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.

Formula and Preparation of Cantharidin Chitosan Bioadhesive Microspheres by Spray Drying / 中国药师

Objective: To optimize the formula and preparation technology of cantharidin chitosan bioadhesive microspheres.Methods: The microspheres were prepared by a spray drying method.A single-factor experiment was used to study the effect of chitosan with different molecular weight on the gastric mucosa adhesion rate were also studied, and the effects of different drug loading ratio, concentration of chitosan acetic acid solution and speed of peristaltic pump on the loading rate were also studied.The cantharidin entrapment efficiency as the studying index, a response surface method was used to further optimize the formula.Results: The best formula and preparation process of cantharidin chitosan bioadhesive microspheres were as follows: the concentration ratio of antharidin to chitosan was 19.83% , the concentration of chitosan acetic acid solution was 0.77% , and the peristaltic pump flow rate was 9.225 ml·min-1.With the best formula, the entrapment efficiency of cantharidin chitosan bioadhesive microspheres was 90.14%.Conclusion: The microsphere preparation by the spray drying method is stable and repeatable.Cantharidin chitosan bioadhesive microspheres have high entrapment efficiency and promising biological adhesion.

Studies on the characteristics and cytotoxicity of gentamicin/chitosan microspheres for local injection / 中国生化药物杂志

Objective To construct the drug delivery system of gentamicin/chitosan microspheres for local injection, and evaluate its physicochemical properties and cell cytotoxicity.Methods Gentamicinwas used as model drug, chitosan as carrier, lecithinand hydroxypropyl-β-cyclodextrin as accessories, and the microspheres of gentamicin/chitosan/lecithin/hydroxypropyl-β-cyclodextrinwas prepared by spray drying method.The physicochemical properties and cell cytotoxicity of themicrospheres were investigated by UV spectrophotometry , scanning electron microscopy, X-ray diffraction, dynamic membrane dialysis and MTT assay.Results Five kinds of chitosan microspheres ( A, B, C, D and E) with different drug/carrier ratios were successfully prepared by spray drying method.The yield, drug loading and entrapment efficiency of the drug-loaded microspheres were 34.38%~46.94%, 10.20% ~18.67%, 61.20% ~74.72%, respectively.SEM results showed that compared with microspheres A, B and C, microspheres D and E own the spherical shape with wrinkled surface and uniform particle size, particle size between 0.5 ~3 μm, no adhesion.X-ray diffraction analysis showed that the drug was encapsulated in the microspheres.The results of in vitro release indicated that microspheres D had a good sustained release effect in the four drug-loaded microspheres.The results of cytotoxicity test showed that when the concentration of gentamicin reached 400 μg/mL, the relative growth rate of microspheres D was still higher than 80% with the cytotoxicity grade was one, ie, no cytotoxicity.Conclusion The microspheres D with good physicochemical properties, sustained-release effect and biocompatibility, is expected to be a good carrier of prostate local drug delivery.

Study on rat small intestinal absorption features of puerarin loaded O-carboxymethyl chitosan microspheres based on single pass perfusion method / 中草药

Objective: To study the rat intestinal absorption characteristic of puerarin loaded O-carboxymethyl chitosan (CMCS) microspheres in situ. Methods: Single-pass intestinal perfusion (SPIP) model was used for rat in situ and HPLC to determine the concentration of puerarin. The effects of different perfusion rate, drug concentration, and intestinal segments on intestinal absorption were investigated, and the absorption characteristics of the puerarin and puerarin loaded O-CMCS microspheres were compared. Results: Perfusion rate had significant effect on the absorption rate constants (Ka) and the apparent absorption coefficient (Papp) (P 0.05); Ka and Papp of drug loaded microspheres in jejunum and ileum showed no significant difference, but they were significantly higher than that in duodenum (P < 0.05); The drug loaded microspheres and puerarin had the significant difference in Ka and Papp in jejunum (P < 0.05). Conclusion: The absorption mechanism of puerarin in the microspheres is passive diffusion, puerarin is absorbed well in jejunum and ileum, and puerarin loaded O-CMCS microspheres can significantly improve the absorption of puerarin.

In vivo pharmacokinetics of curcumin-phospholipid complex-chitosan microspheres in rats / 中草药

Objective: To compare the in vivo pharmacokinetics of curcumin-phospholipid complex-chitosan microspheres (Cur-PLC-CM), Cur-PLC, Cur-CM, and crude drug of Cur, and to discuss the advantage of PLC-CM as carrier. Methods: SD rats were ig administered with the above four preparations 100 mg/kg (corresponding to Cur), respectively. Then blood samples were obtained at certain time points. The concentration of Cur in blood was analyzed by HPLC method using emodin as internal standard. The mobile phase was acetonitrile-2% acetic acid (55:45). Concentration-time curve was drawn and the data were analyzed by DAS program. Results: The tmax and t1/2 of Cur-PLC-CM were 2.0 and 3.2 h, respectively, which were much longer than those of crude drug (0.6 and 1.2 h), Cur-CM (1.4 and 2.3 h), and Cur-PLC (1.2 and 1.7 h). The AUC of Cur-PLC-CM was 7.49, 2.07, and 2.67 times as those of crude drug, Cur-CM, and Cur-PLC. Conclusion: The PLC-CM have better sustained-releasing and absorption property than CM and PLC, which may have a great potential to be used as oral delivery system for the low solubility and short half-life drug.

Study of Immobilization of Yeast Alcohol Dehydrogenase Cross-linked Magnetic Chitosan Microspheres / 中国生物工程杂志

Magnetic chitosan microspheres(M-CS) were prepared and used for yeast alcohol dehydrogenase(YADH) immobilization.The optimum technology and the properties of immobilized YADH were studied.The optimal immobilization conditions for YADH were:20ml of 0.25mg/ml of YADH in phosphate buffer(0.05mol/L,pH 7.0) reacted with 50mg of magnetic M-CS at 4℃ for 2h.The microspheres were characterized by transmission electron microscopy,the results showed that M-CS were regular sphere with an average size of 30nm and had magnetic response characteristic.The M-CS suspended in H2O solution was easily precipitated and separated by magnetic field.Mechanical strength and crosslinking degree of M-CS were influenced by the ratio of carrier and immobilized YADH,ion concentration in phosphate buffer and pH of the solution.The immobilization was slightly influenced by the reaction temperature.The immobilization would improve its thermal,basic resistant and acid resistant stability.After the immobilized enzyme was kept between 35℃ to 75℃ for one hour,it still had 70 % of initial enzyme activity,when it was kept pH between 5.0 to 7.4 for one hour,it still had 80% of initial enzyme activity.The optimal reaction temperature of the immobilized enzyme was 40℃ compared to 30℃ of the free YADH,the optimal reaction pH of the immobilized enzyme was 6.8 as same as one of the free enzyme.Storaged at the temperature of 4℃ for 30 days without any protection by reagent,the free enzyme only kept 26% of the original activity but the immobilized enzyme still retained 60% of the activity.The immobilized enzyme maintained 70% of the activity after circular use 5 times.The Km value of immobilized YADH for Pyruvate was 2.58 mmol/L compared to 3.31 mmol/L of the free YADH,it would reduce its appetency for the substrate.

Preparation of ligustrazine-chitosan microspheres by spray drying method / 中草药

Objective To prepare ligustrazine-chitosan microspheres and to investigate the drug release behavior in vitro. Methods Microspheres were prepared using the spray drying method.The encapsulation efficiency was used to evaluate the influence of different formulation and preparation factors,the formulation was optimized by L9(34) orthogonal design.Results The optimal formulation and preparation factors were as follows: chitosan concentration(0.01 g/mL),ratio of chitosan to ligustrazine(1∶4),inlet temperature(120 ℃),air flow rate(500 L/h).The optimized microspheres had a spherical shape,the loading capacity was(18.60?0.15)%,entrapment efficiency was(93.01?0.76)%,the average diameter was(10.69?0.64) ?m.The drug release profile in vitro could be described by Higuchi equation Q=19.798 t1/2+25.209(r=0.997) at 1-15 h,which showed the prepared microspheres obviously had the sustained release effect.Conclusion The encapsulation efficiency of ligustrazine-chitosan microspheres is higher,the preparation method is simple,and the process is stable.It will provide the basis for realizing the industrialization in Chinese materia medica microspheres.