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or contrary this grouping can to prevent introduction of second molecular of azodye in coordinational sphere. Obviously this effect must to became apparent for ions forming 3, 4 and 5 coordinating bonds.
Presence ofthis group in molecule of organical reagent has allowed as is shown from experimental date to carried out reactions in more acid mediums. increazing of acidility of medium is connected with possibility of protonization N-methylpyperidine, owing to this fact using of azodyes as analytical reagents is more comfortable. At this also it is necessary to take into account fact, that many ions of investigated metals in weak-base and neutral mediums able to formation of forms uncomfortable for interaction with
ligands (owing to such reactions as hydrolysis, polymerization and so on) and by this reason increasing of acidity has carried out to increasing ofprecision and sensibility of determination. Also it is important increasing ofmolecular mass of reagents leconrse at this sensibility of analytical methods of determination of metal ions and their affinity to used organical reagents.have leen increazd.
Owing to purpose ful changing of structure of azodyes not only by effect of additional coordinating groups by also of their immobilization it is possible essential changing of properties of complexes and also theoretical and practical preconditions to selection of specifical analytical reagents are created.
References:
1. Smanova Z. A., Manzurhojaev V. M. Extraction - photometrical determination ofNi by azoreagent 2- (5-meth-ylpyridilazo) - 2-hydroxy - 5-methoxybenzole//Vestnik of NUUz. - Tashkent, 2005. - № 4. - P. 124-126.
2. Smanova Z. A. Reagent 1 - (4-antipyrilazo) -2-naphtol-6 - sulphoacidal sodium for determination of some heavy and toxical metals//Usb. chem. journal. - Tashkent, 2008. - № 2. - P. 52-55.
3. Ivanov V. M. Geterocyclical nitrogen - containing azocompounds. - M.: Zeience, 1982. - P. 129-136.
4. Smanova Z. A. Immobilized organical reagents and their analytical application at determination of heavy toxical metals. Avtoreferat of doctor dis. On the competition of d. ch. s. - Tashkent, 2015. - 88 p.
5. Smanova Z. A. Elaboration of sorptionno - spektroskopical methods of analysis with using of immobilized organical reagents (review)//Vestnic NUUz. - Tashkent, 2010. - № 4. - P. 67-71.
D OI: http://dx.doi.org/10.20534/AJT-17-1.2-134-138
Shomurotov Shavkat Abduganievich, PhD, Senior Researcher, Department of Chemistry of Polysaccharides,
Institute of Bioorganic chemistry UzAS E-mail: [email protected] Akhmedov Oliy Ravshanovich, Institute of Bioorganic chemistry UzAS, Researcher
E-mail: [email protected] Mamatmusaeva Nilufar Erkinovna, PhD, Researcher Department of Chemistry of Polysaccharides
E-mail: [email protected] Sagdullaev Bakhodir Takhirovich, DSc, Senior Researcher, Department of Chemistry of Polysaccharides
E-mail: [email protected] Turaev Abbaskhan Sabirkhanovich, DSc, professor, Institute of Bioorganic chemistry UzAS
E-mail: [email protected]
Modified derivatives of polysaccharides having anti tuberculosis activity
Abstract: The research on the synthesis of polymeric complexes of polygalacturonic acid with anti-TB preparations having antituberculosis activity was conducted. The structures were ascertained and studied
the physicochemical properties of polymeric systems. Pharmaco-toxicological studies have shown that polymeric complexes are less toxic than their low molecular analogues and Mycobacterium of tuberculosis show high sensitivity to the prepared preparations.
Keywords: polymeric complexes, tuberculosis, prolongation, polyglacturonic acid, isoniaside, ethambutol.
In connection with the specific treatment of tuberculosis — complex therapy (at the same time with several anti-TB preparations), duration of treatment, the need for the prescribing of multiple high doses of drugs and the emergence of this toxic and allergic complications — it is very important to find the method to reduce the dosage of anti-TB preparations. One way to improve the conditions of drug therapy is the creation and application of polymeric anti-TB preparations of prolonged action. Such long-acting anti-TB preparations are available including in polymer — carriers of known anti-TB preparations, which allows purposefully change their physico-chemical and medico-biological properties.
In this regard, were carried out the studies on obtaining the macromolecular drug delivery system by the addition of anti-TB preparations of hydrazide of isonicotinic acid (HINA) and ethambutol dihydrochloride (EBHC) to the macromolecule of polymer carrier. As the polymer carrier was used modified polygalacturonic acid (PGA) obtained by demethoxylation of citrus pectin.
Materials and methods
UV spectra were recorded on a UV spectrophotometer "UV 1280" manufactured by "Shimadzu", Japan, in quartz cuvettes with 1 cm thick, in the range of 200-500 nm. in aqueous solutions.
IR spectra were recorded on devices "Bruker Vek-tor-33", in the wavelength range of 500-4000 cm-1 in tablets with KBr.
Synthesis of dialdehyde polygalacturonic acid (DAPGA). Periodate oxidation of PGA was performed
at pH of 4.7 in 3 % aqueous solution of PGA, at oxidant concentration of 0.5M and temperature of 25 °C within 2.5 hours. Degree of oxidation of reaction in product was determined by iodometric method [1] and UV — spectrophotometric method [2] on flow rate JO4- of ions on intensity change of absorption band at \ = 222 nm.
Synthesis of PGA with HINA. The reaction was performed in a three-necked thermostated flask equipped with thermometer and stirrer. Into the flask was placed 0.02 mole of DAPGA and 40 ml. of an aqueous solution containing 0.06 mole of HINA and stirred vigorously within 60 min. at 25 °C. Then the reaction product was filtered, washed repeatedly with mixture of alcohol: water (1:1) and dried over P205 in a desiccator. The content of bound HINA was determined by the content of nitrogen.
Synthesis of PGA complex with HINA and EB. The
reaction was carried out at pH 5.5 in 3 % aqueous solution of the complex PGA with HINA at EBHC concentration of 0.5 M. and temperature of 20 °C for 60 min. The reaction mass was then dialyzed for 24 hours. The product was isolated by rotary drying. The content of HINA and EB was determined on nitrogen content and spectrophotometric method.
Results and discussion
We have studied the synthesis of polymeric complexes HINA and EB with modified macromolecule PGA, which was obtained by demethoxylation of citrus pectin (the content of OCH3 groups, 7.6 %) [3].
Synthesis was carried out as follows.
DAPGA was obtained by periodate oxidation of PGA. The reaction was carried out homogeneously in aqueous solution of NaJ04. The reaction products were precipitated with acetone. The control of the oxidation process was carried out on the spending of periodate-ion (spectrophotometric method) and on changing the content of aldehyde groups (iodometric method).
The dependence of the oxidation degree of the modified PGA on the reaction time, the molecular weight (MW) of PGA and ratio of reagents was studied.
As can be seen from table 1, with increasing of the
samples it is nearly identical, suggesting that the MM almost doesn't influence on the degree of oxidation of PGA. Increasing the reaction time over 2.5 hours leads to some reduction in oxidation state (the content of aldehyde groups). Such a course of reaction, due to the fact that in addition to the main reaction proceeds adverse reaction — the oxidation of the resulting aldehyde groups to carboxyl [4].
Nucleophilic substitution reaction of DAPGA with HINA was conducted. The dependence of the interaction between HINA and DAPGA on the reaction conditions was studied.
reaction time increases the degree of oxidation, in all
Tablel. - The dependence of the oxidation degree of PGA on the reaction time and MW at periodate oxidation
(Reaction conditions: PGA: JO4- = 1 : 1.5; t = 20 °C; pH = 4.0)
Time, hour Molecular mass of PGA
48 500 44 300 40 300 30 000 15 300
I* S* I* S* I* S* I* S* I* S*
0.25 8.6 8.7 8.8 9.0 8.4 8.7 8.4 8.5 9.3 9.5
0.5 15.0 15.4 15.3 15.6 14.4 15.2 15.7 16.3 15.6 15.9
1.0 23.2 23.8 24.1 24.2 24.3 24.6 24.7 25.2 25.2 25.5
1.5 32.7 33.0 32.9 33.2 36.5 37.2 36.6 37.3 35.2 37.5
2.0 43.8 46.4 43.3 47.3 45.8 49.5 44.4 46.6 46.7 47.6
2.5 52.4 55.6 51.6 52.8 51.3 56.1 54.4 56.8 52.9 54.5
3.0 51.5 57.2 49.6 55.8 48.3 48.9 46.9 59.5 50.5 56.7
5.0 49.3 60.8 47.4 58.6 47.2 59.4 46.3 61.7 49.2 58.2
Note: oxidation degree was determined: I*— iodometric method; S* — spectrophotometric method.
Table 2. - Dependence of nucleophilic substitution of DAPGA with HINA on MW and the ratio of DAPGA: HINA (Reaction time 30 min., t = 20 °C, pH = 5, content of oxidized parts 21 to 100 elementary parts)
Ratio of DAPGA: HINA, moles Molecular weight of DAPGA, dalton
75 670 58 530 34 440 26 570 11 520
Content of bound HINA, moles %
1 0.25 7.8 7.2 6.9 7.0 7.2
1 0.50 13.2 15.6 14.4 16.6 15.8
1 1.00 16.6 17.4 16.2 16.4 17.6
1 1.50 18.4 18.8 18.8 19.5 19.3
1 2.50 20.2 19.8 20.7 20.7 20.9
1 5.00 20.8 20.2 21.4 21.6 21.0
Effect of reagents ratio DAPGA: HINA on content of bound HINA (table 2) shows that the increase of HINA in the reaction medium up to 2.5 mole leads to the increase in the content of bound HINA in polymer. However, further increase in its amount does not affect its content in the product, indicating the exhaustion of the aldehyde groups of the polymer matrix at certain ratios of components.
Nucleophilic substitution reaction of DAPGA with HINA passes homogeneously in aqueous solutions. Therefore MW of polymer hardly affects the nucleophilic substitution process. With increasing concentration of HINA increases the content of bound HINA, the limit value of bound HINA almost corresponds to the content of disclosed, pyranose parts, i. e. 50 % of the total number of aldehyde groups.
This indicates that in condensation reaction is involved only one aldehyde group in DAPGA. The second aldehyde group reacts the reduction reaction of pyranose cycle. Similar data was previously obtained by reaction with dialdehydecellulose with
Table 3. - Dependence of content of
phenylhydrazine [5]. To clarify this, the authors carried out a condensation reaction of dialdehyde triphenyl-methylcellulose, in which is eliminated the formation of hemiacetal connection with tolilhydrazine (since all hydroxyl groups in C6 are substituted). The authors demonstrated that during the condensation reaction of triphenylmethylcellulose with tolilhydrazine is proceeding the reduction of C2-C3 bond of glucoprira-nose cycle forming a compound containing arylnitro-group in the third carbon atom.
The reaction of interaction of complex PGA-HINA with EBHC was studied. The reaction was carried out in aqueous solution at pH 5.5. At this pH the largest part of the carboxyl groups is in salt form. Thus, there is a reaction of ion binding of EB with macromolecule of PGA, as evidenced by IR spectroscopy method and elemental analysis. The resulting product is readily soluble in water.
In order to study the effect of the ratio of reagents on the content of bound EB in the macromolecule PGA-HINA reactions were carried out at different ratios of PGA-HINA: EB. Results are shown in Table 3.
bound EB on ratio of PGA-HINA: EBHC
Mole ratio of PGA-HINA*: Nitrogen content, % EB, moles %
EBHC
1 : 0.1 4.25 5.64
1 : 0.5 5.88 22.7
1 : 1 5.99 24.5
1 : 2 6.58 30.4
1 : 5 7.80 42.6
1:8 7.77 42.5
Note: PGA-HINA* — MW 12 000 and containing 20.2 mole % of HINA with hydrozonic bond.
The table shows that with increase in the ratio of PGA-HINA: EBHC increases the content of bound EB in the reaction product. It is interesting to note that even with a molar ratio of PGA-HINA : EBHC = 1 : 1 and large ratios the reaction does not proceed to full substitution of ions Na+ to EB. The latter is due to steric difficulties of ion exchange along the chain of the macromolecule, and, of course, lower basicity of EB.
It is found that in the interaction reaction of PGA-HINA with EBHC molecular parameters of polymer-carrier hardly change. This is evidenced by results of a study of the characteristic viscosity and molecular weight determination of the original PGA-HINA and PGA-HI-NA associated with the EB. The characteristic viscosity, measured in 0.1 M. NaCl solution, almost doesn't change and is in the range of 0.34 ± 0.5.
Pharmaco-toxicological properties of the obtained polymeric complexes were studied, in particular, the
acute toxicity and anti-TB activity. The following polymeric complexes were studied:
- PGA-HINA-EB, containing 20.2 mole % of HINA and 25.6 mole % of EB;
- PGA-HINA, containing 20.2 mole % of HINA;
- PGA-EB, containing 24.5 mole % of EB.
As a control was taken HINA with activity of 99 % and EBHC with a content of active principle of100 % of the German company «Sigma chemical». Determination of acute toxicity of preparations was carried out in 100 white mongrel mice weighing 18-20 g. ofboth sexes by intraperitoneal injection.
Experimental results were treated by variational statistics. LD50 calculations were performed according to the method of Litchfield and Wilcoxon.
On the basis of experiments were determined LD50, which are summarized in table 4.
Table 4. - Composition of studied preparations and their LD5
Composition HINA content Ethambutol content LD50 mg/ml
% Mole % % Mole %
HINA 100 100 - - 224(160-300)
EB - - 100 100 1290 (1100-1500)
CMC + HINA+EB 13.07 20.2 18.67 25.6 More than 5000
CMC + HINA 13.07 20.2 - - 3600(3200-4300)
CMC + EB - - 17.85 24.5 More than 5000
Table 5. - The sensitivity of Mycobacterium tuberculosis to the studied polymeric complexes
Preparations № Cultures
646 824 831 956 806 743 552 765
CMC + HINA+EB + + + + + + + +
CMC + HINA + - - + + + + -
CMC + EB + - - + + + + +
Note: «+» — Sensitive to preparation; «-» — stable to preparation.
Based on the obtained results, we can conclude that the tested preparations by single intraperitoneal administration can be assigned to different classes of toxicity: «HINA» — to the class of low toxic substances; «Ethambutol» — to practically non-toxic class of substances; «PT», «PTE» and «PEB» — to the class of non-toxic substances.
We conducted the study of sensitivity of Mycobacterium tuberculosis to the synthesized polymeric complexes. The study was conducted under conditions in vitro in virulent strains of Mycobacterium tuberculosis H37Rv, Bovinus-8. Tests were conducted by the method of absolute concentrations with content of preparations in the medium of Lewenstein - Jensen 1 mkg/ml and 10 mkg/ml.
The results showed that to the complex CMC + HINA+EB all tested strains remained sensitive. To the CMC + EB complex of eight strains remained
sensitive six cultures, to the CMC + HINA complex five strains of Mycobacterium cultures were sensitive and in all cases, the efficacy depends on active substance concentration in the preparation. The higher the concentration, the more effective its action on mycobacteria. Combinations of two preparations increase the inhibitory effect on mycobacteria.
Conclusions
Thus, in the course of the research were obtained macromolecular medicinal systems having anti-TB action. The reaction conditions were determined and ascertained the structures of the obtained macromo-lecular systems.
Pharmaco-toxicological studies have shown that strains H37Rv, Bovinus-8 show high sensitivity to the synthesized polymeric complexes, and also was observed the decrease in toxicity compared to the initial medicinal preparations.
References:
1. Sjutkin V. N., Nikolaev A. G., Sazhin S. A., Popov V. M., Zamoryansky A. A. Nitrogen-containing derivatives of dialdehyde cellulose//Chemistry of plant raw materials. - 1999. - No. 2. - Р. 91-102.
2. Akhmedov O. P., Shomurotov Sh. A., Turaev A. S. Features of synthesis of the dialdehyde derivatives of polysac-charides//Uzbek chemical journal. - Tashkent, 2013. - No. 1. - Р. 30-33.
3. Shomurotov Sh. A., Muydinov N. T., Akhmedov O. R., Boymirzaev A. S., Turaev A. S. Study of molecular-mass characteristics of carboxymethyl cellulose and polygalacturonic acid by hydrolytic cleavages//Uzbek chemical journal. - Tashkent, 2015. - No. 4. - Р. 15-18.
4. Amanova D. M., Shomurotov Sh. A., Turaev A. S, Ergashev M. R. Study of features of periodate oxidation of galactomannan. Conf. "Actual Problems of Chemistry of Natural Compounds". - Tashkent, 2012. - Р. 128.
5. Nadzhimutdinov Sh., Sarymsakov A., Usmanov Kh. U. Study of some of the laws of synthesis for dialdehydes of cellulose and its ethers//Cellulose Chem. Technol. - 1981. - No. 16. - Р. 613-628.
Amperometrical determination of palladium ions by organical azoreagents
D OI: http://dx.doi.org/10.20534/AJT-17-1.2-139-140
Yakhshieva Zukhra, Ph. D. Assoc. Chemistry Department, National University of Uzbekistan n. a. M. Ulugbek E-mail: [email protected]
Smanova Zulayxo, Dr., assistant Professor Faculty of Chemistry E-mail: smanova. chem @mail.ru
Khaydarov Islomjon, Undergraduate chemistry
Mirzakhmedov Rustam, Student of IV course of the faculty of chemistry National University of Uzbekistan n. a. M. Ulugbek
Amperometrical determination of palladium ions by organical azoreagents
Abstract: Possibility of using of 4-(2-N-methylanabazinazo)-m-phenyldiamine as reagent for determination ions of palladium was shown and conditions of their amperometrical titration on different by acid — base properties phone electrolytes and buffer imixtures have been optimized. Elaborated methods were used to analysis of binarical, triple and more complexe model mixtures imitating industrial materials and natural objects. In all cases the obtained results were treatment by methods and procedures known in literature and were valued from value of metrology.
Keywords: selectivity, amperometry, electroconductivity, titration, expression.
Small content of noble metals in geological and production materials has caused necessarity their preliminary concentration with following determination by hybrid and combinational methods. This problem is very actual for Uzbekistan owing to finding of noble metals and determination of production of their deposits.
To presence time optical, phisical and some others methods of determination of ions Pt (II) have been elaborated but they don't charaeterised by high metro-logical parameters and analytical characteristies they are low selective, complicated, didn't pressision and so on.
By this reason it was necessary to elaborate new, more modern method of determination of ions of noble metals corresponding to all peresence demands. Selectivity of determination of ions palladium in solution can be inereased by precissian sorptional concentrait-ing for following their electrochemical determination, it is very important that complexes of palladium have given sensible analytical signal.
Aim of this work was investigation of possibility of amperometrical determination of palladium in solutions of complex composition after it's concentrating.
Selective and sensibile microquantitave amperometrical method of determination of palladium's ions based on their electrochemical reaction with azoreagent 4-(2-N-methylanabazinazo)-m-phenyldiamine has been elaboratel.
One of advantage of voltamperometry is it's ac-cesibility and determination of small quantities of the determined ions of metal. Modern method of determination of palladium ions have included the stage of decomposition of probe what is caused by partienlitres of apparntnes used for determination and also by necesar-ity of garantie vesohreunoun probe [1]. At determination of mieroquantities of palladium ions including in solutions of complex composition obtained after ores decomposition it is necussary previons concentrating. For this extractional [2] and sorptional methods [3-5] in combination with electrochemical method are wide used. The method of dinamical sorptional concentrating don't requed phases division and elowed to acheave high coefficients of concentrating during very small time what very perspecitival [6].
4-(-2-N-methylanabazinazo)-m-phenyldiamine is azoreagent which was proposed as selective and sensible
