NPs were spherical with a suitable dispersity without noticeable aggregation. The size of the NPs, polydispersity, and zeta were 74 ± 13 nm, 0.080 and 45 mV, respectively. The results of the encapsulation efficiency of the nano-compound showed highly colloidal stability and proper drug maintenance. The results indicated that FA-DEX-5-FU-SPION demonstrated a sustained release profile of 5-FU in both phosphate and citrate buffer solutions separately, with higher cytotoxicity against SNU-423 cells than against other cells types. These findings suggest that FA-DEX-SPION NPs exert synergistic effects for targeting intracellular delivery of 5-FU, apoptosis induction, and gene expression stimulation. CONCLUSIONS: The findings proved that FA-DEX-5-FU-SPION presented remarkable antitumor properties; no adverse subsequences were revealed against normal cells.

Clinical efficacy of controlled-release morphine tablets combined with celecoxib in pain management and the effects on WNK1 expression

OBJECTIVES: This study was designed to evaluate the clinical efficacy of controlled-release morphine tablets combined with celecoxib in relieving osteocarcinoma-related pain and the effects of the combination on WNK1 expression. METHODS: A total of 110 patients with osteocarcinoma-related pain were selected and divided into two groups based on the treatment administered, including the control group (treated with controlled-release morphine tablets alone) and the study group (treated with a combination of controlled-release morphine tablets and celecoxib). We compared the treatment efficacy, pain level (visual analog scale (VAS)), time of onset of breakthrough pain (BTP), dose of morphine, incidence of adverse events, quality of life (QOL) score, and With-no-lysine 1 (WNK1) expression in the peripheral blood (PB) as determined with qRT-PCR before and after treatment, of the two groups. RESULTS: The total effective rate of the study group was higher than that of the control group, while the VAS score, time of onset of BTP, dose of morphine, incidence of adverse events, QOL score, and relative WNK1 expression in the PB were lower than those of the control group (p<0.05). CONCLUSION: Combination treatment with controlled-release morphine tablets and celecoxib can be extensively used in the clinical setting because it effectively improves the symptoms, QOL score, and adverse effects in patients with osteocarcinoma-related pain.

An injectable micelle-hydrogel hybrid for localized and prolonged drug delivery in the management of renal fibrosis

Localized delivery, comparing to systemic drug administration, offers a unique alternative to enhance efficacy, lower dosage, and minimize systemic tissue toxicity by releasing therapeutics locally and specifically to the site of interests. Herein, a localized drug delivery platform ("plum‒pudding" structure) with controlled release and long-acting features is developed through an injectable hydrogel ("pudding") crosslinked

Can nanoparticles and nano‒protein interactions bring a bright future for insulin delivery?

Insulin therapy plays an essential role in the treatment of diabetes mellitus. However, frequent injections required to effectively control the glycemic levels lead to substantial inconvenience and low patient compliance. In order to improve insulin delivery, many efforts have been made, such as developing the nanoparticles (NPs)-based release systems and oral insulin. Although some improvements have been achieved, the ultimate results are still unsatisfying and none of insulin-loaded NPs systems have been approved for clinical use so far. Recently, nano‒protein interactions and protein corona formation have drawn much attention due to their negative influence on the

Formulation and optimization of Enalapril Maleate-loaded floating microsphere using Box–Behnken design: in vitro study

The objective was to prepare an Enalapril Maleate (EnM)-loaded floating microsphere with minimum particle size,maximum drug loading, and drug entrapment efficiency. Formulations were prepared by varying drug-to-polymerratio (A), solvent ratio (B), and stirring time (C). The solvent evaporation method was used to prepare the microsphere.“Box–Behnken’s design” (3 factors × 3 levels) was utilized for optimization. The independent variables were polymerto-drug ratio (A), solvent ratio (B), and stirring time (C), while particle size (R1), drug loading (R2), and entrapmentefficiency (R3) were considered as dependent variables. EnM-loaded alcohol microsphere (Formulation-A) wasprepared and optimized. Both Formulation-A and EnM-loaded acetonitrile microspheres (Formulation-B) weresubjected to morphological, micrometric, characterization, and in vitro release studies. The particle size, drug loading,and entrapment efficiency of Formulation-A and Formulation-B were 143 ± 27.75 µm, 37.31% ± 5.73%, and 76.89%± 4.97%, and 158.13 ± 25.1 µm, 40.13% ± 6.12%, and 99.19% ± 1.14%, respectively. The cumulative drug releasesof Formulation-A and Formulation-B were 90.52% ± 4.11% and 86.23% ± 3.81%, respectively. Both formulationsfollowed the Higuchi model of drug release. EnM-floating microsphere was effectively prepared and both formulationsshowed excellent continuous release properties for more than 12 hours.

Formulation Development, Characterization and In-vitro Evaluation of Tamoxifen Loaded Liposomes

Background: The study was aimed to prepare and evaluate tamoxifen loaded controlled release liposomes to reduce the side effects of tamoxifen during cancer treatment. Methods: Different tamoxifen loaded liposomes were prepared by modified ether injection (MEIM) and thin film hydration method (TFHM) under prescribed conditions. The prepared liposomes were characterized by using optical microscopy, evaluating encapsulation efficiency, in-vitro and ex-vivo diffusion studies by using dialysis membrane and chicken intestinal sac respectively.Results: The data revealed that all of the liposomes were spherical in shape and stable under three physical conditions i.e. 4, 25 and 37 ± 2°C temperatures and 60 ±5% relative humidity. Additionally most of the liposomes followed zero order and class II release kinetics. It was also observed that with the increase of phospholipids and cholesterol, entrapment efficiency of liposome vesicles increased thus giving a controlled release drug delivery system but further increase reduced this efficiency at a certain level.Conclusion: The formulated control release liposomes might be a good drug delivery system for target oriented drug delivery with minimum side effects of tamoxifen during cancer treatment

Controlled release alginate-chitosan microspheres of tolmetin sodium prepared by internal gelation technique and characterized by response surface modeling

Tolmetin sodium (TS) is a powerful non-steroidal mitigating drug for the treatment of rheumatoid joint inflammation, osteoarthritis, and adolescent rheumatoid joint pain. In addition to its gastrointestinal (GIT) problems, TS has a short biological half-life (1 hr). In a trial to overcome these side effects and control the rate of (TS) release, chitosan coated alginate microspheres are recommended. A Box-Behnken experimental design was employed to produce controlled release microspheres of TS in the sodium alginate and chitosan copolymers (Alg-Ch) by emulsification internal gelation methodology. The effect of critical formulation variables namely, drug to polymer ratio (D:P ratio), speed of rotation and span 80% on drug encapsulation efficiency (% EE), drug release at the end of 2 hours (Rel2) and drug release at the end of 8 hours (Rel8) were analyzed using response surface modeling. The parameters were assessed using the F test and mathematical models containing only the significant terms were generated for each parameter using multiple linear regression analysis. The produced microspheres were spherical in shape with extensive pores at D:P ratio 1:1 and small pores at a drug to polymer ratio (D:P ratio) 1:3. Differential scanning calorimetry (DSC) affirmed the steady character of TS in microspheres and revealed their crystalline form. All formulation variables examined exerted a significant influence on the drug release, whereas the speed emerged as a lone factor significantly influencing % EE. Increasing the D: P ratio decreases the release of the drug after two and 8 hours. The increase in speed results in an increase in drug release after two and eight hours. The drug release from the microspheres followed zero order kinetics. TS Alg-Ch microspheres exhibited a significant anti-inflammatory effect on incited rat paw edema after eight hours. These results revealed that the internal gelation technique is a promising method to control TS release and eradicate GIT side effects using Alg-Ch copolymers.

A preformulation strategy for the selection of controlled-release components to simulate a subcutaneous implant / Una estrategia de preformulación para la selección de componentes de liberación controlada para simular un implante subcutáneo

Many chronic diseases require repetitive injections as maintenance treatment. It is therefore important to investigate a possible alternative. A simulated subcutaneous implant prototype was fabricated as a polymer matrix covered by cylinder-shape tubing having a porous membrane. Sucrose, bovine serum albumin, and gelatin were selected as matrix excipients. Eight APIs with different physiochemical properties were used to investigate the releasing mechanism. Drug release was tested through an in vitrodissolution apparatus. Drug release of eight APIs followed zero-order kinetics with a minimum 12-hour duration. Release rates also showed linear correlations with the APIs' solubilities under physiological pH. For releasing mechanism studies, different combinations of matrix and membrane were investigated in detail. A 144-hour continuous zero-order release of caffeine was achieved as the best controlled simulated prototype. The results showed that drug release of our simulated prototype was primarily achieved by drug diffusion rather than dissolution.

Muchas enfermedades crónicas requieren inyecciones repetitivas como tratamiento de mantenimiento. Por lo tanto, es importante investigar una posible alternativa. Se fabricó un prototipo de implante subcutáneo simulado a partir de una matriz de polímero cubierta por un tubo en forma de cilindro que tiene una membrana porosa. La sacarosa, la albúmina de suero bovino y la gelatina se seleccionaron como excipientes matriciales. Se utilizaron ocho APIs con diferentes propiedades fisicoquímicas para investigar el mecanismo de liberación. La liberación del fármaco se probó a través de un aparato de disolución in vitro. La liberación del fármaco de las ocho APIs siguió una cinética de orden cero con una duración mínima de 12 horas. Las tasas de liberación también mostraron correlaciones lineales con las solubilidades de las APIs a pH fisiológico. Para los estudios de mecanismos de liberación, se investigaron en detalle diferentes combinaciones de matriz y membrana. El prototipo simulado con mejor control logró una liberación continua de cafeína de orden cero durante 144 horas. Los resultados mostraron que la liberación del fármaco del prototipo simulado ocurrió principalmente mediante la difusión del fármaco en lugar de la disolución.

Development of controlled release dexketoprofen tablets and prediction of drug release using Artificial Neural Network (ANN) modelling

Dexketoprofen trometamol (DT) is an active S (+) enantiomer of ketoprofen, and a non-steroidal anti-inflammatory agent. DT has a short biological half-life and the dosing interval is quite short when there is a need to maintain the desirable effect for longer time periods. Consequently, a controlled release DT tablet was designed for oral administration aiming to minimize the number of doses and the possible side effects. Calculations of the parameters for controlled release DT tablets were shown clearly. Controlled release matrix-type tablet formulations were prepared using hydroxypropyl methylcellulose (HPMC) (low and high viscosity), Eudragit RS and Carbopol, and the effects of different polymers on DT release from the tablet formulations were investigated. The dissolution rate profiles were compared and analyzed kinetically. An Artificial Neural Network (ANN) model was developed to predict drug release and a successful model was obtained. Subsequently, an optimum formulation was selected and evaluated in terms of its analgesic and anti-inflammatory activity. Although the developed controlled release tablets did not have an initial dose, they were found to be as effective as commercially available tablets on the market. Dissolution and in vivo studies have shown that the prepared tablets were able to release DT for longer time periods, making the tablets more effective, convenient and more tolerable.

Construction of periodontal biomimetic membrane with electrospun poly(Lactic-co-glycolic acid) nanofibers and electrosprayed chitosan microspheres / 中国组织工程研究

BACKGROUND: When the teeth are separated from the alveolar fossa, the periodontal membrane breaks, and the residual periodontal membrane on the avulsed tooth root surface changes from three-dimensional to two-dimensional, thus losing the role of scaffold, and leading to root bone adhesion after replantation of avulsed tooth. How to develop a three-dimensional sustained-release scaffold material that can adhere to the root surface with a certain thickness and strength is one of the key factors for successful regeneration of avulsed tooth periodontal membrane. OBJECTIVE: To construct a three-dimensional periodontal biomimetic membrane that can adhere to the avulsed tooth root surface and allow sustained-release of growth factors. METHODS: Poly(lactic-co-glycolic acid) (PLGA) membrane was prepared using electrospinning technique. The effects of dichloromethane and dimethylformamide mixture, hexafluoroisopropanol, and trichloromethane on electrospun membrane were investigated to obtain the optimal electrospinning solvent. Chitosan microspheres were prepared by electrospray and ion cross-linking techniques. The effects of molecular weight (50, 000, 100, 000) and mass concentration (10, 20 g/L) of chitosan, sodium tripolyphosphate concentration (2%, 5%, 10%) and voltage (14, 28 kV) on chitosan microspheres were studied to screen the optimum parameters. Chitosan microspheres containing stromal cell-derived factor-1 (optimal parameter design) were constructed. The release rate of stromal cell-derived factor-1 alpha in vitro was determined. First, the root surface of teeth was wrapped with electrospun PLGA membrane, then chitosan microspheres were dripped on the surface, and finally the surface was wrapped with a thin layer of electrospun PLGA. Thus, PLGA-chitosan-PLGA biomimetic membrane was constructed. RESULTS AND CONCLUSION: Electrospun PLGA membrane prepared with hexafluoroisopropanol as electrospinning solvent had the smallest average diameter and the largest porosity. When the relative molecular weight of chitosan was 50, 000 and the mass concentration was 20 g/L, the size of chitosan microspheres was basically the same, and the average diameter was 366. 6 μm. In addition, chitosan microsphere had good monodispersity, fullness, and stability. Chitosan microspheres formed under 28 kV voltage and were more in line with the requirements of biomimetic membrane for avulsed tooth. The surface of microspheres prepared by 5% sodium tripolyphosphate had medium-sized pores, which are most conducive to clinical periodontal membrane regeneration. Chitosan microspheres can sustainably release stromal cell derived factor 1alpha for about 1 month. In this study, we constructed a three-dimensional PLGA-chitosan-PLGA periodontal biomimetic membrane that can adhere to the avulsed tooth root surface and allow sustained-release of growth factors and obtained the optimal parameters of constructing the periodontal biomimetic membrane. Based on the PLGA-chitosan-PLGA periodontal biomimetic membrane, the effect and mechanism of tissue engineering on replantation of avulsed tooth can be further studied.

Microencapsulation of immunoglobulin Y: optimization with response surface morphology and controlled release during simulated gastrointestinal digestion / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Immunoglobulin Y (IgY) is an effective orally administered antibody used to protect against various intestinal pathogens, but which cannot tolerate the acidic gastric environment. In this study, IgY was microencapsulated by alginate (ALG) and coated with chitooligosaccharide (COS). A response surface methodology was used to optimize the formulation, and a simulated gastrointestinal (GI) digestion (SGID) system to evaluate the controlled release of microencapsulated IgY. The microcapsule formulation was optimized as an ALG concentration of 1.56% (15.6 g/L), COS level of 0.61% (6.1 g/L), and IgY/ALG ratio of 62.44% (mass ratio). The microcapsules prepared following this formulation had an encapsulation efficiency of 65.19%, a loading capacity of 33.75%, and an average particle size of 588.75 µm. Under this optimum formulation, the coating of COS provided a less porous and more continuous microstructure by filling the cracks on the surface, and thus the GI release rate of encapsulated IgY was significantly reduced. The release of encapsulated IgY during simulated gastric and intestinal digestion well fitted the zero-order and first-order kinetics functions, respectively. The microcapsule also allowed the IgY to retain 84.37% immune-activity after 4 h simulated GI digestion, significantly higher than that for unprotected IgY (5.33%). This approach could provide an efficient way to preserve IgY and improve its performance in the GI tract.