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Abstract

The use of radiolabeled molecules allows a drug and its labeled metabolites to be followed throughout the body and excreta over time. The radioactivity concentration can be tracked in blood and plasma as well as in tissues. Whether the drug with its specific radioactivity administered to the body is completely captured can be proven by calculating the so-called mass balance.

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Notes

  1. 1.

    The estimation of the drug absorption (not to be mixed up with bioavailability) using non-radiolabeled drugs and not using the mass balance approach would be much less reliable, since the entity of metabolites cannot be captured in the matrices necessary to be followed, normally.

  2. 2.

    Half-life of 5,730 year for 14C, making an half-life correction unnecessary. As a weak β – radiator (up to 156 keV) the risk of handling is an acceptable compromise in the laboratory (protection area!).

  3. 3.

    Imagine the case of a projected nonabsorbable drug, for instance, for topical application, and the situation of having detected 3% absorption with a radioanalytical purity of the labeled drug of 97%. Or imagine the case of a minor part of radioactivity with a long terminal half-life suggesting a metabolite with an accumulation potency. The radioactivity represents the sum of the original compound and/or radioactive-labeled metabolites and not to forget possible synthetic side-products which can be present in traces (depending on the purity and content of the synthetic material). Discussing traces of radioactivity, for instance, traces crossing the placenta, keep in mind that these traces may be due to synthetic side-products. Thus, whenever possible try to use radiolabeled compound as clean as possible.

  4. 4.

    For instance, in case of urine samples when the quench is in the range of the calibration curve or bile samples.

  5. 5.

    For instance, with Solvable® from Perkin Elmer for dissolution and H2O2 for discoloration.

  6. 6.

    For instance, with a Tri-Carb® 307 combuster which can be equipped with a robot unit for automatic sample handling from Perkin Elmer. Since carry-over effects are not negligible in case a low radioactivity sample follows a high radioactivity sample, a reasonable arrangement of samples in a sequence is essential.

  7. 7.

    It might be necessary to use a normalized apparent collection interval for graphical reasons in case of dissimilar collection intervals.

  8. 8.

    Instead of the collection interval, the mean time of the collection period is often used in the graphic presentations.

  9. 9.

    Via determination of the rate constant which is calculated by linear regression of ln concentration on time using a least three data points which appeared to be randomly distributed about a single straight line. Half-lives were calculated as ln2/rate constant.

  10. 10.

    The following equation describes the percent of total radioactivity in plasma relative to total radioactivity in blood

    $$ \begin{array}{ll} {\text{Plasma/Blood}}\,{(}\% {)} & = \frac{{({V_B}) \times (P \times [1 - HCT])}}{{({V_B} \times B)}} \times 100 \\ & = \frac{{P \times (1 - HCT)}}{B} \times 100 \end{array} $$

    where

    • VB = volume of blood

    • P = drug concentration in plasma

    • B = drug concentration in blood

    • HCT = hematocrit

  11. 11.

    An example where this assumption is not fulfilled is described by Okuyama et al. (1997); consequently the authors only mention the ratio of AUCs after oral and intravenous administration and do not correlate this ratio to absorption.

  12. 12.

    Mass balance results in rats, mice, dogs, monkeys, and humans after administration of the same drug, including bile excretion results from rat, dog, monkey, and human (!), are described by Donglu Zhang.

  13. 13.

    For an example of a mass balance study in mice (besides rat and dog) refer to Miraglia L.

  14. 14.

    It might be necessary to use a normalized apparent collection interval for graphical reasons in case of dissimilar collection intervals.

  15. 15.

    Instead of the collection interval, the mean time of the collection period is often used in the graphic presentations.

  16. 16.

    Via determination of the rate constant which is calculated by linear regression of ln concentration on time using a least three data points which appeared to be randomly distributed about a single straight line. Half-lives were calculated as ln2/rate constant.

  17. 17.

    The following equation describes the percent of total radioactivity in plasma relative to total radioactivity in blood:

    $$ \begin{array}{ll}{\text{Plasma/Blood}}\,{(}\% {)} & = \frac{{({V_B}) \times (P \times [1 - HCT])}}{{({V_B} \times B)}} \times 100 \\ & = \frac{{P \times (1 - HCT)}}{B} \times 100 \end{array} $$

    where:

    • VB = Volume of blood

    • P = Drug concentration in plasma

    • B = Drug concentration in blood

    • HCT = Hematocrit

  18. 18.

    For instance, blood of exsanguination collected after heart puncture; jugularis puncture, jugularis or carotis catheter, retroorbital blood, blood from the vena femoralis, sublingual blood after short narcosis or blood from the tail vein.

  19. 19.

    Caution: The administration should not be done at the site of sample collection to avoid contamination. For instance, an i.v. administration into the vena femoralis after a short transient anesthesia can be recommended.

  20. 20.

    Instead of an oral an intra-duodenal administration should be chosen, when using anesthetized animals.

  21. 21.

    The procedure as described in the main part still has supporters. See Hoehle et al. (2009).

  22. 22.

    Can be easily constructed connecting a water-jet pump with a microwash bottle; an Eppendorf vessel is placed under the inlet tube; at the other end the inlet tube is fitted with a polyethylene tube and a microfunnel.

    The “microwash bottle” can be assembled from a 15-mL scintillation vessel with two openings in the lid and polyethylene tubing.

References and Further Reading

  • Bermejo M, Gonzalez-Alvarez I (2008) Preclinical development handbook. In: Gad SC (ed) How and where are drugs absorbed? Chapter 8. Wiley, Hoboken, pp 249–280

    Google Scholar 

  • Beumer JH, Eiseman JL, Merrill JE (2008) Preclinical development handbook. In: Gad SC (ed) Mass balance studies, chapter 33. Wiley, Hoboken, pp 103–1131

    Google Scholar 

  • Bornschein RL, Fox DA, Michaelson LA (1977) Estimation of daily exposure in neonatal rats receiving lead via dam’s milk. Toxicol Appl Pharmacol 40:577–587

    Article  PubMed  CAS  Google Scholar 

  • Bruin GJM, Faller T, Wiegand H, Schweitzer A, Nick H, Schneider J, Boernsen K, Waldmeier F (2008) Pharmacokinetics, distribution, metabolism, and excretion deferasirox and its iron complex in rats. Drug Metab Dispos 36(12):2523–2538

    Article  PubMed  CAS  Google Scholar 

  • Cartwright AC, Matthews BR (eds) (1994) International pharmaceutical product registration, aspects of quality, safety and efficacy. Taylor & Francis, London, 581ff

    Google Scholar 

  • Chen L-J, Lebetkin EH, Nwakpuda EI, Burka LT (2007) Metabolism and disposition of n-butyl glycidyl ether in F344 rats and B6C3F1 mice. Drug Metab Dispos 35(12):2218–2224

    Article  PubMed  CAS  Google Scholar 

  • Chiou WL (1989) The phenomenon and rationale of marked dependence of drug concentration on blood sampling site, implications in pharmacokinetics. Pharmacodynamics, toxicology and therapeutics (Part I and II). Clin Pharmacokinet 17:175–199, 275–290

    Article  PubMed  CAS  Google Scholar 

  • Davis CB, Crysler CS, Boppana VK et al (1994) Disposition of growth hormone-releasing peptide (SK&F 110679) in rat and dog following intravenous or subcutaneous administration. Drug Metab Dispos 22:90–98

    PubMed  CAS  Google Scholar 

  • Dix KJ, Coleman DP, Fossett JE et al (2001) Disposition of propargyl alcohol in rat and mouse after intravenous, oral, dermal and inhalation exposure. Xenobiotica 31:357–375

    Article  PubMed  CAS  Google Scholar 

  • Dyer A (1980) Liquid scintillation counting practice. Heyden & Son, London/Philadelphia

    Google Scholar 

  • Endo M, Yamada Y, Kohno M et al (1992) Metabolic fate of the new angiotensin-converting enzyme inhibitor Imidapril in animals. Arzneim Forsch/Drug Res 42:483–489

    CAS  Google Scholar 

  • Gledhill A, Wake A, Hext P, Leibold E, Shiotskuka R (2005) Absorption, distribution, metabolism and excretion of an inhalation dose of [14C] 4,40-methylenediphenyl diisocyanate in the male rat. Xenobiotica 35(3):273–292

    Article  PubMed  CAS  Google Scholar 

  • González JE, León M, Hernández I, Garrido G, Casacó A (2011) Effect of the maternofetal and milk transfer of the anti-epidermal growth factor receptor monoclonal antibody 7A7 in mice. Placenta 32:470–474

    Article  PubMed  Google Scholar 

  • Granero L, Polache A (2008) Preclinical development handbook. In: Gad SC (ed) Absorption of drugs after oral administration, chapter 9. Wiley, Hoboken, pp 281–321

    Google Scholar 

  • Herman JL, Chay SH (1998) Quantitative whole-body autoradiography in pregnant rabbits to determine fetal exposure of potential teratogenic compounds. J Pharmacol Toxicol Methods 39:29–33

    Article  PubMed  CAS  Google Scholar 

  • Hoehle SI, Knudsen GA, Sanders JM, Sipes IG (2009) Absorption, distribution, metabolism, and excretion of 2,2-Bis(bromomethyl)-1,3-propanediol in male Fischer-344 rats. Drug Metab Dispos 37(2):408–416

    Article  PubMed  CAS  Google Scholar 

  • Hoffmann HD, Leibold E, Ehnes C, Fabian E, Landsiedel R, Gamer A, Poole A (2010) Dermal uptake and excretion of 14 C-toluene diisocyante (TDI) and 14 C-methylene diphenyl diisocyanate (MDI) in male rats. Clinical signs and histopathology following dermal exposure of male rats to TDI. Toxicol Lett 199:364–371

    Article  PubMed  CAS  Google Scholar 

  • Huskey S-EW, Dean BJ, Doss GA, Wang Z, Hop CECA, Anari R, Finke PE, Robichaud AJ, Zhang M, Wang B, Strauss JR, Cunningham PK, Feeney WP, Franklin RB, Baillie TA, Chiu S-HL (2004) The metabolic disposition of aprepitant, a substance p receptor antagonist, in rats and dogs. Drug Metab Dispos 32(2):246–258

    Article  PubMed  CAS  Google Scholar 

  • Johnson P, Rising PA (1978) Techniques for assessment of biliary excretion and enterohepatic circulation in the Rat. Xenobiotica 8:27–36

    Article  PubMed  CAS  Google Scholar 

  • Koyama K, Takahashi M, Nakai N, Takakusa H, Murai T, Hoshi M, Yamamura N, Kobayashi N, Okazaki O (2010) Pharmacokinetics and disposition of CS-8958, a long-acting prodrug of the novel neuraminidase inhibitor laninamivir in rats. Xenobiotica 40(3):207–216

    Article  PubMed  CAS  Google Scholar 

  • Krishna R, Yao M, Srinivas NR et al (2002) Disposition of radiolabeled BMS-204352 in rats and dogs. Biopharm Drug Dispos 23:41–46

    Article  PubMed  CAS  Google Scholar 

  • Krull I, Swartz M (1998) Determining limits of detection and quantitation. Liq Chromatogr Gas Chromatogr 16:922–924

    CAS  Google Scholar 

  • Mano Y, Sonoda T, Nakamura E, Usui T, Kamimura H (2004) Absorption, distribution, metabolism and excretion of YM466, a novel factor Xa inhibitor, in rats. Biopharm Drug Dispos 25:253–260

    Article  PubMed  CAS  Google Scholar 

  • Mathews JM, Black SR, Burka LT (1998) Disposition of butanal oxime in rat following oral, intravenous and dermal administration. Xenobiotica 28:767–777

    Article  PubMed  CAS  Google Scholar 

  • Mepham TB (1983) Biochemistry of Milk. In: “Milk Yield” in Chapter 1, Physiological aspects of lactation. Elsevier, Amsterdam/New York, pp. 3–28

    Google Scholar 

  • Miraglia L, Pagliarusco S, Bordini E, Martinucci S, Pellegatti M (2010) Metabolic disposition of casopitant, a potent neurokinin-1 receptor antagonist, in mice, rats, and dogs. Drug Metab Dispos 38(10):1876–1891

    Article  PubMed  CAS  Google Scholar 

  • Mun JG, Grannan MD, Lachcik PJ, Reppert A, Yousef GG, Rogers RB, Janle EM, Weaver CM, Lila MA (2009) In vivo metabolic tracking of 14 C-radiolabelled isoflavones in kudzu (Pueraria lobata) and red clover (Trifolium pratense) extracts. Br J Nutr 102:1523–1530

    Article  PubMed  CAS  Google Scholar 

  • Okuyama Y, Momota K, Morino A (1997) Pharmacokinetics of prulifloxacin. Arzneim Forsch/Drug Res 47:276–284

    CAS  Google Scholar 

  • Oskarsson A, Möller N (2004) A method for studies on milk excretion of chemicals in mice with 2,2,4,4,5-pentabromodiphenyl ether (BDE-99) as a model. Toxicol Lett 151:327–334

    Article  PubMed  CAS  Google Scholar 

  • Pohland RC, Vavrek MT (1991) Ameltolide II: placental transfer of radiocarbon following the oral administration of a novel anticonvulsant in rats. Teratology 44:45–49

    Article  PubMed  CAS  Google Scholar 

  • Saillenfait AM, Payan JP, Beydon D et al (1997) Assessment of the developmental toxicity, metabolism, and placental transfer of N, N-Dimethylformamide administered to pregnant rats. Fundam Appl Toxicol 39:33–43

    Article  PubMed  CAS  Google Scholar 

  • Simonsen L, Petersen MB, Benfeldt E, Serup J (2002) Development of an in vivo animal model for skin penetration in hairless rats assessed by mass balance. Skin Pharmacol Appl Skin Physiol 15:414–424

    Article  PubMed  CAS  Google Scholar 

  • Sumner SCJ, Fennell TR, Snyder RW, Taylorc GF, Lewinc AH (2010) Distribution of carbon-14 labeled C60 ([14 C] C60) in the pregnant and in the lactating dam and the effect of C60 exposure on the biochemical profile of urine. J Appl Toxicol 30(4):354–360

    PubMed  CAS  Google Scholar 

  • Suwelack D, Weber H, Maruha D (1985) Pharmacokinetics of Nimodipine. Arzneim Forsch/Drug Res 35:1787–1794

    CAS  Google Scholar 

  • Tanayama S, Momose S, Kanai Y, Shirakawa Y (1974) Metabolism of 8-chloro-6-phenyl-4 H-s-triazolo[4,3-a][1,4]benzodiazepine (D-40TA), a new central depressant IV. Placental transfer and excretion in milk in rats. Xenobiotica 4:219–227

    Article  PubMed  CAS  Google Scholar 

  • Thomas CR, Lowy C (1995) Bidrectional placental transfer (“leak”) of L-glucose in control and diabetic rats. Acta Diabetol 32:23–27

    Article  PubMed  CAS  Google Scholar 

  • Tse FLS, Ballard F, Jaffe JM, Schwarz HJ (1983) Enterohepatic circulation of radioactivity following an oral dose of [14 C]temazepam in the rat. J Pharm Pharmacol 35(4):225–228

    Article  PubMed  CAS  Google Scholar 

  • Umehara K-I, Seya K, Iwatsubo T, Noguchi K, Usui T, Kamimura H (2008) Tissue distribution of YM758, a novel If channel inhibitor, in pregnant and lactating rats. Xenobiotica 38(10):1274–1288

    Article  PubMed  CAS  Google Scholar 

  • Wang L, He K, Maxwell B, Grossman SC, Tremaine LM, Humphreys WG, Zhang D (2011) Tissue distribution and elimination of [14 C]apixaban in rats. Drug Metab Dispos 39(2):256–264

    Article  PubMed  CAS  Google Scholar 

  • Webber C, Stokes CA, Persiani S et al (2004) Absorption, distribution, metabolism and excretion of the cholecystokinin-1 antagonist dexloxiglumide in the dog. Eur J Drug Metab Pharmacokinet 29:15–23

    Article  PubMed  CAS  Google Scholar 

  • Xu L, Woodworth J, Yang L, Klunk LJ, Prakash C, Dawson K, Stecher S (2009) Metabolism and excretion of BG12 in rats and humans following oral administration of a single oral dose of [14 C]BG12. Drug Metabol Rev 41(Suppl 3):133

    Google Scholar 

  • Zhang D, Wang L, Raghavan N, Zhang H, Li W, Cheng PT, Yao M, Zhang L, Zhu M, Bonacorsi S, Yeola S, Mitroka J, Hariharan N, Hosagrahara V, Chandrasena G, Shyu WC, Griffith Humphreys W (2007) Comparative metabolism of radiolabeled muraglitazar in animals and humans by quantitative and qualitative metabolite profiling. Drug Metab Dispos 35(1):150–167

    Article  PubMed  CAS  Google Scholar 

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Correspondence to Volker Krone .

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Krone, V. (2013). Absorption: In Vivo Tests (Radiolabeled). In: Vogel, H.G., Maas, J., Hock, F.J., Mayer, D. (eds) Drug Discovery and Evaluation: Safety and Pharmacokinetic Assays. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-25240-2_33

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