Application of improved standardization methods and instrumentation in the USP particulate test for SVI

The USP (788) requirement for particulate matter in small volume injections (SVI) became effective January 1, 1986. The standardization component of the requirement is time-consuming and open to subjective interpretation. Current generation light obscuration (LO) counters offer many advantages over those available when (788) was implemented. Significant improvements may be made to the requirement by optimizing the counter standardization procedure and making provisions for use of newer instrumentation. Key improvements to (788) suggested by our experience with the SVI test method include: (1) revision of the requirement to include a time-effective stand-alone standardization procedure; (2) provision for use of currently marketed LO counter systems; (3) development of new standard materials including a count standard; and, (4) deletion of the present requirement for validation of LO counts by microscopy. Significant user advantages accruing to an improved methodology and the use of new instrumentation will include decreased time spent in standardization, lower variability of data between different laboratories, and less instrument down time.