Pharmaceutical Chemistry Journal (v.52, #3)

Effect of N-[Imino(1-Piperidinyl)Methyl]Guanidine on Free-Radical Processes and Antioxidant-Enzyme Activity in Kidneys of Rats with Experimental Type 2 Diabetes Mellitus by E. I. Sklyarova; T. N. Popova; K. K. Shul’gin; V. V. Spitsina; D. V. Kryl’skii; A. V. Semenikhina (191-194).
The effect of the synthetic biguanide derivative N-[imino(1-piperidinyl)methyl]guanidine on free-radical processes, diene conjugate levels, and superoxide-dismutase and catalase activity in kidneys of rats with experimental type 2 diabetes mellitus (DM2) was studied. It was established that administration of this compound to rats with DM2 helped to normalize the studied parameters, which may have been due to its positive regulating effect on free-radical homeostasis.
Keywords: type 2 diabetes mellitus; free-radical processes; antioxidant enzymes; biguanides

Possible Ways of Studying Pharmacokinetic Parameters of Calcium Preparations by N. N. Eremenko; E. V. Shikh; S. Yu. Serebrova; D. V. Goryachev (195-197).
Issues pertaining to determination of the pharmacokinetic parameters of calcium preparations are examined using their comparative bioavailability as an example. Pharmacokinetic parameters of calcium such as area under the concentration—time curve (AUC) and maximum concentration (C max) are calculated considering the background calcium contents in volunteers. Calcium excretion with urine is assessed as clearance of creatinine, a calcium elimination factor. The dynamics of the content of parathormone (PTH), the main hormone regulating calcium homeostasis, are studied. The results can be used to plan clinical trials for assessing the pharmacokinetics of drug analogs of endogenous compounds.
Keywords: comparative pharmacokinetics; clinical trials in vivo ; endogenous compounds; calcium; calcium-creatinine coefficient; parathormone

Synthesis and Biological Activity of 2-amino-1-aryl-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-N-(thiazol-5-yl)-4,5-dihydro-1h-pyrrole-3-carboxamides by S. S. Zykova; N. M. Igidov; A. V. Zakhmatov; M. A. Kiselev; A. R. Galembikova; R. R. Khusnutdinov; P. D. Dunaev; S. V. Boichuk; I. N. Chernov; I. A. Rodin (198-204).
A series of new 2-aminopyrrole derivatives [2-amino-1-aryl-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-N-(thiazol-5-yl)-4,5-dihydro-1H-pyrrole-3-carboxamides IIa-h] were synthesized via the reaction of 4-arylamino-2-tert-butyl-2,5-dihydro-5-oxofuran-2-ylacetates (Ia-h) with 2-cyano-N-(thiazol-2-yl)acetamide in the presence of Et3N. Studies of the biological activity of the synthesized compounds found that they possessed low toxicity and that 2-amino-1-(2-bromophenyl)-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-N-(thiazol-5-yl)-4,5-dihydro-1H-pyrrole-3-carboxamide (IIb) and 2-amino-1-(2,4-dichlorophenyl)-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-N-(thiazol-5-yl)-4,5-dihydro-1H-pyrrole-3-carboxamide (IIg) exhibited radical-binding activity greater than that of trolox and cytotoxic activity against gastrointestinal stromal tumor (GIST) cells, including those resistant to the target drug imatinib (Glivec). The cytotoxic activity of the synthesized compounds was comparable with that of doxorubicin chemotherapeutics and exceeded significantly those of etoposide, paclitaxel, and hydroxyurea. Apossible molecular mechanism of action of the synthesized compounds might be their ability to disrupt cell division and induce selective accumulation of M-phase cells with subsequent death by a mitotic catastrophe pathway.
Keywords: 2-amino-1-aryl-5-(3,3-dimethyl-2-oxobutylidene)-4-oxo-N-(thiazol-5-yl)-4,5-dihydro-1H-pyrrole-3-carboxamides; acute toxicity; cytotoxicity; gastrointestinal stromal tumors (GISTs); chemotherapeutics, chemoresistance

Synthesis and Antioxidant and Cytotoxic Activity of New Dihydroquercetin Derivatives by V. V. Knyazev; V. S. Rogovskii; E. D. Sveshnikova; A. V. Semeikin; A. I. Matyushin; T. A. Fedotcheva; N. L. Shimanovskii; A. O. Pozdeev; A. M. Koroteev; M. P. Koroteev (205-208).
Aseries of new 3-monoacylated dihydroquercetin derivatives were synthesized and possessed antioxidant and cytotoxic activity with respect to HeLa tumor cells.
Keywords: dihydroquercetin; 3-monoacylated dihydroquercetin derivatives; antioxidant activity; cytotoxic activity; taxifolin; ABTS test; HeLa cells

Glucokinase Activators Based on N-Aryl-N′-Pyridin-2-Ylurea Derivatives by A. V. Semenov; I. V. Tarasova; V. S. Khramov; E. V. Semenova; V. I. Inchina; S. S. Vakaeva (209-212).
A series of previously undescribed N-aryl-N′-pyridin-2-ylureas were prepared via the reaction of 2-aminopyridines with benzoyl azides and tested in vitro as activators of glucokinase. Statistically significant reductions of glucose levels as compared with controls were demonstrated for several compounds.
Keywords: glucokinase activators; N-aryl-N -pyridin-2-ylurea

Analgesic Activity of a Polypeptide Modulator of TRPV1 Receptors by I. A. D’yachenko; G. I. Belous; L. A. Skobtsova; T. Yu. Zharmukhamedova; V. A. Palikov; Yu. A. Palikova; E. V. D’yachenko; E. A. Kalabina; V. B. Rudenko; Ya. A. Andreev; Yu. A. Logashina; S. A. Kozlov; A. N. Yavorskii; A. N. Murashev (213-215).
The activity of APHC2, a new polypeptide modulator of TRPV1 receptors that was isolated from Heteractis crispa, is studied. It was established that APHC2 possessed analgesic properties, did not disturb normal locomotor activity, and did not change body temperature and hemostasis of experimental animals. These attributes could be of great practical value for designing a new generation of efficacious analgesics. A brief increase of heart rate was observed during studies of the hemodynamic activity. Further investigation of the binding specifics of this polypeptide with TRPV1 receptors could open approaches to discovering other antagonists of these receptors.
Keywords: polypeptide modulator; TRPV1 receptors; analgesics

Research and Development of Solidago Caucasica Herbal Dry Extract by V. V. Fedotova; D. A. Konovalov (216-219).
The preparation of Solidago caucasica herbal dry extract from the plant was studied by us for the first time. The main quality indicator was a flavonoid content of ≥ 2.5%. Other biologically active compounds, e.g., coumarins, phenolic carboxylic acids, and organic acids, were also present.
Keywords: Solidago caucasica ; dry extract; flavonoids; diuretic effect; antibacterial activity

Estimated Heavy-Metal and Arsenic Contents in Medicinal Plant Raw Materials of the Voronezh Region by N. A. D’yakova; I. A. Samylina; A. I. Slivkin; S. P. Gaponov; A. A. Myndra (220-223).
The levels of pollution by heavy metals and arsenic in top soil layers and medicinal plant raw materials in Voronezh Region were studied using Urtica dioica and Plantago major leaves as examples. The analyses were carried out using atomic absorption spectrometry on a graphite-furnace MGA-915MD spectrometer. Samples were collected from districts with different anthropogenic impacts across the whole region. Leaves of P. major characteristically had the highest coefficients of accumulation from the soil for Cd, As, and Ni. Leaves of U. dioica typically had high accumulation coefficients for Ni.
Keywords: heavy metals; arsenic; accumulation coefficient; Voronezh Region; Urtica dioica ; Plantago major

Study on the Best Initial Processing Technology of Gastrodia Elata by Yang Liu; Rui Ran; Gangliang Huang (224-230).
The effects of different initial processing methods on the amount of gastrodin and gastrodigenin isolated from Gastrodia elata Blume were investigated and the best initial processing technology was optimized. The contents of gastrodin and gastrodigenin were analyzed by high performance liquid chromatography (HPLC). It is established that G. elata boiling in water followed by ethanol extraction is the best initial processing technology, which can provide the basis and reference for the standardized processing of G. elata herbs.
Keywords: Gastrodia elata Blume; initial processing technology; gastrodin; gastrodigenin; optimization

Anisotropic Iron-Oxide Nanoparticles for Diagnostic MRI: Synthesis and Contrast Properties by A. A. Nikitin; M. A. Khramtsov; A. G. Savchenko; M. A. Abakumov; A. G. Mazhuga (231-235).
The scientific and technical literature addressing the synthesis of anisotropic iron-oxide nanoparticles of various shapes (cubic, rod-like, clustered, etc.) sized from 10 to 100 nm and their application for diagnostic magnetic resonance imaging (MRI) of tissues and organs is analyzed. The analysis indicates that the nanoparticle shape, size, and surface chemistry affect considerably relaxation parameters T1 and T2. Thus, cubic iron-oxide nanoparticles had the greatest T2 values. Furthermore, rod-like and octapodal nanoparticles also exhibit rather high T2 values so that they can be used as contrast agents for diagnostic MRI.
Keywords: nanoparticles; iron-oxide nanoparticles; magnetite; magnetic resonance imaging; MRI; contrast agents

Solubility and Stability of Proroxan at Various PH Values by S. P. Krechetov; G. O. Nifontova; O. V. Dolotova; M. S. Veselov (236-240).
The solubility and stability of the nonselective α-adrenoblocker 1-(2,3-dihydro-1,4-benzdioxin-6-yl)-3-(3-phenyl-1-pyrrolidinyl)-1-propanone hydrochloride (proroxan) at various pH values were investigated. It was established that proroxan solubility was reduced for 3 < pH < 5.5, which corresponded to the protonated species; was uncharacteristic for salts of organic bases; and increased its destruction. It was suggested that this peculiarity of proroxan behavior in aqueous solutions could reflect complexation between its protonated and unprotonated molecules. The results indicated that proroxan preparations using dosage forms and delivery systems that provide its maximum absorption in the stomach must be developed.
Keywords: proroxan; solubility; stability; pH

Effect of Solid Dispersions with Polyethylene Glycol 1500 on the Solubility of Indomethacin by I. I. Krasnyuk Jr; T. M. Kosheleva; A. V. Belyatskaya; I. I. Krasnyuk; O. I. Stepanova; Yu. Skovpen; V. V. Grikh; L. V. Ovsyannikova (241-244).
Solid dispersions (SDs) of indomethacin with polyethylene glycol 1500 (PEG-1500) were studied to determine their effect on indomethacin solubility. Production of SDs increased the solubility and dissolution rate of indomethacin in H2O. The solubility and dissolution rate of indomethacin from SDs increased by 1.8 – 2.2 and 3.1 – 4.4 times, respectively. Indomethacin became less crystalline and then amorphous during preparation of the SDs. Dissolution of the SDs solubilized indomethacin and formed colloidal solutions.
Keywords: indomethacin; solid dispersions; polyethylene glycol 1500; solubility; crystallinity

Experimental data on the comparative dissolution kinetics of two ibuprofen preparations from different manufacturers are presented. The study was performed in three buffer solutions at pH 1.2, 4.5, and 6.8 according to requirements of the Scientific Center for Expert Evaluation of Medicinal Products of the Russian Federation. A fourth dissolution medium was buffer solution at pH 7.2, which is included in a draft regulation. The test used a Erweka DT-720 rotating-basket device.
Keywords: ibuprofen; bioavailability; dissolution; in vitro

Development and Validation of a Quantitative Determination Method for the Antitubercular Drug PBTZ169 in Biological Media by E. S. Stepanova; S. S. Barsegyan; L. M. Makarenkova; V. V. Chistyakov (248-253).
An HPLC-MS/MS method for quantitative determination of the new antituberculosis drug PBTZ169 in blood serum, urine, and feces using perindopril as an internal standard was developed and validated. The method was selective, specific, accurate, and precise. Calibration curves were linear in the ranges 2 – 2,000, 5 – 3,000, and 100 – 10,000 ng/mL for blood serum, urine, and feces, respectively, with correlation coefficients >0.99. The detection limits of PBTZ169 were 1, 2.5, and 50 ng/mL for serum, urine, and feces, respectively. The limits of quantitation were 2 ng/mL in serum; 5, urine; and 100, feces.
Keywords: antituberculosis drug; PBTZ169; HPLC-MS/MS; validation

Approaches to Pharmaceutical Analysis of an Innovative Liposomal Preparation for Treating Hepatitis C by V. V. Smirnov; L. M. Krasnykh; I. P. Shilovskii; A. P. Ryzhenkova; M. R. Khaitov; V. N. Drozdov (254-256).
The composite Y14/siUTR, a complex consisting of cationic lipopeptide Y14 as an excipient and pharmaceutical substance of small interfering RNAtargeted against the UTR region of hepatitis C virus (siUTR), was investigated. The composite was intended to inhibit the hepatitis C virus replication cycle. The present work was aimed at developing pharmaceutical analytical methods for the components of this composite using HPLC-UV and UV spectroscopy.
Keywords: hepatitis C; liposomes; RNA interference; HPLC-UV; spectrophotometry

Release Testing of Selected Drugs from Surface Magnetic Nanoparticles and Their Diffusion Through a Membrane by Ewelina Gronczewska; Weronika Worobiec; Alicja Defort; Andrzej Jurkowski; Jacek J. Kozioł (257-265).
In this study, magnetic nanoparticles were functionalized with dextran and immobilized ibuprofen, diclofenac, and dopamine in order to investigate the diffusion of drugs through a dialysis membrane under biological conditions such as a temperature of 37.0°C and pH 7.4. The concentration of released drugs was measured both inside the membrane and upon release into solution using spectrofluorimetric and spectrophotometric methods. The mechanism of drug release from the carrier was analyzed in terms of the Korsmeyer – Peppas model. The results show that differences in the mechanism of drug release depend on the time-diffusion process and the type of drug used. In addition, the atomic force microscopy and confocal microscopy methods were used to investigate the interaction between bacterial cells and functionalized nanoparticles.
Keywords: magnetic nanoparticles; drug release; diffusion; membrane; nonsteroidal anti-inflammatory drugs; NSAIDs, dopamine, Korsmeyer – Peppas model, Lactobacillus bacteria

Reversed-Phase HPLC Method for Determination of Temozolomide in Rat Plasma and Brain: Simple, Sensitive and Robust Method by Zenab Attari; Lalit Kumar; C. Mallikarjuna Rao; K. B. Koteshwara (266-270).
A simple and sensitive HPLC method was developed and validated to detect an anti-glioma drug (temozolomide) in rat plasma and brain. The drug and internal standard (metronidazole) were eluted at proper retention times using BDS C18 column and selected mobile phase (ammonium formate – acetonitrile). The proposed method showed specificity and linearity with R 2 values of 0.9964 and 0.9978 in plasma and brain, respectively. Other parameters such as intraday and interday precision were found to be within acceptable limits. The LOD and LOQ were 84 and 255 ng/mL, respectively. The drug recovery from the spiked plasma varied from 43 to 52%. Furthermore, stability of the method was evaluated and it was found that the drug exhibited good stability except at room temperature. The percentage recovery at room temperature after 24 h was within 69 – 73%; however, the drug was stable up to 15 days at –70°C.
Keywords: temozolomide; chromatography; extraction; stability; precision; recovery

Diethylcarbamazine citrate (DEC) is a piperazine anthelmintic agent indicated for the treatment of individual patients with lymphatic filariasis. Two simple and sensitive UV-spectrophotometric techniques have been developed and validated for the determination of this drug in bulk parent substance and tablets, based on the measurement of the absorbance of DEC solution either in 0.1M HCl at 210 nm (method A) or in 0.1M H2SO4 at 209 nm (method B). Beer’s law was obeyed over the concentration ranges of 1.25 – 25.0 and 2.5 – 30.0 μg · mL-1, for method Aand method B, respectively, and the corresponding molar absorptivity values were 2.02 × 104 and 1.21 × 104 L mol-1 · cm-1. The limits of detection (LOD) and quantification (LOQ) were, respectively, 0.26 and 0.78 μg · mL-1 (method A), and 0.16 and 0.49 μg · mL-1 (method B). These methods were assessed for intra-day and inter-day accuracy and precision, as well as robustness and ruggedness. Both methods were applied to one brand of tablets with percentage label claim of 101.7 and 100.8 for method A and method B, respectively, and the standard deviation was below 2%. In order to establish the stability-indicating ability of these methods, the drug was analyzed after subjecting it to acid and base hydrolysis, oxidation, heat and light stress conditions and the results indicated that the drug degraded extensively under both base- and oxidative-stress conditions, and remained intact under other stress conditions.
Keywords: diethylcarbamazine citrate; assay; UV spectrophotometry; stability-indicating method

Method Development and Stress Degradation Profile of 5-Benzyl-1,3,4-Oxadiazole-2-Thiol Studied by UV Spectroscopy by Shaista Qamar; Khalid Hussain; Nadeem Irfan Bukhari; Naureen Shehzadi; Muhammad Islam; Sabahat Zahra Siddique; Aziz-ur-Rehman (278-283).
Considering the pharmacological activities of 5-benzyl-1,3,4-oxadiazole-2-thiol (OXPA), the present study aimed to develop and validate a UV-spectroscopic method according to the ICH guidelines to be used to study degradation profile of the compound. The method was developed at 263 nm, the wavelength giving maximum absorbance. Linearity of the method was evaluated by analyzing a series of standard solutions. Then, recovery, accuracy and sensitivity were determined. The compound was subjected to a number of stress conditions to determine it in the presence of degradants (specificity). The proposed method showed linearity in a concentration range (0.33 - 40.0 μg/mL) with correlation coefficient (R2) = 0.998. The recovery was within 100.63 – 102.46%, intraday and inter-day accuracy were found to be 99.10 – 102.46% with relative standard deviation less than 2%, and the LOD and LOQ were found to be 0.099 and 0.330 μg/mL, respectively. The OXPA was degraded with the passage of time under acidic conditions and oxidized completely in 35% H2O2, whereas the degradation was 58.47% in 3% H2O2. Dry heat (80°C) exposure for 48 h resulted in 1.09% degradation, whereas UV exposure resulted in complete loss of the compound. These results indicate that the method is simple, sensitive, accurate and specific, hence may be used to carry out quantitative work on OXPA.
Keywords: 5-benzyl-1,3,4-oxadiazole-2-thiol (OXPA); UV spectroscopy; ICH guidelines; method validation; stress-induced degradation

The production of lovastatin by Aspergillus terreus PU-PCSIR-1 was studied using submerged fermentation technique. Effects of pH, incubation temperature, incubation time, and the media components on the production of lovastatin were investigated. Maximum lovastatin yield (198.90 mg/L) was achieved after 14 days of incubation at temperature 28°C and pH 7.4. Peptonized milk, linoleic acid, glucose, yeast extract, and trace elements had a positive impact on the production of lovastatin by A. terreus.
Keywords: cholesterol; high performance liquid chromatography (HPLC); lovastatin; submerged fermentation, Aspergillus terreus