Preparation And Properties Of Ketoconazole/Poly(Lactic-co-glycolic Acid) Sustained-release Materials

Poly(lactic-co-glycolic acid)(PLGA) is a biodegradable polymeric material, which has been approved by the FDA of U.S. to be used in the human body, and it can be decomposed into water and carbon dioxide. PLGA is non-toxic and has excellent biocompatibility. Microspheres and fiber scaffolds made of PLGA are extensively used in medical engineering materials, pharmaceuticals and modern industrial fields. Ketoconazole (KCZ) has widely been used as imidazole antifungal agents such as treating many diseases of dermatology, obstetrics/gynecology, ophthalmology and otology, however, some drawbacks of using it for long term are nausea, vomiting, itching, abdominal pain and drowsiness, and in extreme cases may cause liver damage. These drawbacks limit its application.The main goal of this research work is exploring the biological materials mitigation technology to reduce the side effects of drugs. Ketoconazole microspheres with different particle size were prepared by two different methods with PLGA as carrier material.The composite fiber membrane was prepared by electrostatic spinning. We have discussed the influencing factors in the preparation process. The microspheres and fibers membrane were characterized by optical microscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared (FT-IR) spectroscopy, and high performance liquid chromatography (HPLC). The determination method of the in vitro release content of KCZ in KCZ/PLGA microspheres was established, mice was chosen as the animal model and in vivo drug delivery of KCZ/PLGA microspheres was studied.The main research contents and results are summarized as follows:1. Establishment of determining method of the content of the KCZ in KCZ/PLGA sustained-release microspheres. The loading amount of KCZ in the sustained release microsphere and encapsulation efficiency were measured by HPLC at pH4.5and7.4using phosphate buffer solution as a release medium. Dynamic membrane dialysis method was established to determine the amount of KCZ in microspheres in vitro release. The results showed that the HPLC method has high separation efficiency, high speed, and wide range selectable mobile phase and high sensitivity. The HPLC is applicable for determining of the content of ketoconazole, which is beneficial for screening suitable sustained release microspheres formula, for optimizing preparation and characterization condition of KCZ/PLGA sustained release microspheres.2. Uniform particle size KCZ/PLGA sustained release microspheres were prepared by using microfluidic devices, the composition of KCZ/PLGA microspheres was characterized and in vitro release of the microspheres was determined. The results showed that the morphology of the microspheres is influenced by concentration of the dispersed phase and the mobile phase solution, drug loading and the size of microspheres. The diameter of microspheres is greatly affected by the flow rate of the dispersed phase and mobile phase, while the drug loading contributes minimal effect. Microspheres are analyzed and tested by FT-IR, thermal gravimetric analysis (TGA), and X-ray diffraction (XRD). Physical packing occurred while no chemical reactions were found between PLGA and ketoconazole in the microspheres. The thermal decomposition temperature of PLGA became lower due to the exit of KCZ; meanwhile, the degree of crystallinity of microspheres became lower due to the intermolecular interactions between KCZ and PLGA. Two important results of the in vitro release of the drug-loaded microspheres were obtained. First, in the same particle size of the microspheres, increasing the drug-loading amount increased the drug release; second, in the microspheres containing same amount of KCZ, increasing the particle size, decreased the drug release.3. Various particles size of KCZ/PLGA sustained release microspheres were prepared by emulsion solvent evaporation method (W/O) at different emulsification stirring speed. The drug release in vitro of the microspheres has been examined by different effects, such as the particle size of the microspheres, properties of PLGA and pH value of released solution. The results indicated that emulsion solvent evaporation method is a simple way to provide high encapsulation and high drug loading. The release rate of ketoconazole depends on the smaller size of microspheres, lower molecular weight of PLGA, higher amount of GA and low pH value of released solution. The drug can slowly be released up to three weeks or more.4. KCZ/PLGA microfiber fibers were prepared by electro-spinning, the composition was characterized and in vitro release was tested. The morphology of the fibers was observed by scanning electron microscopy (SEM), the optimum parameters of electrostatic spinning PLGA microfiber were established:the concentration of PLGA spinning solution was15wt%, the spinning voltage was16kV, electrode distance was approximately15cm. The SEM, FT-IR, TGA and XRD test results show that the prepared KCZ/PLGA composite fiber are smooth, ketoconazole can be uniformly dispersed in the PLGA spinning solution without aggregation on the fiber. Ketoconazole is molecular state dispersed in the PLGA fibers, the dispersion process is a physical process, and no chemical reaction occurs between KCZ and the spinning solution of PLGA. The property of ketoconazole in KCZ/PLGA composite fiber membrane is not changed. Adding KCZ changed the thermal property of the PLGA fibers, and the speed of the thermal degradation of the PLGA fibers was accelerated below3000C and plateaued from300to4000C. The studies of fiber in vitro release indicated that the greater amount of drug loading and the higher content of GA in PLGA and the lower of pH of the release liquid results in faster release of the ketoconazole. The KCZ was released faster in the early stage, and then became stable and sustained release of the drug lasted up to three weeks or more.5. HPLC method was established to detect the concentration of ketoconazole in plasma. Mice were used as a model to study the KCZ/PLGA sustained release microspheres degradation and drug release in vivo. The results showed that the absolute recovery of ketoconazole were greater than87.21%, intra-day precision were less than3.09%, the stability of ketoconazole plasma samples was high under the room temperature and repeated freeze-thaw test, the RSD of the concentration of the drug were less than4.43%, which is consistent with the basic requirements of the analysis of biological sample. This can be used for studying pharmacokinetic of ketoconazole in the mice and detecting the blood drug concentration of bioequivalence. The degradation test in vivo indicated that PLGA microspheres have a good sustained release effect and can be degraded completely in vivo. Comparative tests found that microsphere size, carrier molecular weight and the composition of the KCZ/PLGA microspheres have significant effects on the degradation of the microspheres, and among them, the carrier composition plays the most important role.