Drugs online research references
J Antibiot (Tokyo). 1992 Nov;45(11):1785-91.
The in vitro profile of selected 14-membered azalides.
Jones AB, Herbert CM.
Synthetic Chemical Research Department, Merck Research Laboratories, Rahway, NJ 07065.
The in vitro antimicrobial potency of 10-aza-9-deoxo-11-deoxyerythromycin A, the first member of a new class of macrolide antibiotic, was determined. Several other members of this family of azalide were prepared and similarly screened in order to begin to define the antibiotic potential of the class. The results indicate that the SAR for this structural type parallels that of other macrolides and that it offers no apparent benefit over known 15-membered azalides.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1334956&dopt=Abstract
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Antimicrob Agents Chemother. 1992 Dec;36(12):2584-8.
In vitro demonstration of transport and delivery of antibiotics by polymorphonuclear leukocytes.
Frank MO, Sullivan GW, Carper HT, Mandell GL.
Division of Infectious Disease, University of Virginia School of Medicine, Charlottesville 22908.
Several antibiotics are concentrated inside polymorphonuclear leukocytes (PMN). To investigate whether PMN could act as vehicles for delivery of antibiotics, we combined an assay measuring PMN chemotaxis under agarose with a bioassay measuring levels of antibiotic in agar. Double-layer plates were made by pouring a layer of chemotaxis agarose into tissue culture plates and then adding a thin layer of Trypticase soy agar. Neutrophils were incubated with antibiotic for 1 h and then were washed and placed in wells made in the plates. After allowing PMN to migrate under the agar toward a chemoattractant well containing formyl-methionine-leucine-phenylalanine for 3 h, Streptococcus pyogenes was streaked on top of the agar and grown overnight. PMN migration and zones of inhibition of bacterial growth were measured. Neutrophils migrated 2.51 +/- 0.16 mm toward the chemoattractant well and 1.48 +/- 0.12 mm toward the medium well; migration was not significantly affected by any of the antibiotics used. Plates with PMN incubated without antibiotic showed insignificant inhibition of bacterial growth toward chemoattractant and medium wells (0.38 +/- 0.18 and 0.14 +/- 0.12 mm, respectively; for both, P > 0.05 for difference from 0). PMN incubated with oxacillin (3 micrograms/ml), a drug not concentrated in PMN, caused a similar lack of inhibition (0.28 +/- 0.09 mm toward chemoattractant; 0.14 +/- 0.03 mm toward medium). Incubation with 30 microns of ciprofloxacin per ml resulted in inhibition that was similar in both directions (1.40 +/- 0.16 versus 1.18 +/- 0.13 mm). However, for PMN incubated with azithromycin (3 micrograms/ml), an agent highly concentrated inside phagocytes, there was a large degree of inhibition which was significantly greater in the direction of chemoattractant than in the direction of medium (3.47 +/- 0.30 versus 1.89 +/- 0.25 mm; P < 0.001), indicating that release of bioactive azithromycin by neutrophils occurred after migration. Likewise, after incubation with rifampin (10 micrograms/ml), which is also concentrated by PMN, inhibition was significantly greater in the direction of chemoattractant than in the direction of medium (1.54 +/- 0.24 versus 0.81 +/- 0.28 mm; P = 0.001). We conclude that for certain antibiotics, PMN may act as vehicles for transport and delivery of active drug to sites of infection.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1336337&dopt=Abstract
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Antimicrob Agents Chemother. 1992 Dec;36(12):2693-7.
Relationship between antibiotic concentration in bone and efficacy of treatment of staphylococcal osteomyelitis in rats: azithromycin compared with clindamycin and rifampin.
O'Reilly T, Kunz S, Sande E, Zak O, Sande MA, Tauber MG.
Pharma Research, Ciba-Geigy Ltd., Basel, Switzerland.
We examined the effect of azithromycin (CP-62,993), a new oral macrolide-like antibiotic, alone and in combination with rifampin, as treatment for experimental staphylococcal osteomyelitis. Clindamycin was used as a comparison drug. Rats (n = 10 to 15 per group) were infected by direct instillation of Staphylococcus aureus into the tibial medullary cavity. After 10 days, 21-day treatments with azithromycin (50 mg/kg of body weight, once daily, by the oral route), rifampin (20 mg/kg, once daily, subcutaneously), or clindamycin (90 mg/kg, three times daily, by the oral route) were started. The drugs were used singly or in combination (azithromycin plus rifampin or clindamycin plus rifampin). Peak azithromycin concentrations in bone were > 30 times higher than levels in serum, but the drug had little effect on final bacterial titers (5.13 +/- 0.46 log10 CFU/g of bone; for controls, 6.54 +/- 0.28 log10 CFU/g). Clindamycin was more active than azithromycin (3.26 +/- 2.14 log10 CFU/g of bone; 20% of sterilized bones), but rifampin was the most active single drug (1.5 +/- 1.92 log10 CFU/g; 53% of sterilized bones). Therapy with rifampin or clindamycin alone was associated with the emergence of resistance. Rifampin plus azithromycin (0.51 +/- 1.08 log10 CFU/g of bone; 80% of sterilized bones) and rifampin plus clindamycin (0.87 +/- 1.34 log10 CFU/g of bone; 66% of sterilized bones) were the most active regimens. Thus, azithromycin is ineffective as a single drug for the treatment of experimental staphylococcal osteomyelitis, despite high levels in bone that markedly exceeded the MIC, but it may be an attractive partner drug for rifampin.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1336342&dopt=Abstract
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