| 1. |
|
|
| 2. |
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Sundström, Ingela, et al.
(författare)
-
In vivo investigation of brain and systemic ketobemidone metabolism
- 2010
-
Ingår i: The Analyst. - : Royal Society of Chemistry (RSC). - 0003-2654 .- 1364-5528. ; 135:2, s. 405-413
-
Tidskriftsartikel (refereegranskat)abstract
- Ketobemidone metabolites have previously been identified in urine and plasma; here we show, for the first time, that norketobemidone and ketobemidone N-oxide are present in in vivo microdialysate from rat brain (striatum) after reverse microdialysis, suggesting striatal metabolism of ketobemidone. Ketobemidone metabolites were also identified in in vivo microdialysate samples from brain and blood, as well as in urine from rats, after subcutaneous administration of ketobemidone. Three Phase I metabolites (norketobemidone, ketobemidone N-oxide and hydroxymethoxyketobemidone) and three Phase II metabolites (glucuronic acid conjugates of ketobemidone, norketobemidone and hydroxymethoxyketobemidone) were identified in the microdialysates after subcutaneous administration. Coupled capillary liquid chromatography tandem mass spectrometry (LC-MS/MS) and SPE (boronate)-MS/MS were utilized for the analysis of the biological samples. The Phase I metabolites were identified by comparing the retention times and tandem mass spectra of the microdialysates with synthetic standards. The Phase II metabolites were identified by determination of exact masses and by comparing the tandem mass spectra of the microdialysates with those of synthetic standards for the aglycones. Hydroxyketobemidone, a catechol-type Phase I metabolite, was selectively isolated by solid-phase boronate-complexation but identified in urine alone. This work demonstrated that the in vivo microdialysis technique in combination with LC-MS/MS can be used to study the local metabolism of a drug in the brain.
|
|
| 6. |
- Sundström, Ingela, et al.
(författare)
-
Method development for identification of ketobemidone metabolites in microdialysate samples by coupled-column capillary liquid chromatography-tandem mass spectrometry
- 2008
-
Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1189:1-2, s. 503-513
-
Tidskriftsartikel (refereegranskat)abstract
- Methodologies for identification of ketobemidone metabolites in microdialysate samples utilizing coupled-column capillary liquid chromatography-electrospray quadrupole time-of-flight tandem mass spectrometry are presented. Two different methods were developed to efficiently analyze the metabolites norketobemidone, ketobemidone N-oxide and hydroxyketobemidone, respectively. Both methods include on-line desalting and trapping of the analytes on micro-solid-phase extraction columns with different retention mechanisms. Norketobemidone and ketobemidone N-oxide were trapped on a C18 column and then eluted by back-flush followed by isocratic separation on a fluorinated reversed-phase type silica gel column (Fluofix). Retention equations are proposed for the chromatographic observations made on the Fluofix column. Hydroxyketobemidone was trapped on a phenylboronic acid column by complex formation at basic pH and then eluted at acidic pH directly into to the mass spectrometer. Oxidation of hydroxyketobemidone to its corresponding quinone was also observed. The methods were successfully used to analyze synthetic ketobemidone metabolites in dilute low-volume microdialysis samples
|
|
