Study On The PELA Microphere Loaded The BFGF For Sustained Release

In recent years, researchers discovered many growth factors that cause, kinds of cells segmentation and differentiation along with the molecular biology's development, The basic fibroblast growth factor (bFGF) is a type of the fibroblast growth factors(FGF), it brought effect in many fields. The ectogenesis basic fibroblast growth factors can promote the cell division and chemotaxis, and induce the normal growth of embryo, and promote the growth of blood vessel, create to regeneration of nerve and healing of the wound. But the half-life of bFGF is about 3-5 minuts in bodys. If it is applied to whole body, it is quickly caused to inactivation and hard to develope its valid function. The bFGF is unstability in solutions. It is very difficult to effect that it is applied many times though local puncture, and bFGF is not suitable for over a long period of time to the medicine. So it is very important significance that to study on sustained release bFGF microphere of maintenancing the local effect concentration of drug and promoting the regeneration of nerve. Study on the bFGF sustained-microphere is few at present. We use a new type high polymer material polyester-polyether segment homoconjugate (PELA) as carrier material to prepare the sustained microphere, this component of high polymer material is the polye-D, L-lactic-polyethylene glycol (PLA-PEG) homoconjugate. Finally, We obtained the sustained-release bFGF-PELA-MS, and bFGF-PELA-MS can be released the active bFGF, so it can facilitate the cleavage and proliferation of Schwann cell in the long terms.We used Uniform design in the course of study on preparation technology, and obtained the regression equation though step by step multi-regression. Regession equation and "overall feedback dynamic techniques"were adopted to better the preparation technology of bFGF-PELA-MS. Microphere whose D10 was 1.515um , D90 was 3.761um, D50 was 2.255um, whose crossing distance was 0.996 and whose size was uniform were made. The micropheres'drug-loading and entrapment rate were 1.58% and 89.85% respectively. Though electron microscope scaning, we expounded further the interaction and embedding mechanisms between bFGF and carriers. The mechanisms were as follows: the most part interaction between bFGF and the carrier-PELA, the agglomeration of drug on the surface of the micropheres. The surface and electrostatic absorptions among the micropheres maintioned mainly this kind of agglomeration state.Compared with the micropheres before freeze drying, freeze dried bFGF-PELA-MS for Lyophilized powde had no evident changes in theaspects of shape, partical diameter, drug-loading, entrapment rate and so on. Drug relase test in vitro indicated that the drug release law of bFGF-PELA-MS for Lyophilized powde accorded with double-phase kinetical equation and Weibull equation, and had obvious sustained-release specific property compared with the original drug. The observation to the reserving samples at room temperture in three mouthes showed that bFGF-PELA-MS had good stability and that the micropheres' physicochemical properties had no evident difference.We used the Cyometry, the cell activity detect technique and cell cycle analysis technique, to study bFGF-PELA-MS sustained-release micropheres on promoting proliferation of the Schwann cell. The result showed that freeing bFGF have proliferation to the Schwann cell, but its effect is short; bFGF-PELA-MS have long times effect to proliferation the Schwann cells though sustained-release bFGF.According to all the above studies, Application new type high polymer material, polyester and polyether of homhconjugate, and the preparation techniques of sustained-release for bFGF-PELA-MS, we obtain bFGF-PELA-MS that have sustained-release effect. This kind of study has fairly high academic significance and reference values to research the sustained-release preparation of protein or polypeptide drug.