Method for determination and element analysis of particulate contamination in injectable solutions

A method for sampling and evaluating the chemical and physical composition of particles in injectable solutions was developed. The technique facilitates detection of the particles' sources and possible medical hazards. Particles exceeding 0.2 mum are collected on a membrane filter sized for direct application in a scanning electron microscope (SEM). The sampling device shortens the distance between filter and solution and minimizes contamination from the filter holder. Following coating of the membrane filter with gold, the particles are counted by screening at a magnification of 5,000 x in the SEM. Both unused membrane filters and filters through which a solution of 0.9% sodium chloride had been passed were analyzed. X-ray analysis of particles on the clean filter revealed silicon, aluminum (artifact from the stud) and calcium. X-ray analysis of the filter after passage of 1 liter normal saline revealed chromium, copper, iron, magnesium, manganese, aluminum (from study), calcium chlorine, sodium and silicon. Recommendations for standard procedures for particle detection in large-volume injectables are given.