Evaluation of Fluorophotometry to Assess the Vitreal Pharmacokinetics of Protein Therapeutics

PURPOSE. In this work, we assessed the ability of fluorophotometry to measure the vitreal pharmacokinetics (PK) of fluorescently-labeled ranibizumab in the rabbit after intravitreal injection. We compared these values to those obtained using enzyme-linked immunosorbent assays (ELISA). Data obtained in this study were also compared to historical ranibizumab ocular PK data, either measured in-house or previously published. METHODS. Three individual in vivo studies were performed in New Zealand White rabbits to assess the feasibility of using fluorophotometry to measure rabbit ocular PK of ranibizumab; explore the dynamic range of dosing fluorescently-labeled ranibizumab; and directly compare ranibizumab concentrations and calculated PK parameters measured by vitreal fluorophotometry to those measured using ELISA. RESULTS. In direct comparisons between fluorophotometry and ELISA, the calculated clearance (CL) values were 0.26 and 0.21 mL/day, the volumes of distribution at steady state (V ss ) were 0.80 and 0.94 mL, the half-lives (t 1/2 ) were 3.1 and 2.9 days and the dose normalized areas under the curve (AUC/D) were 4.7 and 3.9 lgÁday/mL/lg, respectively. These values fell within the ranges of 0.13 to 0.44 mL/day for CL, 0.5 to 1.8 mL for V ss , 2.8 to 3.5 days for t 1/2 , and 2.3 to 7.9 lgÁday/mL/lg for AUC/D that have been either measured previously in-house or published elsewhere. CONCLUSIONS. Although not suitable for measuring retinal concentrations, fluorophotometry is a valuable, noninvasive method to measure vitreous concentrations of protein therapeutics after intravitreal injection. Keywords: fluorophotometry, vitreous pharmacokinetics, protein therapeutics, ranibizumab, 3Rs (replacement, reduction, refinement) O riginally developed as a clinical instrument to determine blood-retinal barrier permeability, early cataract formation, tear flow rates, and aqueous humor turnover, Ocular fluorophotometry allows continuous measurement of fluorescence along the central axis of the eye. The dynamic range and lower limits of quantitation of fluorophotometry are similar to other techniques such as mass spectrometry (MS) and ELISA. However, these methods often require invasive and/or terminal sampling. Those options result in the use of a large number of animals and the inability to measure drug concentrations longitudinally in the same animal. Ocular fluorophotometry may offer a noninvasive alternative to measure ocular concentrations and the PK of protein therapeutics and sustained delivery technologies. Several groups have successfully used fluorophotometry to measure the ocular PK of nonprotein molecules and to investigate different methods of ocular drug delivery

Discovery of TRPA1 Antagonist <b>GDC-6599</b>: Derisking Preclinical Toxicity and Aldehyde Oxidase Metabolism with a Potential First-in-Class Therapy for Respiratory Disease

Transient receptor potential ankyrin 1 (TRPA1) is a nonselective calcium ion channel highly expressed in the primary sensory neurons, functioning as a polymodal sensor for exogenous and endogenous stimuli, and has been implicated in neuropathic pain and respiratory disease. Herein, we describe the optimization of potent, selective, and orally bioavailable TRPA1 small molecule antagonists with strong in vivo target engagement in rodent models. Several lead molecules in preclinical single- and short-term repeat-dose toxicity studies exhibited profound prolongation of coagulation parameters. Based on a thorough investigative toxicology and clinical pathology analysis, anticoagulation effects in vivo are hypothesized to be manifested by a metabolitegenerated by aldehyde oxidase (AO)possessing a similar pharmacophore to known anticoagulants (i.e., coumarins, indandiones). Further optimization to block AO-mediated metabolism yielded compounds that ameliorated coagulation effects in vivo, resulting in the discovery and advancement of clinical candidate GDC-6599, currently in Phase II clinical trials for respiratory indications

Paleogenomics of animal domestication

Starting with dogs, over 15,000 years ago, the domestication of animals has been central in the development of modern societies. Because of its importance for a range of disciplines – including archaeology, biology and the humanities – domestication has been studied extensively. This chapter reviews how the field of paleogenomics has revolutionised, and will continue to revolutionise, our understanding of animal domestication. We discuss how the recovery of ancient DNA from archaeological remains is allowing researchers to overcome inherent shortcomings arising from the analysis of modern DNA alone. In particular, we show how DNA, extracted from ancient substrates, has proven to be a crucial source of information to reconstruct the geographic and temporal origin of domestic species. We also discuss how ancient DNA is being used by geneticists and archaeologists to directly observe evolutionary changes linked to artificial and natural selection to generate a richer understanding of this fascinating process