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Iodine is a biophilic element with one natural long-lived isotope, 129I (t1/2= 15.6 million years), and one stable isotope, 127I. The inventory of 129I in surface environments has been overwhelmed by anthropogenic releases over the past 50 years. The objective of this study is to utilize the elevated concentration and biophilic nature of 129I and the isotopic ratio of iodine (129I/127I) as a tracer of water mass movement and organic matter. Additionally, the significantly elevated values of 129I/127I could provide a geochronometer, similar to the way 14C is used, particularly for terrestrial organic matter that is less than 50 years old. A series of laboratory experiments and field investigations were carried out to characterize the dominant chemical forms of dissolved iodine, i.e., iodide (I-), iodate (IO 3-), and organic iodine (DOI) in natural waters. Sensitive methods were developed for the analysis of nanomolar quantities of 127I species in a variety of environmental systems using high performance liquid chromatography (HPLC) and an organic iodine decomposition technique, dehydrohalogenation. The potential use of 129I/127I as a hydrological tracer was evaluated through measurements of 129I and 127I, which were carried out in wells in the artificially recharged ground water basin of Orange County, California. Literature values of aquifer ages based on 3H/3He and δ18O tracer data, as well as time-series data of chloride and Santa Ana River flow rates over the past decade were compared to values for 129I and 127I. The iodine isotopes demonstrated a conservative behavior in these aquifers, suggesting that the observed variations of these isotopes reflect past river flow conditions during the time of recharge. The feasibility of using 129I/127I ratios to trace terrestrial organic matter across an estuary was tested. A novel analytical technique to determine 129I/127I ratios in DOI was developed for this investigation. The results of a Galveston Bay transect clearly show that 129I/127I ratios in DOI can remain elevated up to salinity of about 15, but that 129I/127I values of inorganic iodine species do not show any trend with change in salinity gradient due to fast isotopic and chemical equilibration in the estuarine waters.

The study felld into three sections. The first section that a liquid chromatography method with fluorescence detection was developed for simultaneous determination of 11 quinolones (QNs; marbofloxacin, norfloxacin, ciprofloxacin, lomefloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid, nalidixic acid and flumequine) in chicken, pork, fish and shrimp. The analytes were extracted with 0.3% metaphosphoric acid: acetonitrile (1:1, v/v), followed by a HLB cartridge clean-up procedure. The HPLC separation was carried out on a symmetry column C18 (250 mm x 4.5 mm i.d., 5 £gm) with linear gradient elution of 0.1% formic acid: acetonitrile as mobile phase and programmable fluorescence detection. The method was validated by spiking blank animals tissues at three different levels (25, 50 and 250 ng/g; except 6.25, 12.5 and 62.5 ng/g for DAN) and linearity, detection limit, quantification limit, precision and accuracy were checked. Mean recoveries of 11 QNs from edible animal tissues were 71.7-105.3%. The limits of quantification in different muscle tissues ranged from 5.0 to 28.0 ng/g. The results showed it was simple, rapid, sensitive and suitable for routine test. The second section that a LC-ESI-MS/MS method was developed for determining 18 (fluoro)quinolone (QNs) residues in milk, chicken, pork, fish and shrimp. This method is capable of screening and confirming the presence of 12 amphoteric QNs (marbofloxacin, norfloxacin, enrofloxacin, ciprofloxacin, desethylene ciprofloxacin, lomefloxacin, danofloxacin, sarfloxacin, difloxacin, ofloxacin, orbifloxacin and enoxacin) and 6 acidic QNs (oxolinic acid, nalidixic acid, flumequine, cinoxacin, piromidic acid and pipemidic acid). The drugs were extracted from matrix using acetonitrile with 1% formic acid, diluted in 10% acetonitrile and defatted by extraction with hexane. The LC separation was conducted on a XDB C8 (150 x 4.6 mm, 5£gm) column with gradient elution of 20 mM ammonium formate with 0.1% formic acid¡Vacetonitrile as the mobile phase. Mass spectral acquisition was completed in the positive ion mode by applying multiple reaction mode (MRM). The decision limit (CC£\) and detection capability (CC£]) stated in the Decision No. 2002/657/EC and the ISO standard No.11843, has been calculated in the case of the nonauthorized substance. The values of CC£\ ranged from 0.18 to 0.68 ng/g and CC£] ranged from 0.24 to 0.96 ng/g under specified conditions. The third section that the pharmacokinetics of ENR and its active metabolite (CIP and des-CIP) were estimated in tilapia after intravenous (i.v.) and oral (p.o.) administration of a single dose of 2.5 and 10 mg/kg body weigh, respectively. At prefixed time points, from 0.25 h to 7 days after administration, whole blood and main tissue (liver, kidney, bile and muscle) from 4 individuals in each were collected. The concentration of ENR and its active metabolites in the main tissue were simultaneously detected by LC/MS/MS method. Limited of quantitation (LOQ) of this method were 0.01£gg/g. Pharmacokinetic parameters from both routes were described to have a two- compartment open model with first-order elimination. After i.v. administration, the area under the drug concentration-time (AUC), elimination half-life (t1/2£]), maximum plasma concentration (Cmax ), total body clearance (Cltot) and apparent volume of distribution at steady-state (Vss) of ENR were 109.6 ¡Ó 31.33 £gg.h/mL, 55.17 ¡Ó 22.84 h, 4.70 ¡Ó 0.36 £gg/mL, 14.82 ¡Ó 4.24 L/h/kg, 1105 ¡Ó 223.40 L/kg ,respectively. After oral administration, the AUC , t1/2£], Tmax , Cmax of ENR were 599.42 ¡Ó 76.19£gg.h/mL , 75.95 ¡Ó 12.94 h, 0.601¡Ó0.06h, 9.75 ¡Ó 0.46£gg/mL, respectively. After p.o. administration, CIP could be detected in liver, kidney and bile. Regarding des-CIP, the main active metabolite of CIP, could be detected in 120¡ã168 h bile among tissue. ENR and CIP had significance enterohepatic cycle in Tilapia and easily accumulated in bile. It seems reasonable to explain the phenomenon of ENR and CIP maintenance of high concentration in blood and muscle during the test time.

Zugl.: Hannover, Univ., Diss., 2009

Gas phase chemiluminescence nitrogen specific detector (CLND)is used for the direct analysis of underivatized nitrogen-containing components such as alkylamines that can not be detected by the so called universal HPLC detector, the UV detector. However, alkali metal hydroxides can not be used as mobile phase constituents with the CLND because they form non volatile particulate combustion products that foul the detector. Therefore, trimethylsulfonium hydroxide (TMSOH) has been selected as a strong base for use with the CLND, because its combustion products, CO2, H2O and SxOy are volatile. An alkali-stable zirconia-based column was used and coupled to the CLND. Zirconia-based columns are mechanically and hydrolytically more stable than silica-based columns, which have a working pH range from 3 to 8 only. Zirconia-based columns can be used at a pH from 1 to 14 and can be used at temperatures up to 200˚C. The separation of amines was carried out at high pH values where the amino groups were deprotonated. Primary, secondary, tertiary and quaternary amines were separated using a pH=13.7 mobile phase that contained only TMSOH, methanol and water. Good peak shapes were observed for all, except n-alkylamines and samples that contained both amino groups and alcohol groups.

Tetraciklinų nustatymas piene atliktas efektyviąja skysčių chromatografija ir įteisintas remiantis ES išleista direktyva 2002/657/EB. Metodas atitinka visus kriterijus aprašytus šioje direktyvoje. Antibakterinių medžiagų likučiai iš pieno ekstrahuojami Mcllvaine-EDTA buferiniu tirpalu, o po to valymas atliekamas naudojant OASIS HLB kietafazės ekstrakcijos kolonėles. Chromatografinėje kolonėlėje atskyrimas atliekamas naudojant 10 mM oksalo rūgšties vandeninio tirpalo ir ACN gradientinį režimą, tėkmės greitis 0,9 ml/min, 100 μl injekcija, bangos ilgis 355 nm ir optimali kolonėlės temperatūra (LiChroCART Superspher 60 RP C8 (250 x 4,6 mm, dalelių dydis 5 m)) – 30 oC. Visi rezultatai apskaičiuoti naudojant kompiuterinę duomenų apdorojimo programą “Interval”. Tetraciklinų išgavos nuo 86,20 % iki 107,19 %, o nustatymo ribos yra intervale nuo 26,7 μg/l iki 49,3 μg/l. / Analysis of tetracycline compounds was performed using high performance liquid chromatography and validated according to EU commition decision 2002/657/EC. Method is compliant at all criteria described in the decision. Antibacterial material residues were extracted from milk with Mcllvaine-EDTA buffer followed by clean-up on OASIS HLB cartridges. Separation was performed using 10 mM oxalic acid/ACN gradient with flow rate 0.9 ml/min, 100 μl injection, detection at 355 nm and the optimal temperature of column (LiChroCART Superspher 60 RP C8 (250 x 4.6 mm, size of particles 5 m)) – 30 oC. All the results were evaluated statistically with “Interval” data processing program. Recoveries are at the range from 86.20 % to 107.19 %. The determination limits for tetracyclines were carried out from 26.7 μg/L to 49.3 μg/L in this study.

Cyclosporine forms the cornerstone of therapy to prevent rejection after organ transplantation. However, the clinical use of the drug is compromised by a narrow therapeutic window and a wide inter- and intra-individual variation in metabolism. Cyclosporine is metabolised by the CYP3A4 isoenzymes in both the liver and intestine, while it has been reported that the metabolism of the drug can be inhibited by certain furocoumarin derivatives in grapefruit juice. Methoxsalen (8-methoxypsoralen) is a furocoumarin and a potent inhibitor of the cytochrome P450 system in both the liver and intestine. The study was conducted to investigate the possibility whether methoxsalen may inhibit the metabolism of cyclosporine and thereby increase the bioavailability of the drug. The interaction is of clinical relevance since both drugs are used in the treatment of psoriases. The study, conducted in 12 healthy male volunteers, was a three-way comparative bioavailability study with a wash out period of one week between treatments. The patients received 40 mg methoxsalen, 200 mg cyclosporine or a combination of the two on three separate occasions. Blood samples of 10 ml were collected by venupuncture at the following times: 0, 0.5, 1, 1.5, 2, 2.5, 3.4, 5,6, 8, 12 and 24 hours after drug administration. Methoxsalen was analysed by a high pressure liquid chromatograph method (HPLC) with UV detection (LOQ = 10 ng/ml), while cyclosporine was analysed using a fluorescence polarisation immunoassay (FPIA) technique. There was a statistical significant difference in AUCo-00 and Cmax ' for cyclosporine when methoxsalen was added to the drug regimen. When the methoxsalen levels were compared with those in the presence of cyclosporine, the levels were lower, although the difference was not statistical significant. We conclude that methoxsalen increase the levels of cyclosporine by inhibiting the P450 system enzymes in the liver and intestine. However, the absorption of methoxsalen is highly variable in the same individual which needs to be considered before this interaction can be regarded as being of any clinical relevance. / Thesis (M.Sc.(Pharmacology))--North-West University, Potchefstroom Campus, 2004.

Paprastasis rapontikas (Rhaponticum carthamoides (DC.) Iljin) priklauso graižažiedžių šeimai, savaime augantis pietų Sibire [1]. Daugiametis žolinis augalas. Sinonimai: Leuzea carthamoides, Stemmacantha carthamoides, maralinė šaknis [2]. Paprastojo rapontiko ekstraktai pasižymi plačiu spektru teigiamo poveikio: pagerina miegą, apetitą, nuotaiką, fizinę ir psichinę būklę [3], druskų apytaką, virškinimą, stabdomas navikų vystymasis [4], stimuliuoja centrinę nervų, širdies ir kraujagyslių sistemas [1], pasižymi hipolipideminiu [5], psichostimuliuojančiu [4] vabzdžius atbaidančiu, imuninę sistemą stiprinančiu poveikiu, taikomas lėtiniam alkoholizmui, impotencijai gydyti [4]. Darbo tikslas: atlikti biologiškai aktyvių junginių chromatografinę analizę paprastojo rapontiko (Rhaponticum carthamoides (DC.) Iljin) ekstraktuose. Augalinė žaliava. Analizei naudota paprastojo rapontiko augalinė žaliava (lapai) rinkta VDU KBS 2006 metų gegužės – spalio mėnesiais. Džiovinama gerai vėdinamoje patalpoje, vengiant tiesioginių saulės spindulių 15 – 20 °С temperatūroje. Eksperimentinė dalis. Metanoliniai paprastojo rapontiko ekstraktai buvo ruošiami 1g susmulkintos augalinės žaliavos užpilant 10 ml 75 % metanoliu ir paliekant 24 valandoms purtyklėje. Gautas ekstraktas filtruojamas. Optimizuotas kietafazės ekstrakcijos metodas metanoliniams paprastojo rapontiko ekstraktams; nustatyti suminiai fenolinių junginių ir flavonoidų kiekiai bei antioksidacinis aktyvumas fotometriniu metodu; atlikta... [toliau žr. visą tekstą] / Rhaponticum (Rhaponticum carthamoides (DC.) Iljin) is an herbaceous perennial plant from the family Asteraceae that inhabits the sub-alpine zone. It can be found growing wild in Southern Siberia, Kazakhstan, the Altay region. Synonyms founded in literature: Maral root, Leuzea carthamoides, Stemmacantha carthamoides. Research indicates that extracts of Rhaponticum carthamoides may have a beneficial effect on impotence, memory and learning, cardiovascular and CN systems, increasing working capacity of tired skeletal muscles, as well as anabolic and adaptogenic processes, can help break addictive behaviours. The aim of this study is to analyse the biologically active compounds in Rhaponticum carthamoides (dc.) Iljin extracts by means of chromatographic method. Raw material of Rhaponticum carthamoides (DC) Iljin. The plant material (21 samples) was collected from the collection of medicinal plants at Kaunas Botanical Garden of Vytautas Magnus University at different vegetation phases during May–October, 2006. Freshly cut plants were sorted out and dried in the drying room at 15-20°C temperature. Experimental. Into 1g of raw material 10 ml of 75% methanol was added and placed into shaker for 24 h. The methanolic extracts were filtered. For measuring of total amount of phenolics, flavonoids compounds and antioxidant activity in methanolic extracts spectrophotometer was used. For qualitative and quantitative investigation of flavonoids high performance liquid chromatography was... [to full text]