Esmirtazapine maleate

This work presents the development of an enantioselective method to quantify chiral drugs (CDs) in surface water and its application in the Douro River estuary monitoring. Different classes of CDs were targeted, including 23 compounds, namely beta-blockers, antidepressants, one beta₂-adrenergic agonist, non-steroidal anti-inflammatory drugs, stimulants, and some illicit drugs as cocaine (COC) and its metabolites, and amphetamines. The analytical method was based on an innovative application of solid phase extraction (SPE), followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using a triple quadrupole analyzer. The ground-breaking approach of SPE consists in the use of Oasis^® MCX cartridges to pre-concentrate 500 mL of water samples, allowing the simultaneous extraction of acidic, basic and neutral analytes, rather than the conventional recovery of basic compounds only. Two chiral columns were used for enantiomeric separation in reverse elution mode, a Chirobiotic™V and a Pirkle type Whelk-O^®1, for basic and acidic compounds, respectively. The method validation demonstrated good linearity (r² > 0.99), selectivity and sensitivity, with method detection limits between 0.01 and 2.66 ng L^-1 and method quantification limits between 0.02 and 5.71 ng L^-1. The developed method was successfully applied to monitor daily variations along one week in surface waters collected in 5 locations of the Douro River estuary. Tramadol (TRM) and its metabolite N-desmethyltramadol (NDT), presented high concentrations near the affluent of a tributary river, while the second eluted enantiomer of O-desmethyltramadol (ODT) was found at high concentrations at the mouth of the Douro River. The metabolite NDT was quantified at higher concentrations than TRM. Venlafaxine (VNF) was found at high concentrations near the affluent of the same tributary river, but its metabolite, O-desmethylvenlafaxine (ODV), was found at concentrations 3 times higher. COC was found every day at all sampling points along the estuary, with slight variations.

Two identical 12-week, randomized, double-blind, placebo-controlled, multi-arm, parallel-group Phase III studies (Study P012, NCT00560833; Study P013, NCT00535288) evaluated the efficacy and safety of esmirtazapine, an investigational medicine, for the treatment of moderate to severe vasomotor symptoms (VMS) in postmenopausal women.

Participants were randomized to placebo or esmirtazapine (2.25, 4.5, 9.0, or 18.0 mg). Co-primary efficacy endpoints (daily frequency and severity of moderate to severe VMS, both at weeks 4 and 12) were based on participative LogPad daily diaries. Adverse events (AEs) were recorded.

In Studies P012 and P013, 942 and 946 participants were randomized, respectively. Compared with placebo, esmirtazapine significantly reduced the mean daily frequency by 1.4-2.2 moderate to severe VMS at weeks 4 and 12 (both ≥4.5 mg) and mean daily severity by 0.06-0.08 symptoms at weeks 4 (≥4.5 mg) and 12 (9.0 mg P012; 18.0 mg P013 only). Esmirtazapine was generally well tolerated with a more favorable safety profile at lower doses. Somnolence and fatigue were the most frequently reported AEs.

Esmirtazapine reduced the frequency and severity of moderate to severe VMS associated with menopause and was generally well tolerated in the study population.