Preclinical study of pharmacokinetics and toxicokinetics of innovative peptide drug metilin

Relevance. Chronic heart failure (CHF) is one of the leading causes of cardiovascular mortality in Russia and abroad. 
Objective. To investigate the pharmacokinetic and toxicokinetic properties of a formulation of metilin, developed for the treatment of CHF.
Materials and methods. Peptide metilin (H-(NαMe)Arg-Pro-Arg-Leu-Ser-His-Lys-Gly-Pro-Nle-Pro-Phe-OH) was obtained by automated solid-phase synthesis using Fmoc-methodology. The drug was purified by high-performance liquid chromatography (HPLC), and its chemical structure was characterized using 1H-NMR spectroscopy and ESI-MC mass spectrometry. Metilin concentration in rabbit plasma was determined using high-performance liquid chromatography with tandem mass-selective detection (HPLC MS/MS).
Results. A pharmacokinetic study showed that metilin is characterized by a short residence time in the body (half-life 5.13±2.9 min, mean residence time 6.86±3.86 min) and a low volume of distribution (2.70±1.07 L/kg). When assessing the linearity of the concentration/dose response, higher values were noted for 1 mg/kg than for 5 mg/kg and 10 mg/kg, which is likely due to saturation of metilin binding to transport proteins. With repeated administration for 30 days, a statistically significant increase in AUC and a change in the elimination pattern were observed, indicating metilin accumulation in tissues; however, no significant toxic effects or physiological abnormalities in the condition of the animals were noted.
Conclusion. The study's results demonstrate rapid elimination and predictable dose-dependent accumulation of metilin during long-term administration, indirectly confirming its favorable toxicokinetic profile. Based on these data, phase I clinical trials of the drug can be planned.

1. Drapkina OM, Boytsov SA, Omelyanovskiy VV, et al. Socio-economic impact of heart failure in Russia. Russian Journal of Cardiology. 2021;26(6):4490. (In Russ.). doi: 10.15829/1560-4071-2021-4490.

2. Pisarenko OI, Shulzhenko VS, Studneva IM, et al. Signaling pathways of a structural analogue of apelin-12 involved in myocardial protection against ischemia/reperfusion injury. Peptides. 2015 Nov;73:67-76. doi: 10.1016/j.peptides.2015.09.001.

3. Sidorova M, Studneva I, Bushuev V, et al. [MeArg1, NLe10]-apelin-12: Optimization of solid-phase synthesis and evaluation of biological properties in vitro and in vivo. Peptides. 2020 Jul;129:170320. doi: 10.1016/j.peptides.2020.170320.

4. Pisarenko O, Shulzhenko V, Studneva I, et al. Structural apelin analogues: mitochondrial ROS inhibition and cardiometabolic protection in myocardial ischaemia reperfusion injury. Br J Pharmacol. 2015 Jun;172(12):2933-45. doi: 10.1111/bph.13038.

5. Federal Law of 12.04.2010 No. 61-FZ "On the Circulation of Medicines" (as amended and supplemented) (In Russ.).

6. Decision of the EEC Council No. 81 “On approval of the rules of good laboratory practice of the Eurasian Economic Union in the field of circulation of medicines” dated 03.11.2016. (In Russ.).

7. Knorr R, Trzeciak A, Bannwarth W, Gillessen D. New coupling reagents in peptide chemistry. Tetrahedron Letters. 1989:30(15);1927-1930. doi: 10.1016/S0040-4039(00)99616-3.

8. Guide for the care and use of laboratory animals. The National Academy press. – Washington, D.C. 2011

9. Grubb's Test for Detecting Outliers. URL: http://graphpad.com/quickcalcs/GrubbsExplain.cfm

10. Medicines for medical use — Preclinical toxicological and pharmacokinetic safety studies (GOST 56702 2015 (approved on 11.11.2015). (In Russ.).