Reference

Structure-activity relationships in 4-deoxypyrido(1',2'-1,2)imidazo(5,4-c)rifamycin SV derivatives

Structure-activity relationships in 4-deoxypyrido(1',2'-1,2)imidazo(5,4-c)rifamycin SV derivatives. Cellai, L.; Cerrini, S.; Brufani, M.; Marchi, E.; Mascellani, G.; Montecchi, L. (Ist. Strutt. Chim. "G. Giacomello", Rome, Italy). Chemioterapia, 2(5, Suppl.: Mediterr. Congr. Chemother., Proc., 3rd, 1982), 53-4 (English) 1983. CODEN: CHEMEV. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) Section cross-reference(s): 22 The polarity of rifamycin L-105 SV (I) [80621-81-4] and its oxidized S [80621-76-7] form and the contribution of this polarity in the pharmacokinetics of these drugs were investigated. NMR and x-ray crystallog. studies indicated that the pyridoimidazo ring is coplanar with the naphthoquinonic nucleus making the pyridoimidazo ring system arom. with the 2 N both charged. The pyrido-N is pos. charged and the other neg. charged. The contribution of charged forms to the resonance-structure of these compds. renders these agents with pharmacokinetic properties that make them virtually nonabsorbable from the intestine and thus providing high antimicrobial activity in the digestive tract.

Renal excretion of L-105, a new cephalosporin antibiotic in dogs

Renal excretion of L-105, a new cephalosporin antibiotic in dogs. Matsumoto, Fumio; Inokawa, Yoshiyuki; Akai, Nobuko; Takei, Hiroshi; Hiruma, Hideo (Dep. Intern. Med., Kanagawa Prefect. Midwives Nurses Training Sch. Hosp., Kanagawa, Japan). Chemotherapy (Tokyo), 34(Suppl. 3), 100-4 (Japanese) 1986. CODEN: NKRZAZ. ISSN: 0369-4682. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacology) The mechanism of renal excretion of L-105 [80621-81-4] was investigated in dogs with cannula inserted into the ureter. The pelvic urine was collected in fractions and the phase of distal tubular excretion, proximal tubular excretion and glomerular filtration were ascertained by monitoring concns. of Na+/K+ ions, p-aminohippuric acid, and inulin in each fraction. The concn. of creatinine was monitored as a parameter of urine concn. No specific peak of L-105 was recognized in the phase of p-aminohippuric acid excretion nor in the entire phase of Na+/K+ reabsorption in dogs. After pretreatment with probenecid (30 mg/kg), the peak of p-aminohippuric acid disappeared while the stop-flow pattern of L-105 remained virtually unchanged. Thus, the renal excretion of L-105 took place mainly through glomerular filtration in dogs.