Study of pharmacokinetic of new peptide drug 1-deamino-arginine-vasotocin for hypernatremia correction

Introduction: The pharmacokinetics studies are some of the necessary parts of the drugs preclinical investigations. Pharmacokinetic properties of new peptide drug 1-deamino-arginine-vasotocin (dAVT) in the form of an injection solution for intravenous and intramuscular administration for hypernatremia correction were investigated.

Materials and methods: The study was carried out on male rats and rabbits with a single intravenous administration of the drug in three doses, a single intramuscular administration in one dose and multiple administration to rats in one dose. To determine natriiuretic peptide concentration in blood plasma, tissues, and excretes, assays based on a sodium level change measurement using a biochemical analyzer have been developed and validated. Pharmacokinetic parameters were calculated by the model-independent method of statistical moments.

Results and discussion: The pharmacokinetics of the drug was found to be linear after a single administration of dAVT drug in the dose range 3–10 μg/kg for rats and rabbits. The relative bioavailability of dAVT after intramuscular and intravenous administrations was more than 30%. After a biomarker content change, the active substance was intensively distributed into highly vascularized organs (spleen), the organs that provide metabolism and subsequent excretion (liver and kidneys), whereas it hardly reached moderately and weakly vascularized tissues (muscles, omentum). Less than 10% dAVT was excreted with urine; no dAVT was determined in feces; and repeated administration did not lead to its cumulation.

Conclusion: Pharmacokinetics parameters of new nonapeptide drug 1-deamino-arginine-vasotocin were evaluated after original analytical biomarker approach. The study included all main areas necessary to characterize the original drug pharmacokinetic.

Comparison of biomarker and chromatographic analytical approaches to pharmacokinetic study of sitagliptin

The pharmacokinetic profiling of active compounds is necessary for drug development and application. Approaches to a pharmacokinetic study based on biological markers are alternatives to traditional approaches based on chromatographic methods. The aim of the study was to compare two analytical approaches to pharmacokinetics investigation for an example of sitagliptin in rabbits after one dose oral administration. The method for sitagliptin quantification in rabbit plasma samples based on a correlation between its concentration and dipeptidyl peptidase IV activity was proposed, validated, and applied. The high-performance liquid chromatography (HPLC)-ultraviolet (UV) method was also validated and applied for the same sample analysis. The plasma pharmacokinetics of sitagliptin after oral administration to the rabbits in one dose was characterized after two analytical assays. The close values of the main pharmacokinetic parameters were obtained after two approaches. The nontraditional approach based on correlation of special marker activity and active substance concentration appears to be more sensitive than HPLC-UV. Thus, the sitagliptin concentrations determined by biomarker assay were higher than the lower limit of quantification (LLOQ) for a longer period (more timepoints) than after the HPLC-UV assay. This feature may influence the values of some calculated concentration-dependent (area under the curve [AUC]_0-t , etc.) and time-dependent parameters (mean residence time [MRT], T_1/2 , etc.). The values of T_max obtained by the two approaches were similar and adequate for oral drug administration that confirms the correctness of biomarker selection for pharmacokinetics assessment. The obtained results on the example of sitagliptin confirms that the biomarker approach is adequate and applicable for a pharmacokinetics study. Similar approaches may be effective for individual compounds and complex mixtures when it is difficult or impossible to analyze them traditionally by chromatographic methods.

Therapeutic efficacy of arginine-rich exenatide on diabetic neuropathy in rats

Diabetes mellitus is characterized by metabolic dysregulation associated with a number of health complications. More than 50% of patients with diabetes mellitus suffer from diabetic polyneuropathy, which involves the presence of peripheral nerve dysfunction symptoms. The aim of this study was to evaluate the potential of a new synthetic arginine-rich exendin-4 (Peptide D) in the treatment of complications caused by diabetes, including peripheral neuropathy, in rats. Diabetes was induced by administering streptozotocin (STZ). Three groups of diabetic rats were treated with Peptide D (0.1, 1, and 10 μg/kg). One group of diabetic rats was treated with Byetta® (1 μg/kg) for 80 days. Neuropathic pain development was assessed by tactile allodynia. STZ-treated rats showed an increased level of tactile allodynia unlike naïve animals. A histological study revealed that the diameter of the sciatic nerve fibers in STZ-treated rats was smaller than that of the naïve animals. An IHC study demonstrated decreased expression of myelin basic protein (MBP) in the sciatic nerve of diabetic rats compared to that in the naïve animals. Peptide D reduced the severity of tactile allodynia. This effect was more pronounced in the Peptide D treated groups than in the group treated with Byetta®. Peptide D and Byetta® treatment resulted in increased MBP expression in the sciatic nerve and increased diameter of myelinated nerve fibers. These findings suggest that poly-arginine peptides are promising agents for the treatment of peripheral polyneuropathies.

[Evaluation of the cardioprotective effect of ubiquinol on the model of reperfusion injury of rat myocardium]

The cardioprotective effect of ubiquinol on the model of myocardium reperfusion injury in rats was investigated. The study was carried out using mature males of outbred rats. Myocardial ischemia-reperfusion injury was performed after 30-minute ligation of the left coronary artery followed by reperfusion. The main criteria for assessing the development of pathology included the results of electrocardiography, biochemical analysis of blood plasma, histological and histochemical study of the myocardium. Development of the reperfusion damage of the myocardium caused specific changes in non-treated animals. The best therapeutic effect on biochemical indices was provided by a drug with the known cardioprotective activity - Mexidolâ and the tested object ubiquinol at doses of 2-6 mg/kg. Evaluation of the results of electrocardiography allowed to confirm the development of ischemic myocardial damage in all groups. The results of histochemical and histological examination of the myocardium suggest a high cardioprotective activity of ubiquinol at a dose of 3 mg/kg and a potential cardioprotective effect of ubiquinol in doses closest to the therapeutic doses of 2 and 6 mg/kg. Ubiquinol is a dose 9 mg/kg showed signs of prooxidant activity, manifested in the form of aggravation of reperfusion injury of the myocardium. The most effective in the conditions of experimental pathology is 1% solution of ubiquinol, at a dose of 3 mg/kg, whose cardioprotective effect is comparable or higher than that for the reference drug Mexidolâ at the therapeutic dose. In doses that are greater than therapeutic ubiquinol is able to act as a pro-oxidant.

[A study of combination treatment with nacom (levodopa + carbodope) and citicoline in the model of Parkinson disease in rats]

AIM

To evaluate the efficacy of the combined use of citicoline (neipilept) and levodopa/carbidopa (nakom) in the rotenone model of Parkinson's disease in rats.

MATERIAL AND METHODS

Rotenone was administrated during 14 days in dose 2 mg/kg/day subcutaneously. The duration of treatment was 7 days, intragastrically. Alteration of locomotor behavior components, muscular rigidity in resistance to passive flexion in the ankle joint and signs of extrapyramidal disorders were assessed.

RESULTS AND CONCLUSION

Combined therapy led to the decrease in muscle rigidity (the decrease of gibbosity in resistance to passive flexion in the ankle joint). There was a decrease in oligokinesia that emerged in higher vertical and horizontal locomotor activity of experimental animals, decrease in the time of head turning during climbing down the pole and total time of climbing down the pole. The combination of drugs had a more pronounced therapeutic effect on extrapyramidal disorders compared to monotherapy.

A new tridecapeptide with an octaarginine vector has analgesic therapeutic potential and prevents morphine-induced tolerance

A growing body of evidence suggests that peptides may possess analgesic effects without tolerance development. The synthetic tetrapeptide Tyr-d-Arg-Phe-Gly-NH₂ was modified with the inclusion of a (d-Arg)₈ vector to prevent the action of endopeptidase and to increase the duration of the analgesic action of the tetrapeptide when administered orally. The aim of this study was to estimate the analgesic efficacy of the tetrapeptide with (d-Arg)₈ (tridecapeptide, TDP) in experimental models of acute and chronic pain. The analgesic effects of TDP were estimated using a model of acute visceral pain in mice (writhing test) and a model of chronic neuropathic pain (chronic constriction injury (CCI) of the sciatic nerve) in rats. The intravenous administration of morphine (0.32-1mg/kg) and TDP (0.32-1.8mg/kg) produced significant dose-related antinociceptive effects in the writhing test. The potency of TDP after i.g. administration was lower than that after i.v. administration but comparable with that of i.g. morphine. In the CCI model, TDP (0.1, 1 and 10mg/kg, i.g.) induced marked analgesia with repeated administration without any signs of tolerance. The single administration of TDP after morphine treatment (7days) produced a significant analgesic effect in morphine-tolerant rats, indicating the absence of cross-tolerance between these two drugs. The combined administration of TDP and morphine resulted in the reduction of analgesic tolerance to morphine. The absence of cross-tolerance to morphine and the ability to prevent morphine tolerance allows this compound to be a prospective candidate for chronic pain therapy. In order to find the target receptors for TDP, a docking study was performed. It was found that the molecule can bind to the NMDA receptor using electrostatic, hydrogen bonding and hydrophobic interactions.

Chemical Profiling and Bioactivity of Body Wall Lipids from Strongylocentrotus droebachiensis

The lipids from gonads and polyhydroxynaphthoquinone pigments from body walls of sea urchins are intensively studied. However, little is known about the body wall (BW) lipids. Ethanol extract (55 °C) contained about equal amounts of saturated (SaFA) and monounsaturated fatty acids (MUFA) representing 60% of total fatty acids, with myristic, palmitic and eicosenoic acids as major SaFAs and MUFAs, respectively. Non-methylene-interrupted dienes (13%) were composed of eicosadienoic and docosadienoic acids. Long-chain polyunsaturated fatty acids (LC-PUFA) included two main components, n6 arachidonic and n3 eicosapentaenoic acids, even with equal concentrations (15 μg/mg) and a balanced n6/n3 PUFA ratio (0.86). The UPLC-ELSD analysis showed that a great majority of the lipids (80%) in the ethanolic extract were phosphatidylcholine (60 μg/mg) and phosphatidylethanolamine (40 μg/mg), while the proportion of neutral lipids remained lower than 20%. In addition, alkoxyglycerol derivatives-chimyl, selachyl, and batyl alcohols-were quantified. We have assumed that the mechanism of action of body wall lipids in the present study is via the inhibition of MAPK p38, COX-1, and COX-2. Our findings open the prospective to utilize this lipid fraction as a source for the development of drugs with anti-inflammatory activity.

[Cardioprotective effect of new functional food containing salmon oil with motherwort oil extract]

Combination of fish oil with herbal oil extract can extend functional properties of the products. A new functional food of salmon oil with oil extract of motherwort (8:2) was developed and studied. Qualitative profiling was evidenced about presence of flavonoids and iridoids. Quantification of vitamins A (210±3 IU/g), Е (2.8±0.1 mg/g), D3 (12.2±0.4 IU/g) and PUFA (43.3±0.4%, incl. 9.4±0.1% of omega-3 and 33.9±0.1% of omega-6) was done by modern methods. The developed product was found nontoxic (LD50>15 000 mg/kg b.w., intragastriсally, LD50>3000 mg/kg b.w., intraperitoneal). The 14 days intragastric administration of product to the rats (initial b.w. 200-250 g) at the doses of 2340 and 1170 mg/kg b.w. significantly increased the left ventricular pressure after ischemia comparing with control, and normalized the contraction and relaxation of the left ventricle. Biochemical data confirmed the decrease of aspartate amino transferase and creatine kinase activity in rats treated at all experimental doses. Application of fish oil combination with motherwort oil extract is promising for development of new functional foods with cardio protective properties.

[EXPERIMENTAL MODELS OF ALCOHOLIC NEUROPATHY IN RATS.]

The aim of this work was to study the behavioral and histopathomorphological signs of peripheral neuropathy development in male Wistar rats on the model of alcoholic neuropathy. Chronic consumption of ethanol solution with concentration increasing from 7.47 to 26.2% (w/w) resulted in neuropathy (allodynia) de- velopment after 8 weeks of chronic alcohol administration. The behavioral signs of allodynia became significant on the 8th week and were retained up to the end of experiment (15 weeks of ethanol administration). The reference drug gabapentin effectively reduced the manifestation of allodinia. Histological exami- nation of sciatic nerve preparations from animals killed after ethanol consumption for 5, 10 and 15 weeks revealed the development of histopathomorphological pattern with increasing duration of chronic alcoholization. At the initial stage, the morphological basis of observed behavioral manifestations was provided by excess lipid deposition in peri/epineurium of nerve specimens). The further increase in treatment duration (up to 10 and 15 weeks) was associated with demye- lination and development of inflammation of the sciatic nerve. This experimental model allows one to investigate the efficacy of new neuroprotective and ana- lgesic substances - potential drugs for both prevention and management of neuropathy.

COMPARATIVE STUDY OF TWO EXPERIMENTAL MODELS OF CHRONIC ARTHRITIS IN RATS

This work was aimed at comparative analysis of the two experimental models of chronic arthritis induced in rats by the administration of (i) complete Freund's adjuvant (CFA) and (ii) carrageenan. The clinical and histological signs of pathology were assessed using a categorical rating system. It is established that the administration of CFA leads to the development of pathology closely resembling rheumatoid arthritis. In contrast, the administration of c.arrageenan promotes chronic inflammatory arthritis without autoimmune component. The results can serve a basis for selecting a methodological approach to assess the effectiveness of drugs with anti-rheumatoid, anti-inflammatory, and/or immunomodulatory properties.

Bergenia crassifolia (L.) Fritsch--pharmacology and phytochemistry

PURPOSE

Bergenia crassifolia (L.) Fritsch, a species in the Bergenia genus belongs to the family Saxifragaceae, is valuated for its medicinal application. The review focuses on the medicinal uses, phytochemistry, and the biological activities of B. crassifolia to explore its benefits and potential uses.

METHODS

In this review, we summarized data, published in Russia and in other countries related to B. crassifolia.

RESULTS

Rhizomes and leaves of this plant are in use as traditional remedies for the treatment of different disorders in the folk medicine systems of Russia and Asia. The plant is a potential source of tannins, benzanoids, flavonoids, polysaccharides and other active compounds. Due to the presence of a multitude of bioactives, a wide array of pharmacological activities have been ascribed to different parts of this herb and individual compounds, which include adaptogenic, antiinflammatory, antihypertensive, antimicrobial, antioxidant, antiobesity, antitussive, cerebro-protective, hepatoprotective, immunomodulating, and diuretic.

CONCLUSION

The review highlights the potential of B. crassifolia for further development of herbal medicines on its base.

Antiallergic effects of pigments isolated from green sea urchin (Strongylocentrotus droebachiensis) shells

This study was undertaken to evaluate possible antiallergic effects of an extract of pigments from green sea urchin (Strongylocentrotus droebachiensis) shells. Effects were studied on animal models - guinea pig ileum contraction, rabbit eyes allergic conjunctivitis, and rabbit local skin irritation. The extract significantly reduced, in a dose-dependent manner, the histamine-induced contractions of the isolated guinea pig ileum with ID50 =1.2 µg/mL (in equivalents of spinochrome B), had an inhibitory effect on the model of ocular allergic inflammation surpassing the reference drug olopatadine, and did not show any irritating effect in rabbits. The extract predominantly contained polyhydroxy-1,4-naphthoquinone which would be responsible for the pharmacological activity. The active compounds of the extract were evaluated in silico with molecular docking. Molecular docking into H1R receptor structures obtained from molecular dynamic simulations showed that all spinochrome derivatives bind to the receptor active site, but spinochrome monomers fit better to it. The results of the present study suggest possibilities for the development of new agents for treating allergic diseases on the base of pigments from sea urchins shells.

[Effect of a complex preparation of sea urchin shells on blood glucose level and oxidative stress parameters in type II diabetes model]

The experimental preclinical study on mice showed that a complex of polyhydroxylated naphthoquinone pigments and minerals from shells of sea urchins decreases the concentration of glucose, stimulates the synthesis of phospholipids in liver, and has antioxidant properties. On the model of streptozotocin-nicotinamide-induced type II diabetes, this complex of polyhydroxylated naphthoquinone pigments and minerals from sea urchin shells exhibited activity after administration for 10 days in a dose of 1.8 mg/kg.

Effect of Bergenia crassifolia L. extracts on weight gain and feeding behavior of rats with high-caloric diet-induced obesity

The objective of this study was to evaluate the feeding behavior and weight gain in rats with high-calorie diet-induced obesity that are treated with Bergenia crassifolia black and fermented leaves extracts. The daily dietary intake of all treated animals was reduced to 40% compared with the control group on day 22 of the experiment. A significant improvement in glucose tolerance was noted after 7 days of treatment with the Bergenia extracts. In rats treated with an extract of black leaves for 7 days, a significant reduction in the serum triglyceride level, 45% (p<0.05), compared with the control group was observed. However, the treatment did not affect the cholesterol level. Our results provide evidence for the potential use of B. crassifolia as an appetite and energy intake suppressant.

Pharmacological evaluation of Potentilla alba L. in mice: adaptogenic and central nervous system effects

CONTEXT

Potentilla alba L. (Rosaceae) rhizomes have anti-inflammatory, antioxidant, and adaptogenic effects and are used for the treatment of diarrhea and intestinal colic. However, the data concerning the adaptogenic and central nervous system activities of P. alba are fragmentary.

OBJECTIVES

To determine the effect of oral administration of dried P. alba extract on the swimming endurance, light/dark exploration, and open-field tests for mice.

MATERIALS AND METHODS

The mice were orally administered Rhodiola rosea extract (RR group); dry extract of P. alba at doses of 12, 36, or 72 mg/kg (groups: PA12, PA36, and PA72); or distilled water (control group) for 7 consecutive days.

RESULTS

The swimming times of the RR, PA36, and PA72 groups were significantly longer than those of the control group. The administration of P. alba significantly increased the light time, latency time, and the number of rearings in a dose-dependent manner. In the open-field test, the P. alba extract at a dose of 12 mg/kg produced a significant increase in the frequency of head dipping and the number of squares crossed and a significant decrease in grooming compared with the control treatment.

CONCLUSION

The current findings demonstrate that P. alba extracts significantly increased swimming endurance time and have anxiolytic-like action with a predominant locomotor component.

[Bioavailability and metabolism of flavonoids]

In the review the modern data about bioavailability and a metabolism of flavonoids is considered. The data about absorption flavonoids in a digestive path, participation of microorganisms in their hydrolysis, pharmacokinetic the data on the basic classes flavonoids: flavanes (flavan-3-ols), anthocyanes, flavones, flavonols and flavanones is cited.

Anti-inflammatory activity of a HPLC-fingerprinted aqueous infusion of aerial part of Bidens tripartita L

The anti-inflammatory potential of three doses of an aqueous infusion of aerial parts Bidens tripartita L. against carrageenan-induced acute paw edema in rats was investigated. A phytochemical study and qualitative-quantitative analyses revealed the presence of flavonoids, tannins, polysaccharides, phenols, amino acids, ascorbic acid, organic acids and polyacetylenes. Infusion doses of 20ml/kgbody wt. exhibited significant anti-inflammatory activity in rats, as compared with indomethacin. In addition, the infusion showed analgesic properties in a hot-plate test and antipyretic properties in carrageenan-induced local hyperthermia, both in rats. The effects were dose-dependent. Our results provide evidence for the potential usefulness of B. tripartita infusion in the treatment of inflammatory disorders.

Determination and pharmacokinetic study of taxifolin in rabbit plasma by high-performance liquid chromatography

Taxifolin has been widely used in the treatment of cerebral infarction and sequelae, cerebral thrombus, coronary heart disease and angina pectoris. A reliable sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method with UV detection for the pharmacokinetic study of taxifolin in rabbit plasma after enzymatic hydrolysis was developed and validated for the first time. Taxifolin, with biochanin A as the internal standard, was extracted from plasma samples by liquid/liquid extraction after hydrolysis with beta-glucuronidase and sulfatase. Chromatographic separation was conducted on a Luna C18 column (4.6 mm x 150 mm, 5 microm particle size) and pre-column (2.0 mm, the same sorbent). Two-step linear gradient elution with acetonitrile and 0.03% water solution of trifluoroacetic acid as mobile phase at a flow rate of 1.0 ml/min was used. The UV detector is set at 290 nm. The elution time for taxifolin and biochanin A was approximately 7.9 and 18.3 min, respectively. The calibration curve of taxifolin was linear (r > 0.9997) over the range of 0.03-5.0 microg/ml in rabbit plasma. The limit of detection (LOD) and limit of quantification (LOQ) for taxifolin were 0.03 and 0.11 microg/ml, respectively. The present method was successfully applied for the estimation of the pharmacokinetic parameters of taxifolin following intravenous and oral administration of lipid solution to rabbits. The absolute bioavailability of taxifolin after oral administration of lipid solution was 36%.

Effect of lipid-based suspension of Epimedium koreanum Nakai extract on sexual behavior in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Herba of Epimedium koreanum is used in traditional Chinese and Korean herbal medicine as a potent enhancer of erectile function. Icariin, the main active component of Epimedium koreanum, possesses many biological effects, such as improving cardiovascular function, hormone regulation, immunological function modulation, and anti-tumor activity.

AIM OF THE STUDY

This study supports the traditional use of extracts from Epimedium species in erectile dysfunction.

MATERIALS AND METHODS

The Epimedium koreanum dry extract was suspended in wheat germ oil using lecithin and bee wax for oral administration. The effect of oral administration of two compositions (E-01 and E-02) standardized by their icariin content on the number of complete intromissions, the number of ejaculations, and the latent period of ejaculation (LPE) in rats were evaluated. E-01 and E-02 were administered orally for 10 days to the experimental animals. The control animals received olive oil for 10 days. On day 10, 0.5h after the dose was administered to male rats, one virgin female rat was placed with one male rat.

RESULTS

The number of complete intromissions increased to 23.3+/-2.6 in the E-01 and E-02 group (dose 300 mg/kg body weight) (b.wt) and to 20.1+/-2.3 in the E-02 group (dose 750 mg/kg b.wt) compared with 15.2+/-2.4 in the control group of aged rats. The number of ejaculations increased from 1.1+/-0.3 in the control-aged group to 2.6+/-0.4 in the E-01 group. The LPE of male rats was 14.2+/-1.8 min in the control-aged group. The LPE of the aged group was reduced to 9.8+/-1.5 min, 9.8+/-1.6 min, and 11.4+/-1.8 min when treated with E-01 at a dose of 300 mg/kg b.wt, and E-02 at a dose of 300 mg/kg b.wt and 750 mg/kg b.wt, respectively.

CONCLUSION

It was established that oral administration of lipid-based suspension of dry extract of Epimedium koreanum in wheat germ oil improved erectile function of aged rats.

[Nutrimetabolomics from the points of systemic estimation of function of metabolic complexes]

Review, is devoted to questions of experimental investigations of the effect of biologically active compounds of food on three metaboloms, the functionality of which influences on development of pathologic processes: 1) endothelium metabolom, which controls level of vessel tone and processes of blood coagulation; 2) pro- and antiinflammatory metabolom; 3) metabolom, taking part in maintenance of anti-oxidant status of an organism.

[Studying the mechanism of antioxidant effect of vitamins and flavonoids]

In work antiradical activity of vitamins and flafonoids in relation to hydroxyl radical is established. The most antiradical activity is established for flavonoids quercetin, routin, daidzein, biochanin A and luteolin-7glucosid, Among vitamins of group in the most antiradical activity have shown vitamins B12, B2, B5, Bc. In group of fat-soluble vitamins ascorbic palmitat, vitamin K1, vitamin A and beta-carotin have shown activity above, than a known antioxidant vitamin E. The carried out work allows to draw a conclusion that antiradical activity in the relation hydroxyl radical shows the broad audience of vitamins that probably is one of aspects of their therapeutic action.

[Effectiveness and mechanism of action of a new plant complex drug in nonspecific inflammatory processes in the bronchopulmonary system]

The elixir Bronchofit is an aqueous-alcoholic extract from 7 kinds of plants. It is a balanced compound, rich in biologically active substances including essential oils and flavonoids, possessing a wide spectrum of pharmacological activity. On the model of frog's palate the elixir enhanced the transport function of the ciliated epithelium. On the model "karragenin edema" bronchofit showed a marked anti-inflammatory activity. A noticeable therapeutic effect was registered in rats with induced bronchopulmonary inflammation. Bronchial secretion contained reduced content of glycosaminoglycans while bronchial lavage did of histamine. Also, bronchofit demonstrated a prominent antioxidative activity, an antibacterial action in relation to Str. pyogenes and Bac. cereus. By a total complex of the activities bronchofit is a promising medicine against bronchopulmonary inflammation.