| Summary: | 碩士 === 淡江大學 === 化學工程與材料工程學系碩士班 === 95 === In this study, poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)(PHBHHx) nanoparticles containing hydrochloride tetracycline, as a model of water-soluble drugs, were prepared by W1/O/W2 emulsion using a sonicator and a solvent evaporation method. Two PHBHHx copolymers, namely PHBHHx5 and PHBHHx10, were in this study, which had 5.0 and 9.1% HHx content in composition, respectively. GPC results rvealed that they also had different molecular weight, in which PHBHHx5 had a molecular weight (Mw) of 653000, and the other one PHBHHx10, 348000. In double emulsion (W1/O/W2), the ratio of internal aqueous phase (W1), oil phase (O) and external aqueous phase (W2) was 1:5:30 (v/v/v), in which the external aqueous containing surfactant (Tween80) and PVA used as a stabilizer. After emulsification and solvent evaporation, particle size distribution was measured using laser light scattering method, and found to be between 200 and 300nm.Particle size decreasesd from 296nm to 205nm with increasing the PVA content from 0.2%(w/v) to 1%(w/v). Under the same experimental conditions, particles prepared by PHBHHx5 those were smaller than prepared by PHBHHx10.This is because the molecular weight of PHBHHx10 is smaller than that of PHBHHx5 and thus, the viscosity in oil phase would be smaller.Furthermore, the viscosity in oil phase and the particle size decreased as the concentration of PHBHHx in oil phase decreased.
PHBHHx10 was chosen as a carrier to encapsulate hydrochloride tetracycline. ATR-FTIR was utilized to investigate the residual drug on surfaces of nanoparticles. It indicated that the residual drug on surface increased as the added amount of drug were increased.TGA thermograms shows that the maximum degradation temperature of PHBHHx was about 280oC, and that of nanoparticles containing drug were raised up to about 300oC. After encapsulation yield, loading and encapsulation efficiency were all calculated. The results revealed that the yield were between 71-86%, loading 3.5-2.2% and encapsulation efficiency 26-54%, and the encapsulation efficiency decreased with the adding amount of drug. After 10 hours in deionized water, drug release amount of all nanoparticles reached 80%.
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