Ragheb H S
Purdue University, Department of Biochemistry, West Lafayette, IN 47907.
J Assoc Off Anal Chem. 1988 Sep-Oct;71(5):1071-4.
The volume of antibiotic solutions in cylinders used for diffusion assays is assumed to have no significant effect on estimation of potency. The size of zones of inhibition from cylinders containing 0.10, 0.20, and 0.30 mL of sample solution was compared with zones of inhibition from cylinders containing 0.20 mL of standard solutions. For zinc bacitracin, chlortetracycline.HCl, oxytetracycline, lincomycin.HCl, monensin Na, neomycin sulfate, K penicillin, streptomycin sulfate, and tylosin, the percent recovery (95-102) was optimum when both standard and sample cylinders contained the same volume (0.20 mL/cylinder). At 0.30 mL/cylinder for sample and 0.20 mL for standard solutions, there was a positive bias in potency of about 50%. At 0.10 mL/cylinder, there was a negative bias of approximately 25% except for neomycin, monensin, and bacitracin. For these antibiotics, the bias was about -50%. For hygromycin B, variation in volume of solution per cylinder has little effect on assay results. Experiments on commercial feeds and premixes gave essentially the same results as for the standard solutions experiments.
用于扩散试验的量筒中抗生素溶液的体积被认为对效价估计没有显著影响。将含有0.10、0.20和0.30 mL样品溶液的量筒的抑菌圈大小与含有0.20 mL标准溶液的量筒的抑菌圈大小进行比较。对于杆菌肽锌、盐酸金霉素、土霉素、盐酸林可霉素、莫能菌素钠、硫酸新霉素、青霉素钾、硫酸链霉素和泰乐菌素，当标准量筒和样品量筒都含有相同体积（0.20 mL/量筒）时，回收率百分比（95 - 102）最佳。当样品为0.30 mL/量筒且标准溶液为0.20 mL时，效价存在约50%的正偏差。当为0.10 mL/量筒时，除新霉素、莫能菌素和杆菌肽外，存在约25%的负偏差。对于这些抗生素，偏差约为 - 50%。对于潮霉素B，每个量筒中溶液体积的变化对测定结果影响很小。对商业饲料和预混料进行的实验得到的结果与标准溶液实验基本相同。
