Traini Daniela, Rogueda Philippe, Young Paul, Price Robert
Pharmaceutical Technology Research Group, Department of Pharmacy, University of Bath, Bath, UK.
Pharm Res. 2005 May;22(5):816-25. doi: 10.1007/s11095-005-2599-2. Epub 2005 May 17.
To compare experimental measurements of particle cohesion and adhesion forces in a model propellant with theoretical measurements of the interfacial free energy of particulate interactions; with the aim of characterizing suspension stability of pressurized metered dose inhalers (pMDIs).
Interparticulate forces of salbutamol sulfate, budesonide, and formoterol fumarate dihydrate were investigated by in situ atomic force microscopy (AFM) in a model propellant 2H,3H perfluoropentane. The surface thermodynamic properties were determined by contact angle (CA) and inverse gas chromatography (IGC). Experimental data were compared with theoretical work of adhesion/cohesion using a surface component approach (SCA), taking into account both dispersive and polar contributions of the surface free energy.
Results indicated that the measured forces of interaction between particles in model propellant could not be accounted for by theoretical treatment of the dispersive surface free energies via CA and IGC. A correlation between theoretical work of adhesion/cohesion and AFM measurements was observed upon the introduction of the polar interfacial interactions within the SCA model.
It is suggested that the polar contributions of the surface free energy measurements of particles may play a crucial role in particle interaction within propellant-based systems. Together with the application of a SCA model, this approach may be capable of predicting suspension stability of pMDI formulations.
比较模型推进剂中颗粒凝聚力和粘附力的实验测量值与颗粒间相互作用界面自由能的理论测量值；旨在表征压力定量吸入器（pMDIs）的悬浮稳定性。
通过原位原子力显微镜（AFM）在模型推进剂全氟戊烷中研究硫酸沙丁胺醇、布地奈德和富马酸福莫特罗二水合物的颗粒间作用力。通过接触角（CA）和反相气相色谱（IGC）测定表面热力学性质。利用表面成分分析法（SCA），考虑表面自由能的色散和极性贡献，将实验数据与粘附/内聚的理论结果进行比较。
结果表明，通过CA和IGC对色散表面自由能进行理论处理，无法解释模型推进剂中颗粒间的测量相互作用力。在SCA模型中引入极性界面相互作用后，观察到粘附/内聚理论结果与AFM测量值之间存在相关性。
表明颗粒表面自由能测量的极性贡献可能在基于推进剂的系统中的颗粒相互作用中起关键作用。结合SCA模型的应用，这种方法可能能够预测pMDI制剂的悬浮稳定性。
