Comparison of a rational vs. high throughput approach for rapid salt screening and selection.

In recent years, high throughput (HT) screening has become the most widely used approach for early phase salt screening and selection in a drug discovery/development setting. The purpose of this study was to compare a rational approach for salt screening and selection to those results previously generated using a HT approach. The rational approach involved a much smaller number of initial trials (one salt synthesis attempt per counterion) that were selected based on a few strategic solubility determinations of the free form combined with a theoretical analysis of the ideal solvent solubility conditions for salt formation. Salt screening results for sertraline, tamoxifen, and trazodone using the rational approach were compared to those previously generated by HT screening. The rational approach produced similar results to HT screening, including identification of the commercially chosen salt forms, but with a fraction of the crystallization attempts. Moreover, the rational approach provided enough solid from the very initial crystallization of a salt for more thorough and reliable solid-state characterization and thus rapid decision-making. The crystallization techniques used in the rational approach mimic larger-scale process crystallization, allowing smoother technical transfer of the selected salt to the process chemist.

Malposition of a Femoral Tunneled Dialysis Catheter through a Patent Foramen Ovale.

Patent foramen ovale (PFO) is a common congenital abnormality of high prevalence in adults. Its clinical significance is magnified in a right-to-left shunt, where paradoxical embolism can have catastrophic outcomes involving the brain, heart, mesenteric circulation, or extremities. Right-to-left shunting through a PFO is caused by increased right atrial pressure, as seen in the setting of pulmonary artery hypertension or pulmonary embolism. This case highlights the relevance of central venous catheter placement in the setting of a PFO. While the patient did not experience clinical sequelae from line placement, she was at high risk for paradoxical embolus. Recognizing the possibility of a PFO during central venous catheter placement, especially in the setting of increased right pressures, should be a consideration of all interventional radiologists.

Disposition and Mass Balance of Etrasimod in Healthy Subjects and In Vitro Determination of the Enzymes Responsible for Its Oxidative Metabolism.

Etrasimod (APD334) is an investigational, once-daily, oral, selective sphingosine 1-phosphate receptor 1,4,5 modulator (S1P1,4,5 ) in development for treatment of various immune-mediated inflammatory disorders. The disposition and mass balance of a single 2-mg [14 C]etrasimod dose were evaluated in 8 healthy males. An in vitro study was also conducted to identify etrasimod's oxidative metabolizing enzymes. Peak concentrations of etrasimod and total radioactivity in plasma and whole blood were typically reached 4-7 hours postdose. Etrasimod constituted 49.3% of total radioactivity plasma exposure, with multiple minor/trace metabolites making up the remainder. Etrasimod was slowly cleared mainly via biotransformation, predominantly by oxidative metabolism, with unchanged etrasimod recovered in feces accounting for only 11.2% of the dose and none in urine. The mean apparent terminal half-lives of etrasimod and total radioactivity in plasma were 37.8 and 89.0 hours, respectively. Mean cumulative recovery of radioactivity in excreta over 336 hours was 86.9% of the dose, mostly in feces. The prevalent metabolites eliminated in feces were M3 (hydroxy-etrasimod) and M36 (oxy-etrasimod sulfate), accounting for 22.1% and 18.9% of the dose, respectively. From in vitro reaction phenotyping, the predominant enzymes involved in the oxidation of etrasimod were CYP2C8, CYP2C9, and CYP3A4, with minor contributions from CYP2C19 and CYP2J2.

Mode of detection matters: Differences in screen-detected versus symptomatic breast cancers.

OBJECTIVE: Although extensive analyses evaluating screening mammography for breast cancer have been published, some utilized databases do not distinguish between modes of detection, which confounds the conclusions made about the impact of screening mammography. METHODS: A retrospective cohort study of women at our institution with pathologically-proven breast cancer from January 2015 to April 2018 was conducted. Subjects were categorized by their mode of diagnosis: screening or non-screening. Patient demographics, tumor characteristics, and treatments were compared between detection methods using Wilcoxon rank-sum test for continuous variables and chi-squared or Fisher's exact test. RESULTS: 1026 breast cancers were analyzed. 80.8% of screen-detected breast cancers were invasive. Compared to symptomatically detected cancers, screen-detected were smaller (median size 8 mm vs. 15 mm, p < 0.001), less invasive (80.8% vs. 94.3), had a lower pathologic grade (29% grade 3 vs. 45.7%, p < 0.001), a lower clinical stage, and less aggressive histology (51.9% low Ki67 vs. 30.5%, and 88.2% HER2 negative vs. 76.6%, p < 0.001). Screen-detected cancers were less likely to have extramammary disease (13.2% positive lymph nodes vs. 34.0% and 0.4% distant metastases vs. 6.9%, p < 0.001). Women with screen-detected cancers were more likely to undergo conservative treatment (74.8% underwent lumpectomy vs. 59.9%, and 80.0% received no chemotherapy vs. 51.3%, p < 0.001). CONCLUSION: In this study, while the vast majority of screen-detected cancers were invasive, they were more likely to be smaller, less aggressive, and a lower pathologic grade and clinical stage. Furthermore, women with screen-detected cancers were less likely to have extramammary disease and more likely to undergo conservative treatment.

Breast cancer in women under age 40: A decade of trend analysis at a single institution.

BACKGROUND: Women should be evaluated for breast cancer risk by age 30 to assess for screening need. Recent trends in breast cancer in this population may further inform recommendations. OBJECTIVE: The aim of this study was to analyze trends over time in the rate of breast cancer, tumor characteristics and treatment in women under age 40. METHODS: Retrospective cohort study of women under age 40 at our institution diagnosed with breast cancer from January 2007 to April 2018 was conducted. Patient demographics, tumor characteristics and treatment outcomes were collected. Descriptive statistics and the Mann-Kendell Trend test were calculated. Two-proportion z-tests were used to compare proportions of stage, pathology and treatment between 2007-2013 and 2014-2018. RESULTS: 197 women under age 40 were treated for a new diagnosis of breast cancer at our institution. A higher proportion of women were diagnosed with invasive carcinoma in 2013-2018 (91%) compared to 2007-2012 (78%), p = 0.008. A higher proportion of women were diagnosed with advanced stage disease (stage III-IV) in 2013-2018 (24%) compared to 2007-2012 (2%), p = 0.001. No statistically significant evidence for an increasing trend of overall rate of breast cancer over the last 11 years (p = 0.419) was observed. CONCLUSIONS: While no statistically significant increase in overall rate of breast cancer was noted, an increase in invasive and later staged breast cancers was observed. CLINICAL IMPACT: Rise in more aggressive cancers in a population that is largely not screened may have implications both on the individual young woman's morbidity as well as on a public health level.

Stable-form screening: overcoming trace impurities that inhibit solution-mediated phase transformation to the stable polymorph of sulfamerazine.

Solution-mediated phase transformation (SMPT) has been used as a focused technique to rapidly identify the stable polymorph of a given substance. Despite ample precedence for acetonitrile being a good solvent for SMPT of sulfamerazine (SMZ), samples from specific lots of SMZ failed to convert from Form I to Form II after suspension for 2 weeks in acetonitrile. In these lots, an acetyl derivative of SMZ was identified and shown to impede transformation to the stable polymorph. The inhibitory effect of this impurity on polymorphic conversion was overcome with practical adjustments to experimental procedure, which hastened the kinetics of SMPT. The critical factors considered were (1) modifying the solvent to increase solubility, (2) minimizing the level of impurity in the slurries, (3) pre-treatment of the solid to quickly reach maximum supersaturation, and (4) temperatures that optimized kinetics as well as the free energy difference between enantiotropically related polymorphs.

Automated approach to couple solubility with final pH and crystallinity for pharmaceutical discovery compounds.

The design and validation of a novel high-throughput system for thermodynamic solubility determination requiring only 5 mg of sample is described. The system uses a sintered nickel filter assembly to recover excess solids from saturated solutions for rapid crystallinity assessment via powder X-ray diffraction (PXRD). Moreover, the system measures the pH of filtrates to provide a final pH value with the solubility measurement. The limit of detection for the UV-vis plate reader used on this system is approximately 0.001 mg/ml, while the practical upper limit is approximately 3 mg/mL. The solubility measurements of 60 proprietary Pfizer compounds were used to validate the nickel filter assembly against a more conventional polyvinylidenedifluoride (PVDF) filter. Additionally, a comparison was made between a subset of 10 compounds run on the automated system and a more traditional shake-flask method employing HPLC analysis. In both cases, a favorable comparison was obtained.

Discovery of 2-(((1r,4r)-4-(((4-Chlorophenyl)(phenyl)carbamoyl)oxy)methyl)cyclohexyl)methoxy)acetate (Ralinepag): An Orally Active Prostacyclin Receptor Agonist for the Treatment of Pulmonary Arterial Hypertension.

The design and synthesis of a new series of potent non-prostanoid IP receptor agonists that showed oral efficacy in the rat monocrotaline model of pulmonary arterial hypertension (PAH) are described. Detailed profiling of a number of analogues resulted in the identification of 5c (ralinepag) that has good selectivity in both binding and functional assays with respect to most members of the prostanoid receptor family and a more modest 30- to 50-fold selectivity over the EP3 receptor. In our hands, its potency and efficacy are comparable or superior to MRE269 (the active metabolite of the clinical compound NS-304) with respect to in vitro IP receptor dependent cAMP accumulation assays. 5c had an excellent PK profile across species. Enterohepatic recirculation most probably contributes to a concentration-time profile after oral administration in the cynomolgus monkey that showed a very low peak-to-trough ratio. Following the identification of an acceptable solid form, 5c was selected for further development for the treatment of PAH.

Rapid, small-scale determination of organic solvent solubility using a thermogravimetric analyzer.

A rapid gravimetric method for determining drug candidate solubility in organic solvents has been developed. The scale, speed, precision, and accuracy of the method make it ideal for solubility screening of pharmaceutical compounds during early development. The method utilizes a thermogravimetric analyzer to automate drying and weighing. Results for model compounds compare favorably with literature values.

Discovery of APD334: Design of a Clinical Stage Functional Antagonist of the Sphingosine-1-phosphate-1 Receptor.

APD334 was discovered as part of our internal effort to identify potent, centrally available, functional antagonists of the S1P1 receptor for use as next generation therapeutics for treating multiple sclerosis (MS) and other autoimmune diseases. APD334 is a potent functional antagonist of S1P1 and has a favorable PK/PD profile, producing robust lymphocyte lowering at relatively low plasma concentrations in several preclinical species. This new agent was efficacious in a mouse experimental autoimmune encephalomyelitis (EAE) model of MS and a rat collagen induced arthritis (CIA) model and was found to have appreciable central exposure.

(7-Benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic Acids as S1P1 Functional Antagonists.

S1P1 is a validated target for treatment of autoimmune disease, and functional antagonists with superior safety and pharmacokinetic properties are being sought as second generation therapeutics. We describe the discovery and optimization of (7-benzyloxy-2,3-dihydro-1H-pyrrolo[1,2-a]indol-1-yl)acetic acids as potent, centrally available, direct acting S1P1 functional antagonists, with favorable pharmacokinetic and safety properties.

Identifying the stable polymorph early in the drug discovery-development process.

The thermodynamically most stable polymorph under ambient conditions is almost without exception the most desirable crystalline form for development by a pharmaceutical company. It is, therefore, beneficial to discover and to characterize this polymorph at the earliest possible stage of development. A screen for discovering the stable polymorph of a pharmaceutical compound early in the drug discovery-development process is developed and described. In this screen, a small amount of compound is suspended in a diverse group of solvents for two weeks in an effort to crystallize the most stable polymorph. The solubility of the compound in each solvent utilized in the stable polymorph screen is also simultaneously determined using a simple gravimetric method. Ritonavir and an early development candidate (Pfizer compound A) are used as model compounds to demonstrate the utility of the screen for finding the stable polymorph early in the drug discovery-development process.

Semi-empirical relationships between effective mobility, charge, and molecular weight of pharmaceuticals by pressure-assisted capillary electrophoresis: applications in drug discovery.

Relationships between effective mobility (m(eff)), calculated charge (Z(c)), and molecular weight (MW) are semi-empirically derived for pharmaceuticals using pressure-assisted capillary electrophoresis (PACE). We determined the m(eff) at 12 different pH points (2.0-11.4) of 66 pharmaceutical-like compounds ranging in MW from 79 to 825 g/mol. Plots of the observed m(eff) values versus Z(c)/MW(x ) (where x is a fractional coefficient) gave linear relationships. For anions, it was found that the best correlation (R(2) = 0.9666) exists when the fractional coefficient is equal to 0.4920, resulting in the equation m(eff) = 0.1853 (Z(c)/MW (0.4920)). For cations, the best linear relationship (R(2) = 0.9861) gave the equation m(eff) = 0.3888 (Z(c)/MW (0.6330)). The m(eff), Z(c)/MW(x) relationships were then applied to: (i) developing a technique for selecting an appropriate pH to achieve optimal separation of pharmaceuticals and (ii) determining the maximum charge of a molecule in the pH range of determination of negative log of the dissociation constants (pK(a)) by PACE, thus enabling the correct choice of model equation to be automated without structure analysis.