Particulate Matter in Parenteral Products: A Review

Abstract

Particulate matter in parenteral products is a complex subject. This article contains a discussion of several aspects of this topic including the use and limitations of the inspection and counting techniques for visible and subvisible particles, the identification of particles, and the elucidation of sources, mechanisms of formation, and particulate reduction techniques. Two significantly different approaches, human and machine inspection, have been used to detect visible particulate matter in parenteral products. A description of both methods is given along with a discussion of their typical performance characteristics. Criteria for comparison of different visual inspection systems are also presented. A variety of methods have been utilized for the measurement of subvisible particulate matter, including microscopic, electrical zone-sensing, light blockage, light scattering, and holographic techniques. Each of these particle counting methods is described. In addition, the factors that affect the measurement of subvisible particulate matter are discussed. An approach to particle identification is outlined. General comments concerning the analysis of particulate matter in parenteral products are discussed along with a description of various particle identification techniques and several examples illustrating how the methods have been applied. In particular, the techniques that are presented include light microscopy, atomic spectroscopic methods (SEM/EDXRA, electron microprobe, ESCA, and Auger electron spectroscopy), molecular spectroscopic techniques (infrared spectroscopy, Raman spectroscopy, and mass spectrometry), and chromatography. Finally, sources of particulate matter including packaging materials, manufacturing variables, formulation components, and miscellaneous factors are reviewed. The different mechanisms of particle formation, namely, direct contamination, precipitation and agglomeration are discussed. Representative examples of particulate reduction steps are presented.