J Pharm Biomed Anal. 2003 Aug 8;32(4-5):975-81.
Development of electrochemical methods for determination of tramadol--analytical application to pharmaceutical dosage forms.

Garrido EM, Garrido JM, Borges F, Delerue-Matos C.

CEQUP/Departamento Engenharia Quimica, Instituto Superior de Engenharia do Porto, Rua S. Tome, 4200-485 Porto, Portugal.

A square-wave voltammetric (SWV) method and a flow injection analysis system with amperometric detection were developed for the determination of tramadol hydrochloride. The SWV method enables the determination of tramadol over the concentration range of 15-75 microM with a detection limit of 2.2 microM. Tramadol could be determined in concentrations between 9 and 50 microM at a sampling rate of 90 h(-1), with a detection limit of 1.7 microM using the flow injection system. The electrochemical methods developed were successfully applied to the determination of tramadol in pharmaceutical dosage forms, without any pre-treatment of the samples. Recovery trials were performed to assess the accuracy of the results; the values were between 97 and 102% for both methods.

Tramadol reference source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12899984&dopt=Abstract tramadol Ultram [PubMed - in process]

ffa.uni-lj.si

Tramadol is a centrally acting analgesic used for prevention and treatment of moderate to severe pain. It is estimated that 0.1% of the administered dose passes into breast milk causing potentially unwanted effects in nursing babies. Pharmacokinetically, breast milk is supposed to be a separate compartment into which the drug is excreted-mainly by passive diffusion. Due to a complex composition of breast milk, a suitable sample preparation procedure is needed with a subsequent chromatographic analysis for drug determination. Among several sample cleanup procedures tested we chose the liquid-liquid extraction procedure using n-hexane as an organic phase with back extraction into aqueous phase since it was considered the most suitable and the most compatible with the subsequent HPLC analysis. The precision and the reproducibility of the method were improved approximately two times by using metoprolol as an internal standard thus making the method also more robust with regard to a variable composition of milk samples. These characteristics, together with low detection limit and short analysis time, proved that the developed method is suitable for monitoring of tramadol in human breast milk.

Tramadol reference source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12899994&dopt=Abstract tramadol Ultram [PubMed - in process]

pharm.unige.ch

Four chiral basic analytes, namely methadone, fluoxetine, venlafaxine, and tramadol, were selected as model compounds for investigating their stereoselective separation with highly sulfated gamma-cyclodextrin (HS gamma-CD) by capillary electrophoresis (CE)-UV and CE-mass spectrometry (MS). At high concentration of chiral selector, the preferentially bonded enantiomer migrated faster in the anodic mode to the detector and high resolutions were obtained for all analytes. In the cathodic mode, at lower highly sulphated cyclodextrin (HS-CD) concentration, basic compounds could be detected, with the weakly bonded enantiomer migrating first (enantiomeric migration order inversion). It was also then possible, at intermediate HS-CD concentration, that only one enantiomer migrated to the detector as cation while the other enantiomer complexed with the CD was negatively charged and presented an opposite mobility. The latter never reached the detector achieving a perfect enantiomeric selectivity. Infinite chiral resolutions were thus achieved by CE-UV as well as by CE-electrospray ionisation (ESI)-MS where concentrations of HS-CD were adapted according to the negative contribution of the nebulization gas pressure of the interface.

Tramadol reference source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12900876&dopt=Abstract tramadol Ultram [PubMed - in process]

csc.pumch.ac.cn

OBJECTIVE: To assess the analgesic effect and side effects of PCA with lornoxicam compared with morphine and tramadol. METHODS: 89 patients, scheduled for elective hysterectomy or hysteromyomectomy, were randomly divided into Group L, Group M and Group T. Three drugs administered i.v. via a patient-controlled analgesia for up to 24 h postoperatively. RESULTS: Efficacy was assessed by comparing total pain relief (TOTPAR) and sum of pain intensity difference (SPID) over 24 h. Statistically significant equivalence of lornoxicam, morphine and tramadol was shown by TOTPAR values 15.2 +/- 3.9, 16.4 +/- 3.5 and 15.9 +/- 4.4, by SPID values 10.3 +/- 3.1, 9.0 +/- 2.0 and 9.2 +/- 4.7, respectively (P > 0.05). Lornoxicam caused fewer adverse events than morphine and tramadol (10.0%, 26.7% and 17.2% of patients, respectively). CONCLUSION: The study suggests that lornoxicam provides an alternative to morphine or tramadaol for the treatment of postoperative pain.

Tramadol reference source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12905865&dopt=Abstract tramadol Ultram [PubMed - in process]




Sichuan Da Xue Xue Bao Yi Xue Ban. 2003 Jul;34(3):574-5.
[HPLC method for determination of tramadol hydrochloride in human plasma]

[Article in Chinese]

Qu L, Feng S, Wu Y, Wu Y.

Department of Chemistry, Zhengzhou University, Zhengzhou 450052, China.

OBJECTIVE: A reversed-phase high performance liquid chromatography (HPLC) method was established to determine the concentration of tramadol hydrochloride in human plasma. METHODS: HPLC instrument was used with the column: 150 mm x 4.6 mm (Li Chrosorb C18, 5 microns). The mobile phase was composed of phosphate buffer solution (0.02 mol/L, pH = 3.7)-acetamide (83: 17, V/V). Flow rate was 1.0 ml/min. Detection wavelength was 216 nm. RESULTS: The standard curve equation was Y = 0.03244X + 0.6007. The linear range was 25-800 ng/ml. The minimum detection limit was 10.2 ng/ml. CONCLUSION: The reversed-phase HPLC method is simple, rapid and sensitive. It is applicable to the determination of the concentration of tramadol hydrochloride in human plasma.

Tramadol reference source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12910726&dopt=Abstract tramadol Ultram [PubMed - in process]