Drugs online research references
Antimicrob Agents Chemother. 1995 Sep;39(9):2104-11.
Formulation and efficacy of liposome-encapsulated antibiotics for therapy of intracellular Mycobacterium avium infection.
Oh YK, Nix DE, Straubinger RM.
Department of Pharmaceutics, University at Buffalo, State University of New York, Amherst 14260-1200, USA.
Mycobacterium avium is an intracellular pathogen that can invade and multiply within macrophages of the reticuloendothelial system. Current therapy is not highly effective. Particulate drug carriers that are targeted to the reticuloendothelial system may provide a means to deliver antibiotics more efficiently to M. avium-infected cells. We investigated the formulation of the antibiotics ciprofloxacin and azithromycin in liposomes and tested their antibacterial activities in vitro against M. avium residing within J774, a murine macrophage-like cell line. A conventional passive-entrapment method yielded an encapsulation efficiency of 9% for ciprofloxacin and because of aggregation mediated by the cationic drug, was useful only with liposomes containing < or = 50 mol% negatively charged phospholipid. In contrast, ciprofloxacin was encapsulated with > 90% efficiency, regardless of the content of negatively charged lipids, by a remote-loading technique that utilized both pH and potential gradients to drive drug into preformed liposomes. Both the cellular accumulation and the antimycobacterial activity of ciprofloxacin increased in proportion to the liposome negative charge; the maximal enhancement of potency was 43-fold in liposomes of distearoylphosphatidylglycerol-cholesterol (DSPG-Chol) (10:5). Azithromycin liposomes were prepared as a freeze-dried preparation to avoid chemical instability during storage, and drug could be incorporated at 33 mol% (with respect to phospholipid). Azithromycin also showed enhanced antimycobacterial effect in liposomes, and the potency increased in parallel to the moles percent of negatively charged lipids; azithromycin in DSPG-Chol (10:5) liposomes inhibited intracellular M. avium growth 41-fold more effectively than did free azithromycin. Thus, ciprofloxacin or azithromycin encapsulated in stable liposomes having substantial negative surface charge is superior to nonencapsulated drug in inhibition of M.avium growth within cultured macrophages and may provide more effective therapy of M.avium infections.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8540724&dopt=Abstract
J Antimicrob Chemother. 1998 Mar;41(3):391-6.
Trovafloxacin compared with levofloxacin, ofloxacin, ciprofloxacin, azithromycin and clarithromycin against unusual aerobic and anaerobic human and animal bite-wound pathogens.
Goldstein EJ, Citron DM, Hudspeth M, Hunt Gerardo S, Merriam CV.
R. M. Alden Research Laboratory, Santa Monica-UCLA Medical Center, CA 90404, USA.
The activity of trovafloxacin and five other oral agents against 250 aerobic and 137 anaerobic strains isolated from human and animal bite wounds was determined by an agar dilution method. Trovafloxacin was active against all aerobic and fastidious facultative isolates at < or = 0.5 mg/L and all anaerobes at < or = 2 mg/L (Bacteroides tectum, Porphyromonas salivosa and Prevotella heparinolytica, < or = 0.25 mg/L; Porphyromonas spp., < or = 0.5 mg/L; Prevotella spp. and peptostreptococci, < or = 2.0 mg/L), except Fusobacterium nucleatum and other fusobacteria (MIC90 < or = 4 mg/L). Levofloxacin was generally one to two dilutions more active than ofloxacin, while ciprofloxacin was active against aerobes (MIC < or = 1 mg/L) but less active against anaerobic strains (MIC90 < or = 16 mg/L).
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9578167&dopt=Abstract
Scand J Infect Dis. 1992;24(5):619-27.
Delayed antibiotic-induced lysis of Escherichia coli in vitro is correlated with enhancement of LPS release.
Van Den Berg C, de Neeling AJ, Schot CS, Hustinx WN, Wemer J, de Wildt DJ.
Laboratory for Medicines and Medical Devices, National Institute of Public Health and Environmental Protection, Bilthoven, The Netherlands.
A kinetic turbidimetric Limulus amebocyte lysate (LAL) assay was used to study the effects of gentamicin, amoxycillin and ciprofloxacin (16 x MIC) upon release of lipopolysaccharide at different stages of a growing Escherichia coli 055:B5:H culture in vitro. In this model a linear correlation was present between the logarithms of colony counts and free LAL activities. Untreated E. coli grew from log values of 4.9 +/- 0.15 (low inoculum) and 6.8 +/- 0.08 cfu/ml (high inoculum) at t = 0 to 8.9 +/- 0.05 and 9.1 +/- 0.13 cfu/ml at t = 6 h, respectively. The log values of basal free LAL activities at low and high inoculum sizes were 1.9 +/- 0.07 and 3.3 +/- 0.14 endotoxin units/ml, increasing 2100- and 69-fold, respectively during a 6-h growth. Amoxycillin-induced lysis was not significantly associated with an increase in free LAL activity. Efficacy of bacterial killing by gentamicin was high, but free LAL activity increased only 3.2- and 7.7-fold at the low and high inoculum experiments, respectively. Ciprofloxacin induced cell filamentation during the experiments. At low and high inoculum conditions exposure to ciprofloxacin induced a 43- and 68-fold increase in free LAL activities, respectively. Our data indicate that (a) LPS is released as long as E. coli remain structurally intact; (b) LPS release is enhanced when bacterial biomass increases; and (c) are taken as evidence against the concept of lysis-correlated LPS release.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1465580&dopt=Abstract
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