Intravenous Clopidogrel (MDCO-157) Compared with Oral Clopidogrel: The Randomized Cross-Over AMPHORE Study

Background

The extent of P2Y₁₂ inhibition during coronary intervention is an important determinant of ischemic complications. The currently available oral P2Y₁₂ inhibitors are limited by a relatively slow onset of action and variable on-treatment response.

Objective

Our objective was to determine the pharmacodynamic (PD) dose–antiplatelet response relationship and the pharmacokinetics of MDCO-157, an intravenous formulation of clopidogrel complexed with sulphobutylether betacyclodextrin, and to identify the dose level of MDCO-157 that matches the PD effect of oral clopidogrel 300 mg.

Methodology

A randomized open-label crossover study was performed in 33 healthy adult volunteers to determine the pharmacokinetic (clopidogrel and clopidogrel H4 thiol active metabolite) and the PD (vasodilator-stimulated phosphoprotein [VASP]) effects of MDCO-157 at doses of 75, 150, and 300 mg and of oral clopidogrel 300 mg.

Results

Data are presented as %, mean (standard deviation). The maximum effect of P2Y₁₂ receptor inhibition assessed by flow cytometry using VASP was 70.42 (6.7), 69.45 (7.1), and 65.58 (12.6) for intravenous MDCO-157 at doses of 75, 150, and 300 mg, respectively, compared with 56.6 (17.5) with oral clopidogrel 300 mg administration (p < 0.0001). Intravenous administration of MDCO-157 led to a stepwise increase in plasma exposure of clopidogrel, higher than with administration of an oral dose of 300 mg (p < 0.0001). Plasma exposure of H4-thiol also increased with intravenous dose (3.6 ± 2.6, 6.9 ± 4.6, and 12.4 ± 9.1 h·ng/ml for intravenous 75, 150, and 300 mg, respectively) but was lower than with oral administration of a 300-mg dose (34.0 ± 16.0 h.ng/ml; pairwise p < 0.0001).

Conclusions

MDCO-157, an intravenous formulation of clopidogrel complexed with sulphobutylether betacyclodextrin, did not show significant platelet inhibition when administered at doses up to 300 mg. Higher doses with longer infusion may be needed to reach a sufficient threshold of active metabolite generation. Trial Registration: ClinicalTrials.gov identifier: NCT01860105.

     

Anti-Anginal and Metabolic Effects of Carvedilol and Atenolol in Patients with Stable Angina Pectoris: A Prospective,Randomized, Parallel,Open-Label Study

Background

While recent guidelines have suggested the potential for beta-blockers as first-line agents in chronic stable angina, few data regarding comparative anti-anginal and metabolic effects between beta-blockers with and without vasodilating properties have been reported, particularly in patients with angina pectoris.

Objective

Our objective was to compare the anti-anginal and metabolic effects of carvedilol and atenolol in patients with stable angina pectoris.

Methods

A total of 89 patients (mean age 54.9 ± 9.3 years; male 53.9 %) with stable angina pectoris were randomly assigned to carvedilol (n = 43) or atenolol (n = 46). The subjects undertook an exercise treadmill test and completed the Seattle Angina Questionnaire (SAQ); metabolic parameters were measured at baseline and 6 months after treatment.

Results

The baseline characteristics of both groups were well balanced. Both carvedilol and atenolol significantly reduced heart rate from baseline (76 ± 11 to 66 ± 9 beat/min, p < 0.001; 74 ± 9 to 64 ± 9 beat/min, p < 0.001, respectively) with no significant changes in systolic and diastolic blood pressure. Improvement of time to ST-segment depression during the treadmill exercise and the SAQ scores for angina stability and frequency after 6 months of treatment were similar between groups. There was no significant change from baseline in the level of fasting glucose, insulin, or glycated hemoglobin in either group. However, total cholesterol and low-density lipoprotein cholesterol levels significantly reduced to a greater extent with carvedilol than with atenolol (?23 vs. ?10 and –38 vs. –24 %, respectively, p < 0.05 for both), although the rate of statin use was comparable. No changes were seen in high-density lipoprotein cholesterol and triglyceride levels after 6 months of treatment in both groups compared with baseline.

Conclusions

Both carvedilol and atenolol had a similar anti-anginal effect. Compared with atenolol, carvedilol might have more beneficial effects on lipid metabolism in patients with stable angina pectoris [ClinicalTrials.gov identifier: NCT02547597].

     

Gentamicin-Loaded Polysaccharide Membranes for Prevention and Treatment of Post-operative Wound Infections in the Skeletal System

Purpose

To develop polysaccharide-based membranes that allow controlled and localized delivery of gentamicin for the treatment of post-operative bone infections.

Methods

Membranes made of gellan gum (GUM), sodium alginate (ALG), GUM and ALG crosslinked with calcium ions (GUM + Ca and ALG + Ca, respectively) as well as reference collagen (COL) were produced by freeze-drying. Mechanical properties, drug release, antimicrobial activity and cytocompatibility of the membranes were assessed.

Results

The most appropriate handling and mechanical properties (Young’s modulus, E = 92 ± 4 MPa and breaking force, F _MAX  = 2.6 ± 0.1 N) had GUM + Ca membrane. In contrast, COL membrane showed F _MAX  = 0.14 ± 0.02 N, E = 1.0 ± 0.3 MPa and was deemed to be unsuitable for antibiotic delivery. The pharmacokinetic data demonstrated a uniform and sustainable delivery of gentamicin from GUM + Ca (44.4 ± 1.3% within 3 weeks), while for COL, ALG and ALG + Ca membranes the most of the drug was released within 24 h (55.3 ± 1.9%, 52.5 ± 1.5% and 37.5 ± 1.8%, respectively). Antimicrobial activity against S. aureus and S. epidermidis was confirmed for all the membranes. GUM + Ca and COL membranes supported osteoblasts growth, whereas on ALG and ALG + Ca membranes cell growth was reduced.

Conclusions

GUM + Ca membrane holds promise for effective treatment of bone infections thanks to favorable pharmacokinetics, bactericidal activity, cytocompatibility and good mechanical properties.

     

A Dose Ranging Pharmacokinetic Evaluation of IQP-0528 Released from Intravaginal Rings in Non-Human Primates

Purpose

Design of intravaginal rings (IVRs) for delivery of antiretrovirals is often guided by in vitro release under sink conditions, based on the assumption that in vivo release will follow a similar release profile.

Methods

We conducted a dose-ranging study in the female reproductive tract of pigtail macaques using matrix IVRs containing IQP-0528, a poorly soluble but highly potent antiretroviral drug with an IC₉₀ of 146 ng/mL. These IVRs consisted of drug-loaded segments, 15.6% IQP-0528 in Tecoflex 85A, comprising either all, half, or a quarter of the entire ring.

Results

In vitro release under sink conditions demonstrates loading-proportional release, with a cumulative 30-day release of 48.5 ± 2.2 mg for our 100% loaded ring, 24.8 ± .36 mg from our 50% loaded ring, and 13.99 ± 1.58 mg from our 25% loaded ring. In vivo, while drug concentration in vaginal fluid is well in excess of IQP-0528’s EC₉₀, we find no statistical difference between the different ring loadings in either swab drug levels or drug released from our rings.

Conclusions

We show that in vitro release may not accurately reflect in vivo release, particularly for poorly soluble drugs. All tested loadings of our IVRs are capable of delivering IQP-0528 well in excess of the IC₉₀.

     

Lipid-based Formulations for Danazol Containing a Digestible Surfactant,Labrafil M2125CS: <Emphasis Type="BoldItalic">In Vivo</Emphasis> Bioavailability and Dynamic <Emphasis Type="BoldItalic">In Vitro</Emphasis> Lipolysis

Purpose

To evaluate the use of Labrafil® M2125CS as a lipid vehicle for danazol. Further, the possibility of predicting the in vivo behavior with a dynamic in vitro lipolysis model was evaluated.

Methods

Danazol (28 mg/kg) was administered orally to rats in four formulations: an aqueous suspension, two suspensions in Labrafil® M2125CS (1 and 2 ml/kg) and a solution in Labrafil® M2125CS (4 ml/kg).

Results

The obtained absolute bioavailabilities of danazol were 1.5?±?0.8%; 7.1?±?0.6%; 13.6?±?1.4% and 13.3?±?3.4% for the aqueous suspension, 1, 2 and 4 ml Labrafil® M2125CS per kg respectively. Thus administration of danazol with Labrafil® M2125CS resulted in up to a ninefold increase in the bioavailability, and the bioavailability was dependent on the Labrafil® M2125CS dose. In vitro lipolysis of the formulations was able to predict the rank order of the bioavailability from the formulations, but not the absorption profile of the in vivo study.

Conclusions

The bioavailability of danazol increased when Labrafil® M2125CS was used as a vehicle, both when danazol was suspended and solubilized in the vehicle. The dynamic in vitro lipolysis model could be used to rank the bioavailabilities of the in vivo data.

     

Anti-Tuberculosis Bacteriophage D29 Delivery with a Vibrating Mesh Nebulizer,Jet Nebulizer,and Soft Mist Inhaler

Purpose

To compare titer reduction and delivery rate of active anti-tuberculosis bacteriophage (phage) D29 with three inhalation devices.

Methods

Phage D29 lysate was amplified to a titer of 11.8 ± 0.3 log₁₀(pfu/mL) and diluted 1:100 in isotonic saline. Filters captured the aerosolized saline D29 preparation emitted from three types of inhalation devices: 1) vibrating mesh nebulizer; 2) jet nebulizer; 3) soft mist inhaler. Full-plate plaque assays, performed in triplicate at multiple dilution levels with the surrogate host Mycobacterium smegmatis, were used to quantify phage titer.

Results

Respective titer reductions for the vibrating mesh nebulizer, jet nebulizer, and soft mist inhaler were 0.4 ± 0.1, 3.7 ± 0.1, and 0.6 ± 0.3 log₁₀(pfu/mL). Active phage delivery rate was significantly greater (p < 0.01) for the vibrating mesh nebulizer (3.3x10⁸ ± 0.8x10⁸ pfu/min) than for the jet nebulizer (5.4x10⁴ ± 1.3x10⁴ pfu/min). The soft mist inhaler delivered 4.6x10⁶ ± 2.0x10⁶ pfu per 11.6 ± 1.6 μL ex-actuator dose.

Conclusions

Delivering active phage requires a prudent choice of inhalation device. The jet nebulizer was not a good choice for aerosolizing phage D29 under the tested conditions, due to substantial titer reduction likely occurring during droplet production. The vibrating mesh nebulizer is recommended for animal inhalation studies requiring large amounts of D29 aerosol, whereas the soft mist inhaler may be useful for self-administration of D29 aerosol.

     

Fabrication of 3-O-sn-Phosphatidyl-L-serine Anchored PLGA Nanoparticle Bearing Amphotericin B for Macrophage Targeting

Purpose

To fabricate, characterize and evaluate 3-O-sn-Phosphatidyl-L-serine (PhoS) anchored PLGA nanoparticles for macrophage targeted therapeutic intervention of VL.

Materials and Methods

PLGA-AmpB NPs were prepared by well-established nanoprecipitation method and decorated with Phos by thin film hydration method. Physico-chemical characterization of the formulation was done by Zetasizer nano ZS and atomic force microscopy.

Results

The optimized formulation (particle size, 157.3?±?4.64 nm; zeta potential, ? 42.51?±?2.11 mV; encapsulation efficiency, ～98%) showed initial rapid release up to 8 h followed by sustained release until 72 h. PhoS generated ‘eat-me’ signal driven augmented macrophage uptake, significant increase in in-vitro (with ～82% parasite inhibition) and in-vivo antileishmanial activity with preferential accumulation in macrophage rich organs liver and spleen were found. Excellent hemo-compatibility justified safety profile of developed formulation in comparison to commercial formulations.

Conclusion

The developed PhoS-PLGA-AmpB NPs have improved efficacy, and necessary stability which promisingly put itself as a better alternative to available commercial formulations for optimized treatment of VL.

     

Development and Characterization of the Paclitaxel loaded Riboflavin and Thiamine Conjugated Carbon Nanotubes for Cancer Treatment

Purpose

In the present investigation, we prepared and evaluated the paclitaxel loaded riboflavin and thiamine conjugated multi walled carbon nanotubes (PTX-Rf-MWCNTs and PTX-Tm-MWCNTs) for targeted delivery to cancer employing MCF-7 cancer cell lines.

Methods

The developed conjugates were characterized using FTIR, NMR spectroscopy, electron microscopy drug loading, release, stability, hemolytic, ex vivo and in vivo studies etc.

Results

The percent entrapment efficiency was found to be 87.92?±?0.48 and 82.75?±?0.47% of PTX-Tm-MWCNTs, PTX-Rf-MWCNTs, respectively. The percent hemolysis of purified MWCNTs, PTX-MWCNTs, PTX-Tm-MWCNTs and PTX-Rf-MWCNTs was found to be 20.49?±?0.97, 37.39?±?0.78, 14.61?±?0.84 and 11.17?±?0.77% respectively. The PTX-Tm-MWCNTs and PTX-Rf-MWCNTs showed more cytotoxic effect as compared to PTX and PTX-MWCNTs with PTX-Rf-MWCNTs exhibiting the maximum cytotoxic potential.

Conclusion

Thus in final outcome, we concluded that the riboflavin and thiamine conjugated MWCNTs shown great promising potential in the treatment of cancer, but more exhaustive data is needed in future.

     

Conjugated and Entrapped HPMA-PLA Nano-Polymeric Micelles Based Dual Delivery of First Line Anti TB Drugs: Improved and Safe Drug Delivery against Sensitive and Resistant <Emphasis Type="Italic">Mycobacterium Tuberculosis</Emphasis>

Purpose

First line antiTB drugs have several physical and toxic manifestations which limit their applications. RIF is a hydrophobic drug and has low water solubility and INH is hepatotoxic. The main objective of the study was to synthesize, characterize HPMA-PLA co-polymeric micelles for the effective dual delivery of INH and RIF.

Methods

HPMA-PLA co-polymer and HPMA-PLA-INH (HPI) conjugates were synthesized and characterized by FT-IR and ¹H–NMR spectroscopy. Later on RIF loaded HPMA-PLA-INH co-polymeric micelles (PMRI) were formulated and characterized for size, zeta potential and surface morphology (SEM, TEM) as well as critical micellar concentration. The safety was assessed through RBC’s interaction study. The prepared PMRI were evaluated through MABA assay against sensitive and resistant strains of M. Tuberculosis.

Results

Size, zeta and entrapment efficiency for RIF loaded HPMA-PLA-INH polymeric micelles (PMRI) was 87.64 ± 1.98 nm, ?19 ± 1.93 mV and 97.2 ± 1.56%, respectively. In vitro release followed controlled and sustained delivery pattern. Sustained release was also supported by release kinetics. Haemolytic toxicity of HPI and PMRI was 8.57 and 7.05% (p < 0.01, INH Vs PMRI; p < 0.0001, RIF Vs PMRI), respectively. MABA assay (cytotoxicity) based MIC values of PMRI formulation was observed as ≥0.0625 and ≥0.50 μg/mL (for sensitive and resistant strain). The microscopic analysis further confirmed that the delivery approach was effective than pure drugs.

Conclusions

RIF loaded and INH conjugated HPMA-PLA polymeric micelles (PMRI) were more effective against sensitive and resistant M tuberculosis. The developed approach can lead to improved patient compliance and reduced dosing in future, offering improved treatment of tuberculosis.

     

The pharmacokinetic profile of recombinant human erythropoietin is unchanged in patients undergoing cardiac surgery

Background

In anticipation of future studies, we examined the pharmacokinetics profile of erythropoietin (EPO) in patients undergoing cardiac surgery.

Methods

Cardiac surgical patients were enrolled into one of six groups: four cardiopulmonary bypass (CPB) groups [placebo (n?=?6), 250 IU/kg EPO (n?=?3), 500 IU/kg EPO (n =?3), and 500 IU/kg EPO, two doses (n =?6)] and two off-pump coronary artery bypass (OPCAB) groups [placebo (n?=?3) and 500 IU/kg EPO (n?=?3)]. The EPO was administered prior to anesthesia and 10 min after CPB (if required). Blood samples for serum EPO were collected at baseline, 10 min after dosing, 5 min after sternotomy, during CPB or the equivalent for OPCAB (5, 15, 45, 60 min), and post-CPB (5, 15, 45, and 60 min, 6, 12 and 24 h, and daily until day 5).

Results

Endogenous EPO increased within 24 h of surgery in the placebo group and remained elevated. There was approximately a 40% decrease in serum EPO concentration at the initiation of CPB due to an increase in circulatory blood volume. There were no differences in apparent volume of distribution in the plasma (Vc) (42.2?±?9.9, 39.8?±?6.3, 42.3?±?14.0 mL/kg), clearance (CL) (4.63?±?1.14, 3.44?±?0.68, 4.27?±?0.52 mL h/kg), and t_½ (16.4?±?8.0 16.9?±?10.6, 22.4?±?9.3 h) between the CPB treatment groups. The pharmacokinetic profile of EPO in the OPCAB group was similar to that for the CPB groups: Vc = 39.3?±?7.0 mL/kg, CL = 4.98?±?0.17 mL h/kg and t_½ = 17.1?±?18.1 h.

Conclusions

CPB had no apparent effect on the pharmacokinetics of EPO.

     

Preparation,Physicochemical Characterization and Anti-fungal Evaluation of Nystatin-Loaded PLGA-Glucosamine Nanoparticles

Purpose

Nystatin loaded PLGA and PLGA-Glucosamine nanoparticles were formulated. PLGA were functionalized with Glucosamine (PLGA-GlcN) to enhance the adhesion of nanoparticles to Candida Albicans (C.albicans) cell walls.

Method

Quasi-emulsion solvent diffusion method was employed using PLGA and PLGA-GlcN with various drug–polymer ratios for the preparation of nanoparticles. The nanoparticles were evaluated for size, zeta potential, polydispersity index, drug crystallinity, loading efficiency and release properties. DSC, SEM, XRPD, ¹H-NMR, and FT-IR were performed to analyze the physicochemical properties of the nanoparticles. Antifungal activity of the nanoparticles was evaluated by determination of MICs against C.albicans.

Results

The spectra of ¹H-NMR and FT-IR analysis ensured GlcN functionalization on PLGA nanoparticles. SEM characterization confirmed that particles were in the nanosize range and the particle size for PLGA and PLGA-GlcN nanoparticles were in the range of 108.63?±?4.5 to 168.8?±?5.65 nm and 208.76?±?16.85 nm, respectively. DSC and XRPD analysis ensured reduction of the drug crystallinity in the nanoparticles. PLGA-GlcN nanoparticles exhibit higher antifungal activity than PLGA nanoparticles.

Conclusion

PLGA-GlcN nanoparticles showed more antifungal activity with appropriate physicochemical properties than pure Nystatin and PLGA nanoparticles.

     

Improved Stability and Enhanced Oral Bioavailability of Atorvastatin Loaded Stearic Acid Modified Gelatin Nanoparticles

Purpose

The present study evaluates the effects of stearic acid conjugation with gelatin and, its pharmaceutical potential to formulate novel atorvastatin (AT) loaded nanoparticles.

Method

AT loaded stearic acid modified gelatin nanoparticles (AT-MG NPs) were prepared via two-step desolvation method with extensive optimization of different process variables. Further, the developed nanoparticles where evaluated against in vitro Caco-2 cell model and in vivo bioavailability.

Results

Extensive optimization of nanoformulation resulted into the formation of AT-MG NPs with particle size 247.7 ± 10.9 nm, PDI 0.219 ± 0.07, and entrapment efficiency 58.7 ± 5.3%. Freeze dried nanoparticles were found to have spherical shape as determined by SEM and demonstrated excellent stability in simulated gastrointestinal conditions and during storage. Developed nanoparticles exhibited sustained release up to 24 h and remarkably higher Caco-2 cell uptake. Mechanistic studies further revealed the clathrin and caveolae mediated endocytosis as principle mechanism. In line with Caco-2 cell uptake observations, AT-MG NPs showed ～4.84-fold increase in the AUC0-∞ values of AT in comparison with free AT following oral administration.

Conclusion

Overall, the stearic acid conjugated gelatin NPs demonstrates a promising potential in improving the drug payload of BCS class II drugs and enhancing oral bioavailability.

     

Bromelain-Functionalized Multiple-Wall Lipid-Core Nanocapsules: Formulation,Chemical Structure and Antiproliferative Effect Against Human Breast Cancer Cells (MCF-7)

Purpose

This study was conducted a promising approach to surface functionalization developed for lipid-core nanocapsules and the merit to pursue new strategies to treat solid tumors.

Methods

Bromelain-functionalized multiple-wall lipid-core nanocapsules (Bro-MLNC-Zn) were produced by self-assembling following three steps of interfacial reactions. Physicochemical and structural characteristics, in vitro proteolytic activity (casein substrate) and antiproliferative activity (breast cancer cells, MCF-7) were determined.

Results

Bro-MLNC-Zn had z-average diameter of 135 nm and zeta potential of +23 mV. The complex is formed by a Zn-N chemical bond and a chelate with hydroxyl and carboxyl groups. Bromelain complexed at the nanocapsule surface maintained its proteolytic activity and showed anti-proliferative effect against human breast cancer cells (MCF-7) (72.6?±?1.2% at 1.250 μg mL^?1 and 65.5?±?5.5% at 0.625 μg mL^?1). Comparing Bro-MLNC-Zn and bromelain solution, the former needed a dose 160-folds lower than the latter for a similar effect. Tripan blue dye assay corroborated the results.

Conclusions

The surface functionalization approach produced an innovative formulation having a much higher anti-proliferative effect than the bromelain solution, even though both in vitro proteolytic activity were similar, opening up a great opportunity for further studies in nanomedicine.

     

Inter-Subject Variability in OCT1 Activity in 27 Batches of Cryopreserved Human Hepatocytes and Association with OCT1 mRNA Expression and Genotype

Purpose

OCT1/3 (Organic Cation Transporter-1 and -3; SLC22A1/3) are transmembrane proteins localized at the basolateral membrane of hepatocytes. They mediate the uptake of cationic endogenous compounds and/or xenobiotics. The present study was set up to verify whether the previously observed variability in OCT activity in hepatocytes may be explained by inter-individual differences in OCT1/3 mRNA levels or OCT1 genotype.

Methods

Twenty-seven batches of cryopreserved human hepatocytes (male and female, age 24–88 y) were characterized for OCT activity, normalized OCT1/3 mRNA expression, and OCT1 genetic mutation. ASP⁺ (4-[4-(dimethylamino)styryl]-N-methylpyridinium iodide) was used as probe substrate.

Results

ASP⁺ uptake ranged between 75 ± 61 and 2531 ± 202 pmol/(min × million cells). The relative OCT1 and OCT3 mRNA expression ranged between 0.007–0.46 and 0.0002–0.005, respectively. The presence of one or two nonfunctional SLC22A1 alleles was observed in 13 batches and these exhibited significant (p = 0.04) association with OCT1 and OCT3 mRNA expression. However, direct association between genotype and OCT activity could not be established.

Conclusion

mRNA levels and genotype of OCT only partially explain inter-individual variability in OCT-mediated transport. Our findings illustrate the necessity of in vitro transporter activity profiling for better understanding of inter-individual drug disposition behavior.

     

A Quantitative Disintegration Method for Polymeric Films

Purpose

Current in vitro disintegration methods for polymeric films are qualitative and introduce significant user bias. The goal of these studies is to develop a novel, quantitative disintegration technique which can be used to characterize polymeric films in vitro.

Methods

A method was developed using a Texture Analyzer instrument to evaluate film disintegration. Solvent-casted, clinically advanced, anti-HIV, vaginal films as well as marketed vaginal films were used throughout these studies. Method development followed a quality by design (QbD) process and was used to evaluate film products.

Results

The current method developed provided reproducible, quantitative disintegration times for the commercially available vaginal contraceptive film (57.88?±?5.98 s). It distinguished between two clinically advanced antiretroviral containing films based on disintegration time (p value <?0.001): the tenofovir film (41.28?±?3.35 s) and the dapivirine film (88.36?±?10.61 s). This method could also distinguish between tenofovir and dapivirine films which had been altered in terms of volume (p?<?0.0001) and formulation (p?<?0.0001) based on disintegration time.

Conclusions

This method can be applied for pharmaceutical films for ranging indications as part of vigorous in vitro characterization. Parameters of the test can be altered based on site of application or indication.

     

Influence of clinical and genetic factors on warfarin dose requirements among Japanese patients

Objective

The aim of this study was to investigate the influence of clinical and genetic factors on warfarin dose requirements in the Japanese population.

Methods

We enrolled 125 patients on stable warfarin anticoagulant therapy with an international normalized ratio maintained between 1.5 and 3.0. PCR-based methods were performed to analyze genetic polymorphisms in the genes pharmacokinetically and pharmacodynamically related to warfarin reactions, including cytochrome P450 (CYP) 2C9, vitamin K epoxide reductase complex subunit 1 (VKORC1), gamma-glutamyl carboxylase (GGCX) and factor VII (FVII).

Results

The presence of CYP2C9*3 and VKORC1-1639G>A had a significant impact on the mean maintenance dose of warfarin (CYP2C9*1/*1 2.74?±?1.24 mg/day vs. *1/*3 and *3/*3 1.56?±?0.85 mg/day, P?=?0.009; VKORC1-1639AA 2.42?±?0.95 mg/day vs. GA 3.71?±?1.43 mg/day vs. GG 7.25?±?0.35 mg/day, P?<?0.001). In the multiple linear regression model, the combination of age, body surface area, and genotypes of CYP2C9*3 and VKORC1-1639G>A explained 54.8% of the variance in warfarin dose requirements.

Conclusions

The influences of CYP2C9*3 and VKORC1-1639G>A on the maintenance dose of warfarin were well-defined in Japanese patients, while polymorphisms of GGCX and FVII did not affect it. The model established in this study might provide us most likely individual maintenance dose based on clinical and genetic backgrounds.

     

Combining an <Emphasis Type="Italic">In Vitro</Emphasis> Kinetic Model with a Physiologically-Based Pharmacokinetic Model to Assess the Potential <Emphasis Type="Italic">In Vivo</Emphasis> Fate of Polyvinyl Pyrrolidone-Vinyl Acetate Copolymers

Purpose

To understand hydrolysis and alcoholysis of polyvinylpyrrolidone-co-vinylacetate (PVPVA) during formulation and storage, elucidate the reaction mechanism, establish an intrinsic kinetic model, and apply this model coupled with GastroPlus? modeling to predict the amount of PVPVA degradation in vivo.

Methods

The experimental approach includes the detection of the polymer reaction by solution nuclear magnetic resonance (NMR) and the measurement of reaction product concentration via gas chromatography (GC). The theoretical approach includes the establishment of the intrinsic kinetic model and the application of GastroPlus? to predict the degree of PVPVA degradation.

Results

The kinetic model established is a first order reaction between PVPVA and 2-propanol (IPA) or water under an acidic condition. The application of this kinetic model shows that between 1.7 and 6.8 mg of degradant is formed in the GI tract for a 850 mg dose of PVPVA.

Conclusions

The results from this application provide valuable input for process development and the risk analysis of the degradation of PVPVA.

     

Population Pharmacokinetic Modeling to Describe the Total Plasma and Free Brain Levels of Fluconazole in Healthy and <Emphasis Type="BoldItalic">Cryptococcus neoformans</Emphasis> Infected Rats: How Does the Infection Impact the Drug’s Levels on Biophase?

Purpose

The present work aimed to evaluate the influence of experimental meningitis caused by C. neoformans on total plasma and free brain concentrations of fluconazole (FLC) in Wistar rats.

Method

The infection was induced by the administration of 100 μL of inoculum (1.10⁵ CFU) through the tail vein. Free drug in the brain was assessed by microdialisys (μD). Blood and μD samples were collected at pre-determined time points up to 12 h after intravenous administration of FLC (20 mg/kg) to healthy and infected rats. The concentration-time profiles were analyzed by non-compartmental and population pharmacokinetics approaches.

Results

A two-compartmental popPK model was able to simultaneously describe plasma and free drug concentrations in the brain for both groups investigated. Analysis of plasma and μD samples showed a better FLC distribution on the brain of infected than healthy animals (1.04?±?0.31 vs 0.69?±?0.14, respectively). The probability of target attainment was calculated by Monte Carlo simulations based on the developed popPK model for 125 mg/kg dose for rats and 400–2000 mg for humans.

Conclusions

FLC showed a limited use in monotherapy to the treatment of criptoccocosis in rats and humans to value of MIC >8 μg/mL.

     

Synthesis,Characterization and Biocompatibility of <Emphasis Type="BoldItalic">N</Emphasis>-palmitoyl L-alanine-based Organogels as Sustained Implants of Granisetron and Evaluation of their Antiemetic Effect

Purpose

To assess the gelation power of N-palmitoyl L-alanine derivatives in injectable oils and to use the best chosen organogel as parenteral implant of granisetron for the treatment of emesis.

Methods

Twelve N-palmitoyl L-alanine derived organogels were developed and evaluated in terms of morphology, thermal properties and in vivo performance. The ability of the selected formula to form in situ gel upon subcutaneous injection in rats and its biocompatibility were monitored over 2 weeks by histopathological examination of the injection site.

Results

The acid derivative (N-palmitoyl L-alanine; PA) was superior to ester derivatives. The chosen formula (PA/safflower oil 10% w/v) was successful in forming an in situ gel of granisetron when subcutaneously injected in rats, lasting for 2 weeks and proved to be biocompatible by histopathological examination. Moreover, it exerted an extended antiemetic activity by decreasing the cisplatin-induced pica for a duration of 96 h and reduced preprotachykinin A mRNA expression and Substance P level for up to 4 days (gastric tissue) or 5 days (medulla oblongata) in rats.

Conclusion

Granisetron organogel could be considered as a safe, sustained-release and supportive anticancer treatment in both acute and chronic emesis as well as an accompanying treatment with chemotherapeutics in cancer cases.