Preliminary Pharmacokinetic Study Research Articles

Adverse reactions to fentanyl transdermal patches in calves: a preliminary clinical and pharmacokinetic study

ObjectiveTo describe adverse reactions and measure plasma fentanyl concentrations in calves following administration of a fentanyl transdermal patch (FTP). Study designProspective, experimental clinical study. AnimalsSix female Holstein calves and one male Angus calf. Four calves were healthy experimental animals and three calves were clinical patients. MethodsPlasma fentanyl concentrations were measured in blood collected from a jugular vein. FTP 2 μg kg–1 hour–1 and 1 μg kg–1 hour–1 was applied to four and three calves, respectively. Heart rate, respiratory rate, temperature and ataxia were recorded at the same times as blood collection (0, 2, 4, 6, 12, 24, 36, 48, 60, 72, 84 and 96 hours). Substance P concentrations were determined via radioimmunoassay for two calves. ResultsAfter the FTP (2 μg kg–1 hour–1) application, two calves developed tachycardia, hyperthermia, excitement and ataxia within 6 hours; no adverse effect was observed in the other two calves. The three calves administered FTP (1 μg kg–1 hour–1) exhibited tachycardia and excitement, and the FTP were removed at 4 hours. Naloxone was administered to two calves before the adverse clinical signs ceased, while adverse events in the other three calves resolved within 2 hours of FTP removal. Variables returned to previous baseline values by 2–4 hours after FTP removal. Maximum plasma fentanyl concentrations were variable among calves (0.726–6.923 ng mL–1). Substance P concentrations measured in two calves were not consistently depressed during FTP application. Fentanyl concentrations at 4 and 6 hours were significantly associated with the appearance of adverse effects. Conclusions and clinical relevanceFTP (1–2 μg kg–1 hour–1) administered to calves may result in adverse behavioral and cardiovascular effects. Patch removal and treatment with an opioid antagonist may resolve these adverse effects. Additional research is needed to determine optimal FTP dosing for cattle.

Anti-inflammatory hybrids of secondary amines and amide-sulfamide derivatives

The CXCR4/CXCL12 chemokine axis can chemotactically accumulate inflammatory cells to local tissues and regulate the release of inflammatory factors. Developing novel CXCR4 modulators may provide a desirable strategy to control the development of inflammation. A series of novel hybrids were designed by integrating the key pharmacophores of three CXCR4 modulators. The majority of compounds displayed potent CXCR4 binding affinity. Compound 7a exhibited 1000-fold greater affinity than AMD3100 and significantly inhibited invasion of CXCR4-positive tumor cells. Additionally, compound 7a blocked mice ear inflammation by 67% and suppressed the accumulation of inflammatory cells in an in vivo mouse ear edema evaluation. Western blot analyses revealed that 7a inhibited the CXCR4/CXCL12-mediated phosphorylation of Akt and p44 in a dose-dependent manner. Moreover, compound 7a had no observable cytotoxicity and displayed a favorable plasma stability in our preliminary pharmacokinetic study. These results confirmed that this is a feasible method to develop CXCR4 modulators for the regulation and reduction of inflammation.

Novel quinazoline derivatives bearing various 6-benzamide moieties as highly selective and potent EGFR inhibitors

A series of novel quinazoline derivatives bearing various C-6 benzamide substituents were synthesized and evaluated as EGFR inhibitors, and most showed significant inhibitory potency against EGFR kinase. In particular, compound 6g possessed potent inhibitory activity against EGFR wild-type (IC50 = 5 nM), and strong antiproliferative activity against HCC827 and Ba/F3 (L858R) cell lines. Kinase profiling against a panel of 365 kinases showed that 6g was highly selective for EGFR. Furthermore, 6g showed desirable properties in assays of liver microsome metabolic stability and cytochromes P450 inhibition and preliminary pharmacokinetic study. The overall attractive profile of 6g made it an interesting compound for further development.

Sensitive analytical method to quantify clindamycin in plasma and microdialysate samples: Application in a preclinical pharmacokinetic study

Clindamycin is widely used in antimicrobial prophylaxis to prevent surgical site infections. Adequate subcutaneous free tissue concentrations should reach therapeutic levels, which have to be maintained throughout the surgical procedure for antibiotic prophylaxis to be efficient. A method was developed and validated using high performance liquid chromatography coupled to a mass spectrometry to determine clindamycin concentrations in two biological matrices: plasma, for drug monitoring, and subcutaneous microdialysate, to determine free concentrations at the incision site. Gradient separation of clindamycin was carried out using a reverse phase C18 column eluted with a mixture of mobile phases (1% formic acid in water and 1% formic acid in acetonitrile). The monitored transitions were m/z 425.3 > 377.3 for clindamycin, and m/z 407 > 359 for lincomycin, used as the internal standard for plasma samples. Linearity was reached in the 0.5–100 μg/mL range for plasma and 25–1000 ng/mL for microdialysate samples. The method was selective, precise, and accurate, and was successfully employed in a preliminary pharmacokinetics study to investigate plasma and subcutaneous clindamycin penetration, determined by microdialysis, after intravenous administration of a 50 mg/kg dose to Wistar rats.

Design, Synthesis, Molecular Modeling, and Biological Evaluation of Novel Amine-based Histone Deacetylase Inhibitors.

Histone deacetylases (HDACs) are promising drug targets for a variety of therapeutic applications. Herein we describe the design, synthesis, biological evaluation in cellular models of cancer, and preliminary drug metabolism and pharmacokinetic studies (DMPK) of a series of secondary and tertiary N-substituted 7-aminoheptanohydroxamic acid-based HDAC inhibitors. Introduction of an amino group with one or two surface binding groups (SBGs) yielded a successful strategy to develop novel and potent HDAC inhibitors. The secondary amines were found to be generally more potent than the corresponding tertiary amines. Docking studies suggested that the SBGs of tertiary amines cannot be favorably accommodated at the gorge region of the binding site. The secondary amines with naphthalen-2-ylmethyl, 5-phenylthiophen-2-ylmethyl, and 1H-indol-2-ylmethyl (2 j) substituents exhibited the highest potency against class I HDACs: HDAC1 IC50 39-61 nm, HDAC2 IC50 260-690 nm, HDAC3 IC50 25-68 nm, and HDAC8 IC50 320-620 nm. The cytotoxicity of a representative set of secondary and tertiary N-substituted 7-aminoheptanoic acid hydroxyamide-based inhibitors against HT-29, SH-SY5Y, and MCF-7 cancer cells correlated with their inhibition of HDAC1, 2, and 3 and was found to be similar to or better than that of suberoylanilide hydroxamic acid (SAHA). Compounds in this series increased the acetylation of histones H3 and H4 in a time-dependent manner. DMPK studies indicated that secondary amine 2 j is metabolically stable and has plasma and brain concentrations >23- and >1.6-fold higher than the IC50 value for class I HDACs, respectively. Overall, the secondary and tertiary N-substituted 7-aminoheptanoic acid hydroxyamide-based inhibitors exhibit excellent lead- and drug-like properties and therapeutic capacity for cancer applications.

Substituted carbamothioic amine-1-carbothioic thioanhydrides as novel trichomonicidal fungicides: Design, synthesis, and biology

Sexually transmitted diseases like trichomoniasis along with opportunistic fungal infections like candidiasis are major global health burden in female reproductive health. In this context a novel non-nitroimidazole class of substituted carbamothioic amine-1-carbothioic thioanhydride series was designed, synthesized, evaluated for trichomonacidal and fungicidal activities, and was found to be more active than the standard drug Metronidazole (MTZ). Compounds were trichomonicidal in the MIC ranges of 4.77–294.1 μM and 32.46–735.20 μM against MTZ-susceptible and -resistant strains, respectively. Further, compounds inhibited the growth of at least two out of ten fungal strains tested at MIC of 7.50–240.38 μM. The most active compound (20) of this series was 3.8 and 9.5 fold more active than the MTZ against the two Trichomonas strains tested. Compound 20 also significantly inhibited the sulfhydryl groups present over Trichomonas vaginalis and was found to be more active than the MTZ in vivo. Further, a docking analysis carried out with cysteine proteases supported their thiol inhibiting ability and preliminary pharmacokinetic study has shown good distribution and systemic clearance.

Ocular tissue distribution and pharmacokinetic study of a small 13kDa domain antibody after intravitreal, subconjuctival and eye drop administration in rabbits

Domain antibodies (dAb's) comprise the smallest functional unit of human IgG and can be targeted to a range of different soluble cytokine and receptor targets in the eye. In particular their small size may offer advantage for ocular tissue penetration and distribution. To investigate this we used a 13kDa tool molecule to undertake a preliminary short term ocular tissue distribution and pharmacokinetic study in the rabbit eye. The dAb was administered by the intravitreal or subconjunctival route or, as topical eye drops for up to five days and dAb concentrations measured in vitreous, aqueous, conjunctiva, choroid-RPE, retina, iris, sclera, and ciliary body. The observed elimination half-live of the dAb (~3 days) in vitreous showed a similar elimination rate to that of a much larger (∼50kDa) Fab fragment whilst the half-life following subconjunctival administration was ∼24 h and, after eye drop dosing the dAb was detectable in aqueous and conjunctiva. These preliminary data show that the intravitreal half-life of dAb's are similar to much larger antibody fragments, offering the potential to deliver significantly more drug to target on a molar basis with a single intravitreal injection potentially enabling dosing frequencies of once a month or less. Subconjunctival injection may provide short duration therapeutic levels of dAb to the anterior and posterior chamber whilst topical eye drop delivery of dAbs may be useful in front-of-eye disease. These data indicate that small domain antibodies may have utility in ophthalmology. Further studies are warranted.

Abstract 194: Effective targeting of MYC expression with a novel nucleic acid binding (G4-quadruplex) small molecule coupled with HDAC inhibition synergizes to limit myeloma growth

Abstract MYC is deregulated in many malignancies and its aberrant expression is associated with tumorigenesis and tumor maintenance. We employed a therapeutic strategy to target both MYC transcription, and protein stability. Previously, we developed a small molecule microarray and screened it for MYC G4-binding compounds. The stabilization of G-quadraplex (G4) structures by nucleic acid binding small molecules in the NHE III region of the MYC promoter slows MYC transcription. We identified a benzofuran containing small molecule that could selectively and reversibly stabilize MYC-G4 DNA and reduce MYC expression. This compound demonstrated a G4-dependent mechanism of action showing toxicity in multiple myeloma cell lines containing a G4 in their MYC promoter whereas minimal effects were seen in a Burkitt’s lymphoma line lacking the MYC G4 sequence. Gene expression analysis validated that this compound selectively inhibited MYC and other MYC effectors, but did little to limit the expression of other G4 containing genes. The synthesis of more than 15 analogs identified a new benzofuran-containing analog with enhanced inhibitory activity in a diverse panel of human cancer cell lines (NCI-60), including a number of myeloma cell lines. EDGE-seq data confirmed that the new analog is similar to the original compound in having higher affinity for the G4 in MYC compared to the G4 in BCL2, KRAS, VEGFA and HIF1A. In addition, the analog was synergistic with entinostat, an HDAC inhibitor that can affect MYC protein stability, in limiting myeloma cells, but not PBMCs. The more potent growth inhibitory activity of the new analog allowed us to generate sufficient quantities to evaluate its pharmacokinetics and toxicity in mice. The compound was well tolerated in a dose-escalation toxicity study; no adverse effects were observed and preliminary pharmacokinetic studies showed promising serum bioavailability and exposure properties when administered either intravenously, intraperitoneally or orally. In an assessment of short term in vivo activity, MYC protein expression was inhibited in multiple myeloma xenografts. Longer term studies to evaluate the anti-tumor activity of the compound are currently in progress. Thus, our data provide evidence that small molecule stabilization of the MYC G4 can drive transcriptional silencing of oncogenic MYC both in vitro and in vivo. Furthermore, synergistic tumor cell killing was achieved when the MYC G4 inhibitor was coupled with HDAC inhibition. Citation Format: Snehal M. Gaikwad, David R. Calabrese, Elena C. Leon, John K. Simmons, Shuling Zhang, Aleksandra Michalowski, Sayeh Gorjifard, Zaw Phyo, Daniel Connors, John S. Schneekloth, Beverly A. Mock. Effective targeting of MYC expression with a novel nucleic acid binding (G4-quadruplex) small molecule coupled with HDAC inhibition synergizes to limit myeloma growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 194. doi:10.1158/1538-7445.AM2017-194

Development and validation of an LC-ESI-MS/MS approach to determine a highly hydrophobic drug, norcantharidin palmitate, and apply to a preliminary pharmacokinetic study in rats.

In order to investigate the pharmacokinetics of norcantharidin palmitate (NCTD-PAL) in rats, we developed and validated an LC-ESI-MS/MS method. The NCTD-PAL and internal standard (triamcinoloneacetonide palmitate, TAP) were separated on a Phenomenex Kinetex®XB C18 column, and the mobile phase was composed of tetrahydrofuran (THF)-acetonitrile (20/80, v/v) and an aqueous phase containing 0.2% ammonium hydroxide at a flow rate of 0.3 mL/min. The ESI interface operated in positive mode was used to acquire the mass spectrometric data, and the transition ions were m/z 635.50 → 168.95 and 673.65 → 397.13 for NCTD-PAL and IS, respectively. The method had a linear range of 10-2000 ng/mL with a correlation coefficient of >0.99. The accuracy (RE, %) was within ±10.1%, and the intra- and inter-day precisions (RSD, %) were 10.9 and 13.8%, respectively. The extraction recovery of NCTD-PAL at different concentrations ranged from 89.3 to 102.0%. The validated approach was efficaciously applied to a pharmacokinetic study of NCTD-PAL in rats via intravenous injection. Based on these results obtained, this method is practical and suitable for a wide range of applications.

Evaluation of Thymus vulgaris Extract on Hippocampal Injury Induced by Transient Global Cerebral Ischemia and Reperfusion in Rat

Background: A Brief interruption of blood supply to the brain can cause significant changes in the function of central nervous system. Patients usually show cognitive, emotional and electrophysiological changes during recovery from stroke. Preliminary pharmacokinetic studies have shown that Thymus vulgaris is useful in the treatment of seizures, respiratory diseases, smooth muscular spasm and bloating. Methods: In an experimental study, for inducing temporary acute ischemia carotid artery was closed for 60 minutes and then blood flow was restored. Thyme extract (50, 100 and 200 mg/kg) was injected daily after induction of ischemia. Shuttle box test was carried out for the first 4 days and rotarod test was conducted at the last day. After the rotarod test, blood samples were collected from heart and brain tissue was removed under deep anesthesia. One way- ANOVA followed by Tukey and t-paired tests were used for comparing the groups at 0.05 level of significance. All data were analyzed by using the statistical package for social sciences (SPSS-19) software. Results: In passive avoidance test, the initial latency time was significantly longer in the ischemia group compared to the control group. Administration of thyme extract into ischemic rats significantly increased second latency time and reduced MDA levels of brain cortex. Conclusions: Our results indicated that Thymus vulgaris extract has a neuroprotective activity. Mechanisms of neuroprotective action might be associated with antioxidant activity and inhibition of oxidative stress in rat brain.

Novel anti-inflammatory agents targeting CXCR4: Design, synthesis, biological evaluation and preliminary pharmacokinetic study

CXCR4 plays a crucial role in the inflammatory disease process, providing an attractive means for drug targeting. A series of novel amide-sulfamide derivatives were designed, synthesized and comprehensively evaluated. This new scaffold exhibited much more potent CXCR4 inhibitory activity, with more than 70% of the compounds showed notably better binding affinity than the reference drug AMD3100 in the binding assay. Additionally, in the Matrigel invasion assay, most of our compounds significantly blocked the tumor cell invasion, demonstrating superior efficacy compared to AMD3100. Furthermore, compound IIj blocked mice ear inflammation by 75% and attenuated ear edema and damage substantially in an in vivo model of inflammation. Western blot analyses revealed that CXCR4 modulator IIj significantly blocked CXCR4/CXCL12-mediated phosphorylation of Akt. Moreover, compound IIj had no observable cytotoxicity and displayed a favourable plasma stability in our preliminary pharmacokinetic study. The preliminary structure-activity relationships were also summarized. In short, this novel amide-sulfamide scaffold exhibited potent CXCR4 inhibitory activity both in vitro and in vivo. These results also confirmed that developing modulators targeting CXCR4 provides an exciting avenue for treatment of inflammation.

Enhanced LC-MS/MS analysis of alogliptin and pioglitazone in human plasma: Applied to a preliminary pharmacokinetic study.

A new fast LC-MS/MS method was developed for determination of alogliptin and pioglitazone in human plasma. Linearity ranges of 10-400ngmL-1 for alogliptin and 25-2000ngmL-1 for pioglitazone, were found to be suitable for their bioanalysis covering the Cmin and Cmax values of the drugs. Direct precipitation technique was used for simultaneous extraction of the drugs successfully from human plasma samples. Chromatographic separation was achieved on a BEH C18 column (50mm×2.1mm, 1.7μm) with 0.1% aqueous formic acid: acetonitrile (40:60, v/v) at a flow rate of 0.3mLmin-1. The validated method was applied to a preliminary pharmacokinetic study on human volunteers. Monitoring the transition pairs of m/z 340.18 to 116.08 for alogliptin and m/z 356.99 to 133.92 for pioglitazone, using triple quadrupole mass spectrometer with multiple reaction monitoring, was achieved in the positive mode. The validated method is accurate and suitable for further clinical applications and possible bioequivalence studies.

Validation of a SPE HPLC–UV method for the quantification of a new ER-specific photosensitizer OR-141 in blood serum using total error concept

The aim of this work is to develop the first validated HPLC–UV method quantification in blood serum for a new endoplasmic reticulum (ER)-specific benzophenazine photosensitizer (OR-141). A fast solid phase extraction (SPE) cleaning sample procedure was achieved on C18 encapped (ec) SPE cartridges and the separation was performed on a RP-18e column (5μM) using an isocratic elution with methanol. The method has been fully validated according to accuracy profiles based on total error and tolerance intervals. Calibration was performed in the matrix and trueness (<4.25% relative bias), repeatability (<4.75% relative standard deviation (RSD)), intermediate precision (<5.37% RSD), selectivity, response function, linearity, and dilution effect were evaluated for both OR-141 regio-isomers. Afterwards the developed method was successfully applied to perform the quantitative determination of OR-141 in mouse blood serum samples in a preliminary pharmacokinetic study.

LR12-peptide quantitation in whole blood by RP-HPLC and intrinsic fluorescence detection: Validation and pharmacokinetic study.

A simple, sensitive, selective and robust HPLC method based on intrinsic fluorescence detection was developed for the quantitation of a dodecapeptide (designated as LR12), inhibitor of Triggering Receptor Expressed on Myeloid cells-1, in rat whole blood. Sample treatment was optimized using protein precipitation and solid-phase extraction. Chromatographic separation was carried out in a gradient mode using a core-shell C18 column (150 × 4.6 mm, 3.6 μm) with mobile phases of acetonitrile and water containing trifluoroacetic acid at 1.0 mL/min. The method was validated using methodology described by the US Food and Drug Administration guidelines for bioanalytical methods. Linearity was demonstrated within the 50-500 ng/mL range and the lower limit of quantitation was 50 ng/mL. Finally, a preliminary pharmacokinetic study after intraperitoneal injection of LR12 in rats was conducted to evaluate both LR12 monomer and its corresponding disulfide dimer, the main product of degradation. Beyond the fact that this paper describes the first fully validated method for LR12 analysis in blood samples, the approach followed here to optimize pre-analytical steps could be beneficial to develop HPLC and/or MS methods for other pharmaceutical peptides.

Novel approach to determine ghrelin analogs by liquid chromatography with mass spectrometry using a monolithic column.

In our project, ghrelin analogs possessing enhanced stability and potential to significantly increase food intake were used. Three newly synthesized ghrelin analogs with fatty acid residues consisting of 8, 10, and 14 carbon atoms were studied. The main goal of this work was to develop a suitable analytical method for the determination of the stability of the novel ghrelin analogs in plasma. An appropriate liquid chromatography-mass spectrometry method was developed and optimized. The results obtained were compared with the data measured by using a commercial enzyme-linked immunosorbent assay kit, and a good correlation was found. A preparation strategy for plasma samples was optimized and consisted of simple dilution of the plasma samples followed by direct injection onto a very short monolithic column in combination with mass spectrometric detection. The developed analytical method was utilized for the determination of the stability of the prepared lipopeptides in plasma and for the quantification of the lipopeptides in a preliminary pharmacokinetic study. The feasibility of the developed separation method was clearly demonstrated. Accuracy and precision were within 80-120% and ±20% limits, respectively. Calibration curves were constructed in the range of 1-250 μg/mL.

An easy-to-use liquid chromatography assay for the analysis of lamotrigine in rat plasma and brain samples using microextraction by packed sorbent: Application to a pharmacokinetic study.

A simple and rapid high-performance liquid chromatography method with diode-array detection (HPLC-DAD) using microextraction by packed sorbent (MEPS) during the sample preparation step was developed and validated to quantify lamotrigine (LTG) in rat plasma and brain samples. MEPS variables such as pH, number of draw-eject cycles, and washing and desorption conditions were optimized. The chromatographic resolution of LTG and chloramphenicol, used as internal standard (IS), was accomplished in less than 5min on a C18 column, at 35°C, using an isocratic elution with acetonitrile (13%), methanol (13%) and water-triethylamine (99.7:0.3, v/v; pH 6.0) pumped at a flow rate of 1mL/min. Detection was performed at 215nm. Calibration curves were linear over the range of 0.1-20μg/mL (r2≥0.9947) for LTG in both rat plasma and brain homogenate samples. The intra and interday imprecision did not exceed 8.6% and the intra and interday inaccuracy ranged from -8.1 to 13.5%. LTG was extracted from rat plasma and brain homogenate samples with an average absolute recovery ranging from 68.0 to 86.7%, and its stability was demonstrated in the assayed conditions. No interferences were observed at the retention times of the analyte (LTG) and IS. To the best of our knowledge, this is the first bioanalytical assay that uses MEPS procedure for the determination of LTG not only in rat plasma but also in tissue (brain) samples. This novel method was successfully applied to a preliminary pharmacokinetic study in rats and it seems to be a cost-effective tool to support non-clinical pharmacokinetic-based studies involving LTG treatment.

Cardiovascular safety pharmacology studies in dogs enabled for a poorly soluble molecule using spray-dried dispersion: Impact on lead selection

The aim of this study was to identify an adequate formulation for a poorly soluble lead molecule (BI-A) that would achieve sufficiently high plasma concentrations after oral administration in dogs to enable a robust cardiovascular safety pharmacology assessment in telemetry-instrumented conscious dogs during lead optimization in drug discovery.A spray-dried dispersion of BI-A (BI-A-SDD) containing a 1:2 ratio of BI-A and hydroxypropyl methylcellulose acetate succinate-LF was prepared using a Büchi spray dryer B-90 (B-90). Physical form characterization, an in vitro dissolution test and a preliminary pharmacokinetic (PK) study following oral administration of BI-A-SDD were performed. Thereafter, effects on cardiovascular parameters in conscious, chronically-instrumented dogs were investigated for 24h after a single oral dose (5, 10, and 50mg/kg) using a modified Latin square cross-over study design.The BI-A-SDD powder was confirmed to be amorphous and was stable as an aqueous suspension for at least 4h. The BI-A-SDD suspension provided a greater rate and extent of dissolution than the crystalline BI-A suspension and the supersaturation was maintained for at least 4h. In PK studies the Cmax of the BI-A-SDD formulation (25.4μM; 77-fold the projected efficacious Cmax of 0.33μM) was 7.5-fold higher than the Cmax observed using oral administration of a 10% hydroxypropyl-β-cyclodextrin formulation at 100mg/kg in dogs (3.4μM). In conscious, chronically-instrumented dogs, the doses tested and plasma concentrations achieved were sufficient to enable a robust safety pharmacology evaluation. Multiple off-target hemodynamic effects were detected including acute elevations in aortic blood pressure (up to 22% elevation in systolic and diastolic blood pressure) and tachycardia (68% elevation in heart rate), results that were confirmed in other in vivo models. These results led to a deprioritization of BI-A.The study demonstrated that a spray-dried dispersion, prepared using the B-90 in drug discovery, enhanced the oral exposure of a poorly water-soluble molecule, BI-A, and thereby enabled its evaluation in safety pharmacology studies that ultimately resulted in deprioritization of BI-A from a pool of lead compounds.

Quantification of lipid modified estrogenic derivative (ESC8) in rat plasma by LC-MS: application to a pharmacokinetic study.

A lipid-conjugated, estrogenic derivative molecule, ESC8, compared with other estrogenic molecules, encourages cell death in both ER-positive and ER-negative breast cancer cells. A rapid and highly sensitive assay method has been developed and validated for the estimation of a ESC8 in rat plasma using liquid chromatography coupled with mass spectrometry under positive-ion mode with electrospray ionization. The sample process includes using methanol for precipitation of ESC8 and dextromethorphan (internal standard, IS) from plasma. Chromatographic separation was achieved with methanol-water-formic acid (70:30:0.1% v/v/v) pumped at a flow rate of 0.3mL/min and a C18 column (50 × 2.1 mm i.d., 1.7 μm particle size) with a total run time of 5 min. The m/z ions monitored were 568.5 and 272.1 for ESC8 and IS, respectively. The lower limit of quantitation achieved was 1.08 ng/mL and linearity was observed from 5 to 500 ng/mL. The intra- and inter-day precisions were <4%. The proposed method was successfully applied to a preliminary pharmacokinetic study of ESC8 liposomal formulation following an intraperitoneal administration of 3.67 mg/kg in rats. The concentrations of ESC8 in plasma were quantifiable up to 36 h. The peak concentration of ESC8 was found to be 110.72 ng/mL, the area under the concentration-time curve was 1625.23ng/mL h and the half-life was 11.72 h.

Estradiol prodrugs (EP) for efficient oral estrogen treatment and abolished effects on estrogen modulated liver functions

Oral compared to parenteral estrogen administration is characterized by reduced systemic but prominent hepatic estrogenic effects on lipids, hemostatic factors, GH-/IGF I axis, angiotensinogen. In order to avoid such adverse metabolic effects of oral treatment, estradiol (E2) prodrugs (EP) were designed which bypass the liver tissue as inactive molecules. Carbone17-OH sulfonamide [-O2–NH2] substituted esters of E2 (EC508, others) were synthesized and tested for carbonic anhydrase II (CA-II) binding. CA II in erythrocytes is thought to oppose extraction of EP from portal vein blood during liver passage. Ovariectomized (OVX, day minus 14) rats were orally treated once daily from day 1–3. Sacrifice day 4. Uteri were dissected and weighed. Cholesterol fractions and angiotensinogen were determined in plasma. Oral E2 and ethinyl estradiol (EE) generated dose related uterine growth and important hepatic estrogenic effects. EP induced uterine growth at about hundred-fold lower doses. This was possible with almost absent effects on plasma cholesterol or angiotensinogen. Preliminary pharmacokinetic studies with EC508 used intravenous and oral administration in male rats. Resulting blood levels revealed complete oral bioavailability. Further high blood- but low plasma concentrations indicated erythrocyte binding of EC508 in vivo as potential mechanism of low extraction at liver passage. Very high systemic estrogenicity combined with markedly lower or absent adverse hepatic estrogenic effects is evidence for a systemic release of E2 from sulfonamide EP. In conclusion, tested oral EP bypass the liver in erythrocytes furnishing systemic estradiol at hydrolysis. This mechanism avoids the hepatic estrogenic impact of conventional oral estrogen therapy.

Abstract 1244: A novel microtubule-disrupting indole-based chalcone that induces caspase-independent cell death in glioblastoma and melanoma cells

Abstract Indolyl-pyridinyl-propenones (a subclass of synthetic indole-based chalcones) have been shown to induce a novel form of cell death termed ‘methuosis’ in glioblastoma and other tumor cell lines. This form of cell death is caspase-independent and involves massive vacuolization of macropinosome and endosome compartments. In the course of structure-activity relationship studies identifying a lead compound, 3-(5-methoxy-2-methyl-1H-indol-3-yl)-1-(4-pyridinyl)-2-propene-1-one (abbreviated 5-MOMIPP), we discovered that changing the methoxy substitution from the 5-position to the 6-position on the indole ring markedly alters the biological activity of the compound. 6-MOMIPP exhibits potent anti-proliferative and cytotoxic activity in glioblastoma, melanoma and other cancer cell lines at a concentration of 100 nM, nearly two orders of magnitude lower than the maximally effective concentration of 5-MOMIPP. Instead of inducing methuosis, 6-MOMIPP (at &amp;gt; 500 nM) immediately disrupts microtubules, as confirmed by immunofluorescence microscopy. By 24 h the majority of the cells are rounded and arrested in mitosis, and by 48 h cell viability is greatly reduced. The few remaining live cells contain multiple abnormal nuclei. Extensive cell death occurs before activation of caspases 3, 7 and 9 can be detected. Scintillation proximity assays show that 6-MOMIPP competes with 3H-colchicine, but not 3H-vinblastine, for binding to tubulin. Studies aimed at testing the toxicity of 6-MOMIPP in normal cells are in progress, but work with a closely related microtubule-active indole-based chalcone indicates that toxicity is substantially reduced in quiescent human fibroblasts and rat neuronal progenitor cells. Although drugs targeted to microtubules (e.g., Vinca alkaloids and taxanes) are widely used as anti-neoplastic agents, they have shown little efficacy in treating primary or metastatic brain tumors, partly due to limited penetrance of the blood-brain barrier (BBB). Preliminary pharmacokinetic studies in mice show that 6-MOMIPP injected IP can readily cross the BBB, attaining brain concentrations nearly equal to plasma concentrations within 30 min to 1 h. Therefore, these preliminary findings suggest that 6-MOMIPP merits further preclinical evaluation as a potential therapeutic agent for primary and metastatic brain tumors. Supported by NIH grant CA115495 and by the Helen and Harold McMaster Endowment. Citation Format: Shengnan Du, Jeffrey G. Sarver, Christopher J. Trabbic, Paul W. Erhardt, Jean H. Overmeyer, William A. Maltese. A novel microtubule-disrupting indole-based chalcone that induces caspase-independent cell death in glioblastoma and melanoma cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1244.