本研究的主要目的為製備生物可降解性奈米載體，並以所開發之載體包覆能促進骨再生之藥物，在本研究中首先探討製備過程中的變數對於顆粒尺寸的影響，接著再利用最適化條件嘗試包覆三種不同的藥物，分別為：(1)用來模擬第一型纖維母細胞生長因子(FGF-1)包覆情形的牛血清蛋白(BSA)，(2)能促進骨母細胞活性的Lovastatin及(3)能夠抑制蝕骨細胞活性的Alendronate。

在適當的製備條件下，可以控制顆粒的直徑於200nm左右，由穿透式電子顯微鏡(TEM)及掃描式電子顯微鏡(SEM)的照片中顯示，所製備出的顆粒為均一大小之圓球狀，且經由MTT測驗證實，本研究中所製備出的顆粒不具毒性，對細胞的活性不會產生影響。因此本研究中所製備出的顆粒適合用於藥物釋放之領域。

研究中所製備出含有BSA的PLGA顆粒，具有60.65％的包覆效率，顆粒大小為209nm，能在2個月內具有穩定的釋放效果，而在添加制酸劑後，能夠有效地減緩系統的酸化現象，延長其釋放時間。利用包覆具有螢光訊號的BSA之PLGA奈米顆粒來觀察類骨母細胞(UMR-106)之攝入情況，則發現在培養24小時左右，細胞中的螢光訊號分佈地十分明顯。而在適當的條件下，可製備出196nm且具有78.45% Lovastain包覆率的PLGA顆粒，所包覆的Lovastatin會在PBS釋放系統中，7天後釋放完畢，而包覆Lovastain的PLGA顆粒能在細胞培養初期有效地促進鹼性磷酸酶(ALPase)的表現。由於Alendronate為親水性且分子量小的藥物，使包覆Alendronate的PLGA顆粒在釋放初期有劇烈的突發性釋放，而在細胞實驗部份，利用包覆Alendronate的PLGA顆粒在細胞培養初期能略為促進細胞鹼性磷酸酶(ALPase)的表現。

本研究中所製備出的顆粒尺寸均在200nm左右，並具有良好的包覆效果，能夠達到穩定的釋放情形，未來應能應用於治療骨質疏鬆、促進骨再生的領域當中。

The purpose of this work was to prepare the biodegradable PLGA nano-particle encapsulating the drug which can promote the bone regeneration. Firstly, we have investigated the effect of emulsion times and polymer molecular weight on the size of nano-particles and encapsulation efficiency. After finding optimal conditions, three different drugs for bone regeneration were encapsulated, including BSA (Bovine Serum Albumin), Lovastatin and Alendronate. The encapsulation efficiency, releasing profile and cell responses were then investigated. The isoelectric point (pI) of BSA is similar to Fibroblast Growth Factor-1(FGF-1), so BSA was used to simulate the situation for growth factor encapsulation.

The size of the particles could be controlled by changing the emulsion time in preparing process. From the TEM (Transmission Electron Microscope) and SEM (Scanning Electron Microscope) pictures, it showed that the particles were uniform and smooth spheres. The particles have been also proved to be biocompatible by the MTT assay.

With optimized conditions, the encapsulation efficiency of PLGA nano-particles was 60.65% for BSA, 78.45% for lovastatin and 77.39% for Alendronate. All the particle size would be around 200 nm in diameter, which is suitable for the drug delivery system. In order to retard the decrease in pH due to the PLGA degradation, CaCO3 and NaHCO3 were used as neutralizer agent in this study. The experimental results suggested that the self-catalyzed degradation would be suppressed by the addition of neutralizer agents; that is to say, the long-term release would be thus reached.

The release of BSA from nano-particles is stable for 2 months in a controlled buffer system. According to the observation of fluorescent BSA in the in vitro system, the nano-particles prepared in this research would be untaken into osteoblastic-like cells (UMR-106) before 6 hours. The Lovastatin encapsulated in PLGA particles would be released in 7days, which would effectively promote the expression of ALPase.On the other hand, an acute burst release was observed for the particles with Alendronate. It is possibly due to that Alendronate is hydrophilic and with small molecular weight, resulting an easy diffusion from particles.

This research has demonstrated the particles prepared by emulsion method were uniform, biocompatible and also with high encapsulation efficiency for BSA, Lovastatin and Alendronate. It could be applicative for bone regeneration field.

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