Penicill development

Specialized antibiotic formulations have been developed for DCT, with physicochemical properties chosen to confer prolonged retention in the mammary secretions (21,, ). Ziv ( ) has summarized the desirable kinetic and other properties of such a product. The following antibiotic formulations are presently approved by the U.S. Center for Veterinary Medicine, FDA for infusion into the dry mammary gland erythromycin (300 mg), oxytetracycline-HCl (426 mg), benzathine cloxacillin (500 mg), cephapirin benzathine (300 mg), novobiocin (400 penicillin (200,000 lU) novobiocin (400 mg), penicil-... 

Although penicillic acid (59) is produced in high quantities in cultures of Penicillum cyclopium and Penicillum canescens isolated from corn seeds, its toxicity to animals have precluded further development as a herbicidal agent. 

Bacterial resistance to the penicillin antibiotics is a serious problem for the treatment of infections. Bacteria that have developed resistance to penicillin produce an enzyme called penicillinase. Penicillinase hydrolyzes the /3-lactam ring of penicillin, resulting in penicilloic acid. Because penicil-loic acid cannot act as an acylating agent, it is incapable of blocking bacterial cell wall synthesis by the mechanism shown above. 

Thiola (Of-mercaptopropionyl glycine) is a new drug developed to replace D-penicill-amine in the treatment of cystinuria. The drug was used in 9 patients for treatment and post-operative prophylaxis. Dosage was 200—1,000 mg daily for 3-42 months with an average of 13 months. Seven out of 9 patients reacted favourably to the treatment, but the number is too small to allow definitive conclusions. 

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