超临界流体技术在抗生素类药物微粒制备中的应用

综述了超临界流体技术在抗生素行业中的新研究成果和应用概况：不论在抗生素类药物微粒制备或在其提取工艺中都应重视溶解度的基础研究。着重介绍了超临界溶液快速膨胀和超临界抗溶剂工艺在抗生物微粒制备中的进展。所得实例显示出超临界流体技术在抗生索微粒制备中的潜在优势和进一步拓展其应用的良好前景。     

Particulate contamination in solutions of antibiotics packed as dry powders in vials

The particulate contamination in 12 formulations of antibiotic solutions in vials packed as dry powders from five South African sources has been analysed quantitatively using a HIAC PC 320 light blockage particle analyser linked to a CMB 60 sensor. Results showed that the level of particulate contamination fell well within the limits set by the USP XXIst Edition for Small Volume Parenterals although four formulations contained some particles greater than or equal to 50 micron. There was no apparent difference between the quality of the same antibiotics from different sources or between vials of the same antibiotics packed in different strengths.     

Measurement of the surface energy of lubricated pharmaceutical powders by inverse gas chromatography

The objective of the study was to determine whether lubrication of pharmaceutical powders with magnesium stearate (MgSt) results in a change in the surface energy of the powder, and to assess whether surface energy changes, if any, are correlated to lubricant concentration and blend time. The surface energies of microcrystalline cellulose (MCC), lactose, and blends of each material with MgSt, prepared at a range of concentrations and blending times were measured using inverse gas chromatography. The physical distribution of MgSt in the blend was mapped by energy dispersive spectrometry. Overall, there was a reduction in the dispersive surface energy of MCC-MgSt blends with increase in MgSt concentration, that was attributed to increasing coverage of the high-energy sites on microcrystalline cellulose by magnesium stearate. MgSt concentration had a larger effect on dispersive energy than the blending time of the powder with lubricant. X-ray maps of blend samples indicated a heterogeneous distribution of the lubricant in the blend and on the excipient particles. Measurement of the specific component of surface energy indicated that MgSt interacts with excipient powders through non-specific forces rather than acid-base interactions. No distinction among lactose-MgSt blends could be made on the basis of dispersive energy because of similar surface energies of the native materials.     

Measurement of the flow properties of powders with special reference to die fill

The flow behaviour of four pharmaceutical powders was investigated using a model shoe-die-filling system. The variation of mass delivered to the die as a function of shoe velocity provides a measure of flowability. The paper discusses the concept of critical velocity, above which incomplete filling is observed, in the context of pharmaceutical powders. The filling process was recorded using a high-speed video system, which allowed the different flow patterns to be observed, and how this influences the critical velocity to be evaluated. The influence of humidity, which was investigated in detail for one of the powders, was found to be small. The initial conditioning of the material, the die opening and if die filling takes place in air or in vacuum, however, were found to change the flow behaviour significantly.