Comparison of permitted daily exposure (PDE) values for active pharmaceutical ingredients (APIs) - Evidence of a robust approach.

Permitted Daily Exposure Limits (PDEs) are set for Active Pharmaceutical Ingredients (APIs) to control cross-contamination when manufacturing medicinal products in shared facilities. With the lack of official PDE lists for pharmaceuticals, PDEs have to be set by each company separately. Although general rules and guidelines for the setting of PDEs exist, inter-company variations in the setting of PDEs occur and are considered acceptable within a certain range. To evaluate the robustness of the PDE approach between different pharmaceutical companies, data on PDE setting of five marketed APIs (amlodipine, hydrochlorothiazide, metformin, morphine, and omeprazole) were collected and compared. Findings show that the variability between PDE values is within acceptable ranges (below 10-fold) for all compounds, with the highest difference for morphine due to different Point of Departures (PODs) and Adjustment Factors (AFs). Factors of PDE variability identified and further discussed are: (1) availability of data, (2) selection of POD, (3) assignment of AFs, (4) route-to-route extrapolation, and (5) expert judgement and differences in company policies. We conclude that the investigated PDE methods and calculations are robust and scientifically defensible. Additionally, we provide further recommendations to harmonize PDE calculation approaches across the pharmaceutical industry.

Framework for sensitization assessment of extractables and leachables in pharmaceuticals.

During the toxicological assessment of extractables and leachables in drug products, localized hazards such as irritation or sensitization may be identified. Typically, because of the low concentration at which leachables occur in pharmaceuticals, irritation is of minimal concern; therefore, this manuscript focuses on sensitization potential. The primary objective of performing a leachable sensitization assessment is protection against Type IV induction of sensitization, rather than prevention of an elicitation response, as it is not possible to account for the immunological state of every individual. Sensitizers have a wide range of potencies and those which induce sensitization upon exposure at a low concentration (i.e. strong, or extreme sensitizers) pose the highest risk to patients and should be the focus of the risk assessment. The Extractables and Leachables Safety Information Exchange (ELSIE) consortium has reviewed the status of dermal, respiratory, and systemic risk assessment in cosmetic and pharmaceutical industries, and proposes a framework to evaluate the safety of known or potential dermal sensitizers in pharmaceuticals. Due to the lack of specific regulatory guidance on this topic, the science-driven risk-based approach proposed by ELSIE encourages consistency in the toxicological assessment of extractables and leachables to maintain high product quality and ensure patient safety.

Deriving harmonised permitted daily exposures (PDEs) for paracetamol (acetaminophen) CAS #: 103-90-2.

In the pharmaceutical industry, cleaning criteria are required for multipurpose manufacturing facilities. These Health Based Exposure Limits (HBELs), also called permitted daily exposures (PDEs) values, are derived from toxicological and pharmacological evaluation of the active pharmaceutical ingredients (APIs). The purpose of this publication is to show an example of how authors from different companies evaluate a generic drug, paracetamol, and discuss different approaches and relevance of the nonclinical studies for deriving PDEs. PDE limits of 25 mg/day for the oral route, and 20 mg/day for the intravenous (i.v.) and inhalation (inhal.) routes, respectively, were established herein. However, it has been already recognised that there are acceptable differences in the PDE calculations, which may be based on data accessibility, company-specific science-policy decisions or expert judgments. These differences can cause up to a 3-fold lower or higher values. If unnecessarily high factors are applied, this would result in a very conservative PDE value and unneeded additional cleaning and higher manufacturing costs. The PDE values presented are considered to be protective against adverse and pharmacological effects observed in clinical trials and in this case, a very long postmarketing period of paracetamol.

The effect of omalizumab treatment on the low affinity immunoglobulin E receptor (CD23/fc epsilon RII) in patients with severe allergic asthma.

BACKGROUND: Omalizumab is an anti-immunoglobulin E (IgE) monoclonal antibody used in the treatment of severe asthma. Its therapeutic efficacy is primarily attributed to reduction of serum-free IgE and in the expression of high-affinity IgE receptor, fc epsilon RI. However, its effect on the low-affinity IgE receptor fc epsilon RII/CD23 in vivo has not been evaluated. AIM: To determine whether CD23 plays a role in the inflammatory process in severe uncontrolled asthma and whether anti-IgE therapy modulates fc epsilon RII/CD23 expression in these patients. METHODS: We evaluated the expression of IgE receptors fc epsilon RI, fc epsilon RII/CD23, and soluble CD23 (sCD23), and the activation state of peripheral blood monocytes (tumor necrosis factor alpha, interleukin (IL) 1-beta, transforming growth factor (TGF) beta expression) in the patients with severe asthma before and after 24 weeks of omalizumab treatment and in the healthy controls. Cytokine expression of monocytes in response to different stimulation (IL-4, IL-4 plus IgE, IL-4 plus IgE plus anti-IgE, and IL-4 plus IgE plus anti-IgE plus anti-CD23 for 72 hours) was determined by enzyme-linked immunosorbent assay. RESULTS: Treatment with omalizumab (for 24 weeks) improved disease control and pulmonary function (forced expiratory volume in the first second of expiration, 64.5 versus 74%; p = 0.021). Mean ± SE expression of fc epsilon RI on monocytes was higher in the patients with asthma versus the controls (45.7 ± 12.2% versus 18.6 ± 5.8%; p = 0.04) and was reduced after omalizumab treatment (45.7 ± 12.2% versus 15.6 ± 4.4%; p = 0.027). Mean ± SE TGF-beta levels in supernatants from monocytes were reduced in the patients treated with omalizumab (211 ± 6 pg/mL versus 184 ± 9 pg/mL; p = 0.036). CONCLUSION: Modulation of the low affinity IgE receptor CD23 in severe asthma is complex, and sCD23 may inversely reflect disease activity. Treatment with omalizumab was associated with reduced monocyte activation.

Extra domain-A fibronectin is necessary for the development of nasal remodeling in chronic allergen-induced rhinitis.

BACKGROUND: Extra domain A-containing fibronectin (EDA-FN) is necessary for the development of allergen-induced lower airway fibrosis. The pathogenesis of fibrosis in allergic rhinitis has not been well studied. OBJECTIVES: To determine whether EDA-fibronectin is necessary for the development of nasal remodeling in a murine model of chronic allergic rhinitis and in human allergic rhinitis. METHODS: EDA(-/-) and wild-type (WT) C57Bl/6 mice were sensitized intraperitoneally and then challenged with inhaled ovalbumin (OVA) or saline for 2 and 5 weeks. Clinical signs of rhinitis and histological analysis of nasal tissue were evaluated. Immunohistological staining for EDA-FN was performed in human tissue of inferior nasal conchae from patients with allergic rhinitis and controls. RESULTS: After 2 weeks of allergen exposure, only goblet cell hyperplasia and perivascular eosinophilia were observed. After 5 weeks, goblet cell number, thickening of the subepithelial layer, and extent and area of collagen deposition were increased in the nasal tissue of WT OVA (ovalbumin)-challenged mice as compared with saline controls (P < .0001, P < .0001, P = .018, and P = .03, respectively). Clinical signs of rhinitis were observed only in WT OVA-challenged mice. In the EDA(-/-) mice exposed to OVA, collagen deposition, collagen area, and subepithelial thickness showed no increase and were similar to saline control mice, whereas goblet cell hyperplasia was similar to WT OVA-challenged mice. EDA-FN expression was prominent in inferior conchae from patients with allergic rhinitis but was absent in control patients. CONCLUSION: EDA-containing fibronectin is necessary for the development of nasal tissue fibrotic remodeling process in both murine and human allergic rhinitis.

Sensitization Assessment of Extractables and Leachables in Pharmaceuticals: ELSIE Database Analysis.

Quality by design is the foundation of the risk management framework for extractables and leachables (E&Ls) recommended by the Extractables and Leachables Safety Information Exchange (ELSIE). Following these principles during the selection of materials for pharmaceutical product development minimizes the presence of highly toxic substances and decreases the health risk of potential leachables in the drug product. Therefore, in the context of the broad arena of chemicals, it is important to distinguish E&Ls as a subset of chemicals and evaluate this relevant chemical space to derive appropriate analytical and safety thresholds. When considering the health hazards posed by E&Ls, one area presenting a challenge is understanding the sensitization potential and whether it poses a risk to patients. A dataset of E&Ls compiled by ELSIE (n=466) was analysed to determine the prevalence and potency of skin sensitizers in this chemical subset and explore a scientifically justified approach to the sensitization assessment of potential leachables in parenteral drug products. Approximately half of the compounds (56%, 259/466) had sensitization data recorded in the ELSIE database and of these, 20% (52/259) are potential skin sensitizers. Only 3% (8/259) of the E&L dataset with sensitization data were considered potent (strong or extreme) sensitizers following in silico analysis and expert review, illustrating that potent sensitizers are not routinely observed as leachables in pharmaceutical products. Our analysis highlights that in silico potency prediction and expert review are key tools during the sensitization assessment process for E&Ls. The results confirm where material selection is anticipated to mitigate the risk of presence of strong and/or extreme sensitizers (e.g., extractable testing via ISO 10993-10), and that implementing thresholds per ICH M7 and/or Masuda-Herrera et al. provides a reasonably conservative approach for establishing the analytical testing and safety thresholds.

The extra domain A of fibronectin is essential for allergen-induced airway fibrosis and hyperresponsiveness in mice.

BACKGROUND: Asthma is characterized by airway inflammation, airway remodeling, and airway hyperresponsiveness (AHR). Myofibroblast differentiation and subepithelial fibrosis are key features of airway remodeling. Extra domain A (EDA)-containing fibronectin (EDA-FN), an alternatively spliced form of the extracellular matrix protein fibronectin, has been implicated in fibroblast differentiation during wound healing and tissue fibrosis. OBJECTIVES: We sought to investigate the role of EDA-FN in airway remodeling using a murine model of chronic allergen-induced experimental asthma. METHODS: EDA(-/-) and wild-type (WT) mice were sensitized and exposed to inhaled ovalbumin (OVA) or saline for 5 weeks. EDA-FN expression was evaluated by means of PCR and immunostaining. Peribronchial fibrosis, smooth muscle area, mucus-producing cell numbers, bronchoalveolar cell counts, and lung function were assessed in WT and EDA(-/-) mice. Fibroblast activation and differentiation were evaluated ex vivo by using OVA-treated WT and EDA(-/-) lung fibroblasts. RESULTS: Exposure to OVA increased EDA-FN expression in lung tissue and primary lung fibroblasts. OVA-treated EDA(-/-) mice showed reduced airway fibrosis and AHR and impaired expression of TGF-ß1 and IL-13 without changes in airway inflammation or other aspects of remodeling. Lung fibroblasts from OVA-treated EDA(-/-) mice exhibited reduced proliferation, migration, α-smooth muscle actin expression, and collagen deposition and impaired TGF-ß1 and IL-13 release compared with that seen in WT mice. CONCLUSIONS: EDA-FN is essential for the development of OVA-induced airway fibrosis and AHR. The effect of the EDA domain on airway fibrosis after OVA challenge is through activation and differentiation of fibroblasts. Fibroblast activation and airway fibrosis are necessary for the development of AHR.

EDA-containing cellular fibronectin induces fibroblast differentiation through binding to alpha4beta7 integrin receptor and MAPK/Erk 1/2-dependent signaling.

Fibroblast differentiation is an essential step during wound healing and fibrosis. Fibronectin (FN) is a major component of the extracellular matrix and occurs in two main forms: plasma and cellular FN. The latter includes the alternatively spliced domain A (EDA). Although EDA-containing cellular fibronectin (EDA-FN) is associated with fibroblast differentiation, how EDA-FN promotes differentiation is incompletely understood. In this study, we investigate the mechanism by which EDA-FN contributes to fibroblast differentiation with emphasis on the characterization of the EDA-FN receptor. We show that EDA-FN increases α-SMA expression (immunofluorescence), collagen deposition, cell contractility, and focal adhesion kinase (FAK) activation (immunoblotting); whereas plasma FN, a form lacking EDA, shows no effect. Primary lung fibroblasts constitutively express α(4)ß(7) integrin receptor (FACS and RT-PCR). Blocking of α(4)ß(7) reduces fibroblast adhesion to EDA-FN and inhibits α-SMA expression, collagen deposition, and FAK activation induced by EDA-FN. Using recombinant EDA-containing peptides, we demonstrate that the EDA segment is sufficient to induce fibroblast differentiation via binding to α(4)ß(7). EDA-FN induces MAPK-Erk1/2 activation and inhibition of MEK1/2 attenuates EDA-FN-induced α-SMA expression. Our findings demonstrate that EDA-FN induces fibroblast differentiation by a mechanism that involves binding of EDA to α(4)ß(7) integrin followed by activation of FAK and MAPK-associated signaling pathways.

Angiostatic effects of K252a, a Trk inhibitor, in murine brain capillary endothelial cells.

Nerve growth factor (NGF) supports the survival and differentiation of sympathetic and sensory neurons and is also mitogenic for a variety of tumors. K252a, an antagonist of NGF receptor TrkA, was previously used as a pharmacological tool to study NGF actions and as a lead compound for developing anti-tumor drugs. Since recently, NGF was characterized as an angiogenic factor, we sought to investigate the angiostatic properties of K252a on endothelial cells (ECs). For this purpose, we used a murine brain microcapillary ECs model in which we found autocrine release of NGF in the culture medium and activation of TrkA receptor-induced downstream signaling molecules Erk1/2, Akt, and PLCgamma. In this model, we demonstrated the angiostatic property of K252a based on its ability to affect several important angiogenic steps. K252a, but not its cell membrane impermeable analogue K252b at 100 nM: (i) inhibited the proliferation of the ECs by 45 +/- 9%; (ii) reduced by 70 +/- 4% the migration of the ECs measured in a wound-closure model; (iii) reduced by 29 +/- 9% the formation of tube-like structures of the ECs cultured on Matrigel; (iv) stimulated by 100 +/- 25% the collagen deposition by the ECs, a process responsible for the increased endothelial barrier functions expressed by 22 +/- 5% reduction of paracellular permeability and by 17 +/- 3% elevation of transendothelial electrical resistance. These data suggest that NGF/TrkA may represent a target for the development of novel, K252a-derived multikinase inhibitors drugs with anti-tumor and angiostatic dual activities.

Osteopontin induces airway remodeling and lung fibroblast activation in a murine model of asthma.

Airway remodeling is a central feature of asthma; however, the mechanisms underlying its development have not been fully elucidated. We have demonstrated that osteopontin, an inflammatory cytokine and an extracellular matrix glycoprotein with profibrotic properties, is up-regulated in a murine model of allergen-induced airway remodeling. In the present study, we determined whether osteopontin plays a functional role in airway remodeling. Osteopontin (OPN)-deficient (OPN(-/-)) and wild-type mice were sensitized and exposed to inhaled ovalbumin (OVA) or saline for 5 weeks. Collagen production, peribronchial smooth muscle area, mucus-producing cell number, and bronchoalveolar cell counts were assessed. The functional behavior and phenotype of lung fibroblasts from OVA-treated OPN(-/-) and from wild-type mice were studied using ex vivo cultures. OVA-treated OPN(-/-) mice exhibited reduced lung collagen content, smooth muscle area, mucus-producing cells, and inflammatory cell accumulation as compared with wild-type mice. Reduced matrix metalloproteinase-2 activity and expression of transforming growth factor-beta1 and vascular endothelial growth factor were observed in OVA-treated OPN(-/-) mice. Lung fibroblasts from OVA-treated OPN(-/-) mice showed reduced proliferation, migration, collagen deposition, and alpha-smooth muscle actin expression in comparison with OVA-treated wild-type lung fibroblasts. Thus, OPN is key for the development of allergen-induced airway remodeling in mice. In response to allergen, OPN induces the switching of lung fibroblasts to a pro-fibrogenic myofibroblast phenotype.

Eotaxin-2/CCL24 and eotaxin-3/CCL26 exert differential profibrogenic effects on human lung fibroblasts.

BACKGROUND: Eotaxin-2/CCL24 and eotaxin-3/CCL26 play an important role in eosinophil chemotaxis and activation in asthma. We previously demonstrated that eotaxin/CCL11 is profibrogenic for human lung fibroblasts. The effect of eotaxin-2/ CCL24 and eotaxin-3/CCL26 on lung fibroblasts has not yet been investigated. OBJECTIVE: To evaluate whether eotaxin-2/CCL24 and eotaxin-3/CCL26 modulate fibrotic properties of lung fibroblasts. METHODS: Fibroblast proliferation was evaluated by means of 3-hydroxythymidine incorporation. Collagen production was assessed by means of 3-hydroxyproline incorporation and biochemical staining. Chemotaxis was determined using Boyden chambers. Expression of alpha-smooth muscle actin was evaluated by means of immunostaining. Transforming growth factor beta1 release was assessed using enzyme-linked immunosorbent assay. Parametric analysis of variance, followed by the Tukey-Kramer multiple comparisons test, was used to calculate statistical significance. RESULTS: Eotaxin-2/CCL24 but not eotaxin-3/CCL26 stimulated human lung fibroblast proliferation and collagen synthesis. In contrast, eotaxin-3/CCL26 but not eotaxin-2/CCL24 promoted fibroblast migration. Neither eotaxin-2/CCL24 nor eotaxin-3/ CCL26 induced the expression of alpha-smooth muscle actin or transforming growth factor beta1 from lung fibroblasts. CONCLUSIONS: Eotaxin-2/CCL24 and eotaxin-3/CCL26 have differential profibrogenic effects on human lung fibroblasts. These CC chemokines may, therefore, contribute to airway remodeling in asthma.

Association between CD14 gene polymorphisms and disease phenotype in sarcoidosis.

Although the etiology of sarcoidosis is unknown, genetic susceptibility has been demonstrated. Granuloma formation is a key feature in the pathophysiology of sarcoidosis and Crohn's Disease, raising the possibility that these diseases share common pathogenetic pathways. An association between sarcoidosis and the protein "CD14", a molecule that is part of the lipopolysaccharide (LPS) cell surface receptor complex, has been suggested. In the current study we evaluated the CD14 gene promoter 159 C-->T polymorphic site and soluble CD14 levels in a cohort of 74 sarcoidosis patients compared to 85 healthy controls. We further sought to identify correlations between clinical phenotype, specific genotypes and soluble CD14 levels. We found the TT genotype to be more prevalent in the sarcoidosis patient group than in controls (p=0.03). Serum levels of soluble CD14 were higher in the sarcoidosis patients (p=0.001). Within the patient cohort, CC homozygous patients presented at an older age with milder disease as assessed with the SAC score, longer time to diagnosis, and less impairment of pulmonary function tests. Our study suggests a role of CD14 in the pathogenesis of sarcoidosis, and a clinical phenotype-genotype association. Further mechanistic and epidemiologic studies are needed in order to establish the specific role of CD14 in the etiology, pathogenesis and clinical phenotype of sarcoidosis.