Metabolomics reveals novel biomarkers of illegal 5-nitromimidazole treatment in pigs. Further evidence of drug toxicity uncovered

The aim of the study was to investigate the potential of a metabolomics platform to distinguish between pigs treated with ronidazole, dimetridazole and metronidazole and non-medicated animals (controls), at two withdrawal periods (day 0 and 5). Livers from each animal were biochemically profiled using UHPLC–QTof-MS in ESI+ mode of acquisition. Several Orthogonal Partial Least Squares-Discriminant Analysis models were generated from the acquired mass spectrometry data. The models classified the two groups control and treated animals. A total of 42 ions of interest explained the variation in ESI+. It was possible to find the identity of 3 of the ions and to positively classify 4 of the ionic features, which can be used as potential biomarkers of illicit 5-nitroimidazole abuse. Further evidence of the toxic mechanisms of 5-nitroimidazole drugs has been revealed, which may be of substantial importance as metronidazole is widely used in human medicine.

Home medication management practices and associated factors among patients with selected chronic diseases in a community pharmacy in Uganda

ABSTRACT: BACKGROUND: Chronic diseases are rapidly increasing and are currently the major cause of death and disability worldwide. Patients with chronic diseases experience many challenges including medicine-related problems. However, there is limited information about the home management of medicines among these patients. This study therefore was to determine home medication management practices and associated factors among patients with chronic diseases seeking care in a community pharmacy in Uganda. METHODS: A cross-sectional study was conducted in a community pharmacy in Kampala from June to July 2010. A total of 207 consenting chronic disease patients or caregivers of children with chronic disease were consecutively sampled. The patients were visited at home to evaluate their drug management practices and to check their medical forms for disease types and drugs prescribed. An interviewer-administered questionnaire and an observation checklist were used to collect the data. RESULTS: Overall home medication management was inappropriate for 70% (n = 145) of the participants (95% CI = 63.3-76.2) and was associated with perceived severity of disease (not severe OR =0.40, moderately severe OR = 0.35), duration of disease >5 years (OR = 2.15), and health worker not assessing for response to treatment (OR = 2.53). About 52% (n = 107) had inappropriate storage which was associated with inadequate information about the disease (OR = 2.39) and distance to the health facility >5 kilometres (OR = 2.82). Fifteen percent (n = 31) had no drug administration schedule and this was associated with increasing age (OR = 0.97), inadequate information about the disease (OR = 2.96), and missing last appointment for medical review (OR = 6.55). About 9% (n = 18) had actual medication duplication; 1.4% (n = 3) had expired medicines; while 18.4% (n = 38) had drug hoarding associated with increasing number of prescribers (OR = 1.34) and duration of disease (OR = 2.06). About 51% (n = 105) had multiple prescribers associated with perceiving the disease to be non severe (OR = 0.27), and having more than one chronic disease (OR = 2.37). CONCLUSIONS: Patients with chronic disease have poor home management of medicines. In order to limit the occurrence of poor outcomes of treatment or drug toxicity, health providers need to strengthen the education of patients with chronic disease on how to handle their medicines at home.

Limbal stem cell deficiency:Concept, aetiology, clinical presentation, diagnosis and management

Defects in renewal and repair of ocular surface as a result of limbal stem cell deficiency are now known to cause varying ocular, surface morbidity including persistent photophobia, repeated and persistent surface breakdown and overt conjunctivalisation of the cornea. Ocular conditions with abnormalities of ocular surface repair include pterygium, limbal tumours, aniridia, severe scarring following burns, cicatricial pemphigoid and Stevens-Johnson Syndrome, sequelae of mustard gas exposure and Herpes simplex epithelial disease, radiation keratopathy, contact lens induced keratopathy, neuroparalytic keratitis and drug toxicity. Restoring ocular health in these eyes has traditionally been frustrating. An understanding of these intricate cell renewal and maintenance processes has spurred the evolution in recent years of new treatment methods for several blinding diseases of the anterior segment; many more exciting modalities are in the offing. However, there is inadequate awareness among ophthalmologists about the current principles of management of ocular surface disorders. The purpose of this article is to help elucidate the important principles and current treatment methods relevant to ocular surface disorders.

Dried blood spot liquid chromatography assay for therapeutic drug monitoring of metformin

The use of blood spot collection cards is a simple way to obtain specimens for analysis of drugs for the purpose of therapeutic drug monitoring, assessing adherence to medications and preventing toxicity in routine clinical setting. We describe the development and validation of a microanalytical technique for the determination of metformin from dried blood spots. The method is based on reversed phase high-performance liquid chromatography with ultraviolet detection. Drug recovery in the developed method was found to be more than 84%. The limits of detection and quantification were calculated to be to be 90 and 150 ng/ml, respectively. The intraday and interday precision (measured by CV%) was always less than 9%. The accuracy (measured by relative error, %) was always less than 12%. Stability analysis showed that metformin is stable for at least 2 months when stored at -70 degrees C. The small volume of blood required (10 mu L), combined with the simplicity of the analytical technique makes this a useful procedure for monitoring metformin concentrations in routine clinical settings. The method is currently being applied to the analysis of blood spots taken from diabetic patients to assess adherence to medications and relationship between metformin level and metabolic control of diabetes. (c) 2006 Elsevier B.V. All rights reserved.

Nitric oxide synthase gene therapy enhances the toxicity of cisplatin in cancer cells

BACKGROUND AIMS: Cell-based gene therapy is an alternative to viral and non-viral gene therapy. Emerging evidence suggests that mesenchymal stem cells (MSC) are able to migrate to sites of tissue injury and have immunosuppressive properties that may be useful in targeted gene therapy for sustained specific tissue engraftment. METHODS: In this study, we injected intravenously (i.v.) 1x10(6) MSC, isolated from green fluorescent protein (GFP) transgenic rats, into Rif-1 fibrosarcoma-bearing C3H/HeN mice. The MSC had been infected using a lentiviral vector to express stably the luciferase reporter gene (MSC-GFP-luci). An in vivo imaging system (IVIS 200) and Western blotting techniques were used to detect the distribution of MSC-GFP-luci in tumor-bearing animals. RESULTS: We observed that xenogenic MSC selectively migrated to the tumor site, proliferated and expressed the exogenous gene in subcutaneous fibrosarcoma transplants. No MSC distribution was detected in other organs, such as the liver, spleen, colon and kidney. We further showed that the FGF2/FGFR pathways may play a role in the directional movement of MSC to the Rif-1 fibrosarcoma. We performed in vitro co-culture and in vivo tumor growth analysis, showing that MSC did not affect the proliferation of Rif-1 cells and fibrosarcoma growth compared with an untreated control group. Finally, we demonstrated that the xenogenic MSC stably expressing inducible nitric oxide synthase (iNOS) protein transferred by a lentivirus-based system had a significant inhibitory effect on the growth of Rif-1 tumors compared with MSC alone and the non-treatment control group. CONCLUSIONS: iNOS delivered by genetically modified iNOS-MSC showed a significant anti-tumor effect both in vitro and in vivo. MSC may be used as a target gene delivery vehicle for the treatment of fibrosarcoma and other tumors

Digoxin toxicity in the aged. Characterising and avoiding the problem

Digoxin is one of the most frequently prescribed drugs, particularly in the elderly population where there is an increased prevalence of atrial fibrillation and cardiac failure. The drug has a narrow therapeutic range and has gained a reputation for producing adverse effects in older patients. The more frail elderly patients with coexistent disease, often taking other treatments, are more at risk from digoxin toxicity due to inappropriate dosing, noncompliance, or increased sensitivity to digoxin resulting from pharmacokinetic or pharmacodynamic interactions. Application of basic pharmacological principles may be helpful in anticipating these problems. Elderly patients more commonly receive digoxin than younger patients, which in part accounts for the higher rates of toxicity in this group. Numerous components contribute to the development of toxicity, and diagnosis of toxicity is difficult in this age group. The measurement of serum concentrations can contribute to the clinical diagnosis. A major problem is the accurate diagnosis of digoxin toxicity which may have numerous nonspecific clinical manifestations, many of which are related to coexisting disease in elderly patients. This diagnostic imprecision is well recognised but has been helped by the introduction of serum digoxin measurement. However, reliance on serum concentrations should not replace clinical judgement, since these do not always correlate with toxicity. The apparently decreasing incidence of toxicity over recent years probably reflects several factors: the improvement in digoxin formulations, awareness of digoxin pharmacology, utilisation of serum concentrations, and the realisation that digoxin withdrawal is a viable proposition in elderly patients. Greater knowledge about the causes and prevention of digoxin toxicity should further reduce the morbidity and mortality arising from digoxin overdose, especially in the elderly population.

Toxicity of non-steroidal anti-inflammatory drugs to Gyps vultures:a new threat from ketoprofen

Three Gyps vulture species are on the brink of extinction in South Asia owing to the veterinary non-steroidal anti-inflammatory drug (NSAID) diclofenac. Carcasses of domesticated ungulates are the main food source for Asia's vultures and birds die from kidney failure after consuming diclofenac-contaminated tissues. Here, we report on the safety testing of the NSAID ketoprofen, which was not reported to cause mortality in clinical treatment of scavenging birds and is rapidly eliminated from livestock tissues. Safety testing was undertaken using captive non-releasable Cape griffon vultures (Gyps coprotheres) and wild-caught African white-backed vultures (G. africanus), both previously identified as susceptible to diclofenac and suitable surrogates. Ketoprofen doses ranged from 0.5 to 5 mg kg(-1) vulture body weight, based upon recommended veterinary guidelines and maximum levels of exposure for wild vultures (estimated as 1.54 mg kg(-1)). Doses were administered by oral gavage or through feeding tissues from cattle dosed with ketoprofen at 6 mg kg(-1) cattle body weight, before slaughter. Mortalities occurred at dose levels of 1.5 and 5 mg kg(-1) vulture body weight (within the range recommended for clinical treatment) with the same clinical signs as observed for diclofenac. Surveys of livestock carcasses in India indicate that toxic levels of residual ketoprofen are already present in vulture food supplies. Consequently, we strongly recommend that ketoprofen is not used for veterinary treatment of livestock in Asia and in other regions of the world where vultures access livestock carcasses. The only alternative to diclofenac that should be promoted as safe for vultures is the NSAID meloxicam.

Apparent tolerance of turkey vultures (Cathartes aura) to the non-steroidal anti-inflammatory drug diclofenac

The nonsteroidal anti-inflammatory drug diclofenac is extremely toxic to Old World Gyps vultures (median lethal dose -0.1-0.2 mg/kg), evoking visceral gout, renal necrosis, and mortality within a few days of exposure. Unintentional secondary poisoning of vultures that fed upon carcasses of diclofenac-treated livestock decimated populations in the Indian subcontinent. Because of the widespread use of diclofenac and other cyclooxygenase-2 inhibiting drugs, a toxicological study was undertaken in turkey vultures (Cathartes aura) as an initial step in examining sensitivity of New World scavenging birds. Two trials were conducted entailing oral gavage of diclofenac at doses ranging from 0.08 to 25 mg/kg body weight. Birds were observed for 7 d, blood samples were collected for plasma chemistry (predose and 12, 24, and 48 h and 7 d postdose), and select individuals were necropsied. Diclofenac failed to evoke overt signs of toxicity, visceral gout, renal necrosis, or elevate plasma uric acid at concentrations greater than 100 times the estimated median lethal dose reported for Gyps vultures. For turkey vultures receiving 8 or 25 mg/kg, the plasma half-life of diclofenac was estimated to be 6 h, and it was apparently cleared after several days as no residues were detectable in liver or kidney at necropsy. Differential sensitivity among avian species is a hallmark of cyclooxygenase-2 inhibitors, and despite the tolerance of turkey vultures to diclofenac, additional studies in related scavenging species seem warranted.

Toxicity of diclofenac to Gyps vultures

Three endemic vulture species Gyps bengalensis, Gyps indicus and Gyps tenuirostris are critically endangered following dramatic declines in South Asia resulting from exposure to diclofenac, a veterinary drug present in the livestock carcasses that they scavenge. Diclofenac is widely used globally and could present a risk to Gyps species from other regions. In this study, we test the toxicity of diclofenac to a Eurasian (Gyps fulvus) and an African (Gyps africanus) species, neither of which is threatened. A dose of 0.8 mg kg(-1) of diclofenac was highly toxic to both species, indicating that they are at least as sensitive to diclofenac as G. bengalensis, for which we estimate an LD50 of 0.1-0.2 mg kg(-1). We suggest that diclofenac is likely to be toxic to all eight Gyps species, and that G. africanus, which is phylogenetically close to G. bengalensis, would be a suitable surrogate for the safety testing of alternative drugs to diclofenac.

Graphene Nanoribbons as a Drug Delivery Agent for Lucanthone Mediated Therapy of Glioblastoma Multiforme

We report use of PEG-DSPE coated oxidized graphene nanoribbons (O-GNR-PEG-DSPE) as agent for delivery of anti-tumor drug Lucanthone (Luc) into Glioblastoma Multiformae (GBM) cells targeting base excision repair enzyme APE-1 (Apurinic endonuclease-1). Lucanthone, an endonuclease inhibitor of APE-1, was loaded onto O-GNR-PEG-DSPEs using a simple non-covalent method. We found its uptake by GBM cell line U251 exceeding 67% and 60% in APE-1-overexpressing U251, post 24 h. However, their uptake was ~ 38% and 29% by MCF-7 and rat glial progenitor cells (CG-4), respectively. TEM analysis of U251 showed large aggregates of O-GNR-PEG-DSPE in vesicles. Luc-O-GNR-PEG-DSPE was significantly toxic to U251 but showed little/no toxicity when exposed to MCF-7/CG-4 cells. This differential uptake effect can be exploited to use O-GNR-PEG-DSPEs as a vehicle for Luc delivery to GBM, while reducing nonspecific cytotoxicity to the surrounding healthy tissue. Cell death in U251 was necrotic, probably due to oxidative degradation of APE-1.

Graphical abstract

We used O-GNR-PEG-DSPE as a reliable, non-toxic vehicle for delivery of APE-1 inhibiting Lucanthone into GBM tumor cell lines. LUC-O-GNR-PEG-DSPE particles showed 60% or more uptake by CMV/U251 and A1-5/CMV/U251 where as the uptake by MCF7 and normal CG4 glial cells was much lower (38% and 29% respectively). Different concentrations of Luc (5–80 μM) loaded onto O-GNR-PEG-DSPE showed lower toxicity in the exposed cells compared to the free drug, due to possible slow release of the drug from this particle, which ensures minimum non-specific release of the drug from the particle once it is injected in vivo.
http://ars.els-cdn.com/content/image/1-s2.0-S1549963414004249-fx1.jpg

Nanoencapsulation of ABT-737 and camptothecin enhances their clinical potential through synergistic antitumor effects and reduction of systemic toxicity

The simultaneous delivery of multiple cancer drugs in combination therapies to achieve optimal therapeutic effects in patients can be challenging. This study investigated whether co-encapsulation of the BH3-mimetic ABT-737 and the topoisomerase I inhibitor camptothecin (CPT) in PEGylated polymeric nanoparticles (NPs) was a viable strategy for overcoming their clinical limitations and to deliver both compounds at optimal ratios. We found that thrombocytopenia induced by exposure to ABT-737 was diminished through its encapsulation in NPs. Similarly, CPT-associated leukopenia and gastrointestinal toxicity were reduced compared with the administration of free CPT. In addition to the reduction of dose-limiting side effects, the co-encapsulation of both anticancer compounds in a single NP produced synergistic induction of apoptosis in both in vitro and in vivo colorectal cancer models. This strategy may widen the therapeutic window of these and other drugs and may enhance the clinical efficacy of synergistic drug combinations.

Novel Supercritical Carbon Dioxide Impregnation Technique for the Production of Amorphous Solid Drug Dispersions: A Comparison to Hot Melt Extrusion

The formulation of BCS Class II drugs as amorphous solid dispersions has been shown to provide advantages with respect to improving the aqueous solubility of these compounds. While hot melt extrusion (HME) and spray drying (SD) are among the most common methods for the production of amorphous solid dispersions (ASDs), the high temperatures often required for HME can restrict the processing of thermally labile drugs, while the use of toxic organic solvents during SD can impact on end-product toxicity. In this study, we investigated the potential of supercritical fluid impregnation (SFI) using carbon dioxide as an alternative process for ASD production of a model poorly water-soluble drug, indomethacin (INM). In doing so, we produced ASDs without the use of organic solvents and at temperatures considerably lower than those required for HME. Previous studies have concentrated on the characterization of ASDs produced using HME or SFI but have not considered both processes together. Dispersions were manufactured using two different polymers, Soluplus and polyvinylpyrrolidone K15 using both SFI and HME and characterized for drug morphology, homogeneity, presence of drug-polymer interactions, glass transition temperature, amorphous stability of the drug within the formulation, and nonsink drug release to measure the ability of each formulation to create a supersaturated drug solution. Fully amorphous dispersions were successfully produced at 50% w/w drug loading using HME and 30% w/w drug loading using SFI. For both polymers, formulations containing 50% w/w INM, manufactured via SFI, contained the drug in the γ-crystalline form. Interestingly, there were lower levels of crystallinity in PVP dispersions relative to SOL. FTIR was used to probe for the presence of drug-polymer interactions within both polymer systems. For PVP systems, the nature of these interactions depended upon processing method; however, for Soluplus formulations this was not the case. The area under the dissolution curve (AUC) was used as a measure of the time during which a supersaturated concentration could be maintained, and for all systems, SFI formulations performed better than similar HME formulations.

Controlled release of a model antibacterial drug from a novel self-lubricating silicone biomaterial

Abstract There is considerable interest in developing medical devices that provide controlled delivery of biologically active agents, for example, to reduce the incidence of device-related infection. Silicone elastomers are one of the commonest biomaterials used in medical device production. However, they have a relatively high coefficient of friction and the resulting lack of lubricity can cause pain and tissue damage on device insertion and removal. Novel silicone cross-linking agents have recently been reported that produce inherently ‘self-lubricating’ silicone elastomers with very low coefficients of friction. In this study, the model antibacterial drug metronidazole has been incorporated into these self-lubricating silicone elastomers to produce a novel bioactive biomaterial. The in vitro release characteristics of the bioactive component were evaluated as a function of cross-linker composition and drug loading. Although conventional matrix-type release kinetics were observed for metronidazole from the silicone systems, it was also observed that increasing the concentration of the cross-linking agent responsible for the lubricious character (tetra(oleyloxy)silane) relative to that of the standard non-lubricious cross-linking agent (tetrapropoxysilane) produced an increase in the metronidazole flux rate by up to 65% for a specified drug loading. The results highlight the potential for developing lubricious silicone medical devices with enhanced drug release characteristics.