Assessment of bioavailability

Several tools have been investigated for assessing the bioavailability of contaminants in addition to the use of toxicity testing. Typically each of these methods is developed for specific purposes and may not be applicable directly outside of the original purpose of their development. It is also important to keep in mind that the total amount of a compound that can be extracted from sediment using analytical techniques does not correlate to the exposure or bioavailability of a toxicant. 

These examples of various techniques are not meant to be exhaustive but rather to provide the reader with an understanding of tools that can be utilized. 

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Park J-H, Feng Y, Ji P, Voice TC, Boyd SA (2003) Assessment of bioavailability of soil-sorbed atrazine. Appl Environ Microbiol 69 3288-3298 Pignatello JP, Sawhney BL, Frink CR (1987) EBD persistence in soil. Science 236 898... 

Technical information based on in vivo standards and specifications are generally incorporated in various official compendia. Hence, in order to record a legitimate assessment of bioavailability, in vivo test is an absolute necessity and the relative data obtained therefrom should form an integral part of the standard specifications in the offcial standard. 

Huckins, J.N. Petty, J.D. Lebo, J.A. Orazio, C.E. Prest, H.E Tillitt, D.E. Ellis, G.S. Johnson, B.T. Manuweera, G.K. 1996, Semipermeable Membrane Devices (SPMDs) for the Concentration and Assessment of Bioavailable Organic Contaminants in Aquatic Environments. In Techniques in Aquatic Toxicology, Ostrander, G.K., Ed. CRC Press Boca Raton, FL pp. 625-655. 

Verweij, F. Booij, K. Satumalay, K. van der Molen, N. van der Oost, R. 2004, Assessment of bioavailable PAH, PCB, and OCP concentrations in water using semipetmeable membrane devices (SPMDs), sediments and caged carp. Chemosphere 11 1675-1689. 

In regulatory assessment of bioavailability/bioequivalence, increased emphasis is being directed toward in vitro methods. 

Zhao X, Voice TC (2000) Assessment of bioavailability using a multicolumn system. Environ Sci Technol 34 1506-1512... 

ISO] International Organization for Standardization. 2008. Soil quality requirements and guidance for the selection and application of methods for the assessment of bioavailability of contaminants in soil and soil materials. Geneva ISO 17402 2008. 

Huesemann, M. H., Hausmann, T. S. Fortman, T. J. (2003). Assessment of bioavailability limitations during slurry biodegradation of petroleum hydrocarbons in aged soils. Environmental Toxicology and Chemistry, 22, 2853—60. 

A Chiral Challenge to the Pharmacokinetic and Pharmacodynamic Assessment of Bioavailability and Bioequivalence... 

In light of these developments, we felt that it was necessary to review the content of the first edition and to update or supplement the information presented in this work. The new topics examined in this edition include (1) enzymatic synthesis and resolution of enantiomerically pure compounds (Chapter 8) (2) toxicological consequences and implications of stereoselective biotransformations (Chapter 9) (3) stereoselective transport across epithelia (Chapter 10) and (4) assessment of bioavailability and bioequivalence of stereoisomeric drugs (Chapter 11). The chapter on stereoselective protein binding (Chapter 12) has been completely revmtten and new contributions are presented on the regulatory, industrial, and clinical aspects of stereoisomeric drugs (Chapters 13-16). In addition, the chapters... 

Jackson, M.J. 1997. The assessment of bioavailability of micronutrients introduction. Fur. J. Clin. Nutr. 5LS1-S2. 

Paton, G.I., Campbell, C.D., Glover, L.A. and Killham, K. (1995) Assessment of bioavailability of heavy-metals using lux modified constructs of Pseudomonas fluorescens. Letters in Applied Microbiology, 20, 52-56. 

FLS Tse, WT Robinson, MG Choc. Study design and the assessment of bioavailability and bioequivalence. In PG Welling, FLS Tse, SV Dighe, eds. Pharmaceutical Bioequivalence. New York Marcel Dekker, 1991, pp 17—34. 

II Bolaji, et al. Assessment of bioavailability of oral micronized progesterone using a salivary progesterone enzyme immunoassy. Gynecol Endocrinol 7 101, 1993. 

Speciation-solubility models deal with a closed, static, batch or beaker-type system. However, speciation-solubility models also serve as the basis for the reaction path and reactive transport models discussed below. Equilibrium calculations are also useful to evaluate kinetic rates as a function of the deviation from equilibrium. Direct applications of speciation-solubility models include assessment of bioavailability because the toxicity of some contaminants (e.g., chromium and arsenic) varies drastically for different species. 

Level 3b If it can be justified that the bioavailability model of a species within the same trophic level can be applied to those species for which no specific bioavailability model has been developed (e.g. insects, amphibians, molluscs), the option of full read-across (Level 3b) should be preferred as it can be considered the most realistic assessment of bioavailability refinement. In case of a full read-across, the chronic Daphnia magna (water flea) BLM is used to predict metal toxicity to all other invertebrates, the chronic Pseudokirchneriella subcapitata BLM to predict metal toxicity to all other algae, and the chronic Oncorhynchus mykiss (rainbow trout) BLM to predict the toxicity to all other fish, for example. 

When plasma concentration versus time data are not as obviously and clearly different, as they are in Figs 7.9 and 7.10, the following procedure is recommended for the assessment of bioavailability of two dmgs in order to make a decision as to which formulation is better. 

Rodriguez-Amaya, D.B. (2010) Quantitative analysis, in vitro assessment of bioavailability and antioxidant activity of food carotenoids - A review. J. Food Compos. Anal, 23 (7), 726-740. 

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