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At least 1,711 records · Page 95Linked to original sources
PubMed2000

Investigation of unknown related substances in commercial erythromycin samples with liquid chromatography/mass spectrometry.

A selective reversed phase liquid chromatography/mass spectrometry (LC/MS(n)) method is described for the identification of erythromycin impurities and related substances in commercial erythromycin samples. Mass spectral data are acquired on a LCQ ion trap mass spectrometer equipped with an electrospray interface operated in positive ion mode. The LCQ is ideally suited for identification of impurities and related substances because it provides on-line LC/MS(n) capability. Compared with UV detection, this hyphenated LC/MS(n) technique provides as a main advantage efficient identification of novel substances without time-consuming isolation and purification procedures. Using this method four novel related substances were identified in commercial samples.

Animals↗
PubMedDate not supplied

Intra- and intersubject variation of erythromycin absorption from single-unit and multiple-unit enteric-coated products.

Based on the in vitro dissolution test for erythromycin capsules introduced in USP XX, Suppl. 3, there are no reasons to expect any difference in bioavailability after administration of two enteric-coated products, tablets and pellets in hard capsules. The present results in vivo are contradictory and, following duplicate administrations of the two preparations to 12 volunteers after a standardized breakfast, it is apparent that the multiple-unit, pellets, produce a better reproducibility in absorption both within and between subjects than the single-unit tablets. All subjects attained measurable levels of erythromycin on all occasions after administration of pellets, while levels were below the detectable limit on six out of the 24 occasions tested after administration of tablets. The better reproducibility of serum levels after pellets than after tablets was also shown in a descriptive way and is given as a low median discrepancy value of 23.5 per cent (moderate) compared to 73.2 per cent (large).

Adult↗
PubMed1993

Cyclosporin A and erythromycin: a study of a drug interaction in the in situ perfused rat liver model.

Using the in situ perfused rat liver model, the effect of erythromycin (Ery) on the disposition of cyclosporin A (CyA) and the major human metabolite, AM1, was investigated. Prior to perfusion experiments, oral dosing was carried out for three days on three groups of male Sprague-Dawley rats (300-350 g), involving pretreatment with water (control and H2O/Ery groups) or erythromycin (Ery oral group). On the fourth day, perfusion experiments took place using standard techniques, with the addition of 20 mg Ery to the H2O/Ery and Ery oral groups, and 2.5 mg CyA to all groups. Perfusate and bile samples were collected and assayed for CyA and AM1 by HPLC. Results indicated that inhibition of CyA metabolism had occurred as the CyA concentration in perfusate was significantly higher in both Ery groups at all times compared to the control group, and the levels of AM1 in both perfusate and bile were significantly lower than in the control group. There was also a marked reduction in the apparent metabolic clearance of CyA in the Ery groups. It was concluded that AM1 production had been inhibited by Ery, the most likely mechanism being inhibition of the isoenzyme CYP3A with which Ery forms a stable complex.

Animals↗
PubMed2003

Modeling the performance of pilot-scale countercurrent chromatography: scale-up predictions and experimental verification of erythromycin separation.

Biosynthesis of polyketide antibiotics, such as erythromycin A (EA), can result in the formation of analogues of the main compound that are chemically and structurally extremely similar. The large-scale purification of these antibiotics by conventional high-performance liquid chromatography (HPLC) can be prohibitively expensive due to the large volume of both solvent and adsorbent required. This study examines the feasibility of using a novel pilot-scale countercurrent chromatography (CCC) machine as an alternative to HPLC. CCC is a low-pressure (typically <4000 kN m(-2)) liquid-liquid chromatographic technique that allows the separation of solutes on the basis of their partitioning between two immiscible liquid phases. The effects of mobile phase flow rate, column rotational speed, and sample injection volume on the attainable yield and purity of EA were investigated. Our results show that, at a mobile phase flow rate of 40 mL min(-1), a rotational speed of 1200 rpm, and an injection volume of 100 mL (10 g total erythromycin), EA could be satisfactorily fractionated with a purity of approximately 92% (w/w) and a recovery yield of approximately 100% (w/w). The total solute throughput was estimated to be 0.41 kg day(-1). More importantly, we demonstrated simple and predictive linear scale-up of the CCC separation based on data obtained from a single laboratory-scale CCC chromatogram, and verified this experimentally. The retention time and peak width of the target compound at the pilot scale could be predicted to within 4% for operation at a range of mobile-phase flow rates and injection volumes. This predictable nature of CCC separations, unlike HPLC methods, can greatly reduce process development times and enable a complete process-scale operating scenario to be planned.

Chromatography, Liquid↗
PubMed1978

Bioavailability of erythromycin ethylsuccinate in pediatric patients.

A parallel treatment group bioavailability study was undertaken in children 6 to 65 months of age, comparing fasting and nonfasting erythromycin serum levels after a single oral dose of erythromycin ethylsuccinate granules. Results demonstrated significantly higher levels in the nonfasting than in the fasting state, while fasting state levels were comparable to those found in studies of adult subjects receiving recommended doses of the same compound.

Bacterial Infections↗
PubMedDate not supplied

Influence of bariatric surgery on erythromycin absorption.

Seven adult, morbidly obese patients scheduled for bariatric surgery were studied in an identical manner preoperatively and postoperatively. Six patients underwent gastroplasties, and one patient underwent a gastric bypass procedure. A single 250-mg dose of erythromycin as a Filmtab was administered orally after an overnight fast. Multiple venous blood samples were collected over a 12-hour period. After surgery, each patient had a decrease in peak concentration and an increase in the time to reach peak concentration compared to presurgery values. Mean peak concentration was reduced from 1.04 micrograms/ml preoperatively to 0.55 micrograms/ml postoperatively, and the mean time to peak increased from 3.9 hours to 6.7 hours. Mean weight-corrected AUC was reduced 41 per cent, with two patients having no detectable serum levels postoperatively. The results suggest that the erythromycin product evaluated is of questionable value for use in bariatric surgery patients.

Adult↗
PubMed1998

Effect of multiple doses of rifampin on the [14C N-methyl] erythromycin breath test in healthy male volunteers.

The erythromycin breath test (EBT), which measures 14CO2 produced from [14C N-methyl] erythromycin, is one of the most frequently employed measures to examine drug interactions involving cytochrome P450 3A4 (CYP3A). However, the reproducibility and reliability of this test, and the effects of drugs that alter CYP3A activity, continue to be defined. In this study, the reproducibility of the EBT was evaluated in eight healthy volunteers before and after oral administration of 600 mg of rifampin daily for 8 days. Two sequential EBT determinations performed 5 days apart before rifampin administration were highly reproducible. Rifampin induced CYP3A, reflected in a mean percent (+/- standard deviation) increase in EBT values of 86 +/- 30%. Recovery of enzyme function after discontinuation of rifampin for 17 days was manifested as a return of EBT values to preinduction levels. These results support the utility of EBT as a valid, reproducible, and reliable measure of CYP3A activity in vivo.

Administration, Oral↗
PubMed1991

Effects of purine nucleoside analogues with a cyclobutane ring and erythromycin A oxime derivatives on duck hepatitis B virus replication in vivo and in cell culture and HIV-1 in cell culture.

The effects on duck hepatitis B virus (DHBV) replication of specific analogues of two classes of chemical compounds not previously tested against hepadnaviruses are described. One is erythromycin A-9-methyloxime (EMO) and other oxime derivatives of erythromycin A, and the other is purine nucleoside analogues (cyclobut A and cyclobut G) with cyclobutane rings. Viral replication was assessed by measuring serum levels of DHBV DNA in infected ducklings and DHBV DNA in infected primary duck hepatocyte cultures. Administration of EMO 15 mg/kg of body weight IM to infected ducklings resulted in a rapid fall in DHBV DNA levels during therapy and a return to pretreatment levels after EMO administration was stopped. There was local toxicity at injection sites with muscle necrosis in some animals. When 100 mg/kg EMO was administered by gastric tube no such viral response was observed. The difference in virus response to EMO 15mg/kg IM and 100 mg/kg by gastric tube was not due to failure to achieve comparable blood and tissue levels of EMO administered by the different routes. The results suggest an indirect effect dependent on IM injection of EMO rather than a direct antiviral effect of the compound. Administration of cyclobut G or cyclobut A at 70 mg/kg IM led to a rapid reduction of DHBV DNA to undetectable levels in serum, and in only 1 of 4 animals did DHBV DNA became detectable again within 10 days after stopping the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine↗
PubMed1985

Interspecies correlation of the pharmacokinetics of erythromycin, oleandomycin, and tylosin.

Knowledge of the disposition of macrolides in a single animal species has been insufficient for the prediction of the pharmacokinetics of macrolides in humans. To better understand the species differences in the pharmacokinetics of macrolide antibiotics, the disposition of erythromycin, oleandomycin, and tylosin in several mammalian species was examined. Generally, the serum concentration versus time profiles of these drugs after intravenous administration were described by two-compartment kinetic models and were similar within each species. These drugs were rapidly cleared, resulting in terminal half-lives of less than 2 h. Comparison of their pharmacokinetics showed greater variation in antibiotic disposition among animal species than noted for the differences within a species. When the pharmacokinetic data was fitted to an allometric model, the logarithms of volume of distribution, clearance, and half-life were linearly related to the logarithms of body weight. From these relationships, the human pharmacokinetics of erythromycin and oleandomycin were extrapolated and found to approximate observed human pharmacokinetics.

Animals↗
PubMed1989

Microbioluminometry assay: determination of erythromycin activity in plasma or serum.

A microbioluminometry assay (MBA) was developed for the quantitative analysis of erythromycin activity in human plasma or serum. The MBA method is adapted from turbidimetric methods and utilizes an enzyme-catalyzed bioluminescence reaction to quantitate the growth of Staphylococcus aureus in liquid culture medium. Statistical analysis of data obtained in method validation studies and in more than 500 assays of standard curve and control samples demonstrates consistent reproducibility and accuracy within theoretical limits. The MBA was shown to be more sensitive than agar diffusion assays with a lower limit of sensitivity less than 20.0 ng/mL and coefficients of variation less than 10%. Cumulative results of 178 assays of spiked control plasma samples in the range of 0.14-2.18 micrograms/mL show 11.2% of individual determinations are greater than +/- 15% the expected value, and 5.6% of individual determinations are greater than +/- 20% the expected value. Bioavailability profiles obtained with MBA are consistent with reported data for erythromycin. Values for 206 subject samples analyzed by MBA and agar diffusion assays showed a high degree of correlation (r = 0.9525) between the two methods. The MBA technique provided high sample throughput because of the use of microtiter plate technologies; it is also economical since it requires less sample and reagents.

Biological Availability↗
PubMed2007

Usage of the claim database of national health insurance programme for analysis of cisapride-erythromycin co-medication in Taiwan.

PURPOSE: This study aimed to use the National Health Insurance Research Database, Taiwan for risk analysis of concomitant use of cisapride and erythromycin. METHODS: The sample consisted of subjects identified in the Outpatient Sampling Database (OSD) and Longitudinal Health Insurance Database 2000 (LHID 2000), derived from the original claim data of the National Health Insurance Research Database, Taiwan. RESULTS: According to the LHID 2000, a total of 464 individuals experienced 685 episodes of cisapride-erythromycin co-medication prescribed by 295 physicians, revealing a prevalence of 4.5% concomitant use, with higher prevalence in clinics (9.2%) than in other medical institutes (3.7-5.4%). Among the co-medication episodes, 81.9% and 61.2% were prescribed from the same health institutes and by the same physicians, respectively. No medical record of cardiac arrhythmias was found among these patients in 2001 and 2002, probably due to the fact that 78.9% of the 464 individuals were under age 16, 84.0% had short exposure duration (1-4 days) and 98.0% of the episodes were prescribed with a cisapride dose of less than 0.8 mg/kg/day. CONCLUSIONS: Findings from this study suggest that there exists an urgent need for accreditation in terms of pharmacovigilance of clinical sites and their practicing physicians for the prevention of irrational concomitant prescription in Taiwan. Our findings also indicate that it is necessary to investigate other possible conditions of potentially dangerous co-medication in Taiwan and other developing countries.

Adolescent↗
PubMed1994

Purification of a thymidine-diphospho-4-keto-6-deoxy-D-glucose epimerase from an erythromycin-producing strain of Saccharopolyspora erythraea.

A thymidine-diphospho-4-keto-6-deoxy-D-glucose epimerase was purified from Saccharopolyspora erythraea, the producer of the macrolide antibiotic erythromycin, by a high resolution chromatographic method that exploited the difference in behavior of the protein on ion exchange columns at pH 7.5 and 5.5. By this procedure and by hydrophobic interaction chromatography, the enzyme was purified more than 400-fold to apparent homogeneity. The epimerase is a monomer of M(r) 55,000, as determined by reducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration. The apparent Michaelis-Menten kinetic constants were determined to be K'm of 120 microM and V'max of 0.38 mumol mg-1 min-1. Southern analysis indicates that this epimerase is encoded by a gene that is not located within the known confines of the erythromycin biosynthetic gene cluster.

Amino Acid Sequence↗
PubMed1999

Erythromycin resistance mutations in ribosomal proteins L22 and L4 perturb the higher order structure of 23 S ribosomal RNA.

We have used chemical modification to examine the conformation of 23 S rRNA in Escherichia coli ribosomes bearing erythromycin resistance mutations in ribosomal proteins L22 and L4. Changes in reactivity to chemical probes were observed at several nucleotide positions scattered throughout 23 S rRNA. The L4 mutation affects the reactivity of G799 and U1255 in domain II and that of A2572 in domain V. The L22 mutation influences modification in domain II at positions m5U747, G748, and A1268, as well as at A1614 in domain III and G2351 in domain V. The reactivity of A789 is weakly enhanced by both the L22 and L4 mutations. None of these nucleotide positions has previously been associated with macrolide antibiotic resistance. Interestingly, neither of the ribosomal protein mutations produces any detectable effects at or within the vicinity of A2058 in domain V, the site most frequently shown to confer macrolide resistance when altered by methylation or mutation. Thus, while L22 and L4 bind primarily to domain I of 23 S rRNA, erythromycin resistance mutations in these ribosomal proteins perturb the conformation of residues in domains II, III and V and affect the action of antibiotics known to interact with nucleotide residues in the peptidyl transferase center of domain V. These results support the hypothesis that ribosomal proteins interact with rRNA at multiple sites to establish its functionally active three-dimensional structure, and suggest that these antibiotic resistance mutations act by perturbing the conformation of rRNA.

Drug Resistance, Microbial↗
PubMed1998

Molecular identification of a Stenotrophomonas species used in the bioassay for erythromycin in aquaculture samples.

A bacterial strain isolated from aquaculture pond slurry, which was extremely sensitive to erythromycin, was used to detect erythromycin at levels as low as 0.05 micrograms ml-1 in aquaculture water, sediments and soil samples. Identification of the indicator organism was attempted by 16S rRNA sequencing, biochemical profile, fatty-acid analysis and polymerase chain reaction (PCR). GenBank comparison showed that the 16S rRNA sequence of the strain was similar to those of more than 20 copies of Xanthomonas and Stenotrophomonas. The position of the strain in a phylogenetic tree based on the 16S rRNA gene sequence comparison is in a cluster of Stenotrophomonas. The fatty-acid analysis also showed that the strain is similar to Stenotrophomonas maltophilia. However, the biochemical profile of the strain is most similar to Xanthomonas campestris, except that it can utilize maltose, which is similar to S. maltophilia. Polymerase chain reaction results showed that the strain is different from X. campestris, S. maltophilia and other Xanthomonas species tested. Based on these results, the authors named this strain as Stenotrophomonas sp. strain NCTR.

Aquaculture↗
PubMed1994

Molecular characterization of a plasmid-borne (pGT633) erythromycin resistance determinant (ermGT) from Lactobacillus reuteri 100-63.

Lactobacillus reuteri 100-63 contains a 9.8 kb plasmid (pGT633) encoding resistance to the macrolide-lincosamide-streptogramin (MLS) type B antibiotics. The restriction endonucleases AccI, BamHI, BclI, EcoRI, EcoRV, HhaI, HindII, HpaI, KpnI, SalI, and SspI were employed to establish a physical map of pGT633. Next, genetic transfer experiments were conducted to establish the host range of pGT633. The results revealed that pGT633 replicated autonomously and encoded constitutive resistance to erythromycin in a variety of bacterial hosts, including Bacillus subtilis BD170, Streptococcus sanguis DL1, Staphylococcus aureus RN4220, and Enterococcus faecalis 19433, as well as several Lactobacillus spp. A 2.2 kb BamHI fragment of pGT633 containing the genetic determinant (ermGT) encoding resistance to erythromycin was cloned into Escherichia coli. Determination of the nucleotide sequence of ermGT revealed a methylase gene 731 bp in length that was highly related (ca. 81% nucleotide and ca. 78% amino acid identity) to the ermC gene from S. aureus plasmid pE194. The leader sequences of ermGT and ermC were identical except for a single base change at nt 51.

Amino Acid Sequence↗
PubMed1997

Molecular properties of the erythromycin resistance plasmid pPV141 from Staphylococcus chromogenes.

The 2.3-kb erythromycin resistance (EmR) plasmid pPV141 of Staphylococcus chromogenes 3688 was isolated and characterized. Nucleotide sequence analysis identified ORF1 and ORF2 separated by a 445-bp spacing, encoding a 158-residue replication protein (Rep141) and a 244-residue erythromycin resistance protein (Erm, rRNA adenine N-6-methyltransferase), respectively. Structural analysis and Southern hybridization showed that the rep and ermM genes in pPV141 shared homology with other known EmR plasmids. Based on sequence analysis, pPV141 was classified as a unique member of the pSN2 family of EmR plasmids.

Amino Acid Sequence↗
PubMed1993

Influence of topical erythromycin preparations for acne vulgaris on skin surface pH.

Topical erythromycin is a standard regimen for inflammatory acne vulgaris because of its action against Propionibacterium acnes. Changes in P. acnes colonization are inducible by long-lasting changes of skin surface pH. Therefore, the influence of six erythromycin preparations with approximative pH values of 7.5 (preparation A) to 10.2 (C) on the skin surface pH was evaluated in healthy volunteers using a cross-over design. Following a 14-day run-in period, a constant skin surface pH (5.0) was found. Ten subjects received single doses 2-3 days apart; 20 volunteers applied preparations A and C for 28 days. Single doses of preparations A and E (pH 8.0) increased skin pH to 6.99 and 8.61, respectively, at 15 min; it then gradually declined. The other preparations induced only a minor rise of short duration. At the end of the long-term application, the skin surface pH amounted to 5.73 (A) and 5.39 (C). There was no correlation between the effect on skin surface pH and the approximative pH of the preparations. A close relation of single-dose and long term-effects was observed, however. The skin surface pH during the application of preparation A is high enough to increase P. acnes growth about fourfold as compared with normal skin and thus may counteract the antibacterial effect. Clinical relevance should be evaluated in a controlled clinical trial comparing the efficacy of preparation A with that of preparation C.

Acne Vulgaris↗
PubMed1977

Properties of ribosomes from erythromycin resistant mutants of Escherichia coli.

We have studied the in vitro properties of ribosomes from several mutants resistant to erythromycin. Mutations in three different genes may confer resistance to erythromycin. Two of them are structural genes for proteins L4 and L22 of the large subunit. The third mutation (in eryC gene) seems to affect mainly the small subunit. The mechanism of action of the antibiotic may involve both subunits.

Drug Resistance, Microbial↗