Vol 52, No 9 (2018)

Literature data and domestic and foreign methodological documentation for preclinical studies of the safety and toxicokinetics of pharmaceuticals are analyzed. According to Marketing Authorization and Assessment Rules for Medicinal Products in the EAEU, a developer must include in a General Technical Document information on toxicokinetic studies that is evaluated during a review of preclinical test results. The main approaches to expert evaluation of drug toxicokinetic studies are formulated. The main content of the expert analysis includes the methodological basis and results of the research, safety profile characteristics, extrapolation of preclinical data, risk factor characteristics, and predicted clinical patient safety profile. The inclusion of toxicokinetic studies in a program of preclinical toxicological studies is important in principle for an adequate extrapolation of experimental data and prediction of the safety of pharmaceuticals in humans. Expert analysis of toxicokinetic data allows toxicology study results, drug toxicity profile characteristics, and the risk of toxic side effects to be interpreted correctly.

A structure–activity relationship model was constructed to predict adverse drug effects on the cardiovascular system. Models were constructed using sets of drug structures compiled by us with information about adverse effects from analyses and data integrated from various sources. The five most common cardiovascular adverse effects, i.e., myocardial infarction, ischemic stroke, cardiac failure, ventricular tachycardia, and arterial hypertension were analyzed in the work. The PASS software that has proved to be efficient in numerous studies was used to construct the appropriate models. The obtained models were accurate enough to be useful for estimating cardiovascular adverse effects of new drugs. An appropriate evaluation could be made in the very early stages of drug discovery because only the structural formula was needed for the prediction.

A dimeric dipeptide mimetic of brain-derived neurotrophic factor loop 2, bis-(N-hexanoyl-seryl-lysine) hexamethylenediamide or GTS-201, was designed and synthesized. It exhibited neuroprotective activity at concentrations of 10^–5 – 10^–8 M in HT-22 immortalized hippocampal neuronal cell culture under H₂O₂-induced oxidative stress. Western-blot analysis showed that it activated TrkB receptors and Erk but not Akt. GTS-201 did not exhibit antidepressant activity in a Porsolt forced swim test on BALB/c mice at i.p. doses of 0.1, 1.0, and 5.0 mg/kg, in contrast with previously synthesized GSB-106, a dimeric dipeptide mimetic of loop 4. The results confirmed the previous original hypothesis about the possible discrimination of neurotrophin functions by low-molecular-mass mimetics of their separate loops.

A composition and preparation method for new analgesic rectal suppositories containing a nonsteroidal anti-inflammatory drug (ketorolac), tricyclic antidepressant (amitriptyline), and transmucosal conductor (silicon glycerolates) as the active ingredients in a poly(ethylene glycol) (PEG-4000) base were proposed. The acute toxicity was determined and showed they were safe to use. The high analgesic activity of the suppositories was confirmed using electrical stimulation. Their high transmucosal activity in vitro was revealed by measuring the degree of diffusion of one of the active ingredients (amitriptyline) through a natural biological membrane. The results indicated that the developed suppositories could be recommended for further investigations of future medical use to relieve pain of various etiologies.

A spectrophotometric assay for ormustine active ingredient for a liposomal dosage form with antitumor activity was selected and validated for specificity, linearity, accuracy, precision, and intermediate (intralaboratory) precision in order to ensure accurate and precise results. The obtained statistical characteristics were shown to satisfy acceptance criteria for the validation parameters given in domestic regulatory documentation. Ormustine was determined at 396 ± 2 nm because excipients in the dosage form did not absorb in this spectral region. The correlation coefficient for the linearity was >0.997. The relative error of the mean result was <1% for the accuracy. The confidence interval included 100%. The coefficient of variation for the precision and intermediate precision determinations was <1%. The studied method could be used in the range 80 – 120% of the nominal ormustine content in the liposomal dosage form.

A quantitative spectrophotometric determination method for papaverine in medicinal preparations based on formation of a colored ionic associate of papaverine, Ti(IV), and bromopyrogallol red (BPR) was developed. The conditions for forming {[TiO(H₂R)₂]^2– · 2PP⁺} were determined. Addition of papaverine to a solution of anionic Ti-BPR caused a bathochromic shift to 640 nm with a simultaneous intensity gain. The molar absorption coefficient (ε = 8,800) indicated that the reaction was rather sensitive. The specificity of the reaction for papaverine enabled it to be determined without separating excipients. The method was highly sensitive, simple to perform, and adaptable to scale up. Toxic reagents were not required. The results had good precision (S_r = 0.007 – 0.02) and accuracy.

Planning issues for darunavir (DRV) bioequivalence studies are considered. DRV is an antiviral (HIV) agent classified as an HIV protease inhibitor. Bioequivalence test results must be submitted for registration of generic drugs in the RF according to Federal Law 61-FZ. Bioequivalence study protocols and reports for DRV preparations that were submitted for review to the SCEEMP were analyzed. Differences in study designs including administration after fasting or meals, with or without a low dose of ritonavir, numbers of volunteers included in the study, and intra-subject variability were found. The internet was also searched for data on DRV variability. Recommendations for planning bioequivalence studies of DRV preparations were formulated based on the analysis.

An efficient synthesis of 21-acetoxypregna-1,4,9(11),16-tetraene-3,20-dione, a key intermediate in the synthesis of highly active fluorinated corticosteroids from phytosterols, was developed. The method consisted of an original sequence of chemical and microbiological reactions and could be used to synthesize betamethasone, sinaflan, triamcinolone, and other fluorinated corticoids.

The physicochemical properties of the novel original anxiolytic GML-1 drug substance were studied, analytical techniques for it were developed, and its main pharmacopoeial quality parameters were determined using IR spectroscopy, UV spectrophotometry, HPLC, and the Kjeldahl method.