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BACKGROUND: Statins plays a significant role in regulating blood lipids, treating and preventing cardiovascular and cerebrovascular diseases. Studies have shown that statins has certain potential in promoting bone formation and treating osteoporosis. OBJECTIVE: To prepare the drug release scaffolds for the sustained release of atorvastatin calcium, which consist of bovine serum albumin microspheres and polycaprolactone electrostatic spinning fibers, and to investigate the effects of the drug sustained release scaffolds on osteoblast adhesion and proliferation. METHODS: Bovine serum albumin microspheres containing atorvastatin calcium were prepared by desolvation. A layer of chitosan was coated on the surface of the bovine serum albumin microspheres by electrostatic adsorption, which can increase the stability of the microspheres. Bovine serum albumin microspheres were purified and lyophilized for later use. The lyophilized powder of microspheres was dissolved in organic solvent. An appropriate amount of hydroxyapatite was added in the solvent. The nanofiber scaffolds for sustained release of atorvastatin calcium were prepared via electrospinning. The micromorphology, degradation performance, and sustained-release performance of the nanofiber scaffolds were characterized. The prepared nanofiber scaffolds for sustained-release of atorvastatin calcium were co-cultured with MC3T3-E1 cells to observe cell adhesion and proliferation. RESULTS AND CONCLUSION: (1) Transmission electron microscopy revealed that the shape of the bovine serum albumin nanospheres was regular and circular. Bovine serum albumin nanospheres were discarded in the electrostatic spinning fibers. The basic morphology of the microspheres was retained. (2) Scanning electron microscopy revealed that the nanofibers used for preparation of nanofiber scaffolds for sustained-release of atorvastatin calcium were composed of filaments with uniform diameters and continuous smooth surface. Filaments were intertwined to form a network structure. (3) The nanofiber scaffolds exhibited the fastest degradation in the first month. The material was incomplete when degraded for 3 months. (4) The nanofiber scaffolds had the ability to slow down the release of drugs. The effect could last for more than 1 month. The overall process of drug release was similar to the zero-order kinetic process. (5) The nanofiber scaffolds for sustained-release of atorvastatin calcium can promote MC3T3-E1 cell adhesion and proliferation. (6) These results suggest that the nanofiber scaffolds for sustained-release of atorvastatin calcium have good biocompatibility and can promote the adhesion and proliferation of osteoblasts.
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OBJECTIVE:To prepare Hyaluronic acid-methyl collagen-terpolymer (HEMA-MMA-MAA)/Doxorubicin com-pound membranes-loaded tantalum stent,and to optimize the formulation. METHODS:Electrostatic self-assembly reaction was ad-opted to prepare compound membranes using metal tantalum stent as carrier,hyaluronic acid,methyl collagen and terpolymer as ex-cipients. With 1 and 30 d accumulative release rate as index,orthogonal test was used to optimize mass concentrations of hyaluron-ic acid,methyl collagen and terpolymer,and validated. The drug release behavior in vitro were investigated. RESULTS:The opti-mal formulation was as hyaluronic acid 1 mg/ml,methyl collagen 4.5 mg/ml and terpolymer 100 mg/ml. 1 and 30 d accumulative release rates of prepared tantalum stent were 7.57%(RSD=2.3%,n=3) and 84.14%(RSD=2.1%,n=3),respectively. 20 d later,dissolution rate approximated to zero level rate of drug release. CONCLUSIONS:Hyaluronic acid-methyl collagen-terpoly-mer/Doxorubicin compound membranes-loaded tantalum stent with sustained-release property is prepared successfully.
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Objective To produce a kind of biliary stent with Mitomycin C-eliting and evaluate the availability and safety in biliary benign stricture model of rabbit.Methods 36 New Zealand rabbits were fulgurize choledochus to establish model of biliary benign stricture.Rabbits were randomly divided into Mitomycin C-eluting stent group 1 (n =12),polyurethane stent group 2 (n =12) and control group 3 (n =12) one month later.General conditions,survival of the animals and changes in liver function were observed after surgery.The histological changes of bile duct were observed after 30 days.The immunohistochemistry SP method was used to measure transforming growth factor-β1 (TGF-β1) and α-Smooth muscle actin (α-SMA) expression.Results Stricture was improved in the two stent groups.In Mitomycin C-Eluting stent group total bilirubin dropped from 5.56 μmol/l to 0.82 μmol/l,and in polyurethane stent group total bilirubin dropped from 6.72 μmol/1 to 0.87 μmol/l.The total bilirubin decreased in both two stent groups but no statistically significant between the two stent groups,and there were no improvement in control group.Diameter of the stricture bile duct in group 1 was expanded bigger than in group 2 according to histology observation.Inflammatory cell infiltration and collagen fibroplasia in the submucosal were obviously observed in control group.The immunohistochemistry results showed that the TGF-β1 and α-SMA strongly expressed in the stenosis bile duct of group 3.The expressions in group 2 were lower than group 3,but higher than in group 1.And there was significant difference between the two stent groups (P ＜ 0.05).Conclusion The new Mitomycin C-Eluting stent is safe and provides enhanced local drug delivery.It also can inhibit the form of Biliary scar to a certain degree.
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OBJECTIVE: To evaluate the in vitro drug release properties of modified hyaluronic acid films. METHODS: The drug release rates of the films were measured by dictyo-dish method and UV-Vis absorption spectroscopy. The effects of modifier contents and the solubility of medicines on the release were investigated. RESULTS: The release of some hydrophobic drugs from the films were sustained. The drug release pattern followed Higuchi equation, and was controlled by diffusion mechanism. Drug release rates were delayed by increasing contents of modifier. CONCLUSION: The films made of modified hyaluronic acid have excellent potentials as carriers for the sustained release of some hydrophobic drugs. Copyright 2012 by the Chinese Pharmaceutical Association.
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Objective: To prepare a mitomycin C (MMC)-eluting stent for biliary tract, and to observe the drug delivery from the stent. Methods: The mixed powder of MMC and polylactic glycolic acid (PLGA) was dissolved with their common solvent tetrahydrofuran (THF), with a drug concentration of 1%. The 6Fr biliary stent was soaked in the above solution for 10 min, and then was subjected to vacuum drying and was stored at room temperature. Then MMC-eluting stent was weighed and the MMC load was calculated. The MMC-eluting stents were soaked in 8 ml phosphate buffered saline (PBS, pH 7. 4) and placed in a shaker at a constant temperature of 37°C for 24 h soaking; then fresh PBS was changed every day for 30 days. The leaching solutions of the 1-30 days were subjected to chromatographic analysis to determine the concentrations of MMC. Results: MMC load on each stent was (216. 20 ± 2. 04) g, with the load per unit area being (0. 732 ± 0. 007) g/mm2. MMC could be released from the stent surface in a sustainable manner. The elution concentration of MMC was (1. 81 ± 0. 06) g/ml on first day and (1. 24 ± 0. 04) g/ml on the second day; then it fluctuated within 0. 61-0. 84 g/ml. The concentration of MMC began to decrease from the 21st day, and it was (0. 51 + 0. 01) g/ml on the 30th day. Conclusion: MMC-eluting biliary stents can be successfully prepared using polylactic acid as a drug carrier. In vitro study shows that the drug-eluting stents can sustainably and stably release MMC for over 30 days.