Particle detection pits man against machine

"Slightly greater than zero percent." That's the probability of a QC inspector seeing a 50-micron particle in a 10-mL vial of clear solution  at 2000 and 3000 lux illumination, says John Shabushnig, senior manager at Pfizer and a leader on the PDA and U.S. Pharmacopeia visual inspection teams. Particles of 1 to 100 microns might be pollen, hair, large bacteria and fine sand, says Engineering ToolBox.

Up to 100 microns, the probability of detection rises to 40 percent. And it's greater than 95 percent for 200-micron matter, which might include hail, insect debris, room dust and coarse sand.

Not perfect, but not bad, either. In addition to the mainstay human visual inspection of drug products, the FDA permits automated inspections as long as systems are validated, according to Pharmaceutical Technology magazine.

It turns out that neither method is perfect, but both are effective. The sensitivity of automated systems is similar to that of human visual inspection, but automation can provide greater consistency overall.

Such information may be of use to those who have recently conducted particle-contamination recalls and decided that some sort of system adjustment is needed.

An APP Pharmaceuticals cancer parenteral recall from March was triggered by foreign material and non-sterility in one lot. The contaminant was fungal, in contrast to recent particle-based recalls of injectables traced to glass delamination. Particle contamination in injectables also sideswiped Daiichi Sankyo unit Luitpold. A December 23 recall involved unexpired lots of single-dose vials of sodium bicarbonate, which had been distributed to wholesalers and distributors.

The sodium bicarbonate recall followed right on the heels of the company's callback of certain lots of dexamethasone sodium phosphate injection in multiple-dose vials. Some vials either contained particles or particles may have formed prior to expiration.

[The careful reader will note the scrupulous substitution of the word "particle" for the grandiose deviant used in the source material, part of our 2011 editorial mission.-Ed.]

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