Determination of Tramadol in human plasma by HPLC with fluorescence detection

Tramadol is a centrally acting analgesic, atypical opioid, and although it is generally considered as a medicinal drug with a low potential for dependence, there is growing evidence of tramadol abuse in some countries. The ultraviolet detection is not suitable for analysis of tramadol in plasma, due to the lack of sensitivity and selectivity. However, it was shown that tramadol has a weak fluorescence, and the latest techniques for determination of tramadol in plasma include liquid chromatographic methods with fluorescence detection (FL). The objective of the paper was to develop a HPLC-FL method applicable for quantification of tramadol in human plasma.The separation was achieved by reverse phase HPLC method, using as stationary phase C18 – Kromasil® column and a mobile phase consisted of acetonitrile:0.1% formic acid (20:80). The fluorescence detection has been applied with λex/em= 280/310 nm. A solid phase extraction procedure using C18 cartridge was carried out. The linearity of the method has been demonstrated in the range of both therapeutic and toxic plasma tramadol levels (concentrations of 0.100 – 1µg/mL). The selectivity, precision, and accuracy of the method have been demonstrated. The limit of detection (LOD= 0.010 µg/mL) and the limit of quantification (LOQ = 0.100 µg/mL) have been established.The proposed method can be used to assess tramadol levels in human plasma in pharmacokinetic studies, as well as in overdose cases. The utility of the method for the quantification of therapeutic levels of tramadol has been shown on the plasma samples from the patients with tramadol treatment as analgesic (doses ranging from 100 mg to 400 mg/day).The developed method is rapid, using simple experimental conditions and an accurate and short extraction procedure

Therapeutic Drug Monitoring and Methods of Quantitation for Carbamazepine

Carbamazepine is an early anticonvulsant still used today in the treatment of several forms of epilepsy. An active metabolite in the human body contributes to its pharmacological effect. Carbamazepine metabolism has high inter-individual variability, such that it is relatively difficult to establish a direct link between dose and concentration, or between concentration and pharmacological effect. Carbamazepine is thus a good candidate for therapeutic drug monitoring (TDM). Good UV specific absorbance and high plasmatic concentrations allow for the use of UV detection, which is often more accessible than other methods of detection. This paper presents several methods used for the detection of carbamazepine in plasma, methods that are capable of detecting drug and metabolites at adequate levels/ acceptance criteria. These methods have possible application not only in pharmacokinetic, bioequivalence, and permeability studies, but also in the therapeutic drug monitoring of carbamazepine