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 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.

     

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.

     

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.

     

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.

     

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.

     

Multivessel Revascularization Does Not Increase Contrast-Induced Acute Kidney Injury Incidence in Acute Myocardial Infarction: A Meta-Analysis

Background

Recent studies and meta-analysis have shown that complete revascularization (CR) compared with infarct-related artery revascularization (IRA) during percutaneous coronary intervention for ST-segment elevation myocardial infarction (STEMI) is associated with decreased mortality. However, it is unclear if CR versus IRA in STEMI during indexed hospitalization is associated with risk of contrast-induced acute kidney injury (CI-AKI).

Methods

A database search was conducted for all randomized controlled trials that enrolled STEMI patients and compared CR versus IRA and reported CI-AKI. Comprehensive Meta-Analysis Version 2.0 (Wiley, Chichester) was used to determine summary effect size with a fixed-effect model and expressed as a risk ratio with 95 % confidence intervals.

Results

A total of four trials were identified and had a mean follow-up of 24.5 ± 9.9 months, a total sample size of 1537, a mean age of 63.8 ± 1.2 versus 64.2 ± 2.1 years, 31.2 ± 5.3 versus 30.1 ± 4.7 % three-vessel disease, and 33.7 ± 4.1 versus 37.2 ± 4.5 % anterior STEMI in the CR versus IRA groups, respectively. A total of 276.7 ± 25.2 versus 186.7 ± 15.3 mL contrast was used in the CR versus IRA respectively (p = 0.006). There were no statistical significant differences between the two groups in the reported incidence of CI-AKI (1.3 % CR vs. 1.9 % IRA; p = 0.4), major bleeding (1.7 % CR vs. 2.5 % IRA; p = 0.4) and stroke (1.1 % CR vs. 0.4 % IRA; p = 0.24). However, there was a significantly increased incidence of cardiovascular death (2.0 % CR vs. 4.7 % IRA; p = 0.01) and ischemia-driven revascularization (6.2 % CR vs. 18.3 % IRA; p < 0.01).

Conclusion

In the index hospitalization, CR in STEMI patients is associated with significant risk reduction in cardiac death and revascularization and a non-significant reduced trend of CI-AKI, despite increased use of contrast when compared with IRA.

     

Serum P-glycoprotein level: a potential biomarker of DMARD failure in patients with rheumatoid arthritis

Objectives

To evaluate the utility of elevated serum P-glycoprotein (P-gp) as a risk marker of therapeutic response failure in rheumatoid arthritis (RA) patients treated with disease-modifying antirheumatic drugs (DMARDs).

Methods

A cross-sectional study was conducted in 151 RA patients. Patients were classified into two groups according to the response achieved in terms of the disease activity score (DAS)28 after ≥?6 months: (1) patients with a therapeutic response to DMARDs, with DAS28 <?3.2; and (2) patients without a response to DMARDs, with persistent DAS28?≥?3.2. We explored a wide group of clinical factors associated with therapeutic resistance. Serum P-gp levels were measured by ELISA. The risk of P-gp elevation as a marker of failure to achieve a therapeutic response to DMARDs was computed using multivariate logistic regression.

Results

Serum P-gp levels were significantly higher in RA patients (n?=?151) than in the controls (n?=?30) (158.70?±?182.71 ng/mL vs. 14.12?±?8.97 ng/mL, p?<?0.001). The P-gp level was correlated with the DAS28 score (r?=?0.39, p?<?0.001). RA patients with DMARD failure had higher serum P-gp levels than patients with a therapeutic response (206?±?21.47 ng/mL vs 120.60?±?15.70 ng/mL; p?=?0.001). High P-gp levels increased the risk of DMARD failure (OR 3.36, 95% CI 1.54–7.27, p?=?0.001). After adjusting for confounding variables, elevated P-gp remained associated with DMARD failure (OR 2.64, 95% CI 1.29–5.40, p?=?0.01).

Conclusion

Elevated serum P-gp is associated with DMARD failure. The P-gp level can be considered a clinical tool for evaluating the risk of DMARD failure in patients; however, future prospective studies should be performed to evaluate the utility of this marker in predicting long-term responses.

     

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.

     

Efficacious Cefazolin Prophylactic Dose for Morbidly Obese Women Undergoing Bariatric Surgery Based on Evidence from Subcutaneous Microdialysis and Populational Pharmacokinetic Modeling

Purpose

To determine the efficacious cefazolin prophylactic dose for bariatric surgery using free subcutaneous concentrations accessed by microdialysis after 2 g or 3 g i.v. bolus dosing to morbidly obese women and POPPK modeling.

Methods

A POPPK model with variable plasma and subcutaneous tissue protein binding was developed to simultaneously describe plasma and tissue data sets. The outcomes was predicted for common surgical site infection (SSI) bacteria over 3, 4, 5 and 6 h periods postdose, as probability of target attainment (PTA) using Monte Carlo simulation.

Results

CFZ 2 g warrant up to 5 h SSI prophylaxis for bacteria with MICs ≤1 mg/L such as Escherichia coli and Staphylococcus aureus. For species such as Klebsiella pneumoniae, which present MIC distribution frequency of 2 mg/L, the maintenance of PTA?≥?90% occurs with a 3 g dose for surgeries lasting up to 5 h, and 2 g dose provide an adequate response up to 4 h (PTA of 89%).

Conclusions

Effectiveness of CFZ 2 g is similar to 3 g against bacteria with a MIC up to 2 mg/L, especially if the surgery does not last for more than 4 h.

     

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.

     

Optimization of Process Parameters for Formulation of Ayurvedic Fermented Medicine <Emphasis Type="Italic">Arjunarishta</Emphasis> by Response Surface Methodology

Purpose

Utilization of traditional medicines increased worldwide. However, lack of modern technology creates problems for rejection of such preparations. Good manufacturing practices (GMPs) advocate uniformity and stability in the development of modern pharmaceuticals. Implementation of appropriate formulation strategies may enhance regulatory acceptance of complementary medicines. Herewith an attempt has been made to identify the impact of process parameter temperature, pH, and yeast cell number (inoculum volume) on manufacturing of ayurvedic fermented cardiotonic—arjunarishta.

Method

Optimization of the selected three process parameters was carried out for maximum production of alcohol in arishta using Box–Behnken design of response surface methodology with support of Design Expert software. Alcohol produced in formulation was detected after solvent extraction by dichromate oxidation method.

Result

Quadratic model was found significant with sum of squares 86.76 and F value 250.60. The incubation temperature 33.33 °C, pH 4.73, and inoculum volume 3.25 ml (4?×?10⁷ yeast cells/ml) have been identified as the best for maximal production of alcohol. It shows 7.68 % (v/v) production of alcohol which is identified by dichromate oxidation method. Presence of gallic acid also detected in optimized formulation by HPTLC with concentration 0.296 % (w/v).

Conclusion

This kind of study will definitely make formulation of arishta easier with higher consistency; moreover, manufacturing is possible in any season at any place.

     

A Comparison of Two Methods for the Preparation Cefquinome-Loaded Gelatin Microspheres for Lung Targeting

Purpose

The aim of this study was to prepare CEQ-loaded gelatin microspheres and compare two preparation methods, evaluate targeting to the lungs.

Methods

Gelatin microspheres containing CEQ were prepared by an emulsion cross-linking method (ECLM) and a spray-drying method (SDM) and were characterized in terms of morphology, size, drug-loading coefficient, encapsulation ratio and in vitro release.

Results

The microspheres prepared by ECLM gave a drug loading (DL) of 19.4?±?2.4% and an entrapment efficiency (EE) of 80.8?±?3.2%. The microspheres prepared by SDM resulted in a DL value of 20.8?±?2.7% and an EE of 95.3?±?3.8%. The average particle size of microspheres was 7-30 μm by both methods and both preparations sustained CEQ release for 36 h in the target tissue (lungs). The in vitro release profile of the microspheres matched the Korsmeyer-Peppas release pattern. In vivo studies identified the lung as the target tissue and the region of maximum CEQ release. Histopathological examination showed a partial lung inflammation that disappeared spontaneously as the microspheres were biodegraded. In general, the formulations were safe.

Conclusion

The well-sustained CEQ release from the microspheres revealed its suitability as a drug delivery vehicle that minimized injury to healthy tissues while achieving the accumulation of therapeutic drug for lung targeting. The intravenous administration of CEQ gelatin microspheres prepared by SDM is of potential value in treating lung diseases in animals.

     

Hyaluronic Acid Layer-By-Layer (LbL) Nanoparticles for Synergistic Chemo-Phototherapy

Purpose

The aim of this study was to design hyaluronic acid (HA) layer-by-layer (LbL) nanoparticles, which carried paclitaxel (PTX) and Indocyanine green (ICG) to both tumor cells and tumor associated cells to achieve synergistic chemo-photothermal therapeutic effect.

Methods

The LbL-engineered nanoparticles (PDIH) were prepared by dopamine self-polymerization on PTX nanocrystal to form thin, surface-adherent polydopamine (PDA) films, which subsequently absorbed ICG and HA. The tumor cell and tumor associated cell targeting and antitumor efficacy of PDIH were investigated both in vitro an in vivo using 4 T1 murine mammary cancer cell lines and mice bearing orthotopic 4 T1 breast tumor.

Results

PDIH presented a long-rod shape in TEM and showed enhanced photothermal effect and cytotoxicity upon NIR laser irradiation both in vitro and in vivo. PDIH also displayed high target ability to CD44 overexpressed tumor cells and tumor associated cells mediated by HA. In vivo antitumor study indicated that PDIH therapeutic strategy could achieve remarkable antitumor efficacy.

Conclusion

PDIH showed excellent tumor-targeting property and chemo-photothermal therapeutic efficacy.

     

Evaluations of the Effect of Sodium Metabisulphite on the Stability and Dissolution Rates of Various Model Drugs from the Extended Release Polyethylene Oxide Matrices

Purpose

This study examines the effect of sodium metabisulphite (SMB) as an antioxidant on the stability and release of various model drugs, namely, propranolol HCl, theophylline and zonisamide from the polyethylene oxide (PEO) tablets. The antioxidant was used to minimise degradation and instability of the manufactured tablets when stored at 40 °C (55 ± 5% RH) over 8 weeks.

Method

Multiple batches of tablets weighing 240 mg (50% w/w) with a ratio of 1:1 drug/polymer and 1% (w/w) sodium metabisulphite containing different model drugs and various molecular weights of PEO 750 and 303 were produced.

Results

The results indicated that the use of sodium metabisulphite marginally assisted in reducing drug release and degradation via oxidation in propranolol HCl tablets containing both PEO 750 and 303. In the case of poorly and semi-soluble drugs (zonisamide and theophylline), the formulations with both PEO showed entirely superimposable phenomenon and different release profiles compared to control samples (matrices without SMB). DSC study demonstrated the modifications of the polymer due to degradation and observed the effect of SMB on the thermal degradation of the PEO matrices.

Conclusion

The use of antioxidant has assisted in retaining the stability of the manufactured tablets with different model drugs especially those with the highly soluble drug that are susceptible to rapid degradation. This has been reflected by an extended release profile of various drugs used at various stages of the storage time up to 8 weeks.

     

Pharmacokinetic/Pharmacodynamic Relationship of Gabapentin in a CFA-induced Inflammatory Hyperalgesia Rat Model

Purpose

Gabapentin displays non-linear drug disposition, which complicates dosing for optimal therapeutic effect. Thus, the current study was performed to elucidate the pharmacokinetic/pharmacodynamic (PKPD) relationship of gabapentin’s effect on mechanical hypersensitivity in a rat model of CFA-induced inflammatory hyperalgesia.

Methods

A semi-mechanistic population-based PKPD model was developed using nonlinear mixed-effects modelling, based on gabapentin plasma and brain extracellular fluid (ECF) time-concentration data and measurements of CFA-evoked mechanical hyperalgesia following administration of a range of gabapentin doses (oral and intravenous).

Results

The plasma/brain ECF concentration-time profiles of gabapentin were adequately described with a two-compartment plasma model with saturable intestinal absorption rate (K _m ?=?44.1 mg/kg, V _max ?=?41.9 mg/h?kg) and dose-dependent oral bioavailability linked to brain ECF concentration through a transit compartment. Brain ECF concentration was directly linked to a sigmoid E _max function describing reversal of hyperalgesia (EC _{50, plasma} ?=?16.7 μg/mL, EC _{50, brain} ?=?3.3 μg/mL).

Conclusions

The proposed semi-mechanistic population-based PKPD model provides further knowledge into the understanding of gabapentin’s non-linear pharmacokinetics and the link between plasma/brain disposition and anti-hyperalgesic effects. The model suggests that intestinal absorption is the primary source of non-linearity and that the investigated rat model provides reasonable predictions of clinically effective plasma concentrations for gabapentin.

     

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.

     

A randomized double-blind placebo-controlled trial of a multi-strain probiotic in treatment of symptomatic uncomplicated diverticular disease

Background

Diverticular disease is a significant burden on healthcare systems that is managed, surgically or medically, mainly as an emergency or acute condition. There are no standardized treatment recommendations for symptomatic uncomplicated disease. We hypothesized that a probiotic would reduce abdominal pain in such patients.

Methods

We conducted a single-center, double-blind, placebo-controlled trial of probiotic treatment (Symprove) in adult patients with moderate-to-severe chronic, non-acute symptomatic diverticular disease. 143 patients were randomized to receive 1 mL/kg/day of probiotic liquid (N = 72) or placebo (N = 71) daily for 3 months. The primary endpoint was abdominal pain severity. Secondary endpoints consisted of the change in the frequency of eight abdominal symptoms and the level of intestinal inflammation (fecal calprotectin).

Results

120 patients completed the trial. Abdominal pain score, the primary end point, decreased in both groups, but no significant difference between the groups was found (P = 0.11). In relation to placebo, the probiotic significantly decreased the frequency of four of the eight secondary endpoints: constipation, diarrhea, mucorrhea, and back pain (P < 0.04). No significant differences were found in frequency of abdominal pain, PR bleeding, dysuria, and bloating.

Conclusions

Multi-strain liquid probiotic did not improve abdominal pain scores significantly, but significantly improved the frequency of four other symptoms associated with chronic, non-acute symptomatic diverticular disease.

     

Real-Time UV Imaging of Nicotine Release from Transdermal Patch

Purpose

This study was conducted to characterize UV imaging as a platform for performing in vitro release studies using Nicorette® nicotine patches as a model drug delivery system.

Methods

The rate of nicotine release from 2 mm diameter patch samples (Nicorette®) into 0.067 M phosphate buffer, pH 7.40, was studied by UV imaging (Actipix SDI300 dissolution imaging system) at 254 nm. The release rates were compared to those obtained using the paddle-over-disk method.

Results

Calibration curves were successfully established which allowed temporally and spatially resolved quantification of nicotine. Release profiles obtained from UV imaging were in qualitative agreement with results from the paddle-over-disk release method.

Conclusion

Visualization as well as quantification of nicotine concentration gradients was achieved by UV imaging in real time. UV imaging has the potential to become an important technology platform for conducting in vitro drug release studies.