Application of high-performance liquid chromatography to the analysis, stability and pharmacokinetics of erythromycin
- Authors: Stubbs, Christopher
- Date: 1988
- Subjects: Erythromycin High performance liquid chromatography
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3809 , http://hdl.handle.net/10962/d1004372
- Description: Erythromycin is a macrolide antibiotic used mainly in the treatment of infections caused by gram-positive organisms. Erythromycin base is rap idly degraded in acidic media necessitating the use of structurally modified erythromycin derivatives or acid resistant dosage forms in order to decrease gastric inactivation of the drug. The majority of pharmacokinetic studies to-date have utilized relatively non-specific microbiological assay procedures which are unable to differentiate between concentrations of active erythromycin base and the inactive pro-drug derivatives. A high-performance liquid chromatographic (HPLC) technique is described for the simultaneous determination of erythromycin base and propionate (inactive pro-drug form) in human serum and urine following the oral administration of erythromycin estolate, an acid stable derivative of erythromycin. The method involves a solid-phase extraction step prior to chromatography on a C18 reversed-phase column with coulometric electrochemical detection. Sample handling and storage techniques are presented which minimize hydrolysis of the inactive ester moiety between sample collection and analysis, thereby more accurately reflecting the in vivo situation than in previously published studies. Results from single dose pharmacokinetic studies indicate that only 10-15% of the total erythromycin concentration in vivo is present as the active base component following oral administration of erythromycin estolate. This percentage increases to approximately 25% during multiple dose administration. Novel urinary excretion data are presented which reveal that approximately 40% and 55% of the total erythromycin excreted in urine is excreted as erythromycin base following single and multiple dosages respectively. Computer fitting of mean serum concentration-time data revealed that an open one compartment model with linear first order absorption and elimination best described the absorption and disposition of erythromycin, although poor computer fits for individual data sets were observed. Some evidence of non-linear elimination is presented utilizing both compartmental and non-compartmental pharmacokinetic techniques. Large intra-and inter-personal variability in erythromycin absorption and disposition was experienced which was evaluated in five subjects who each received one 500 mg erythromycin estolate tablet from the same batch, on three separate occasions. In addition. an HPLC method is described for the analysis of "total erythromycin" concentrations following erythromycin estolate administration which involves hydrolysis of the ester component prior to chromatography. as well as an HPLC method utilizing amperometric electrochemical detection capable of monitoring the stability of erythromycin base in stored biological fluids. These methods were uti I ized in various stability studies involving erythromycin base and propionate as well as for the analysis of erythromycin estolate dosage forms.
- Full Text:
- Date Issued: 1988
A stability-indicating liquid chromatographic method for the analysis of erythromycin in stored biological fluids using amperometric detection
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1987
- Language: English
- Type: Article
- Identifier: vital:6430 , http://hdl.handle.net/10962/d1006592
- Description: A simple, sensitive and reliable high-performance liquid chromatographic procedure has been developed for the determination of erythromycin in human serum and urine using amperometric detection. A solid-phase extraction procedure was used followed by chromatography on a reverse-phase column. The mean recovery of erythromycin from serum and urine was 80%. This method allows both erythromycin and its principle degradation product, anhydroeythromycin, to be determined during a period of sample storage at 4 degree C and minus 15 degree C. The method is sufficiently sensitive and precise and is thus highly suited for use in both pharmacokinetic and stability studies.
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- Date Issued: 1987
High performance liquid chromatographic analysis of oleandomycin in serum and urine
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1986
- Language: English
- Type: text , Article
- Identifier: vital:6429 , http://hdl.handle.net/10962/d1006590
- Description: The determination of oleandomycin in serum and urine by high-performance liquid chromatography using erythromycin as internal standard is described. The separation was achieved on a reversed-phase C 1 s column employing acetonitrile-0.05 A4 phosphate buffer (30:70), adjusted to pH 7.0, as the mobile phase with UV detection at 200 nm. A solid-phase extraction procedure, combined with a simple phaseseparation step was used prior to chromatographic analysis. Linear calibration curves were obtained in the concentration ranges 0.25-5.0 pg/ml (serum) and 1 .O-25.0 pg/ml (urine). Precise quantitative analysis has been achieved at these levels with relative standard deviations of < 5%.
- Full Text:
- Date Issued: 1986
Determination of erythromycin in serum and urine by high performance liquid chromatography with ultraviolet detection
- Authors: Stubbs, Christopher , Haigh, John M , Kanfer, Isadore
- Date: 1985
- Language: English
- Type: text , Article
- Identifier: vital:6428 , http://hdl.handle.net/10962/d1006576
- Description: A high-performance liquid chromatographic analysis of erythromycin in human serum and urine with UV detection at 200 nm is presented. The method involves a solid-phase extraction procedure followed by a simple phase separation step and chromatography on a reversed-phase column. The method has sensitivity limits of 0.25 and 1.0 g/mL in serum and urine, respectively, and is sufficiently sensitive to monitor concentrations of erythromycin in human serum and urine after the administration of a single 500-mg erythromycin stearate tablet.
- Full Text:
- Date Issued: 1985
High performance liquid chromatographic analysis of erythromycin in serum and urine
- Authors: Stubbs, Christopher
- Date: 1985 , 2013-03-13
- Subjects: High performance liquid chromatography , Erythromycin , Erythromycin -- Pharmacokinetics , Chromatographic analysis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3813 , http://hdl.handle.net/10962/d1004581 , High performance liquid chromatography , Erythromycin , Erythromycin -- Pharmacokinetics , Chromatographic analysis
- Description: Erythromycin, a macrolide antibiotic used mainly against gram-positive bacteria has been in clinical use since 1952 (1). Previous pharmacokinetic data published on this antibiotic have been derived predominantly from microbiological assay techniques. However, these techniques are relatively imprecise as well as being non-specific and extremely tedious to perform. A novel high performance liquid chromatographic analysis of erythromycin in human serum and urine using U.V. detection at 200 nm and/or electrochemical detection using both an amperometric and a coulometric electrochemical detector is presented. The method involves a solid phase extraction procedure followed by a simple phase separation step and chromatography on a reverse phase column. In order to select the optimum U.V. detector for this analysis, five "state of the art" detectors were compared in terms of their signal-to-noise ratios at U.V. wavelengths between 200 and 210 nm. A known metabolite des-N-methylerythromycin is readily detectable using U.V. detection, whilst another metabolite/degradation product anhydroerythromycin is not seen using U.V. detection but is readily observable using an electrochemical detector. The method has a limit of sensitivity of 0.25 μg/mL and 1.00 μg/mL in serum and urine respectively (U.V. detection) and is sufficiently sensitive to monitor serum and urine concentrations of erythromycin in man after administration of a single 500 mg erythromycin stearate tablet. , KMBT_363 , Adobe Acrobat 9.53 Paper Capture Plug-in
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- Date Issued: 1985