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Stricker-Krongrad A.,Sinclair Research Center | Shoemake C.R.,Sinclair Research Center | Pereira M.E.,HSRL Inc. | Gad S.C.,Gad Consulting Services | And 2 more authors.
Toxicologic Pathology | Year: 2016

The use of miniature swine as a nonrodent species in safety assessment has continued to expand for over a decade, and they are becoming routinely used in toxicology and in pharmacology as well as a model for human diseases. Miniature swine models are regularly used for regulatory toxicity studies designed to assess safety of new therapeutic compounds given through different routes of exposure and are used as an alternative model to the canine or the nonhuman primate. Translational preclinical swine study data presented support the current finding that miniature swine are the animal model of choice for assessment of drug absorption, tolerance, and systemic toxicity following systemic exposures. Because research investigators need to be familiar with important anatomic and histopathologic features of the miniature swine in order to place toxicopathologic findings in their proper perspective, clinical and anatomic pathology data from a large number of Sinclair, Hanford, Yucatan, and Göttingen breeds from control groups from a wide variety of studies performed between 2004 and 2014 will be presented, compared, and partially illustrated. © Society of Toxicologic Pathology. Source


Steinbach T.,EPL Inc. | Gad-Mcdonald S.,Gad Consulting Services | Powley M.,Office of New Drugs | Greene N.,Pfizer
International Journal of Toxicology | Year: 2015

A continuing education (CE) course at the 2014 American College of Toxicology annual meeting covered the topic of (Quantitative) Structure-Activity Relationships [(Q)SAR]. The (Q)SAR methodologies use predictive computer modeling based on predefined rules to describe the relationship between chemical structure and a chemicals associated biological activity or statistical tools to find correlations between biologic activity and the molecular structure or properties of a compound. The (Q)SAR has applications in risk assessment, drug discovery, and regulatory decision making. Pressure within industry to reduce the cost of drug development and societal pressure for government regulatory agencies to produce more accurate and timely risk assessment of drugs and chemicals have necessitated the use of (Q)SAR. Producing a high-quality (Q)SAR model depends on many factors including the choice of statistical methods and descriptors, but first and foremost the quality of the data input into the model. Understanding how a (Q)SAR model is developed and applied is critical to the successful use of such a tool. The CE session covered the basic principles of (Q)SAR, practical applications of these computational models in toxicology, how regulatory agencies use and interpret (Q)SAR models, and potential pitfalls of using them. © The Author(s) 2015. Source


Grabowski T.,Biologics | Jaroszewski J.J.,University of Warmia and Mazury | Gad S.C.,Gad Consulting Services | Feder M.,Adamed Sp. Z O.o
International journal of toxicology | Year: 2014

The minimal inhibitory concentration (MIC) of an antimicrobial agent for a microbial population (MIC(50, obs) and MIC(90, obs)) is an interpolated value determined for antibacterial drugs by in vitro methods. Many studies have tried to determine the correlation between the MIC(50, obs) or MIC(90, obs) value and the physicochemical parameters to allow quantitaive structure activity relationship (QSAR) predictions of efficacy. A rigorous evaluation of approaches to this problem is presented here. In order to find a correlation between chemical structure and the derivatives of the MIC values for 9 indicatory bacterial strains, it is necessary to employ a number of physicochemical parameters in combination. Only an arithmetic expression composed of many features illustrating the chemical structure of the molecule can be linked to the ƒMIC(50, obs) value. This article demonstrated that, despite the complexity of the MIC value used as the end point, it is possible to validate the model in a limited extent. © The Author(s) 2014. Source


Sullivan Jr. D.W.,Gad Consulting Services | Gad S.C.,Gad Consulting Services | Julien M.,Gattefosse
Food and Chemical Toxicology | Year: 2014

Transcutol® (Diethylene glycol monoethyl ether, DEGEE), CAS # 111-90-0, is commonly used as a vehicle in the formulation or manufacturing process of pharmaceuticals, cosmetics, and food additives. This paper presents unpublished nonclinical safety data using a form of DEGEE which includes a significantly decreased level of impurities, specifically ethylene glycol and diethylene glycol. It also reviews the history of use, regulatory status, and previously published toxicity data for DEGEE. The review supports that DEGEE is well tolerated across animal species and gender with toxicity occurring only at levels well above those intended for human use. At high levels of exposure, the kidney is identified as the critical target organ of DEGEE toxicity. DEGEE is negative for genotoxicity in in vitro and in vivo studies. Subchronic and chronic toxicity studies produced no reports of preneoplastic changes in organs, but the animal data is insufficient to allow a definitive opinion as to carcinogenicity. In silico data suggested that DEGEE is not carcinogenic or genotoxic. Developmental toxicity was seen in rats but only at levels 200 times greater than the estimated oral Permissible Daily Exposure Level of 10. mg/kg/day. The nonclinical data along with the long history of DEGEE use as a vehicle and solvent by multiple routes provide evidence of its safety. Furthermore, the novel data discussed herein provides evidence that toxicity previously associated with high levels of DEGEE in nonclinical studies conducted prior to 1990 could possibly be attributed to the presence of significant amounts of ethylene glycol or other impurities. © 2014 Elsevier Ltd. Source


Sullivan D.W.,Gad Consulting Services | Gad S.C.,Gad Consulting Services | Laulicht B.,Perosphere | Bakhru S.,Perosphere | Steiner S.,Perosphere
International Journal of Toxicology | Year: 2015

A new molecular entity, PER977 (di-arginine piperazine), is in clinical development as an anticoagulant reversal agent for new oral anticoagulants and heparins. The good laboratory practices (GLP)-compliant studies were conducted to evaluate the toxicity of PER977 and its primary metabolite, 1,4-bis(3-aminopropyl)piperazine (BAP). PER977 and BAP were negative for systemic toxicity in dogs and rats. PER977 was rapidly eliminated from the blood with little to no accumulation. PER977 was negative for genotoxicity and did not alter neurological, respiratory, or cardiovascular function. Maximum tolerated doses for PER977 were 40 (rat) and 35 mg/kg (dog), and greater than 80 mg/kg (rat) for BAP. The no observable adverse effect level (NOAEL) for 14-day intravenous exposure to both rats and dogs was 20 mg/kg/d. For BAP, the NOAELs for 14-day intravenous exposure to rats and dogs were 5 and 20 mg/kg, respectively. Based on these results, a safe and conservative dose level of 19.4 mg/d was used for the PER977 first in human study. © The Author(s) 2015. Source

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