Evaluation of a micromethod for determination of antibiotic concentrations in plasma

Oral cefadroxil prophylaxis in hip fracture surgery

“…Inhibition zones were read after 16 hours, a standard curve prepared, and the serum concentration calculated. This gives a 95 percent confidence limit of f 15 percent of the measured value (Jalling et al 1972). Determination of staphylococcal MIC.…”

Paper Disk-Agar Diffusion Assay of Penicillin in the Presence of Streptomycin

“…A disk-diffusion assay of penicillin with Sarcina lutea ATCC 9341 as the test organism is widely used (2,6,8), and the experiments presented here will further deal with the determination of penicillin in the presence of streptomycin.…”

“…On the other hand, much less attention has been drawn to the separate determination of penicillin, justified by the fact that compared with the aminoglycosides, penicillin is widely used without frequent serious toxic side effects. The addition of semicarbazide hydrochloride, 1 mg per ml of culture medium, to inactivate streptomycin when assaying penicillin in a mixture has been advocated (6). A separate determination could also be obtained indirectly by adding to the penicillin standards the previously estimated content of streptomycin (5).…”

“…This is all the more evident when the patient receives more than one drug at the same time. The specificity of a microbiological assay of individual antibiotics during combined treatment, then, depends on the use of both selective inhibitors and suitable strains of test bacteria (6). Thus, a reliable assay of any of the aminoglycosides (streptomycin, kanamycin, gentamicin, and neomycin) is possible in the presence of any penicillin or cephalosporin (other than cephalexin) by the use of 0-lactamase (7,11).…”

“…The need for laboratory control as a guide to antibiotic treatment to ensure therapeutic concentrations in serum, tissues, and body fluids and to avoid toxic side effects has been stressed by many authors (3,6,9,10). This is all the more evident when the patient receives more than one drug at the same time.…”