Barron Melisa K, Young Timothy J, Johnston Keith P, Williams Robert O
Theravance Inc, South San Francisco, CA, USA.
AAPS PharmSciTech. 2003;4(2):E12. doi: 10.1208/pt040212.
The objective of this study was to investigate the influence of processing parameters on the morphology, porosity, and crystallinity of polymeric polyethylene glycol (PEG) microparticles by spray freezing into liquid (SFL), a new particle engineering technology. Processing parameters investigated were the viscosity and flow rate of the polymer solution, nozzle diameter, spray time, pressure, temperature, and flow rate of the cryogenic liquid. By varying the processing parameters and feed composition, atomization and heat transfer mechanisms were modified resulting in particles of different size distribution, shape, morphology, density, porosity, and crystallinity. Median particle diameter (M50) varied from 25 microm to 600 microm. Particle shape was spherical or elongated with highly irregular surfaces. Granule density was between 0.5 and 1.5 g/mL. In addition to producing particles of pure polymer, drug particles were encapsulated in polymeric microparticles. The encapsulation efficiency of albuterol sulfate was 96.0% with a drug loading of 2.4%, indicating that SFL is useful for producing polymeric microparticles for drug delivery applications. It was determined that the physicochemical characteristics of model polymeric microparticles composed of PEG could be modified for use as a drug delivery carrier.
本研究的目的是通过喷雾冷冻成液（SFL）这一新型颗粒工程技术，研究加工参数对聚乙二醇（PEG）聚合物微粒的形态、孔隙率和结晶度的影响。所研究的加工参数包括聚合物溶液的粘度和流速、喷嘴直径、喷雾时间、压力、温度以及低温液体的流速。通过改变加工参数和进料组成，雾化和传热机制得以改变，从而得到具有不同尺寸分布、形状、形态、密度、孔隙率和结晶度的颗粒。中位粒径（M50）在25微米至600微米之间变化。颗粒形状为球形或细长形，表面高度不规则。颗粒密度在0.5至1.5克/毫升之间。除了制备纯聚合物颗粒外，药物颗粒也被包裹在聚合物微粒中。硫酸沙丁胺醇的包封率为96.0%，载药量为2.4%，这表明SFL可用于制备用于药物递送应用的聚合物微粒。已确定由PEG组成的模型聚合物微粒的物理化学特性可被改变，以用作药物递送载体。
