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Uveitis, a complex ocular disorder with numerous etiologies, can result from infection, autoimmune, and various physicochemical and mechanical injury factors. The treatment of this disease is difficult, and failure to receive timely and effective treatment can often lead to blindness. With the deepening of people's understanding of uveitis and its related mechanisms, various new sustained-release drug delivery systems for uveitis have been studied. However, due to the existence of various anatomical and physiological barriers in the eye, there are multiple obstacles to the sustained release treatment of uveitis. In this paper, the main research results in this field in recent years are reviewed, and the innovations and limitations of various new sustained-release drug delivery systems are discussed in order to provide new ideas for the sustained-release drug delivery treatment of uveitis in the future. These new sustained-release drug delivery systems will help to completely change the traditional treatment mode of uveitis with side effects and poor compliance in the future, bringing longer targeted sustained release and less toxic reactions.
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BACKGROUND:High-dose antibiotics for bone infection have many adverse reactions, and its outcomes are not perfect. Thus, to explore a degradable material as a vector to prevent bone infection is valuable. OBJECTIVE:To study drug release characteristics of gatifloxa-poly sebacic anhydride local control ed release system in vivo. METHODS:A 3 mm × 6 mm bone window was made at right knee joint of New Zealand rabbits. The gatifloxacin-poly sebacic anhydride sustained release preparation was implanted. Heart blood, bone tissue and myeloid tissue specimens were obtained at 1, 2, 3, 6, 9, 12, 15, 18, 25 and 30 days after surgery. High-performance liquid chromatography was utilized to determine gatifloxacin concentration. Scanning electron microscope was employed to observe the structural changes before and after implantation of gatifloxacin-poly sebacic anhydride sustained release preparation. RESULTS AND CONCLUSION:After implantation of gatifloxacin-poly sebacic anhydride sustained release preparation, drug concentration gradual y decreased in the myeloid tissue, peaked at 1 day, stabilized at 3-15 days, gradual y reduced at 15-30 days. However, the drug concentration was stil higher than the minimal inhibitory concentration 0.1 mg/L against Staphylococcus aureus at 30 days. The peak of drug concentration in the bone tissue occurred at 3 days, and stabilized at other days, which was higher than 0.1 mg/L. At the same time point, drug concentration in the blood specimen was lower than that in the myeloid tissue and bone tissue. The degradation of gatifloxacin-poly sebacic anhydride sustained release preparation was surface erosion, and the shape of the degradation residue is smal globular. The change of the internal structure of gatifloxacin-poly sebacic anhydride sustained release preparation was not found. In the drug release procedure, gatifloxacin-poly sebacic anhydride sustained release preparation did not show disintegration or fragmentation. These results indicated that gatifloxacin-poly sebacic anhydride local sustained release preparation has good abilities of drug load and drug release.
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10.3969/j.issn.2095-4344.2013.25.009
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Objective: To prepare stable, small-sized injectable sustained-release nanoparticles harboring brain-derived neurotrophic factor (BDNF) and to evaluate its drug releasing process. Methods: The nanoparticles were prepared using poly (D,L-lactic-co-glycolic acid) (PLGA) as the carrier by w/o/w double emulsion-solvent evaporation method. The formula and technique were optimized; the shape,size and the distribution of the diameters of the particles were observed; and recovery rate, precision, repeatability, encapsulation efficiency,and drug releasing characteristics were assessed. Results: With the optimized formula, the drug loading rate was 1%,the polymer concentration was 3.3 mg/ml, and the ultrasound time was 40 s; mannitol was used as the supporting agent. BDNF nanoparticles were round, homogenous in size, with a mean diameter of 156.7 nm. The prepared particles had high recovery rate, precision, repeatability, and encapsulation efficiency. The drug release was characterized by slow corrosion and the process lasted for 30 days. Conclusion: We have successfully prepared slow-release nanoparticles harboring BDNF, which are stable and have high encapsulation efficiency.
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Objective: To investigate microencapsulation technique, release of HBsAg-PLGA microspheres and degradation of the polymer in vitro, and the level of immune response after the single-dose HBsAg-PLGA microspheres subcutaneously injected (sc) to BALB/c mice. Methods: HBsAg-PLGA microspheres were prepared by double emulsion microencapsulation technique with orthogonal experiments. The pharmaceutical characteristics of size and surface morphology, antigen loading efficiency, release of HBsAg-PLGA microspheres and degradation of the polymer in vitro, and the level of immune response after single sc of PLGA microspheres in BALB/c mice were investigated. Results: The concentration of PVA was the significant factor affecting the particle size (P
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Objectives To evaluate the valproate plasma l ev els,the clinical efficacy and adverse effects in patients with epilepsy treated with the conventional preparations and the sustained-release preparations of sodium valproate (VPA-Na?SR).Methods 33 patients received oral conventional formul ation of sodium valproate for over six months and a similar dosage of VPA-Na?SR for 4 weeks.After 12 or 24 hours,the valproate plasma concentr ations of the two formulations were measured respectively before taking drugs in the early mor ning.The valproate plasma concentrations and the clinical efficacy of the VPA-N a?SR were assessed by comparing with that of conventional valproate.The adverse effects were recorded.Results The average valproate plasma trough concentration was s ignificantly higher in patients receiving VPA-Na?SR than that of those receiving conventional valproate.Seizure free in patients was achi eved by 76%(n=25) with VPA-Na?SR and by 45%(n=15) with conventional valproate resp ectively.There was statistical difference between the two formulations.The seizu re frequency was significantly reduced in 5 patients treated with VPA-Na?SR.A dverse ef fects were observed in 2 patients with conventional valproate,5 patients with V PA-Na?SR whose valproate plasma levels were higher than that of conventional p reparations.Adverse effects were related to increased valproate plasm a levels and individual drugtolerance. Conclusions The advantage of VPA-Na?SR is that serum valproa te con centrations may increase smoothly and minimize fluctuation in serum dr ug concentrations during a dosing interval. It is a more effective and more convenient antiepileptic agent.