19 research outputs found
Nouvelles strategies permettant l'acces aux petits cyclopeptides
No full textSIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Seminar Nasional Penelitian, Pendidikan, dan Penerapan MIPA 2009
No full textAntihistamin merupakan salah satu jenis obat yang pemanfaatannya dalam
bidang medis dan farmasi sangat luas. Selain dipakai untuk mengobati bermacam
gangguan alergi juga dipakai sebagai antikolinergis, antiemetis, antiphlogistis,
sedativum, antiserotonin dan memiliki aktivitas anastetik lokal. Beragamnya
penggunaan dan prevalensi penyakit yang terus meningkat mendorong perlunya
pengawasan dan kontrol kualitas obat. Deksklorfeniramin maleat adalah antihistamin
derivat propilamin dan merupakan salah satu antihistamin yang banyak
direkomendasikan. Penelitian ini bertujuan mempelajari perilaku antihistamin
deksklorfeniramin maleat di permukaan elektroda pasta karbon pada pengukuran
secara voltametri. Studi voltametri terhadap deksklorfeniramin maleat telah dilakukan
dengan menggunakan teknik voltametri siklik dan voltametri pulsa diferensial. Rentang
potensial pengukuran yang dapat dipakai untuk studi antihistamin deksklorfeniramin
maleat adalah -200 sampai dengan 600 mV terhadap potensial Ag/AgCl. Studi
voltametri dilakukan dengan menggunakan elektroda kerja pasta karbon dengan
perbandingan komposisi grafit : parafin adalah 70 % : 30 %. Berdasarkan data arus
puncak yang diperoleh dari voltamogram siklik dan kajian awal voltametri pulsa
diferensial, dapat disimpulkan bahwa penentuan deksklorfeniramin maleat dapat
dilakukan dengan menggunakan metode voltametri
Proceeding of The International Seminar on Chemistry
No full textAbstract Cetirizine is one of antihistamine (H1-receptor antagonist) drugs which many applied in medical and pharmacy. Allergy prevalence increases recently, so that usage of this drug also increases. Therefore, monitoring improvement need to be done. Usage of some surfactant types as mediator in increasing sensitivity of cetirizine determination has been done by using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. The optimum composition of carbon paste electrode is 70:30% for graphite and paraffin, respectively. Potential interval to determination of cetirizine is 0 -400 mV. Optimization some parameters have also been done to obtain optimum values of measurement. The research found that optimum values such as accumulation potential, pulse amplitude, frequency and scan rate are 1 mV, 25 mV, 15 Hz and 15 mVs -1 , respectively. Based on square wave voltammogram, cetyltrimethylammonium bromide (CTAB) shows the best performance as mediator. The result shows that increase of peak current is equal to 5.01 times as effect of CTAB influence
Characterization of Extracellular Penicilin G Acylase Produced by A New Local Strain of Bacillus subtilis BAC4
Get PDFPenicillin G acylase (PGA) which catalyses penicillin G hydrolysis reaction is a key enzyme for the industrial production of penicilin G derivatives used in therapeutics. A new local strain of Bacillus subtilis BAC4 was found capable of producing extracellular PGA. However, characteristics of this extracellular PGA are not known. The goal of this research was to characterize the extracellular PGA produced by B. subtilis BAC4. Enzyme production was carried out by batch fermentation, followed by enzyme purification and characterization of the PGA. The PGA activity was determined by the Kornfeld method, with optimal activity for hydrolysing penicillin G observed at 43 oC and pH 8.5. The activation energy of penicillin G hydrolysis by the PGA of B. subtilis BAC4 was determined as 4.9 kcal.mol-1 and Vmax and Km values were found to be 0.7 µmole.min-1.mg-1 and 3.5 mM respectively. PGA catalytic activity was competitively inhibited by phenylacetic acid with an inhibition constant, Ki(PAA), of 347.2 mM. It was concluded that the extracellular PGA of B. subtilis BAC4 can hydrolyse penicillin G efficiently
MODIFIED GAS-LIQUID SEPARATOR FOR THE DETERMINATION OF Sn(II) WITH HYDRIDE GENERATION-QUARTZ FURNACE FLAME â?? ATOMIC ABSORPTION SPECTROPHOTOMETRY (HG-QFAAS)
No full textThe performance of determination of Sn(II) ion with hydride generation-quartz furnace atomic absorption spectrophotometry (HG-QFAAS) has been studied, by modifying the gas-liquid separator used. This modified gas-liquid separator at various sizes was able to increase sensitivity in the determination of Sn(II) in liquids. It has been determined that separators perform best at tube lengths of 9 cm and tube diameters of 3 cm, in which the mixing techniques reagent of acid, sample and reductant occur in a coil before going to the gas-liquid separators. The analytical performance in this method is good, which is shown by detection limit 3.74 &m
Synthesis of dipeptide benzoylalanylglycine methyl ester and corrosion inhibitor evaluation by Tafel equation
No full textCorrosion is one of the major problems in petroleum mining and processing industry. The pipelines used to transport crude oil from reservoir to the processing installation were made from carbon steel that is susceptible towards corrosion. One of the best methods to prevent corrosion that occurred at the inner parts of carbon steel pipelines is to use organic corrosion inhibitor. One of the potent organic corrosion inhibitors is amino acids derivatives. In this study, dipeptide compound namely benzoylalanylglycine methyl ester and benzoylalanylglycine have been synthesized. The structure elucidation of the products was performed by IR, MS and NMR spectroscopy. The determination of corrosion inhibition activity utilized the Tafel method. The corrosion inhibition efficiency of glycine methyl ester, benzoylalanine, dipeptide benzoylalanylglycine methyl ester and dipeptide benzoylalanylglycine were 63.34%, 35.86%, 68.40% and 27.72%, respectively. These results showed that the formation of dipeptide benzoylalanylglycine methyl ester, derived from carboxylic protected glycine and amine protected alanine, increased the corrosion inhibition activity due to the loss of acidity center in the structure of glicine and L-alanine that would induce the corrosive environment towards carbon steel
The Synthesis of Imidazoline Derivative Compounds as Corrosion Inhibitor towards Carbon Steel in 1% NaCl Solution
Get PDFTHE MICROWAVE ASSISTED SYNTHESIS OF SOME IMIDAZOLE DERIVATIVE COMPOUNDS AS POTENTIAL CORROSION INHIBITORS TOWARD CARBON STEEL IN 1% NACL SOLUTION
No full textFour imidazole derivative compounds: imidazole, compound 1 (4,5-diphenyl-1H-imidazole), 2 (2-ethyl-4,5-diphenyl-1H-imidazole) and 3 (1-(2-methyl-4,5-diphenyl-1H-imidazol-1-yl)ethanol) have been synthesized utilizing microwave assisted organic synthesis (MAOS) method, in order to investigate their corrosion inhibition mechanism on carbon steel surface. The determination of corrosion inhibition activities of the compounds utilized Tafel plot method. Based on the analysis of Tafel plot data, there was linearity of each Langmuir isotherm adsorptions of each compound, which represent the monolayer formation of each compound on the carbon steel surface. The Temkin adsorption isotherm was also well obeyed by compound 1, 2 and 3, indicated the chemisorption on metal surface. All of free Gibbs adsorption energy values, G0ads, for each compound is negative, which indicated the spontaneity of adsorption process of each compound on carbon steel surface. Imidazole, compound 1, 2 and 3 have the potent to interact with carbon steel through semi-physiosorption or semi-chemisorption because of their G0ads values are in between &ndas
A Long Chain Alcohol as Support in Solid Phase Organic Synthesis
No full textThe solid phase synthesis is a method by which organic compound synthesis are performed on a support. With this method, the purification can be carried out easily by simple filtration and washing procedures. Long-chain alcohol (C-100 alcohol) can be used as a support because of its insolubility in organic solvents and its simple structure which enables it to be stable in various reaction conditions. In this study, a 4-aminopyridine derivative has been synthesized from C-100 beta-keto ester and a cyano enamine using tin(VI) chloride as catalyst. C-100 beta-keto ester was obtained by transesterification of long chain alcohol (the support) with ethyl acetoacetate using boric acid protocol. The cyano enamine was successfully synthesized by Thorpe-Ziegler cyclization initiated by sodium hydride. The 4-aminopyridine derivative was successfully cleaved from the support using sodium isopropoxide in refluxing isopropanol. From the H-1-NMR spectrum at similar to 120 degrees C, it was found that the cleaved support has the same spectrum with the long-chain alcohol used in the beginning of reaction, thus, this long chain alcohol can be reused for other reactions.</p
