Differential Mobility Spectrometry Coupled with Multiple Ion Monitoring in Regulated LC-MS/MS Bioanalysis of a Therapeutic Cyclic Peptide in Human Plasma

A differential mobility spectrometry (DMS) in combination with a multiple ion monitoring (MIM) method was developed and validated for quantitative LC-MS/MS bioanalysis of pasireotide (SOM230) in human plasma. Pasireotide, a therapeutic cyclic peptide, exhibits poor collision-induced dissociation (CID) efficiency for multiple reaction monitoring (MRM) detection. Therefore, in an effort to increase the overall sensitivity of the assay, a DMS-MIM approach was explored. By selecting the most abundant doubly charged precursor ion in both the Q1 and Q3 of the mass analyzer in MIM and combining the DMS capability to significantly reduce the high matrix/chemical background noise, this new LC-DMS-MIM method overcomes the sensitivity challenge in the typical MRM method due to poor CID fragmentation of the analyte. Human plasma was spiked with pasireotide with concentrations in the range 0.01–50 ng/mL. Weak cation-exchange solid-phase extraction was employed for sample preparation. The sample extracts were analyzed with a SCIEX QTRAP 6500 system equipped with an ESI source and DMS device. The separation voltage and compensation voltage of the DMS and other parameters of the MS system were optimized to maximize signal responses. The performance of the LC-DMS-MIM assay for quantitative analysis of pasireotide in human plasma was evaluated and compared to those obtained via LC-MRM and LC-MIM without DMS. Overall, the assay sensitivity with DMS-MIM was approximately 5-fold better than that observed in MRM or MIM without DMS. The assay was validated with accuracy (% bias) and precision (% CV) of the QC results at eight concentration levels (0.01, 0.02, 0.05, 0.15, 0.3, 1.5, 15, and 37.5 ng/mL) evaluated ranging from −4.8 to 5.0% bias and 0.7 to 8.6% CV for the intraday and interday runs. The current LC-DMS-MIM workflow can be expanded to quantitative analysis of other molecules that have poor fragmentation efficiency in CID

Disposition and metabolism of [¹⁴C] Sacubitril/Valsartan (formerly LCZ696) an angiotensin receptor neprilysin inhibitor, in healthy subjects

<p>1. Sacubitril/valsartan (LCZ696) is an angiotensin receptor neprilysin inhibitor (ARNI) providing simultaneous inhibition of neprilysin (neutral endopeptidase 24.11; NEP) and blockade of the angiotensin II type-1 (AT1) receptor.</p> <p>2. Following oral administration, [¹⁴C]LCZ696 delivers systemic exposure to valsartan and AHU377 (sacubitril), which is rapidly metabolized to LBQ657 (M1), the biologically active neprilysin inhibitor. Peak sacubitril plasma concentrations were reached within 0.5–1 h. The mean terminal half-lives of sacubitril, LBQ657 and valsartan were ∼1.3, ∼12 and ∼21 h, respectively.</p> <p>3. Renal excretion was the dominant route of elimination of radioactivity in human. Urine accounted for 51.7–67.8% and feces for 36.9 to 48.3 % of the total radioactivity. The majority of the drug was excreted as the active metabolite LBQ657 in urine and feces, total accounting for ∼85.5% of the total dose.</p> <p>4. Based upon <i>in vitro</i> studies, the potential for LCZ696 to inhibit or induce cytochrome P450 (CYP) enzymes and cause CYP-mediated drug interactions clinically was found to be low.</p

Clinical disposition, metabolism and <i>in vitro</i> drug–drug interaction properties of omadacycline

<p>1. Absorption, distribution, metabolism, transport and elimination properties of omadacycline, an aminomethylcycline antibiotic, were investigated <i>in vitro</i> and in a study in healthy male subjects.</p> <p>2. Omadacycline was metabolically stable in human liver microsomes and hepatocytes and did not inhibit or induce any of the nine cytochrome P450 or five transporters tested. Omadacycline was a substrate of P-glycoprotein, but not of the other transporters.</p> <p>3. Omadacycline metabolic stability was confirmed in six healthy male subjects who received a single 300 mg oral dose of [¹⁴C]-omadacycline (36.6 μCi). Absorption was rapid with peak radioactivity (∼610 ngEq/mL) between 1–4 h in plasma or blood. The AUC_last of plasma radioactivity (only quantifiable to 8 h due to low radioactivity) was 3096 ngEq h/mL and apparent terminal half-life was 11.1 h. Unchanged omadacycline reached peak plasma concentrations (∼563 ng/mL) between 1–4 h. Apparent plasma half-life was 17.6 h with biphasic elimination. Plasma exposure (AUC_inf) averaged 9418 ng h/mL, with high clearance (CL/F, 32.8 L/h) and volume of distribution (Vz/F 828 L). No plasma metabolites were observed.</p> <p>4. Radioactivity recovery of the administered dose in excreta was complete (>95%); renal and fecal elimination were 14.4% and 81.1%, respectively. No metabolites were observed in urine or feces, only the omadacycline C4-epimer.</p