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Skin sensitization is a critical end point in occupational toxicology that necessitates the use of fast, accurate, and affordable models to aid in establishing handling guidance for worker protection. While many in silico models have been developed, the scarcity of reliable data for active pharmaceutical ingredients (APIs) and their intermediates (together regarded as pharmaceutical compounds) brings into question the reliability of these tools, which are largely constructed using publicly available nonspecialty chemicals. Here, we present the quantum-mechanical (QM) Computer-Aided Discovery and REdesign (CADRE) model, which was developed with the bioactive and structurally complex chemical space in mind by relying on the fundamentals of chemical interactions in key events (versus structural attributes of training-set data). Validated in this study on 345 APIs and intermediates, CADRE achieved 95% accuracy, sensitivity, and specificity and a combined 79% accuracy in assigning potency categories compared to the mouse local lymph node assay data. We show how historical outcomes from CADRE testing in the pharmaceutical space, generated over the past 10 years on ca. 2500 chemicals, can be used to probe the relationships between sensitization mechanisms (or the underlying chemical classes) and the probability of eliciting a sensitization response in mice of a given potency. We believe this information to be of value to both practitioners, who can use it to quickly screen and triage their data sets, as well as to model developers to fine-tune their structure-based tools. Lastly, we leverage our experimentally validated subset of APIs and intermediates to show the importance of dermal permeability on the sensitization potential and potency. We demonstrate that common physicochemical properties used to assess permeation, such as the octanol-water partition coefficient and molecular weight, are poor proxies for the more accurate energy-pair distributions that can be computed from mixed QM and classical simulations using model representations of the stratum corneum.
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Protein therapeutics represent a rapidly growing proportion of new medicines being developed by the pharmaceutical industry. As with any new drug, an Occupational Exposure Limit (OEL) should be developed to ensure worker safety. Part of the OEL determination addresses bioavailability (BA) after inhalation, which is poorly understood for protein therapeutics. To explore this, male Sprague-Dawley rats were exposed intravenously or by nose-only inhalation to one of five test proteins of varying molecular size (10-150â¯kDa), including a polyethylene glycol-conjugated protein. Blood, lung tissue and bronchoalveolar lavage (BAL) fluid were collected over various time-points depending on the expected test protein clearance (8 minutes-56 days), and analyzed to determine the pharmacokinetic profiles. Since the BAL half-life of the test proteins was observed to beâ¯>â¯4.5â¯h after an inhalation exposure, accumulation and direct lung effects should be considered in the hazard assessment for protein therapeutics with lung-specific targets. The key finding was the low systemic bioavailability after inhalation exposure for all test proteins (â¼≤1%) which did not appear molecular weight-dependent. Given that this study examined the inhalation of typical protein therapeutics in a manner mimicking worker exposure, a default 1% BA assumption is reasonable to utilize when calculating OELs for protein therapeutics.
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Polietilenglicoles/farmacocinética , Proteínas/farmacocinética , Administración por Inhalación , Animales , Disponibilidad Biológica , Líquido del Lavado Bronquioalveolar/química , L-Lactato Deshidrogenasa/metabolismo , Pulmón/metabolismo , Masculino , Concentración Máxima Admisible , Ratas Sprague-Dawley , Receptores Fc/metabolismoRESUMEN
INTRODUCTION: Irritation reactions are a frequently reported occupational illness. The potential adverse effects of pharmaceutical compounds (PCs) on eye and skin can now be assessed using validated in vitro methods. OBJECTIVES: Our overall aim is to reduce animal testing by replacing the historically utilized in vivo test methods with validated in vitro test methods which accurately determine the ocular and dermal irritation/corrosion potential of PCs to inform worker safety within the pharmaceutical space. Bristol-Myers Squibb (BMS) and the Institute for In Vitro Sciences (IIVS) have therefore conceptualized and internally qualified a tiered in vitro testing strategy to inform occupational hazards regarding eye and skin irritation and corrosivity of PCs. For the small scale pre-qualification phase, we paired historical in vivo and newly generated in vitro data for 15 PCs to determine the predictive capacity of in vitro assays already validated for the eye and skin irritation/corrosion endpoints and accepted for certain regulatory submissions. During the post-qualification phase, a group of 24 PCs were subjected exclusively to the developed tiered testing strategy, which is based on three Organisation for Economic Co-operation and Development (OECD) in vitro methods. MATERIALS AND METHODS: The qualified in vitro testing strategy utilizes the Corrositex® assay for the corrosivity (OECD TG 435), the Bovine Corneal Opacity and Permeability (BCOP) assay for ocular irritation (OECD TG 437), and the EpiDerm™ tissue model-based Skin Irritation Test (SIT) for dermal irritation (OECD TG 439). In the first step, the pH of each PC was determined. For compounds with pH extremes ≥11 or ≤2, the Corrositex® assay was generally conducted first. For compound(s) that were incompatible with or were negative in the Corrositex® assay or had pH values between 2 and 11, the BCOP assay and SIT were performed first. RESULTS: The results of the tiered testing strategy's qualification phase demonstrated that the BCOP assay is sensitive enough to identify a wide range of eye irritation/corrosion potentials and its over-prediction rate was considered acceptable to inform occupational hazards and ensure the proper handling practices of PCs. The SIT correctly predicted the skin irritation potential of 14 out of the 15 PCs included in the qualification phase, only over-predicting one PC. In the post-qualification phase, four PCs out of four tested were predicted corrosive by the Corrositex® assay and thus no further testing was needed or conducted. The rest of the PCs were evaluated in the BCOP assay (both neat and as a 20% dilution), with the higher response being used for hazard classification. Four PCs were determined to be severe eye irritants, 1 a moderate irritant, 8 were mild irritants, and 8 were non-irritants. The same set of PCs was evaluated using the SIT and were classified as non-irritants to skin. These results are consistent with the BMS historical in vivo results showing a very low number of PCs as skin irritants. CONCLUSIONS: This tiered in vitro testing strategy, which replaces the use of animal studies, was found to be reasonably accurate in its predictive capacity when compared to historical in vivo results and represents a conservative and reliable platform that can be utilized for the prediction of ocular and dermal irritation/corrosion potential of PCs and for subsequent GHS classification and worker safety hazard communications.
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Alternativas a las Pruebas en Animales , Industria Farmacéutica , Oftalmopatías/inducido químicamente , Irritantes/toxicidad , Enfermedades Profesionales/prevención & control , Salud Laboral , Enfermedades de la Piel/inducido químicamente , Animales , Bovinos , Oftalmopatías/patología , Humanos , Concentración de Iones de Hidrógeno , Técnicas In Vitro , Irritantes/clasificación , Preparaciones Farmacéuticas , Valor Predictivo de las Pruebas , Enfermedades de la Piel/patologíaRESUMEN
Dermal contact with chemicals may lead to an inflammatory reaction known as allergic contact dermatitis. Consequently, it is important to assess new and existing chemicals for their skin sensitizing potential and to mitigate exposure accordingly. There is an urgent need to develop quantitative non-animal methods to better predict the potency of potential sensitizers, driven largely by European Union (EU) Regulation 1223/2009, which forbids the use of animal tests for cosmetic ingredients sold in the EU. A Nearest Neighbours in silico model was developed using an in-house dataset of 1096 murine local lymph node (LLNA) studies. The EC3 value (the effective concentration of the test substance producing a threefold increase in the stimulation index compared to controls) of a given chemical was predicted using the weighted average of EC3 values of up to 10 most similar compounds within the same mechanistic space (as defined by activating the same Derek skin sensitization alert). The model was validated using previously unseen internal (n = 45) and external (n = 103) data and accuracy of predictions assessed using a threefold error, fivefold error, European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC) and Globally Harmonized System of Classification and Labelling of Chemicals (GHS) classifications. In particular, the model predicts the GHS skin sensitization category of compounds well, predicting 64% of chemicals in an external test set within the correct category. Of the remaining chemicals in the previously unseen dataset, 25% were over-predicted (GHS 1A predicted: GHS 1B experimentally) and 11% were under-predicted (GHS 1B predicted: GHS 1A experimentally). Copyright © 2017 John Wiley & Sons, Ltd.
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Dermatitis Alérgica por Contacto/etiología , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/etiología , Modelos Biológicos , Preparaciones Farmacéuticas/química , Alternativas al Uso de Animales , Animales , Simulación por Computador , Conjuntos de Datos como Asunto , Ensayo del Nódulo Linfático Local , Ratones , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Relación Estructura-ActividadRESUMEN
Recently, a guideline has been published by the European Medicines Agency (EMA) on setting safe limits, permitted daily exposures (PDE) [also called acceptable daily exposures (ADE)], for medicines manufactured in multi-product facilities. The ADE provides a safe exposure limit for inadvertent exposure of a drug due to cross-contamination in manufacturing. The ADE determination encompasses a standard risk assessment, requiring an understanding of the toxicological and pharmacological effects, the mechanism of action, drug compound class, and the dose-response as well as the pharmacokinetic properties of the compound. While the ADE concept has broad application in pharmaceutical safety there are also nuances and specific challenges associated with some toxicological endpoints or drug product categories. In this manuscript we discuss considerations for setting ADEs when the following specific adverse health endpoints may constitute the critical effect: genotoxicity, developmental and reproductive toxicity (DART), and immune system modulation (immunostimulation or immunosuppression), and for specific drug classes, including antibody drug conjugates (ADCs), emerging medicinal therapeutic compounds, and compounds with limited datasets. These are challenging toxicological scenarios that require a careful evaluation of all of the available information in order to establish a health-based safe level.
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Industria Farmacéutica , Nivel sin Efectos Adversos Observados , Exposición Profesional/prevención & control , Salud Laboral , Preparaciones Farmacéuticas , Proteínas/efectos adversos , Pruebas de Toxicidad/métodos , Animales , Relación Dosis-Respuesta a Droga , Contaminación de Medicamentos/prevención & control , Hipersensibilidad a las Drogas/inmunología , Hipersensibilidad a las Drogas/prevención & control , Industria Farmacéutica/legislación & jurisprudencia , Industria Farmacéutica/normas , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/inmunología , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/prevención & control , Guías como Asunto , Política de Salud , Humanos , Pruebas de Mutagenicidad , Exposición Profesional/efectos adversos , Exposición Profesional/legislación & jurisprudencia , Exposición Profesional/normas , Salud Laboral/legislación & jurisprudencia , Salud Laboral/normas , Preparaciones Farmacéuticas/clasificación , Preparaciones Farmacéuticas/normas , Farmacocinética , Formulación de Políticas , Proteínas/clasificación , Proteínas/normas , Medición de Riesgo , Pruebas de Toxicidad/normas , ToxicocinéticaRESUMEN
A literature review and analysis of inhalation bioavailability data for large therapeutic proteins was conducted in order to develop a practical estimate of the inhalation bioavailability of these drugs. This value is incorporated into equations used to derive occupational exposure limits(OELs) to protect biopharmaceutical manufacturing workers from systemic effects. Descriptive statistics implies that a value of 0.05, or 5% is an accurate estimate for large therapeutic proteins (molecular weight ≥ 40kDa). This estimate is confirmed by pharmacokinetic modeling of data from a human daily repeat-dose inhalation study of immunoglobulin G. In conclusion, we recommend using 5% bioavailability by inhalation when developing OELs for large therapeutic proteins.
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Exposición por Inhalación , Pulmón/metabolismo , Exposición Profesional/normas , Proteínas/farmacocinética , Seguridad , Disponibilidad Biológica , Humanos , Inmunoglobulina G/metabolismo , Concentración Máxima Admisible , Exposición Profesional/análisis , Preparaciones Farmacéuticas/análisis , Proteínas/uso terapéutico , Valores Limites del Umbral , Lugar de TrabajoRESUMEN
Classical risk assessment models for setting safe occupational exposure limits (OEL) have used multiple uncertainty factors (UF) applied to a point of departure (POD), e.g., a No Observed Effect Level (NOEL), which in some cases is the pharmacological effect. Dapagliflozin promotes glucosuria by inhibiting the renal sodium-glucose cotransporter-2 transporter. The initial OEL for dapagliflozin (0.002mg/m(3)) was calculated when low dose clinical data was not available to identify a NOEL resulting in the need to use excessive UFs. To reduce the UFs from the OEL, a clinical pharmacodynamic [glucosuria and urinary glucose dipstick (UGD)] and pharmacokinetic study was conducted with single oral doses of 0.001, 0.01, 0.1, 0.3, 1.0 or 2.5mg administered to 36 healthy subjects. Dose-related dapagliflozin systemic exposures were observed at doses ⩾0.1mg and glucosuria was observed at doses ⩾0.3mg and corroborated by UGD. The NOEL was therefore 0.1mg for glucosuria. For setting the new OEL, no UFs were required. Dividing the POD by 10m(3) (the volume of air an adult inhales in a workday), the resulting OEL was 0.01mg/m(3). In conclusion, low-dose clinical pharmacodynamic and pharmacokinetic data can allow the OEL to be adjusted to the highest safe level.
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Glucósidos/administración & dosificación , Glucósidos/farmacocinética , Riñón/efectos de los fármacos , Exposición Profesional/análisis , Inhibidores del Cotransportador de Sodio-Glucosa 2 , Compuestos de Bencidrilo , Relación Dosis-Respuesta a Droga , Femenino , Glucósidos/efectos adversos , Glucosuria/inducido químicamente , Glucosuria/metabolismo , Humanos , Riñón/metabolismo , Masculino , Exposición Profesional/efectos adversos , Transportador 2 de Sodio-Glucosa/metabolismoRESUMEN
Dermal reactions are the most frequently reported chemical health-related occupational hazard. Identifying dermal sensitizers is important for improving workplace safety. This paper takes a close look at the physico-chemical properties and results from the Local Lymph Node Assay (LLNA) to better understand and predict potent dermal sensitizers. The LLNA was used to identify 28 pharmaceutical agents or chemical intermediates as potent dermal sensitizers, EC3 < 1%. Certain parameters were examined to determine if there was any predictability to identify potent dermal sensitizers. These included a computer structure activity analysis using Derek for Windows, molecular weight (Mw), calculated log P, and the log-linear extrapolation approach for estimating the potency. With Derek for Windows, 13 compounds were identified as negative and 15 as positive for structural alerts, the most common being haloalkanes, and hydrazines. Additional mechanisms of reactivity were postulated for the remaining compounds. The examination of the Mw showed that all molecules had Mw < 550 Da. For 21 compounds, the interpolated vs extrapolated methods for determining the EC3 value were compared. For eight of the 21 compounds, the extrapolated EC3 was in the correct order of magnitude, eight were incorrect (five were too high and three were too low) and five could not be calculated. The use of a tiered approach including examination of the structural and physico-chemical properties and the LLNA to identify potent dermal sensitizers is integral in the selection of effective safe handling guidance to protect from sensitization hazards.