Low Drug Levels Research Articles

Development of a dietary formulation of the SHetA2 chemoprevention drug for mice

SummaryDevelopment of cancer chemoprevention compounds requires enhanced consideration for toxicity and route of administration because the target population is healthy. The small molecule drug, SHetA2 (NSC 726189), exhibited in vivo chemoprevention activity and lack of toxicity when administered by oral gavage. Our objective was to determine if a dietary formulation of SHetA2 could achieve effective tissue drug levels without toxicity. C57bl/6 J mice were monitored on modified American Institute of Nutrition (AIN)76A diet mixed with SHetA2 in a 3:1 ratio with Kolliphor HS15, a self-emulsifying drug delivery system (SEDDS) to deliver 37.5, 62.5, 125, 187 or 250 mg SHetA2/kg/day. Blood and tissues were evaluated after 1, 3 and 6 weeks. The 187 mg/kg/day dose was identified as optimal based on achievement of maximum blood and tissue drug levels in the effective micromolar range without evidence of toxicity. The 250 mg/kg/day group exhibited lower drug levels and the highest intestinal drug content suggesting that an upper limit of intestinal absorption had been surpassed. Only this highest dose resulted in liver and kidney function tests that were outside of the normal range, and significant reduction of cyclin D1 protein in normal cervical tissue. SHetA2 reduced cyclin D1 to greater extents in cancer compared to non-cancer cell cultures. Given this differential effect, optimal chemoprevention without toxicity would be expected to occur at doses that reduced cyclin D1 in neoplastic, but not in normal tissues. These findings support further development of SHetA2 as a chemoprevention agent and potential food additive.

Comparison of the ecarin chromogenic assay and diluted thrombin time for quantification of dabigatran concentrations

Background Although routine coagulation monitoring is unnecessary, measuring plasma dabigatran concentrations can be useful for detecting drug accumulation in renal failure or overdose, assessing the contribution of dabigatran to serious bleeding, planning the timing of urgent surgery or intervention, or determining the suitability for thrombolytic therapy for acute ischemic stroke. Dabigatran concentrations can be quantified using chromogenic or clot-based tests, such as the ecarin chromogenic assay (ECA) and the diluted thrombin time (dTT), respectively. Objective The purpose of this study was to compare the results of these assays with dabigatran concentrations measured by the reference standard of mass spectrometry in samples from 50 dabigatran-treated patients collected at peak and trough after at least 4 months of drug intake. Methods Drug levels measured with either the STA Ecarin Chromogenic Assay-II (STA-ECA-II) or dTT were linearly correlated with those determined by mass spectrometry over a wide range of concentrations. Results and Conclusions For detection of levels below 50 ng mL-1 both tests have specificities of at least 96%, suggesting that they accurately detect even low levels of drug. Therefore, regardless of whether a chromogenic or clot-based platform is preferred, the STA-ECA-II and dTT are useful tests for measuring dabigatran concentrations. Unfortunately, neither test is licensed by the United States Food and Drug Administration. Although approved in other jurisdictions, the dTT and STA-ECA-II are not widely or rapidly available in most hospitals. Therefore, cooperation between regulators and hospitals is urgently needed to render these tests readily available to inform patient care.

Tissue Drug Concentrations of Anti-tumor Necrosis Factor Agents Are Associated with the Long-term Outcome of Patients with Crohn's Disease.

Many reports indicate that a high-serum trough level of anti-tumor necrosis factor (TNF) agents is required for sustained remission in patients with Crohn's disease The pharmacokinetics of anti-TNF agents in inflamed intestinal tissue, however, is not well investigated. We investigated the association between the tissue concentration of anti-TNF agents and long-term disease outcome. This was a prospective single-center study that enrolled 25 patients with Crohn's disease who were administered infliximab or adalimumab. All participants underwent endoscopy 2 weeks after administration of the anti-TNF agents, and biopsy samples were obtained from both inflamed and noninflamed intestinal tissue. Tissue concentrations of anti-TNF agents were evaluated and the correlation with serum trough levels was compared. The relation between the tissue drug concentration and clinical course over 24 months was also investigated. Concentrations of anti-TNF agents were significantly higher in inflamed tissue than in noninflamed tissue. Patients with high-serum trough concentrations of anti-TNF agents had significantly higher drug levels in the noninflamed tissue than those with low-serum trough concentrations, but no difference in the levels was detected in the inflamed tissue. Patients with high-drug levels in the noninflamed tissue had a significantly higher sustained response rate than patients with low-drug levels. Concentrations of anti-TNF agents in the noninflamed tissue can reflect sustained remission and may be a useful biomarker for monitoring therapeutic intensity in patients with Crohn's disease treated with anti-TNF agents (see Video Abstract, Supplemental Digital Content 1, http://links.lww.com/IBD/B623).

Lipid Based Nanoparticles as Inherent Reversing Agents of Multidrug Resistance in Cancer.

Multidrug resistance in cancer is the ability of a cancer cell to resist treatment with a wide range of structurally and functionally dissimilar chemotherapeutics. The resistant phenotype could arise in response to several cellular changes that ultimately result in a decrease in intracellular drug accumulation (or effectiveness), either by limiting cellular drug entry, or by expulsion of those molecules that have made it into the cell. Both blocking drug cellular entry and its expulsion are mostly brought about by the cell membrane. Several pharmaceutical excipients (mainly lipids, surfactants and amphililc copolymers) have been reported to reverse multidrug resistance by addressing cell membrane related changes resulting in low intracellular drug levels in resistant cells. These excipients are routinely used in the preparation of lipid based nanoparticles endowing inherent multidrug resistance reversing properties to these nanoparticles. In this review, cell membrane alterations resulting in multidrug resistance will be initially reviewed, followed by a discussion of the different types of lipid NPs and the potential held by the excipients used in their preparation in multidrug resistance reversal. Finally, a discussion on how lipid nanoparticles have been engineered and used in different occasions to enable multidrug resistance reversal is included. The superior role held by lipid nanoparticles in comparison to free excipients will be highlighted.

High titers of both rheumatoid factor and anti-CCP antibodies at baseline in patients with rheumatoid arthritis are associated with increased circulating baseline TNF level, low drug levels, and reduced clinical responses: a post hoc analysis of the RISING study

BackgroundAlthough both rheumatoid factor (RF) and anticyclic citrullinated peptide antibodies (anti-CCP) are useful for diagnosing rheumatoid arthritis (RA), the impact of these autoantibodies on the efficacy of tumor necrosis factor (TNF) inhibitors has been controversial. The aim of this post hoc analysis of a randomized double-blind study (the RISING study) was to investigate the influences of RF and anti-CCP on the clinical response to infliximab in patients with RA.MethodsMethotrexate-refractory patients with RA received 3 mg/kg of infliximab from weeks 0 to 6 and then 3, 6, or 10 mg/kg every 8 weeks from weeks 14 to 46. In this post hoc analysis, patients were stratified into three classes on the basis of baseline RF/anti-CCP titers: “low/low-C” (RF < 55 IU/ml, anti-CCP < 42 U/ml), “high/high-C” (RF ≥ 160 IU/ml, anti-CCP ≥ 100 U/ml), and “middle-C” (neither low/low-C nor high/high-C). Baseline plasma TNF level, serum infliximab level, and disease activity were compared between the three classes.ResultsBaseline RF and anti-CCP titers showed significant correlations with baseline TNF and infliximab levels in weeks 2–14. Comparison of the three classes showed that baseline TNF level was lowest in the low/low-C group and highest in the high/high-C group (median 0.73 versus 1.15 pg/ml), that infliximab levels at week 14 were highest in the low/low-C group and lowest in the high/high-C group (median 1.0 versus 0.1 μg/ml), and that Disease Activity Score in 28 joints based on C-reactive protein at week 14 was lowest in the low/low-C group and highest in the high/high-C group (median 3.17 versus 3.82). A similar correlation was observed at week 54 in the 3 mg/kg dosing group, but not in the 6 or 10 mg/kg group. Significant decreases in both RF and anti-CCP were observed during infliximab treatment.ConclusionsRF/anti-CCP titers correlated with TNF level. This might explain the association of RF/anti-CCP with infliximab level and clinical response in patients with RA. Baseline RF/anti-CCP titers may serve as indices that aid infliximab treatment.Trial registrationClinicalTrials.gov, NCT00691028. Retrospectively registered on 3 June 2008.

Drug-Level Monitoring on Admission for Presurgical Epilepsy Evaluation

Objective: Evaluation for surgical treatment is offered to patients who do not respond to antiepileptic drugs. Pseudo-pharmacoresistance (PPR) has been described in the context of impaired compliance, incorrect diagnosis of epilepsy or pharmacological interference resulting in too low blood levels. We were interested to determine the frequency and causes of PPR in patients admitted for presurgical evaluation. Methods: We reviewed 553 drug levels in 199 patients and analyzed the relative frequency of drugs below reference range (10 and 20% below the range). Results: Patients who had at least one serum level below the 10% cut-off amounted to 33% and 9% of patients had at least one serum level below the 20% cut-off. Only in 2 patients (1%), this was due to poor compliance. Low levels were equally frequent in mono- or polytherapy. Drugs that were most frequently found out of range were phenytoin, valproate, and topiramate. In monotherapy, lamotrigine was often prescribed in too low dosages. Conclusion: Low drug levels are frequently observed in surgical candidates due to pharmacological interference or insufficient dosing. Poor compliance or incorrect diagnosis does not appear to be a significant concern in this patient group. Our data strengthen the need for regular drug monitoring even in advanced chronic epilepsy to avoid unnecessary health costs by too low and ineffective dosages.

Slow release of etoposide from dextran conjugation shifts etoposide activity from cytotoxicity to differentiation: A promising tool for dosage control in anticancer metronomic therapy

Drug conjugation, improving drug stability, solubility and body permanence, allows achieving impressive results in tumor control. Here, we show that conjugation may provide a straightforward method to administer drugs by the emerging anticancer metronomic approach, presently consisting of low, repeated doses of cytotoxic drugs used in traditional chemotherapy, thus reducing toxicity without reducing efficiency; however, low dose maintenance in tumor sites is difficult. We show that conjugating the antitumor drug etoposide to dextran via pH-sensitive bond produces slow releasing, apoptosis-proficient conjugates rapidly internalized into acidic lysosomes; importantly, release of active etoposide requires cell internalization and acidic pH. Conjugation, without impairing etoposide-induced complete elimination of tumor cells, shifted the mode of apoptosis from cytotoxicity- to differentiation-related; interestingly, high conjugate doses acted as low doses of free etoposide, thus mimicking the effect of metronomic therapy. This indicates slow release as a promising novel strategy for stabilizing low drug levels in metronomic regimens.

Local delivery of novel MRTF/SRF inhibitors prevents scar tissue formation in a preclinical model of fibrosis

The myocardin-related transcription factor/serum response factor (MRTF/SRF) pathway represents a promising therapeutic target to prevent fibrosis. We have tested the effects of new pharmacological inhibitors of MRTF/SRF signalling in a preclinical model of fibrosis. CCG-222740, a novel MRTF/SRF inhibitor, markedly decreased SRF reporter gene activity and showed a greater inhibitory effect on MRTF/SRF target genes than the previously described MRTF-A inhibitor CCG-203971. CCG-222740 was also five times more potent, with an IC50 of 5 μM, in a fibroblast-mediated collagen contraction assay, was less cytotoxic, and a more potent inhibitor of alpha-smooth muscle actin protein expression than CCG-203971. Local delivery of CCG-222740 and CCG-203971 in a validated and clinically relevant rabbit model of scar tissue formation after glaucoma filtration surgery increased the long-term success of the surgery by 67% (P < 0.0005) and 33% (P < 0.01), respectively, and significantly decreased fibrosis and scarring histologically. Unlike mitomycin-C, neither CCG-222740 nor CCG-203971 caused any detectable epithelial toxicity or systemic side effects with very low drug levels measured in the aqueous, vitreous, and serum. We conclude that inhibitors of MRTF/SRF-regulated gene transcription such as CCG-222740, potentially represent a new therapeutic strategy to prevent scar tissue formation in the eye and other tissues.

EFFICACY AND SAFETY OF ARTEMISININ-BASED COMBINATION THERAPIES IN PEOPLE WITH PLASMODIUM FALCIPARUM MALARIA RECEIVING ANTIRETROVIRAL THERAPY IN ZAMBIA

BackgroundThe coverage of Artemisinin-based Combination Therapies (ACTs) for treatment of malaria and antiretroviral therapy (ART) is increasing rapidly in Sub-Saharan Africa. Because of the geographical overlap in areas of high...

P436 Secondary loss of response to anti-TNF in inflammatory bowel diseases. Therapeutic drug monitoring. Utility in clinical practice

Background: Secondary loss of response (LOR) occurs in 23–46% when determined acording to dose intensification. Intensification of treatment is effective in about 60–90% of the cases and switching to non antiTNF drugs in 19–68%. Immunogenicity is not the only factor affecting anti-TNF drug clearance and efficacy. The assessment of disease activity by measuring the seric levels of anti-TNF drug levels facilitates rational decisions on management of LOR. Methods: Restrospective study in our institution in patients with ulcerative colitis (UC) or Crohn's disease (CD) with LOR and therapeutic drug monitoring from february 2015 to september 2016.The measurement of anti-TNF drug levels and anti-drugs antibodies (ADAS) levels was performed with ELISA assays drug concentration. The cut-off for drug levels in therapeutic range was 3–5 ug/mL for infliximab and 5–8 ug/mL for adalimumab. Results: A total of 42 patients were included, 32 with CD (76%) with Harvey-Bradshaw Index (HBI) >4 points and 10 patients with UC with Partial Mayo Score (PMS) >2 points with increase in C-reactive protein (PCR) or fecal calprotectin. 18 patients underwent in treatment with infliximab and 24 with adalimumab. The average time of evolution of disease was 12.6±8.77 years. The average time under biological treatment was 55.92±30.6 months. 38% had previously received another biological drug, 52% had previous intensifications and 58% received concomitant immunomodulators. 24% of patients presented levels in therapeutic range, 40% had low drug levels and absence of anti drugs antibodies (ADAS−), 10% had undetectable drug levels and positive anti drug antibodies (ADAS+), 26% of patients had high drugs level. The therapeutic strategy chosen for each group was: 15% of patients no change in treatment, 44% increase antiTNF dose or decrease infusion interval (intensification), 10% switch to another antiTNF drug, 24% switch to non anti-TNF. The clinical response (decrease of the PMS for UC ≥3 points and decrease of HBI ≥3 points for CD) was reached in 42.8% of patients and remission (PMS≤2 for CU and HBI ≤4 for CD) in 57% at the end of follow-up. The baseline CRP was associated with a baseline mean CRP of 4.12±4.98 mg/L (p=0.018). A HBI >8 and a PMS >8 allowed to identify low drug levels with accuracy AUC = 0.689 and 0.88 (p<0.0001) respectively. Conclusions: Patients with LOR frequently had low drug levels and negative anti-drug antibodies. Intensification treatment sought to be effective despite the high number of patients who previously needed an increase in the dose of their anti-TNF treatment. 26% of patients needed to switch to non anti-TNF and, in these patients, monitoring anti-TNF, drug levels might allow to change the drug prescribed in order to avoid non-effective treatments.

Compatibility study of a parenteral microdose polyethylene glycol formulation in medical devices and identification of degradation impurity by 2D-LC/MS

Polyethylene glycol (PEG) based formulation and polyvinylchloride (PVC) tubing are frequently used for drug delivery and administration. The compatibility of a parenteral drug microdose formulation in intravenous infusion (IV) devices was studied to support the clinical determination of absolute bioavailability by the microdosing method. The investigational microdose formulation containing PEG was found prone to significant loss of potency within hours of storage in the PVC IV tubing due to degradation. Degradation occurred only when both PEG and PVC tubing were present. The degradation product could not be detected by LC/MS due to the significant interference from the high concentration of PEG (4%) matrix and the extremely low level of drug (0.6ppm). To obtain structural information of the degradation impurity and understand the cause of the degradation, a simple heart-cutting 2D-LC/MS approach was utilized to effectively separate the impurity from the complex PEG oligomers and overcome the matrix interference, enabling mass spectrometric analysis of the impurity. An oxidation- dominated mechanism was proposed in which the combination of PEG auto-oxidation and dehydrochlorination of the PVC tubing yielded an oxidative environment that enhanced radical propagation and accelerated degradation of the investigational parent drug.

Residues of veterinary drugs in milk in Brazil

ABSTRACT: Veterinary drugs are used in dairy cattle management mainly for therapy and prophylaxis of diseases, which chemicals may leave residues in milk. Human exposure and the unintentional consumption of residues of drugs can lead to side effects and development of resistant bacteria, representing a considerable concern to consumer health. This paper presents the occurrence of residues of veterinary drugs in milk from 2009 to 2011 in Brazil, monitored by the Official Program for Analysis of Residues of Veterinary Drugs in Foods of Animal Origin. A total of 961 samples were collected in the retail and evaluated for the main β-lactams, tetracyclines, amphenicol, aminoglycosides, quinolones, sulfonamides and avermectins. Residues of veterinary drugs did not exceed maximum residue limit (MRL); although, there is a considerable use of critically/highly important antimicrobials and avermectins in dairy cows, especially quinolones and tetracyclines. Doxycycline (9%) and abamectin (1.6%) were detected, even though these substances are not intended to be used in milk producing animals for human consumption. Norfloxacin (15%) was observed; although, there are no MRL established, consequently, no residue level should have been detected. No residues of streptomycin, chloramphenicol and β-lactams were confirmed. Milk in Brazil contains low levels of veterinary drugs so that toxicological risk regarding milk consumption could not be considered as a public health concern. However, due to the nature of the samples, which correspond to milk from several farms, it could occur a dilution effect. The absence of MRL established for norfloxacin prevents suitable interpretation of the findings and makes tough the control of these chemical residues in food. Detection of some antimicrobials and avermectins may be linked to extra-label use or noncompliance withdrawal periods suggesting that good veterinary practices are not being followed, since residues of unauthorized drugs have been detected.

Improving Treatment Outcomes for Tuberculosis

Major issues are currently associated with Tuberculosis (TB) treatment, particularly in patients infected by Multi-drug Resistant Tuberculosis/Extensively Drug Resistant Tuberculosis (mdr-TB/XDR-TB) resistant mycobacteria. A new threat recently reported in various Asian countries is totally Drug Resistant Tuberculosis (TDR). The presence of such Mycobacterium tuberculosis strains is disturbing also for the reasons they spread beyond the continent of Asia. The currently recommended tuberculosis treatment regimen is not well received by patients due to its minimum six-month, complexity, and common adverse events. The prevalence of MDR-TB and XDR-TB are inversely correlated with the quality of TB control and the proper use of second-line anti-TB drugs. Moreover, cost is extraordinary high. Since the mid-1960s only two new anti-TB drugs, bedaquiline and delamandine, have come to market; however, these drugs are not available in many regions and are limited to severely resistant cases. Currently, new derivatives such as spectinoamide are of interest in tuberculosis treatment. In vitro results and animal studies are used to aid in drug development. There is an urgent need for treatment improvement through enhancement of existing agents. Namely, individual differences in absorption and excretion of the primary anti-TB drugs, isoniazid and rifampin, require consideration. Recently, several studies attempted to evaluate the effect of anti-TB drug concentrations on treatment outcomes. Authors showed that 50-76% of the tested patients had low concentrations of INH (Isoniazid) and RMP (Rifampin). Because Therapeutic Drug Monitoring (TMD) was performed in small numbers of selected patients with comorbidities or slow treatment responses, the studies did not clearly demonstrate the effect of low drug levels on treatment outcomes. Future coordinated research is required. New molecular tests allow for research using supervised, individualized treatment of tuberculosis. In addition, effective tuberculosis outcomes require coordinated action multiple parameters for patient detection through implementation of rapid microbiological and clinical tests as well as reliable drug resistant tests of Mycobacterium tuberculosis. This leads to a break in the chain of transmission, and prevents the spread of disease in community. Education plays in important role for patients and families concerning the causes of disease and prevention methods. Additionally, medical staff should also themselves improve the level of diseases knowledge. Behaviour changes in tuberculosis infection control among medical personnel is also required. Keep in mind that one of the reasons for the relapse of tuberculosis is its disregard.

High pre‐exposure prophylaxis uptake and early adherence among men who have sex with men and transgender women at risk for HIV Infection: the PrEP Brasil demonstration project

Introduction: The efficacy of pre-exposure prophylaxis (PrEP) in preventing sexual acquisition of human immunodeficiency virus (HIV) is well established. Little is known about the feasibility of PrEP implementation in middle-income settings with concentrated epidemics among men who have sex with men (MSM) and transgender women (TGW).Methods: PrEP Brasil is a prospective, multicentre, open-label demonstration project assessing PrEP delivery in the context of the Brazilian Public Health System. HIV-uninfected MSM and TGW in 3 referral centres in Rio de Janeiro and São Paulo were evaluated for eligibility and offered 48 weeks of daily emtricitabine/tenofovir for PrEP. Concentrations of tenofovir diphosphate in dried blood spot samples (DBS) at week 4 after enrolment (early adherence) were measured. Predictors of drug levels were assessed using ordinal logistic regression models considering the DBS drug level as a 3 level variable (<350 fmol/punch, ≥350–699 fmol/punch and ≥700 fmol/punch).Results: 1,270 individuals were assessed for participation; n = 738 were potentially eligible and n = 450 were offered PrEP (PrEP uptake was 60.9%). Eligible but not enrolled individuals were younger, had lower HIV risk perception and had lower PrEP awareness. At week 4, 424 participants (of the 450 enrolled) had DBS TFV-DP concentrations, 94.1% in the protective range (≥350 fmol/punch, consistent with ≥2 pills per week), and 78% were in the highly protective range (≥700 fmol/punch, ≥4 pills per week). Participants with ≥12 years of schooling had 1.9 times the odds (95%CI 1.10–3.29) of a higher versus lower drug level than participants with <12 years of schooling. Condomless receptive anal intercourse in the prior 3 months was also associated with higher drug levels (adjusted OR = 1.78; 95% CI 1.08–2.94).Conclusions: The high uptake and early adherence indicate that PrEP for high-risk MSM and TGW can be successfully delivered in the context of the Brazilian Public Health System. Interventions to address disparities on PrEP awareness and HIV risk perception among the younger and less educated are urgently needed in order to maximize the impact of this prevention strategy on the reduction of HIV infection among MSM and TGW in Brazil.

Permeability Profiles and Intestinal Toxicity Assessment of Hydrochlorothiazide and Its Inclusion Complex with β-Cyclodextrin Loaded into Chitosan Nanoparticles.

Here, a novel drug delivery system was developed for the hydrochlorothiazide (HCT):β-cyclodextrin (βCD) inclusion complex loaded into chitosan (CS) nanoparticles (NPs) [CS/HCT:βCD NPs]. It was found, for the first time, that exposure of the intestinal mucosa to free HCT resulted in an increased and abnormal intestinal permeability associated with several injuries to the intestinal epithelium. Nevertheless, the HCT delivery system obtained ameliorated the damage of the intestinal epithelium induced by HCT. Furthermore, we found that the corresponding permeability profiles for both the free HCT and the CS/HCT:βCD NPs were exponential and lineal, respectively. We propose that the increased intestinal uptake and severe tissue injury of HCT to the intestinal epithelium could be directly related to possible effects of this drug on the ionoregulatory Na+/K+-ATPase channel. Thus, it is postulated that the CS/HCT:βCD NPs may increase the gastrointestinal retention of the HCT, which would provide increased adherence to the mucus barrier that lines the intestinal epithelium; consequently, this would act as a slow HCT release delivery system and maintain lower drug levels of luminal gut in comparison with the administration of free HCT, leading to less severe local injury.

Novel Validated RP-HPLC Method for Bendamustine Hydrochloride Based on Ion-pair Chromatography: Application in Determining Infusion Stability and Pharmacokinetics.

Ion pair chromatography was used for quantifying bendamustine hydrochloride (BH) in its marketed vial. The permissive objective was to investigate time duration for which highly susceptible drug content of the marketed vial remained stable after reconstitution. However, the method could also be used to measure extremely low levels of drug in rat plasma and a pharmacokinetic study was accordingly conducted to further showcase method's applicability. Optimized separation was achieved on C-18 Purospher®STAR (250 mm×4.6 mm, 5 μm particle size) column. Mobile phase flowing at 1.5 mL/min consisted of 5 mM sodium salt of octane sulfonic acid dissolved in methanol, water and glacial acetic acid (55:45:0.075) maintained at pH 6. Detection was carried out at 233 nm with BH eluting after 7.8 min. Validation parameters were determined as per ICH guidelines. Limit of detection and limit of quantification were found to be 0.1 µg/mL and 0.33 µg/mL, respectively. The recoveries were 98-102% in bulk and 85-91% in plasma. The developed method was specific for BH, and utilized for assessing its short-term stability in physiologic solvents and forced degradation products in acid, base, oxidative, light and temperature induced stress environments.

Scolicidal and apoptotic activities of albendazole sulfoxide and albendazole sulfoxide-loaded PLGA-PEG as a novel nanopolymeric particle against Echinococcus granulosus protoscoleces.

Treatment failures of human cystic echinococcosis (CE) with albendazole (ABZ) have attributed to its low solubility and poor drug absorption rate, resulting in low drug level in plasma. The scolicidal effects of ABZ-loaded liposome nanoparticles have recently evaluated; however, these particles have several challenges due to their low encapsulated load. This investigation was designed to evaluate and compare in vitro apoptotic activities of ABZ sulfoxide (ABZs) and ABZs-loaded poly(lactic-co-glycolic acid) (PLGA)-PEG against protoscoleces (PSCs). ABZs-loaded PLGA-PEG was prepared by a double-emulsion method (W1/O/W2). Various concentrations of ABZs and ABZs-loaded PLGA-PEG (50, 100, 150, and 200μg/ml) were experimentally tested against PSC of CE at different exposure times (5, 10, 20, 30, and 60min). ABZs-loaded PLGA-PEG at concentrations of 150 and 200μg/ml was able to act at a 100% scolicidal rate in all exposure times (5 to 60min), while ABZs at a concentration of 200μg/ml demonstrated 94, 100, and 100% mortality rates following 20, 30, and 60min of exposure times, respectively. The messenger RNA (mRNA) expression of caspase-3 was assessed by semi-quantitative RT-PCR after 15h of exposure. Caspase-3 mRNA expression was higher in both PSC treated with ABZs and PSC treated with ABZs-loaded PLGA-PEG than that in control groups (P < 0.05). No significant difference was observed between the apoptotic intensity of PSC treated with ABZs and that of PSC treated with ABZs-loaded PLGA-PEG (P > 0.05). DNA fragmentation assay and ultrastructural changes revealed that ABZs and ABZs-loaded PLGA-PEG induced the apoptosis of PSC by activation of caspase-3. The higher permeability and scolicidal rate of ABZs-loaded PLGA-PEG can be addressed as an effectual alternative strategy to improve the treatment of human CE.

Quetiapine Carboxylic Acid and Quetiapine Sulfoxide Prevalence in Patient Urine.

Treatment adherence is often an issue with mental health patients. For those prescribed quetiapine (Seroquel®), the low levels of parent drug and plasma metabolite(s) (e.g., 7-hydroxyquetiapine) typically used in urine drug monitoring can result in false negatives with concomitant unfavorable impacts on patient care. Literature review coupled with liquid chromatography/time-of-flight mass spectrometry analysis of patient positive urine samples indicated the presence of quetiapine carboxylic acid and quetiapine sulfoxide as significant urinary metabolites of quetiapine. Analysis of these two metabolites determined that they are abundant in the urine of quetiapine patients and can result in apparent adherence rates that are improved relative to those determined using only quetiapine and 7-hydroxyquetiapine. For example, analysis of a random set of 114 patients who were prescribed quetiapine exhibited an apparent adherence rate of 47% using the quetiapine carboxylic acid and quetiapine sulfoxide metabolites. Traditional metabolite testing with quetiapine and 7-hydroxyquetiapine yielded apparent adherence rates of ~31% while all four analytes resulted in apparent adherence of 48%. The prevalence of these metabolites suggests that quetiapine urine drug testing would be more consistent with prescriptions when they are included in the analysis.

Abstract B25: The critical importance of the blood-brain barrier in modulating the response to otherwise highly effective targeted therapies in patient-derived orthotopic glioblastoma xenografts

Abstract Clinical data indicate that certain regions within glioblastoma (GBM) have a relatively intact blood-brain barrier (BBB), but controversy surrounds whether associated heterogeneous delivery may limit efficacy for otherwise highly active drugs with poor brain distribution. In this study, the efficacy of molecularly targeted therapies was compared in relevant GBM patient-derived xenograft (PDX) models grown either as heterotopic or orthotopic tumors. The impact of further disrupting BBB integrity in non-responsive orthotopic tumors was evaluated by over-expressing vascular endothelial growth factor (VEGF) and measuring drug distribution by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). The brain:plasma ratio for five targeted agents was determined by LC-MSMS and treatment efficacy was evaluated in target-relevant GBM PDX lines: erlotinib (brain:plasma = 0.02 ± 0.02; efficacy tested in GBM6), palbociclib (brain:plasma = 0.06; efficacy tested in GBM22), AZD1775 (brain:plasma = 0.05; efficacy tested in GBM22), SAR405838 (brain:plasma = 0.01 ± 0.003; efficacy tested in GBM108), and AZD4547 (brain:plasma = 0.045 ± 0.02; efficacy tested in GBM150). Each of these drugs was effective in relevant GBM PDX flank tumor models with a 27% to 218% prolongation in the median time to exceed their pre-specified endpoint compared to placebo treatment (p≤0.02 for each drug). In contrast, none of these drugs were effective in prolonging survival in the same target-relevant orthotopic tumor models (-6% to 8% extension in median survival; p&amp;gt;0.05 for each drug). Consistent with partial and heterogeneous disruption of the BBB, MALDI-MSI of erlotinib, AZD1775 or SAR405838 distribution within orthotopic tumors demonstrated highly heterogeneous drug levels with large regions within each tumor approaching the low drug levels observed within surrounding normal brain. To further evaluate whether heterogenous drug distribution in orthotopic tumors could account for poor treatment efficacy, GBM108 was transduced with lentiviral constructs encoding for VEGF or empty vector (EV). While both GBM108-sublines were readily detectable with gadolinium-enhanced magnetic resonance imaging (MRI), the GBM108-VEGF tumors had a significantly more disrupted BBB, as evidenced by a more uniform and intense distribution of a brain-impenetrant TexasRed-dextran vascular marker. Similarly, the distribution of SAR405838, measured by MALDI-MSI, was markedly higher and more uniform in the GBM108-VEGF tumors when compared to the GBM108-EV tumors. Enhanced delivery of SAR405838 into orthotopic GBM108-VEGF models translated into a marked enhancement in treatment efficacy in comparison to GBM108-EV with a median survival prolongation of 37 vs. 4 days, respectively (p=0.0055). Collectively, these data highlight the importance of testing novel therapeutic agents in orthotopic tumor models and suggest that limited brain penetration for many molecules may significantly limit their efficacy in brain tumors that have a partially intact BBB. In the face of continued failure to develop effective targeted agents for GBM, these in vivo results highlight the importance of re-evaluating the dogma in neuro-oncology that the BBB is fully disrupted in GBM and, therefore, drug delivery across the BBB is not a major factor limiting treatment efficacy. Citation Format: Jann N. Sarkaria, David Calligaris, Daniel Ma, Karen Parrish, Ann C. Mladek, Janice Laramy, Minjee Kim, Shuangling Zhang, Mark Schroeder, Brett L. Carlson, Katrina Bakken, Aaron Johnson, Nathalie Agar, William Elmquist. The critical importance of the blood-brain barrier in modulating the response to otherwise highly effective targeted therapies in patient-derived orthotopic glioblastoma xenografts. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr B25.

Towards an implantable bio-sensor platform for continuous real-time monitoring of anti-epileptic drugs.

The need of continuous real-time monitoring device for in-vivo drug level detection has been widely articulated lately. Such monitoring could guide drug posology and timing of intake, detect low or high drug levels, in order to take adequate measures, and give clinicians a valuable window into patients' health and their response to therapeutics. This paper presents a novel implantable bio-sensor based on impedance measurement capable of continuously monitoring various antiepileptic drug levels. This portable point-of-care microsystem replaces large and stationary conventional macrosystems, and is a one of a kind system designed with an array of electrodes to monitor various anti-epileptic drugs rather than one drug. The micro-system consists of (i) the front-end circuit including an inductive coil to receive energy from an external base station, and to exchange data with the latter; (ii) the power management block; (iii) the readout and control block; and (iv) the biosensor array. The electrical circuitry was designed using the 0.18-um CMOS process technology intended to be miniature and consume ultra-low power.