USP Antibiotic Testing
Antibiotic Potency (Zone of Inhibition—USP <81>)
This is a microbiological means of determining quantitatively the activity of antibiotics. The test sample’s activity is compared directly to that of a known reference standard by measuring the diameter of zones surrounding the samples in which bacterial growth is inhibited.
Qualitative Testing
The zone of inhibition is a qualitative test. Samples usually 100 g or 100 mL each are submitted in sterile containers. Our microbiologists cultivate these samples in a nutrient (agar) medium. Any zones wherein bacterial growth is inhibited are measured, and compared to controls.
Quantitative Testing
MDS also conducts quantitative testing to measure microgram quantities of antibiotics in biological products, drug products, or animal tissue using the cylinder plate method. Endotoxin tests also help quantify the amount of antibiotic in the sample.
Preservative Efficacy (USP <51>)
The USP defines four product categories, and directs that five challenge organisms be tested at defined intervals to demonstrate preservative effectiveness. Additional organisms may be selected.
Bioburden Determination
MDS follows the bioburden procedure described in ANSI/ISO/AAMI 11737-1 1995. Following extraction, aliquots are plated to determine the number of mesophilic aerobes, fungi and bacterial spores. Incubation under anaerobic conditions is available on request.
Environmental Testing (viable and non-viable) and Package/Container Integrity Microbiology
We will assist in the evaluation of the microbiological levels and of the nonviable contamination levels of your facility. This service is designed on an individual basis to meet the specific needs of each client. We can supply personnel and materials to perform the monitoring or just supply materials, and culture and enumerate bacterial plates that are returned to us by courier.
- Sterility testing—uses the USP 40-item product immersion procedure described above under Pharmacopeial Sterility
- Microbial aerosol challenge as recommended in ISO 11607
- Seal leak test by dye penetration—ASTM F 1929. Aqueous dye is injected into the package near the seal and integrity of the seal is assessed visually.
- Package Burst Testing—air is injected into the sealed package and the pressure at which a seal fails is recorded. A modification of this procedure is called Creep to Burst Testing; in this test the package is pressurized to 80% of its theoretical burst value and held for a defined period of time. It is then further pressurized until it bursts and the final burst pressure is recorded.
- Vial Test