Search results for "Drug concentration"

Identification of chemosensitizers by drug repurposing to enhance the efficacy of cancer therapy

2020

Abstract The progressively rising drug resistance has driven the development of chemosensitizers, which aim to enhance the current chemotherapeutic efficacy through either quantitatively increasing intracellular drug concentration by inhibiting drug efflux, vesicle sequestration, and metabolic inactivation or qualitatively exerting concomitant effects on cellular regulation to promote apoptosis. Given the high failure rates and costs during standard drug development, drug repurposing represents an effective and economic approach for chemosensitizer identification. By applying drug repurposing, a wide range of existing clinic drugs including anticardiovascular agents, immunosuppressants, ant…

Unraveling the behavior of oral drug products inside the human gastrointestinal tract using the aspiration technique: History, methodology and applic…

2020

Fluid sampling from the gastrointestinal (GI) tract has been applied as a valuable tool to gain more insight into the fluids present in the human GI tract and to explore the dynamic interplay of drug release, dissolution, precipitation and absorption after drug product administration to healthy subjects. In the last twenty years, collaborative initiatives have led to a plethora of clinical aspiration studies that aimed to unravel the luminal drug behavior of an orally administered drug product. The obtained drug concentration-time profiles from different segments in the GI tract were a valuable source of information to optimize and/or validate predictive in vitro and in silico tools, freque…

Variability in protein binding of teicoplanin and achievement of therapeutic drug monitoring targets in critically ill patients: Lessons from the DAL…

2014

The aims of this study were to describe the variability in protein binding of teicoplanin in critically ill patients as well as the number of patients achieving therapeutic target concentrations. This report is part of the multinational pharmacokinetic DALI Study. Patients were sampled on a single day, with blood samples taken both at the midpoint and the end of the dosing interval. Total and unbound teicoplanin concentrations were assayed using validated chromatographic methods. The lower therapeutic range of teicoplanin was defined as total trough concentrations from 10 to 20 mg/L and the higher range as 10-30 mg/L. Thirteen critically ill patients were available for analysis. The followi…

Stability of opiates in hair fibers after exposure to cosmetic treatment.

1996

Abstract The stability of opiates in clipped natural human hair was investigated. Hair fibers were incubated with defined solutions of morphine, codeine and dihydrocodeine (pH 7.4) until saturated. Original opiate-positive hair samples collected from drug addicts also were examined. Commercially available bleaching as well as perming formulas (Poly Blonde Ultra®, Poly Lock®; Henkel, Dusseldorf, Germany) were applied in vitro to the hair strands of both groups under investigation. After these treatments, the drug concentration had decreased for both bleaching and permanent waving. In the spiked hair, only 2–18% of the starting solution could be found after bleaching. About 20–30% of the drug…

Kinetics and state-dependent effects of verapamil on cardiac L-type calcium channels.

1996

The voltage dependence and the kinetics of block by verapamil of L-type calcium current (ICa) were investigated in ventricular myocytes from rat hearts using the whole-cell patch-clamp technique. ICa was elicited repetitively in response to depolarizing voltage pulses from -80 mV to 0 mV at different pulse intervals and durations. Verapamil reduced the magnitude of ICa in a frequency-dependent manner without tonic component. The time course of ICa remained unchanged suggesting that not open but inactivated channels were affected by the drug. The interaction of verapamil with inactivated channels was investigated by the application of twin pulses. In the presence of verapamil, the duration o…

Human Drug Pollution in the Aquatic System: The Biochemical Responses of Danio rerio Adults

2021

Simple Summary The release of medicinal products for human use in the aquatic environment is now a serious problem, and can be fatal for the organisms that live there. Danio rerio is a freshwater fish that provides the possibility to study the effects of these pollutants on the health of aquatic organisms. The results of the various existing scientific studies are scarce and conflicting. Here, we review the scientific studies that have analyzed these effects, highlighting that the impacts of drugs are evident in the biochemical responses of these animals. Abstract To date, drug pollution in aquatic systems is an urgent issue, and Danio rerio is a model organism to study the toxicological ef…

Blocking of an ion channel by a highly charged drug: Modeling the effects of applied voltage, electrolyte concentration, and drug concentration

2005

We present a simple physical model to estimate the blocked pore probability of an ion channel that can be blocked by a highly charged drug in solution. The model is inspired by recent experimental work on the blocking of the ${\mathrm{PA}}_{63}$ channel, involved in the anthrax toxin infection, by a highly charged drug [Karginov et al. PNAS 102, 15075 (2005)]. The drug binding to the pore is highly specific but the strong dependence of blocking on the applied voltage and electrolyte concentration suggests that long range electrostatic interactions are important. Since basic electrostatic concepts rather than detailed molecular models are considered, the microscopic details of the channel bl…

Correlation between a marker of oxidative stress and few indexes of endothelial dysfunction in essential hypertensive patients

2005

Effect of comprehensive vasodilation vs usual care on mortality and heart failure rehospitalization in women with acute heart failure

2020

Abstract Background Guidelines recommend evaluating the risk/benefit ratio of novel therapies individually in women and men, as the pathophysiology and the response to treatment may differ between women and men. Among patients with acute heart failure (AHF), a strategy of intensive vasodilation, compared with usual care, overall did provide comparable outcomes. Purpose To evaluate the effect of a strategy that emphasized early intensive and sustained vasodilation in women with AHF. Methods In a randomized, open-label blinded-end-point trial patients hospitalized for AHF were enrolled in 10 hospitals in Switzerland, Bulgaria, Germany, Brazil, and Spain. Inclusion criteria were AHF expressed …

A hyaluronic acid/cyclodextrin based injectable hydrogel for local doxorubicin delivery to solid tumors

2020

Localized delivery of anticancer drugs is often the most useful therapeutic approach for the treatment of solid tumors. The use of injectable polymeric systems that maximize drug concentration in the proximal area of the tumor represents an extremely advantageous therapeutic strategy. Here, the development of an injectable in situ forming hydrogel was accomplished by exploiting the azo-type Michael reaction between an amine derivative of hyaluronic and vinylsulfone functionalized -cyclodextrins complexing doxorubicin. This injectable system can be easily prepared and administered with timelines compatible with normal operating room procedures, as demonstrated by rheological tests. In vitro…