B cell-specific mAb-siRNA conjugates improve experimental myasthenia.

Myasthenia gravis (MG) is a debilitating autoimmune disease characterized by muscle fatigue and weakness caused by autoantibody- and complement-mediated damage to the neuromuscular junction. This study sought to compare the efficacy of unique sets of monoclonal antibody-siRNA conjugates, individually (mono) or in combination (duo), against the crucial receptors predominantly or solely expressed on two subsets of B cells-plasma B cells and their precursor (transitional mature B) cells in a mouse model of MG. At the optimized doses, the conjugates, likely due to the combined activities of mAb and siRNA, substantially decreased the expression levels of CD268 (B cell-activating factor receptor) in mature B cells and CD269 (B-cell maturation antigen) in plasma cells concomitantly with reducing the levels of acetylcholine receptor (AChR)-specific autoantibodies. PEGylation, but not pretreatment with an antibody against type 1 interferon receptor, further improved duoconjugate-induced reduction in the autoantibody levels. Our results show that the duoconjugate treatment significantly improved the clinical symptoms of MG, consistent with the preservation of bungarotoxin-bound functional AChRs. In the future, developing similar target-specific combination molecules can potentially turn into a new and effective therapeutic approach for MG.

Prediction of maternal and fetal pharmacokinetics of indomethacin in pregnancy.

AIMS: Indomethacin is used for the treatment of preterm labour, short cervices and idiopathic polyhydramnios during pregnancy. Few studies have described the pharmacokinetics (PK) of indomethacin during pregnancy. This study aimed to determine maternal and fetal PK of indomethacin during different trimesters of pregnancy using physiologically based PK (PBPK) modelling and simulations. METHODS: Full PBPK simulations were performed in nonpregnant subjects and pregnant subjects from each trimester of pregnancy at steady state using Simcyp's healthy volunteers and pregnancy PBPK model, respectively. The fetal exposures were predicted using a fetoplacental pregnancy PBPK model. The models were verified by comparing PBPK-based predictions with observed PK profiles. RESULTS: Predicted exposure (AUC0-6h ) and clearance of indomethacin in nonpregnant women and pregnant women are similar to the clinical observations. AUC0-6h of indomethacin is approximately 14, 24 and 32% lower, consistent with 18, 34 and 52% higher clearance in the first, second and third trimesters of pregnancy, respectively, compared to nonpregnant women. Predicted fetal plasma exposures increased by approximately 30% from the second trimester to the third trimester of pregnancy. CONCLUSION: A mechanistic PBPK model adequately described the maternal and the fetal PK of indomethacin during pregnancy. As the pregnancy progresses, a modest decrease (≤32%) in systemic exposures in pregnant women and a 33% increase in fetal exposures to indomethacin were predicted. Higher fetal exposures in the third trimester of pregnancy may pose safety risks to the fetus. Additional studies are warranted to understand the exposure-response relationship and provide appropriate dosing recommendations during pregnancy that consider both safety and efficacy.

A randomized pilot clinical trial of pravastatin versus placebo in pregnant patients at high risk of preeclampsia.

BACKGROUND: Preeclampsia remains a major cause of maternal and neonatal morbidity and mortality. Biologic plausibility, compelling preliminary data, and a pilot clinical trial support the safety and utility of pravastatin for the prevention of preeclampsia. OBJECTIVE: We previously reported the results of a phase I clinical trial using a low dose (10 mg) of pravastatin in high-risk pregnant women. Here, we report a follow-up, randomized trial of 20 mg pravastatin versus placebo among pregnant women with previous preeclampsia who required delivery before 34+6 weeks' gestation with the objective of evaluating the safety and pharmacokinetic parameters of pravastatin. STUDY DESIGN: This was a pilot, multicenter, blinded, placebo-controlled, randomized trial of women with singleton, nonanomalous pregnancies at high risk for preeclampsia. Women between 12+0 and 16+6 weeks of gestation were assigned to receive a daily pravastatin dose of 20 mg or placebo orally until delivery. In addition, steady-state pravastatin pharmacokinetic studies were conducted in the second and third trimesters of pregnancy and at 4 to 6 months postpartum. Primary outcomes included maternal-fetal safety and pharmacokinetic parameters of pravastatin during pregnancy. Secondary outcomes included maternal and umbilical cord blood chemistries and maternal and neonatal outcomes, including rates of preeclampsia and preterm delivery, gestational age at delivery, and birthweight. RESULTS: Of note, 10 women assigned to receive pravastatin and 10 assigned to receive the placebo completed the trial. No significant differences were observed between the 2 groups in the rates of adverse or serious adverse events, congenital anomalies, or maternal and umbilical cord blood chemistries. Headache followed by heartburn and musculoskeletal pain were the most common side effects. We report the pravastatin pharmacokinetic parameters including pravastatin area under the curve (total drug exposure over a dosing interval), apparent oral clearance, half-life, and others during pregnancy and compare it with those values measured during the postpartum period. In the majority of the umbilical cord and maternal samples at the time of delivery, pravastatin concentrations were below the limit of quantification of the assay. The pregnancy and neonatal outcomes were more favorable in the pravastatin group. All newborns passed their brainstem auditory evoked response potential or similar hearing screening tests. The average maximum concentration and area under the curve values were more than 2-fold higher following a daily 20 mg dose compared with a 10 mg daily pravastatin dose, but the apparent oral clearance, half-life, and time to reach maximum concentration were similar, which is consistent with the previously reported linear, dose-independent pharmacokinetics of pravastatin in nonpregnant subjects. CONCLUSION: This study confirmed the overall safety and favorable pregnancy outcomes for pravastatin in women at high risk for preeclampsia. This favorable risk-benefit analysis justifies a larger clinical trial to evaluate the efficacy of pravastatin for the prevention of preeclampsia. Until then, pravastatin use during pregnancy remains investigational.

Formulation effects on paclitaxel transfer and uptake in the human placenta.

Diagnosis and treatment of breast cancer in pregnancy can result in morbidity and mortality for the mother and fetus. Many new paclitaxel nanoformulations commercially available worldwide for breast cancer treatment are being adopted due to favorable dosing regimens and side effect profiles, but their transplacental transport and resultant fetal exposure remain unknown. Here, we examine three formulations: Taxol (paclitaxel dissolved in Kolliphor EL and ethanol); Abraxane (albumin nanoparticle); and Genexol-PM (polymeric micelle). In the ex vivo dually perfused human placental cotyledon, placental accumulation of Genexol-PM is higher than Taxol, and both nanoformulations have lower maternal concentrations of paclitaxel over time. In vitro studies of these formulations and fluorescent nanoparticle analogs demonstrate that Genexol-PM allows paclitaxel to overcome P-glycoprotein efflux, but Abraxane behaves as a free drug formulation. We anticipate that these findings will impact future development of rational and safe treatment strategies for pregnancy-associated breast cancer and other diseases.

Mucosal bromodomain-containing protein 4 mediates aeroallergen-induced inflammation and remodeling.

BACKGROUND: Frequent exacerbations of allergic asthma lead to airway remodeling and a decrease in pulmonary function, producing morbidity. Cat dander is an aeroallergen associated with asthma risk. OBJECTIVE: We sought to elucidate the mechanism of cat dander-induced inflammation-remodeling. METHODS: We identified remodeling in mucosal samples from allergic asthma by using quantitative RT-PCR. We developed a model of aeroallergen-induced experimental asthma using repetitive cat dander extract exposure. We measured airway inflammation using immunofluorescence, leukocyte recruitment, and quantitative RT-PCR. Airway remodeling was measured by using histology, collagen content, myofibroblast numbers, and selected reaction monitoring. Inducible nuclear factor κB (NF-κB)-BRD4 interaction was measured by using a proximity ligation assay in situ. RESULTS: Enhanced mesenchymal signatures are observed in bronchial biopsy specimens from patients with allergic asthma. Cat dander induces innate inflammation through NF-κB signaling, followed by production of a profibrogenic mesenchymal transition in primary human small airway epithelial cells. The IκB kinase-NF-κB signaling pathway is required for mucosal inflammation-coupled airway remodeling and myofibroblast expansion in the mouse model of aeroallergen exposure. Cat dander induces NF-κB/RelA to complex with and activate BRD4, resulting in modifying the chromatin environment of inflammatory and fibrogenic genes through its atypical histone acetyltransferase activity. A novel small-molecule BRD4 inhibitor (ZL0454) disrupts BRD4 binding to the NF-κB-RNA polymerase II complex and inhibits its histone acetyltransferase activity. ZL0454 prevents epithelial mesenchymal transition, myofibroblast expansion, IgE sensitization, and fibrosis in airways of naive mice exposed to cat dander. CONCLUSIONS: NF-κB-inducible BRD4 activity mediates cat dander-induced inflammation and remodeling. Therapeutic modulation of the NF-κB-BRD4 pathway affects allergen-induced inflammation, epithelial cell-state changes, extracellular matrix production, and expansion of the subepithelial myofibroblast population.

Efficacy of Novel Highly Specific Bromodomain-Containing Protein 4 Inhibitors in Innate Inflammation-Driven Airway Remodeling.

NF-κB/RelA triggers innate inflammation by binding to bromodomain-containing protein 4 (BRD4), an atypical histone acetyltransferase (HAT). Although RelA·BRD4 HAT mediates acute neutrophilic inflammation, its role in chronic and functional airway remodeling is not known. We observed that BRD4 is required for Toll-like receptor 3 (TLR3)-mediated mesenchymal transition, a cell-state change that is characteristic of remodeling. We therefore tested two novel highly selective BRD4 inhibitors, ZL0420 and ZL0454, for their effects on chronic airway remodeling produced by repetitive TLR3 agonist challenges, and compared their efficacy with that of two nonselective bromodomain and extraterminal (BET) protein inhibitors, JQ1 and RVX208. We observed that ZL0420 and ZL0454 more potently reduced polyinosinic:polycytidylic acid-induced weight loss and fibrosis as assessed by microcomputed tomography and second harmonic generation microscopy. These measures correlated with the collagen deposition observed in histopathology. Importantly, the ZL inhibitors were more effective than the nonselective BET inhibitors at equivalent doses. The ZL inhibitors had significant effects on lung physiology, reversing TLR3-associated airway hyperresponsiveness and increasing lung compliance in vivo. At the molecular level, ZL inhibitors reduced elaboration of the transforming growth factor-ß-induced growth program, thereby preventing mucosal mesenchymal transition and disrupting BRD4 HAT activity and complex formation with RelA. We also observed that ZL0454 treatment blocked polyinosinic:polycytidylic acid-associated expansion of the α-SMA1+/COL1A+ myofibroblast population and prevented myofibroblast transition in a coculture system. We conclude that 1) BRD4 is a central effector of the mesenchymal transition that results in paracrine activation of myofibroblasts, mechanistically linking innate inflammation to airway hyperresponsiveness and fibrosis, and 2) highly selective BRD4 inhibitors may be effective in reversing the effects of repetitive airway viral infections on innate inflammation-mediated remodeling.

Pharmacokinetics of Bupropion and Its Pharmacologically Active Metabolites in Pregnancy.

Bupropion sustained release is used to promote smoking cessation in males and nonpregnant females. However, its efficacy as a smoking cessation aid during pregnancy is not reported. The pregnancy-associated changes in maternal physiology may alter the pharmacokinetics and pharmacodynamics of bupropion and consequently its efficacy in pregnant smokers. Therefore, the aims of this study were to determine the steady-state pharmacokinetics of bupropion during pregnancy and the effect of functional genetic variants of CYP2B6 and CYP2C19 on bupropion pharmacokinetics in pregnant women. Plasma and urine concentrations of bupropion and its metabolites hydroxybupropion (OHBUP), threohydrobupropion, and erythrohydrobupropion were determined by liquid chromatography-mass spectrometry. Subjects were genotyped for five nonsynonymous single-nucleotide polymorphisms that result in seven CYP2B6 alleles, namely *2, *3, *4, *5, *6, *7, and *9, and for CYP2C19 variants *2, *3, and *17 The present study reports that the isoform-specific effect of pregnancy on bupropion-metabolizing enzymes along with the increase of renal elimination of the drug could collectively result in a slight decrease in exposure to bupropion in pregnancy. In contrast, pregnancy-induced increase in CYP2B6-catalyzed bupropion hydroxylation did not impact the plasma levels of OHBUP, probably due to a higher rate of OHBUP glucuronidation, and renal elimination associated with pregnancy. Therefore, exposure to OHBUP, a pharmacologically active metabolite of the bupropion, appears to be similar to that of the nonpregnant state. The predicted metabolic phenotypes of CYP2B6*6 and variant alleles of CYP2C19 in pregnancy are similar to those in the nonpregnant state.

Placental origins of adverse pregnancy outcomes: potential molecular targets: an Executive Workshop Summary of the Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Although much progress is being made in understanding the molecular pathways in the placenta that are involved in the pathophysiology of pregnancy-related disorders, a significant gap exists in the utilization of this information for the development of new drug therapies to improve pregnancy outcome. On March 5-6, 2015, the Eunice Kennedy Shriver National Institute of Child Health and Human Development of the National Institutes of Health sponsored a 2-day workshop titled Placental Origins of Adverse Pregnancy Outcomes: Potential Molecular Targets to begin to address this gap. Particular emphasis was given to the identification of important molecular pathways that could serve as drug targets and the advantages and disadvantages of targeting these particular pathways. This article is a summary of the proceedings of that workshop. A broad number of topics were covered that ranged from basic placental biology to clinical trials. This included research in the basic biology of placentation, such as trophoblast migration and spiral artery remodeling, and trophoblast sensing and response to infectious and noninfectious agents. Research findings in these areas will be critical for the formulation of the development of future treatments and the development of therapies for the prevention of a number of pregnancy disorders of placental origin that include preeclampsia, fetal growth restriction, and uterine inflammation. Research was also presented that summarized ongoing clinical efforts in the United States and in Europe that has tested novel interventions for preeclampsia and fetal growth restriction, including agents such as oral arginine supplementation, sildenafil, pravastatin, gene therapy with virally delivered vascular endothelial growth factor, and oxygen supplementation therapy. Strategies were also proposed to improve fetal growth by the enhancement of nutrient transport to the fetus by modulation of their placental transporters and the targeting of placental mitochondrial dysfunction and oxidative stress to improve placental health. The roles of microRNAs and placental-derived exosomes, as well as messenger RNAs, were also discussed in the context of their use for diagnostics and as drug targets. The workshop discussed the aspect of safety and pharmacokinetic profiles of potential existing and new therapeutics that will need to be determined, especially in the context of the unique pharmacokinetic properties of pregnancy and the hurdles and pitfalls of the translation of research findings into practice. The workshop also discussed novel methods of drug delivery and targeting during pregnancy with the use of macromolecular carriers, such as nanoparticles and biopolymers, to minimize placental drug transfer and hence fetal drug exposure. In closing, a major theme that developed from the workshop was that the scientific community must change their thinking of the pregnant woman and her fetus as a vulnerable patient population for which drug development should be avoided, but rather be thought of as a deprived population in need of more effective therapeutic interventions.

Metabolism and disposition of bupropion in pregnant baboons (Papio cynocephalus).

Recent in vitro data obtained in our laboratory revealed similarities between baboons and humans in the biotransformation of bupropion (BUP) by both hepatic and placental microsomes. These data supported the use of baboons to study BUP biotransformation during pregnancy. The aim of this investigation was to determine the pharmacokinetics of BUP in baboons during pregnancy and postpartum, as well as fetal exposure to the drug after intravenous administration. Pregnant baboons (n = 5) received a single intravenous bolus dose of bupropion hydrochloride (1 mg/kg) at gestational ages 94-108 days (midpregnancy), 142-156 days (late pregnancy), and 6 weeks postpartum. Blood and urine samples were collected for 12 and 24 hours, respectively. The concentrations of BUP, hydroxybupropion (OH-BUP), threohydrobupropion, and erythrohydrobupropion in plasma were determined by liquid chromatography-tandem mass spectrometry. Relative to the postpartum period, the average midpregnancy clearance of BUP trended higher (3.6 ± 0.15 versus 2.7 ± 0.28 l/h per kg) and the average C(max) (294 ± 91 versus 361 ± 64 ng/ml) and the area under the curve (AUC) of BUP values (288 ± 22 versus 382 ± 42 h·ng/ml) trended lower. AUC(OH-BUP) also tended to be lower midpregnancy compared with postpartum (194 ± 76 versus 353 ± 165 h·ng/ml). Whereas the observed trend toward increased clearance of BUP during baboon pregnancy could be associated with a pregnancy-induced increase in its biotransformation, the trend toward increased renal elimination of OH-BUP may overshadow any corresponding change in the hydroxylation activity of CYP2B.

Influences of nanomaterials on the barrier function of epithelial cells.

Recent advances in nanotechnology have led to exciting opportunities in medicine, energy, manufacturing, and other fields. Nevertheless, it is important to adequately assess the potential impacts of nanomaterial exposure. This chapter focuses on the interactions of nanomaterials with epithelial barriers in the lungs, intestine, kidneys, skin, and placenta. Methods for determining transepithelial electrical resistance and paracellular permeability are described. Effects on cell viability and barrier integrity depend on the chemical nature of the nanomaterial, nanoparticle size, surface coatings, and concentration. Disruption of tight junctions can affect permeability and interfere with normal regulatory processes of the epithelial barrier. Future research is needed to better understand the possibilities and the limits of novel approaches in nanotechnology.

Indomethacin Pharmacokinetics and Pharmacodynamics in Pregnancies With Preterm Labor: The Need for Dose-Ranging Trials.

The use of indomethacin to delay delivery in preterm labor (PTL) is widely accepted; however, the optimal dosage of indomethacin in pregnancy is unknown. Here, we perform population pharmacokinetic (PK) and pharmacodynamic (PD) analyses, characterize the plasma disposition of indomethacin in pregnant women with PTL, and relate indomethacin exposure to delayed delivery and maternal/neonatal safety. We analyzed plasma and urine samples collected from a multicenter, prospective, opportunistic PK/PD study of indomethacin in pregnant women 12-32 weeks gestation admitted with PTL. Ninety-four participants with 639 plasma concentrations for indomethacin were included in the analysis. The final population PK (popPK) model for indomethacin was a 2-compartment structural model with first-order absorption and elimination and a covariate effect of body mass index on apparent oral clearance. We observed a 21%-60% increase in apparent oral clearance observed during pregnancy. There was no clear association between indomethacin exposure and maternal or neonatal safety outcomes, or with the magnitude of delayed delivery; however, 96.7% of women treated with indomethacin had a delivery that was delayed at least 48 hours. Given the changes to indomethacin apparent oral clearance during pregnancy, and the lack of relationship between indomethacin exposure and safety, dose-finding studies of indomethacin in pregnant women with PTL may help clarify the most safe and efficacious dosage and duration of indomethacin.

Quantitative determination of famotidine in human maternal plasma, umbilical cord plasma and urine using high-performance liquid chromatography-mass spectrometry.

Liquid chromatography with electrospray ionization mass spectrometry for the quantitative determination of famotidine in human urine, maternal and umbilical cord plasma was developed and validated. The plasma samples were alkalized with ammonium hydroxide and extracted twice with ethyl acetate. The extraction recovery of famotidine in maternal and umbilical cord plasma ranged from 53 to 64% and 72 to 79%, respectively. Urine samples were directly diluted with the initial mobile phase then injected into the HPLC system. Chromatographic separation of famotidine was achieved by using a Phenomenex Synergi™ Hydro-RP™ column with a gradient elution of acetonitrile and 10 mm ammonium acetate aqueous solution (pH 8.3, adjusted with ammonium hydroxide). Mass spectrometric detection of famotidine was set in the positive mode and used a selected ion monitoring method. Carbon-13-labeled famotidine was used as internal standard. The calibration curves were linear (r(2) > 0.99) in the concentration ranges of 0.631-252 ng/mL for umbilical and maternal plasma samples and 0.075-30.0 µg/mL for urine samples. The relative deviation of method was <14% for intra- and inter-day assays, and the accuracy ranged between 93 and 110%. The matrix effect of famotidine in human urine, maternal and umbilical cord plasma was less than 17%.

Folate-mediated transport of nanoparticles across the placenta.

BACKGROUND: In this study, a prototype of a targeted nanocarrier for drug delivery for prenatal therapy of the developing fetus was developed and examined in vitro and ex vivo. The folate transport mechanism in the human placenta was utilized as a possible pathway for the transplacental delivery of targeted nanoparticles. METHODS: Several types of folic acid-decorated polymeric nanoparticles were synthesized and characterized. During transport studies of targeted and non-targeted fluorescent nanoparticles across the placental barrier, the apparent permeability values, uptake, transfer indices, and distribution in placental tissue were determined. RESULTS: The nanoparticles had no effect on BeWo b30 cell viability. In vitro, studies showed significantly higher apparent permeability of the targeted nanoparticles across the cell monolayers as compared to the nontargeted nanoparticles (Pe = 5.92 ± 1.44 ×10-6 cm/s for PLGA-PEG-FA vs. 1.26 ± 0.31 ×10-6 cm/s for PLGA-PEG, P < 0.05), and the transport of the targeted nanoparticles was significantly inhibited by excess folate. Ex vivo placental perfusion showed significantly greater accumulation of the targeted nanoparticles in the placental tissue (4.31 ± 0.91%/g for PLGA-PEG-FA vs. 2.07 ± 0.26%/g for PLGA-PEG). CONCLUSION: The data obtained suggested different mechanisms for the uptake and transplacental transfer of targeted versus nontargeted nanoparticles. This targeted nanoformulation may be a promising strategy for fetal drug therapy.

PEGylated Polymeric Nanoparticles Loaded with 2-Methoxyestradiol for the Treatment of Uterine Leiomyoma in a Patient-Derived Xenograft Mouse Model.

Leiomyomas, the most common benign neoplasms of the female reproductive tract, currently have limited medical treatment options. Drugs targeting estrogen/progesterone signaling are used, but side effects and limited efficacy in many cases are major limitation of their clinical use. Previous studies from our laboratory and others demonstrated that 2-methoxyestradiol (2-ME) is promising treatment for uterine fibroids. However, its poor bioavailability and rapid degradation hinder its development for clinical use. The objective of this study is to evaluate the in vivo effect of biodegradable and biocompatible 2-ME-loaded polymeric nanoparticles in a patient-derived leiomyoma xenograft mouse model. PEGylated poly(lactide-co-glycolide) (PEG-PLGA) nanoparticles loaded with 2-ME were prepared by nanoprecipitation. Female 6-week age immunodeficient NOG (NOD/Shi-scid/IL-2Rγnull) mice were used. Estrogen-progesterone pellets were implanted subcutaneously. Five days later, patient-derived human fibroid tumors were xenografted bilaterally subcutaneously. Engrafted mice were treated with 2-ME-loaded or blank (control) PEGylated nanoparticles. Nanoparticles were injected intraperitoneally and after 28 days of treatment, tumor volume was measured by caliper following hair removal, and tumors were removed and weighed. Up to 99.1% encapsulation efficiency was achieved, and the in vitro release profile showed minimal burst release, thus confirming the high encapsulation efficiency. In vivo administration of the 2-ME-loaded nanoparticles led to 51% growth inhibition of xenografted tumors compared to controls (P < 0.01). Thus, 2-ME-loaded nanoparticles may represent a novel approach for the treatment of uterine fibroids.

Physicochemical and Biological Properties of Membrane Vesicles Derived from Human Term Placentas.

The purpose of this study was to conduct initial characterization of membrane vesicles isolated from human placenta by agitation of villous tissue (apical and basal) as well as vesicles obtained following dual perfusion of placental lobule. The morphology, physical and biological properties of the isolated vesicles were determined by electron microscopy, dynamic light scattering, and immunoblotting as well as nanoflow liquid chromatography-mass spectrometry proteomics analysis. CD-1 male mice were used to test the biocompatibility of the vesicles in vivo and assess the biodistribution of fluorescently labeled apical and perfusion vesicles. The vesicles obtained following placental perfusion and the apical vesicles had Z-average diameters of 199±23 nm and 246±24 nm, respectively, and demonstrated nanocarrier stability, low toxicity, and low immunogenicity. On the other hand, administration of basal vesicles resulted in animal demise with LD50 of 0.85 µgprotein/g. Both fluorescently labeled apical and perfusion vesicles were detected in the lungs, liver, kidneys, and spleen of CD-1 mice within 24 h of administration. However, there were differences in organ distribution of these vesicles over 24 hours time period. These data suggest that placental apical and perfusion vesicles have a potential for further development as biological vehicles for drug delivery.

Effect of deuteration on the single dose pharmacokinetic properties and postoperative analgesic activity of methadone.

Although methadone is effective in the management of acute pain, the complexity of its absorption-distribution-metabolism-excretion profile limits its use as an opioid of choice for perioperative analgesia. Because deuteration is known to improve the pharmacokinetic, pharmacodynamic and toxicological properties of some drugs, here we characterized the single dose pharmacokinetic properties and post-operative analgesic efficacy of d9-methadone. The pharmacokinetic profiles of d9-methadone and methadone administered intravenously to CD-1 male mice revealed that deuteration leads to a 5.7- and 4.4-fold increase in the area under the time-concentration curve and maximum concentration in plasma, respectively, as well as reduction in clearance (0.9 ± 0.3 L/h/kg vs 4.7 ± 0.8 L/h/kg). The lower brain-to-plasma ratio of d9-methadone compared to that of methadone (0.35 ± 0.12 vs 2.05 ± 0.62) suggested that deuteration decreases the transfer of the drug across the blood-brain barrier. The estimated LD50 value for a single intravenous dose of d9-methadone was 2.1-fold higher than that for methadone. Moreover, d9-methadone outperformed methadone in the efficacy against postoperative pain by primarily activating peripheral opioid receptors. Collectively, these data suggest that the replacement of three hydrogen atoms in three methyl groups of methadone altered its pharmacokinetic properties, improved safety, and enhanced its analgesic efficacy.

Influence of morphology and drug distribution on the release process of FITC-dextran-loaded microspheres prepared with different types of PLGA.

The aim of the present work was to understand the collaborative roles and the comprehensive effects of polymer nature, morphology, drug distribution and release behaviour for PLGA microspheres prepared by the double emulsion method. The morphology and drug distribution of the FITC-dextran-loaded microspheres were investigated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM), respectively. The results show that the morphology and release profiles depend on the polymer nature. For the capped PLGA RG502, the porosity, pore size and drug distribution had no pronounced influence on the release profile beyond the initial release. No significant changes in size and morphology were found and there was negligible water uptake during the release process. PEG addition as a pore maker indicated a possible way to modify the release rate at the second release stage. However, in the case of the uncapped PLGA RG503H, release profiles were dependent upon changes in porosity, pore size and drug loading. Increases in porosity, internal pore size and loading resulted in a continuous release profile. Previous studies have shown the importance of different process parameters on morphology and drug release, but in this work it is clear that polymer nature is a determining factor.

Effect of CYP2C9 Polymorphisms on the Pharmacokinetics of Indomethacin During Pregnancy.

BACKGROUND AND OBJECTIVE: Cytochrome P450 (CYP) 2C9 catalyzes the biotransformation of indomethacin to its inactive metabolite O-desmethylindomethacin (DMI). The aim of this work was to determine the effect of CYP2C9 polymorphisms on indomethacin metabolism in pregnant women. METHODS: Plasma concentrations of indomethacin and DMI at steady state were analyzed with a validated LC-MS/MS method. DNA was isolated from subject blood and buccal smear samples. Subjects were grouped by genotype for comparisons of pharmacokinetic parameters. RESULTS: For subjects with the *1/*2 genotype, the mean steady-state apparent oral clearance (CL/Fss) of indomethacin was 13.5 ± 7.7 L/h (n = 4) and the mean metabolic ratio (AUCDMI/AUCindomethacin) was 0.291 ± 0.133. For subjects with the *1/*1 genotype, these values were 12.4 ± 2.7 L/h and 0.221 ± 0.078, respectively (n = 14). Of note, we identified one subject who was a carrier of both the *3 and *4 alleles, resulting in an amino acid change (I359P) which has not been reported previously. This subject had a metabolic ratio of 0.390 and a CL/Fss of indomethacin (24.3 L/h) that was nearly double the wild-type clearance. CONCLUSION: Although our results are limited by sample size and are not statistically significant, these data suggest that certain genetic polymorphisms of CYP2C9 may lead to an increased metabolic ratio and an increase in the clearance of indomethacin. More data are needed to assess the impact of CYP2C9 genotype on the effectiveness of indomethacin as a tocolytic agent.

Contributions of phosphorylation to regulation of OCTN2 uptake of carnitine are minimal in BeWo cells.

Physiological functions of organic cation transporters (OCTs) in the placenta include transporting essential nutrients from the maternal to fetal circulations. OCTN2 transports carnitine with high affinity, and the transport of several drugs has also been shown to be mediated by this transporter. In this work, the role of phosphorylation and dephosphorylation mechanisms in regulating OCTN2 was investigated by observing the effects of various activators and inhibitors of kinases and phosphatases on the uptake of carnitine in BeWo cells, a human choriocarcinoma trophoblast cell line frequently used as an in vitro model of the rate-limiting barrier for maternal-fetal exchange. Preincubation with genistein resulted in significant increases in both alkaline phosphatase (ALP) activity and carnitine uptake. Levamisole, an ALP inhibitor, caused a more substantial decrease in carnitine uptake than expected from its corresponding decrease in ALP activity. It was determined that levamisole competitively inhibits carnitine uptake, with a K(i) value of 1.01+/-0.05mM, and this effect has a greater role in decreasing carnitine uptake than any indirect effects of ALP inhibition upon OCTN2 function. Progesterone also competitively inhibited carnitine uptake (K(i)=48.6+/-5.0muM), but had no effect on ALP activity in BeWo cells.

Biodegradable polymeric nanocarriers for pulmonary drug delivery.

BACKGROUND: Pulmonary drug delivery is attractive for both local and systemic drug delivery as a non-invasive route that provides a large surface area, thin epithelial barrier, high blood flow and the avoidance of first-pass metabolism. OBJECTIVE: Nanoparticles can be designed to have several advantages for controlled and targeted drug delivery, including controlled deposition, sustained release, reduced dosing frequency, as well as an appropriate size for avoiding alveolar macrophage clearance or promoting transepithelial transport. METHODS: This review focuses on the development and application of biodegradable polymers to nanocarrier-based strategies for the delivery of drugs, peptides, proteins, genes, siRNA and vaccines by the pulmonary route. RESULTS/CONCLUSION: The selection of natural or synthetic materials is important in designing particles or nanoparticle clusters with the desired characteristics, such as biocompatibility, size, charge, drug release and polymer degradation rate.