Development and validation of an UHPLC-MS/MS method for simultaneous quantification of ibrutinib and its dihydrodiol-metabolite in human cerebrospinal fluid.

Ibrutinib is an orally administered first-in-class irreversible Bruton's tyrosine kinase (BTK) covalent inhibitor for the treatment of patients with B-cell malignancies. Several isolated clinical observations reported its efficacy in central nervous system dissemination. Herein, we described the development and validation of an ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) procedure for the quantification of ibrutinib and its active metabolite PCI-45227 in cerebrospinal fluid (CSF). This is the first complete validated method for quantification of ibrutinib and PCI-45227 in CSF. The compounds were eluted on a Waters BEH C18 column (50.0 × 2.1 mm; 1.7 µm) using a gradient elution with a mobile phase composed of ammonium formate buffer 5 mM pH 3.2 and acetonitrile +0.1% formic acid with a flow rate of 400 µL·min-1. Two deuterated internal standards were used to obtain the most accurate quantification. The CSF samples were prepared by a simple and rapid dilution. The method was validated by testing the selectivity, response function, intra-day and inter-day precisions, trueness, limits of detection (LOD) and lower limits of quantification (LLOQ). The validation results proved that the methods were suitable to quantify ibrutinib and PCI-45227 in real biological CSF samples from 0.50 (ibrutinib) or 1.00 (PCI-45227) to 30.00 ng·mL-1. Furthermore, the developed method was adapted to allow the quantification of both compounds in plasma and the results were compared to those reported in literature. The plasmatic samples were treated by protein precipitation and the method was validated to quantify ibrutinib and PCI-45227 in real biological plasmatic samples from 5.00 to 491 ng·mL-1. Lastly, for both matrices, accuracy profiles were plotted from the trueness and precision results using a 20% α-risk (ß = 80%) and the tolerance intervals were comprised within the acceptance limits fixed at ±25% for the LLOQ and ±15% for the other concentrations. Finally, these methods were successfully applied to quantify ibrutinib and PCI-45227 in real human CSF and plasma samples.

Effect of angiotensin-converting enzyme inhibitor therapy in mitral regurgitation with normal left ventricular function.

Mitral regurgitation (MR) is a common, frequently asymptomatic valvulopathy that can ultimately lead to left ventricular failure. With the objective of forestalling MR progression, a prospective, placebo controlled, double-blind study was conducted. It measured the effectiveness of lisinopril, an angiotensin-converting enzyme inhibitor, in reducing the echocardiographic signs of MR severity over a one-year period. Severe coronary disease was excluded by stress echocardiography. Treatment effectiveness was estimated to be proportional to the reduction in MR fraction and cardiac chamber dimensions, compared with baseline, according to intention-to-treat analysis. A final patient population of 23 asymptomatic adults aged 53.3 +/- 2.4 years (mean +/- SEM), with moderate, organic MR and normal left ventricular function was selected from the echocardiographic database. All baseline patient characteristics were comparable in the two treatment groups, including the MR fraction (55 +/- 3%). Twelve patients received lisinopril (18 +/- 1 mg) and 11 received placebo. After one year of treatment, a statistically significant difference in the MR fraction was observed between the two groups. For the lisinopril group the MR fraction dropped by 6.4 +/- 3.5% and for the placebo group it increased by 3.7 +/- 3.2% versus baseline (P < 0.05). No differences in left atrial or ventricular dimensions were observed. The study drug was stopped in four patients after one patient presented with rapid atrial fibrillation and angina while three patients were intolerant to lisinopril. Only one patient receiving placebo was taken off therapy. In conclusion, treatment with lisinopril indicates some reduction in the severity of chronic moderate MR in asymptomatic patients with normal left ventricular function. This approach appears to be safe, but side effects are not uncommon, warranting regular follow-up.

Retroviruses and their play-pals.

A 28-year-old man with a previous history of Neissena infection presented with diminished vision, disc swelling, and panuveitis. Serologic tests revealed positive titers for both HIV and syphilis. Current epidemiology and treatment of such cases are discussed.