LC-MS/MS method development for quantification of doxorubicin and its metabolite 13-hydroxy doxorubicin in mice biological matrices: Application to a pharmaco-delivery study.

This study describes the development of simple, rapid and sensitive liquid chromatography tandem mass spectrometry method for the simultaneous analysis of doxorubicin and its major metabolite, doxorubicinol, in mouse plasma, urine and tissues. The calibration curves were linear over the range 5-250 ng/mL for doxorubicin and 1.25-25 ng/mL for doxorubicinol in plasma and tumor, over the range 25-500 ng/mL for doxorubicin and 1.25-25 ng/mL for doxorubicinol in liver and kidney, and over the range 25-1000 ng/mL for doxorubicin and doxorubicinol in urine. The study was validated, using quality control samples prepared in all different matrices, for accuracy, precision, linearity, selectivity, lower limit of quantification and recovery in accordance with the US Food & Drug Administration guidelines. The method was successfully applied in determining the pharmaco-distribution of doxorubicin and doxorubicinol after intravenously administration in tumor-bearing mice of drug, free or nano-formulated in ferritin nanoparticles or in liposomes. Obtained results demonstrate an effective different distribution and doxorubicin protection against metabolism linked to nano-formulation. This method, thanks to its validation in plasma and urine, could be a powerful tool for pharmaceutical research and therapeutic drug monitoring, which is a clinical approach currently used in the optimization of oncologic treatments.

Simultaneous ultra-high performance liquid chromathograpy-electrospray ionization-quadrupole-time of flight mass spectrometry quantification of endogenous anandamide and related N-acylethanolamides in bio-matrices.

We describe and validate a sensitive UHPLC-ESI-QTOF-MS method for the simultaneous quantification of seven endocannabinoids and non-endocannabinoids related N-acylethanolamides: N-arachidonoylethanolamide, N-palmitoylethanolamide, N-stearoylethanolamide, N-oleoylethanolamide, N-linoleoylethanolamide, N-α-linolenoylethanolamide and N-eicosapentaenoylethanolamide in several bio-matrices for the purpose of research and clinical application. We examined effects of different liquid-liquid and solid phase extraction on the recovery of endocannabinoids and N-acylethanolamides. Protein precipitation with cooled acetone and extraction with acetonitrile (1% v/v formic acid) using OASIS HLB cartridge gave better results. Separation was performed on a Waters Acquity UPLC HSST3 column using a 9min elution gradient coupled with high resolution mass spectrometry (QTOF/MS). The high sensitivity of the developed method allow its application on sample with low volumes or low levels of endocannabinoids and N-acylethanolamides and make the method suitable for routine measurement in human bio-matrices, such as plasma, serum (500µL), urine (1mL) and tissues (10-30mg). Its application in clinical research could contribute to unravel pathophysiological roles of these family of lipid mediators and disclose novel diagnostic and prognostic markers.

Pharmacokinetics study about topical clobetasol on oral mucosa.

BACKGROUND: Clobetasol is the most potent topical corticosteroid used in oral medicine for muco-cutaneous diseases. Several papers reported about patients with cushingoid appearance, suggesting an adrenal suppression related to clobetasol systemic absorption after local application. Owing to the lack of studies, our goal is to assess whether transmucosal assimilation, after its application on oral mucosa, really occurs and to define clobetasol pharmacokinetics profile. METHODS: Data were recorded by collecting blood samples both on 10 patients in clobetasol therapy and on 14 healthy volunteers instructed about standardized clobetasol applications. A new technique of analytical chemistry was employed to detect its serum concentrations. RESULTS: Clobetasol absorption was ascertained, showing a certain accumulation rate. Different levels have been found in relation to oral disease and individual features (as smoking habits and presence of oral mucosa erosion). CONCLUSIONS: Our study validates clobetasol systemic transmucosal absorption, also recommending a careful monitoring of patients in corticosteroid therapy to avoid local and systemic adverse effects.

Predictive performance of the 'Minto' remifentanil pharmacokinetic parameter set in morbidly obese patients ensuing from a new method for calculating lean body mass.

BACKGROUND AND OBJECTIVES: In a previous article, we showed that the pharmacokinetic set of remifentanil used for target-controlled infusion (TCI) might be biased in obese patients because it incorporates flawed equations for the calculation of lean body mass (LBM), which is a covariate of several pharmacokinetic parameters in this set. The objectives of this study were to determine the predictive performance of the original pharmacokinetic set, which incorporates the James equation for LBM calculation, and to determine the predictive performance of the pharmacokinetic set when a new method to calculate LBM was used (the Janmahasatian equations). METHODS: This was an observational study with intraoperative observations and no follow-up. Fifteen morbidly obese inpatients scheduled for bariatric surgery were included in the study. The intervention included manually controlled continuous infusion of remifentanil during the surgery and analysis of arterial blood samples to determine the arterial remifentanil concentration, to be compared with concentrations predicted by either the unadjusted or the adjusted pharmacokinetic set. The statistical analysis included parametric and non-parametric tests on continuous variables and determination of the median performance error (MDPE), median absolute performance error (MDAPE), divergence and wobble. RESULTS: The median values (interquartile ranges) of the MDPE, MDAPE, divergence and wobble for the James equations during maintenance were -53.4% (-58.7% to -49.2%), 53.4% (49.0-58.7%), 3.3% (2.9-4.7%) and 1.4% h(-1) (1.1-2.5% h(-1)), respectively. The respective values for the Janmahasatian equations were -18.9% (-24.2% to -10.4%), 20.5% (13.3-24.8%), 2.6% (-0.7% to 4.5%) and 1.9% h(-1) (1.4-3.0% h(-1)). The performance (in terms of the MDPE and MDAPE) of the corrected pharmacokinetic set was better than that of the uncorrected one. The predictive performance of the original pharmacokinetic set is not clinically acceptable. Use of a corrected LBM value in morbidly obese patients corrects this pharmacokinetic set and allows its use in obese patients. The 'fictitious height' can be a valid alternative for use of TCI infusion of remifentanil in morbidly obese patients until commercially available infusion pumps and research software are updated and new LBM equations are implemented in their algorithms.