Antibiotic Potency testing measures the bioactivity or potency of various antibiotics. All antibiotics must undergo potency testing before being put on the market. EUROLABHe has experience testing many different antibiotics, including Vancomycin, Gentamicin, and Amphotericin B.
This test is performed in accordance with the roller plate method described in USP Antibiotic-Microbial Tests General Section 81. Our scientifically robust testing includes stringent controls that can give customers a high level of confidence in their test results.
In the Antibiotic Potency test procedure, cultures are grown and adjusted using turbidimetric measurement techniques. A portion of the set culture is added to a thin layer of agar to form a seed layer. Test samples are diluted to a suitable test concentration according to the labeled strength claims. A reference standard antibiotic is diluted similarly with the various dilutions used to generate a standard curve.
Three plates are used for each sample tested. Six stainless steel penicillins are placed in each plate so that they are about 5 ° apart with a center spacing of about 60 cm. Three cylinders are filled with average dilution standard and three cylinders are filled with sample. Plates are incubated and zones of inhibition measured with calibrated calipers sensitive to 0.01 mm.
A standard curve is prepared on the day of the test. For the standard curve, three plates are prepared for each of the four concentrations supporting the median test dilution. Six cylinders are placed in each plate so that they are spaced approximately 5 ° apart with a center spacing of approximately 60 cm. Three alternative cylinders are filled with the average test dilution and the other three cylinders are filled with the dilution concentration of the standard curve. Plates are incubated and regions of inhibition growth observed are measured with calibrated calipers sensitive to 0.01 mm.
The measured zone values are entered into a validated spreadsheet for zone diameter correction, linear regression output, and potency calculations. A reference point can be interpolated using the straight line method of a log transformation with the least squares fitting procedure. Log-linear regression is used to calculate an R2 value to estimate linearity.
Sample strength is estimated by averaging the reference standard zone diameters and sample zone diameters on the three used plates. Concentrations are calculated from the corresponding corrected values of the zone diameters. The log value is converted to antilog. The antilog value is multiplied by the dilution factor to obtain the concentration in mg / mL of active antibiotic. These calculations are made with a spreadsheet approved for antibiotic potency.
EUROLAB, with its highly expert team and internationally accredited laboratories, Antibiotic Potency (Effect) Test It performs all test, analysis, measurement, evaluation and report generation services completely and reliably.
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