Absorption and excretion of suprofen in both sexes of rats, guinea pigs, and rabbits

DL-2-(4-2-Thienylcarbonyl)phenyl)propionic acid (suprofen) was rapidly absorbed in both sexes of rats, guinea pigs, and rabbits after oral administration. Blood levels after a single dose of 2 mg/kg 3H-suprofen in all the animals reached maxima within 15 min, and elimination of the 3H from blood was rapid; the radioactivity was mostly excreted in the urine and feces within 24 h after dosing.     

Novel approach to performing metabolite identification in drug metabolism

A novel online method is developed, using liquid chromatography (LC)-accurate radioisotope counting dynamic-flow (ARC) coupled with a radioactivity detector and mass spectrometer, for metabolite identification in drug discovery and development. This method offers the advantages of improved sensitivity for detecting radiolabeled drugs as well as streamlining the process of identifying and characterizing metabolites. For the purposes of evaluating this method, in vitro human liver microsomal incubations with [(14)C]dextromethorphan are conducted. Online separation and identification of [(14)C]dextromethorphan metabolites are achieved without intensive sample preparation, concentration, or fraction collection. Mass spectrometric analysis identified and characterized the metabolites of dextromethorphan formed by N - and O -dealkylation, correlated well with previously published results. Chromatographic peaks for [(14)C]dextromethorphan and its metabolites are collected online, then infused for extended periods of time at a flow rate of 10 microL/min while maintaining the column pressure. The continuous analytical signal input allowed acquisition of a higher order of multistage fragmentation for both major and minor metabolites. The multistage MS fragmentation pattern obtained for the metabolites allowed defining the sites of metabolism for dextromethorphan. Further evaluations of this method are also conducted using a [(14)C]compound A to check the linearity and sensitivity of the dynamic-flow method. The R(2) value is 0.996 for the dynamic-flow method between 50 and 600 disintegrations per minute (dpm); the limit of detection for LC-ARC is 20 dpm, which is approximately 10 times more sensitive than conventional continuous-flow radioactivity detection techniques. The overall results suggest that the combination of LC-ARC with radioactivity detection and mass spectrometry has great potential as a powerful tool for enhancing the sensitivity of radioisotope measurement in metabolite identification studies during drug discovery and development.     

Determination of plasma lactic acid concentration and specific activity using high-performance liquid chromatography.

Assessment of lactate metabolism is of particular interest during exercise and in disease states such as diabetes, shock, and absorptive abnormalities of short-chain fatty acids by the colon. We describe an analytical method that introduces radio-active tracers and high-performance liquid chromatography (HPLC) to simultaneously analyze concentrations and specific activities (SAs) of plasma lactate. The HPLC conditions included separation on a reversed-phase column (octadecylsilane) and an isocratic buffer (30% acetonitrile in water). [3H]Acetate served as an internal standard. Lactate and acetate were extracted from plasma samples with diethyl ether following a pH adjustment to less than 1.0 and back-extracted into a hydrophilic phase with sodium carbonate (2 mM, pH greater than 10.0). Lactate is detected in the ultraviolet range (242 and 320 nm) by derivatization with alpha-bromoacetophenone. Control plasma samples were studied after an overnight fast for precision and analytical recovery. Calibration curves were linear in the range 0.18-6.0 mM (r = 0.92). The precision was 3% and the analytical recovery was 87%. The detection limit of the method was 36 pmol. Determination of lactate metabolism was performed in a patient with chronic congestive heart failure who was administered primed-continuous L-[U-14C]lactate (10 microCi bolus and 0.3 microCi/min continuously) during a 60-min rest period. Mean arterial lactate concentration and SA were 1.69 +/- 0.2 mM and 253.8 +/- 22 dpm/mumol, respectively. Systemic lactate turnover was 25.65 mumol/kg per min. Lactic acid systemic turnover, organ uptake and release rates can be accurately determined by isocratic HPLC.     

Separation of radioactive metabolites in cultured tea cells fed with [14C]phenylalanine using high-speed counter-current chromatography

Separation of radioactive metabolites in cultured tea cells fed with [14C]phenylalanine was conducted using high-speed counter-current chromatography. Among seven components obtained our studies focused two metabolites, i.e. (-)-epicatechin and D,L-catechin. The specific radioactivity of (-)-epicatechin was 212.01 KBq/mg, amounting to 8.5% of the total radioactivity of ethyl acetate extract while that of D,L-catechin was 1.0006 MBq/mg or 5.4% of the total.     

High-yield synthesis of 14C labeled alicyclic amino acids with high specific radioactivity using potassium (14C) cyanide

In order to study the tumor specificity of synthetic nonmetabolizing amino acids, 10 different 14C labeled alicyclic amino acids (3a-3j) were synthesized in high yield and with high specific radioactivity. Carbon-14 labeled alicyclic hydantoins (2a-2j) were synthesized from a small amount of radioactive potassium [14C] cyanide and corresponding ketones (1a-1j). Th 14C hydantoins (2a-2j) thus obtained were hydrolyzed without isolation to give 14C labeled alicyclic amino acids (3a-3j). The overall radiochemical yields of the amino acids (3a-3j) from potassium [14C] cyanide were 55.6-93.2% with radiochemical purity more than 99%. Specific activities of these 14C labeled compounds (3a-3j) were 209- 250 MBq/mmol (5.66-6.75 mCi/mmol). When non-radioactive potassium cyanide was not added as a carrier, 1-aminocyclopentane[14C]-carboxylic acid (3b) and 1-aminocyclooctane[14C]carboxylic acid (3e) were synthesized in the yield of 64.9 and 19.0% respectively with the specific activity exceed more than 1.85 GBq/mmol (50mCi/mmol).     

An assessment of mucosal damage in vivo: effect of oral pretreatment with 5-fluorouracil on the intestinal first-pass metabolism of salicylamide in rabbits.

An assessment of 5-fluorouracil (5-FU)-induced mucosal damage in vivo by measuring the metabolism of salicylamide (SAM) was investigated in rabbit intestine. The mucosal damage in the intestine 48 h after oral administration of 5-FU (30 mg/kg) was examined using a scanning electron microscope. By the oral pretreatment with 5-FU, the morphological changes of jejunal and ileal mucosa were recognized compared with the control. The intestinal first-pass metabolism of SAM was studied using in situ intestinal sacs with complete mesenteric venous blood collection. The appearance of both SAM and its metabolites into the mesenteric venous blood was measured directly by cannulating the mesenteric vein of exposed intestine and collecting all venous blood draining from the absorbing region. Following oral pretreatment with 5-FU, the appearance of SAM glucuronide (SAMG) in the mesenteric venous blood was significantly increased. The increased blood concentration of SAMG following intraduodenal administration of SAM in vivo was observed in rabbits pretreated with 5-FU orally. However, the blood concentration of SAMG after intravenous administration of SAM was not increased compared with the control. These findings suggest that the change in intestinal first-pass metabolism of SAM may be due to the intestinal mucosal damage by oral pretreatment with 5-FU. The alteration of intestinal first-pass metabolism of a marker compound may be utilized for the assessment of intestinal mucosal damage in vivo.     

Absolute humidity measurement utilizing alpha-ray absorption

Changes in air density due to humidity were measured by a scintillation detector with alpha-particles. The distance between the scintillator and an alpha-ray source of 241 Am, 3.7 MBq (100 microCi), was fixed at 25 mm which was a little shorter than the range of alpha-particles from the source. The measured absolute humidities were in a range of 7.9 g/m3 to 52.2 g/m3 at temperatures of 35 degrees C and 45 degrees C and under atmospheric pressure. The counting rate of alpha-particles in an absolute humidity of 31.7 g/m3 (80% in relative humidity) at 35 degrees C increased 28% compared with that in dry air. From experimental results and theoretical calculation, the counting rate difference between humid air and dry air was shown to be almost proportional to the absolute humidity in air. The absolute humidity can be measured with an accuracy of +/- 3 g/m3, that is +/- 5% in relative humidity at 45 degrees C.     

Use of an immobilized enzyme reactor for the analysis of residues of 17 alpha-methyltestosterone in trout by high-performance liquid chromatography

We have recently observed in trout that 48 h after ingestion of a single dose of [14C]-17 alpha-methyltestosterone ([14C]-MT), 25% of the radioactivity was still in the carcass, corresponding to metabolites of 17-MT. These compounds have no appreciable chromophore, fluorophore or electrophore, therefore the usual detection systems was not satisfactory for their analysis. Consequently a method was developed for high-performance liquid chromatographic separation and detection of two of the major tissue metabolites of 17-MT: 5 alpha-androstane-17 alpha-methyl-3 alpha,17 beta-diol and 5 beta-androstane-17 alpha-methyl-3 alpha,17 beta-diol. A column of immobilized 3 alpha-hydroxysteroid dehydrogenase was prepared and used for detection. The NADH produced from 3-hydroxysteroids by this immobilized enzyme reactor was monitored fluorimetrically. The detection limit of this method, as obtained from the calibration curve, was at the picomole level; the limit of quantification in muscle was 1 microgram/kg, at a signal-to-noise ratio of 4.     

Liquid chromatography-accurate radioisotope counting and microplate scintillation counter technologies in drug metabolism studies

The present study involves an analysis of the performance of liquid chromatography (LC)-accurate radioisotope counting (ARC) and microplate scintillation counter (TopCount) technologies in drug metabolism studies. For the purpose of evaluating these systems, biological samples resulting from the metabolism of a radiolabeled [14C] compound, known as compound B, are analyzed using LC-ARC and TopCount under similar high-performance LC conditions. Counting efficiency is 83% for LC-ARC, 77% for TopCount, and linearity is R2 of 0.9998 versus 0.9984, respectively. The limit of detection for LC-ARC is 12 disintegrations per minute (dpm) with 1-min/fraction counting, yet for TopCount it is 8.7 dpm with 5-min/fraction counting. Under optimal conditions for each, the total run time of LC-ARC is approximately half that of TopCount. These results indicate that there is no significant difference between these two systems in terms of efficiency, linearity, and limit of detection. However, the LC-ARC system does not involve any manual operations, yet TopCount requires manual sample transfer and data import. This study shows that impressive progress has been made in the technology of radioisotope counting in drug metabolism using LC-ARC. This system enhances the resolution of radiochromatograms and is able to measure volatile metabolites that TopCount cannot detect at all. The ability to acquire mass spectra online is also a major advancement. The overall results suggest that the combination of LC-ARC with radioactivity detection and mass spectrometry has great potential as a powerful tool for radioisotope measurement in metabolite identification studies during drug discovery and development.     

Effect of L-cysteine on plasma concentration and urinary excretion of 1-(tetrahydro-2-furanyl)-5-fluorouracil metabolites

Effects of L-cysteine (CySH) on the plasma concentrations and the urinary excretion of 1-(tetrahydro-2-furanyl)-5-fluorouracil (FT) and its metabolites were studied by high performance liquid chromatography in rats. Significantly higher plasma concentrations of FT, 5-fluorouracil (5-FU) and cis-4'-OH-FT were obtained after an oral administration of FT (500 mg/kg) combined orally with CySH (500 mg/kg) when compared to FT alone. The urinary excretions of 5-FU, trans-3'-OH-FT, cis-4'-OH-FT, trans-4'-OH-FT and 4',5'-dehydro-FT significantly decreased up to 12 h but that of alpha-fluoro-beta-alanine significantly increased up to 24 h by the combined administration of CySH. Furthermore, the plasma concentration of 5-FU significantly increased at 0.5 h and its urinary excretion significantly decreased up to 4 h after an intraperitoneal administration of 5-FU (10 mg/kg) combined orally with CySH (500 mg/kg) when compared to 5-FU alone. The urinary pH significantly changed to acidic and the urinary volume significantly increased by the combined administration of CySH, so it was thought that the reabsorption of 5-FU through renal tubules from urine could increase and the increment of the urinary excretion of alpha-fluoro-beta-alanine was caused by this. Then it was suggested that the increase of the plasma concentrations of 5-FU and cis-4'-OH-FT could be attributed to the decrease of their urinary excretions after an administration of FT combined with CySH when compared to FT alone.     

Comparison of γ-radiation and electron beam irradiation effects on gelatin

Gelatin is a heterogeneous mixture of water-soluble proteins of high average molecular weight derived by hydrolytic action from collagen, a protein of mammal external protective tissues. There are many characteristics of a material that can indicate its quality or performance in its intended use. The knowledge of a material's rheological characteristics is valuable to predict its pourability, its performance in a dipping or coating operation or the ease with which it may be handled, processed or used. In this work bovine powder gelatin was submitted to γ-radiation from a ⁶⁰Co source, dose rate about 7 kGy/h and to electron beam irradiation, dose rate about 11 kGy/s. The doses applied were 5, 10, 20 and 50 kGy. The radiation effects were measured following viscosity changes at 40°C of gelatin powder 10% aqueous solutions. The relationship between the decrease in viscosity of gelatin solutions and radiation dose presented close comparable values for both irradiation processes.     

Tissue-protective effects of fullerenol C60(OH)24 and amifostine in irradiated rats

Polyhydroxylated fullerenes, named fullerenols (C(60)(OH)(n); n=12-26) are excellent antioxidants. Harmful effects of ionizing radiation on living organism are mainly mediated by free radical species and fullerenols attract an attention as a potential radioprotectors. Our preliminary investigations on mice and rats subjected to radiation injury show that fullerenol C(60)(OH)(24) provides high survival rate of irradiated small rodents. Radioprotective effect was comparable to that of the standard radioprotector amifostine. The aim of this study was to compare the efficacy of fullerenol C(60)(OH)(24) (10 and 100mg/kg i.p.) and amifostine (300 mg/kg i.p.) in protection of rats against harmful effects of ionizing radiation. The animals were whole-body irradiated by X-rays (8 MV). Both compounds were given 30 min before irradiation. In order to evaluate the general radioprotective efficacy of fullerenol and amifostine rats were irradiated with an absolutely lethal dose of X-rays (8 Gy) and their survival and body mass gain were monitored during the period of 30 days after irradiation. The aim of the second part of the study is to investigate the tissue-protective effects of tested compounds (100 mg/kg i.p. of fullerenol and 300 mg/kg i.p. of amifostine, 30 min before irradiation). It was carried out on rats irradiated with a sublethal dose of X-rays (7 Gy). Influence of ionizing radiation on hematopoesis as well as the radioprotective efficiency of the compounds given were evaluated by determining blood cell count during 28 days after irradiation. For this purpose the blood was taken from tail vein before irradiation and on the 3rd, 7th, 14th, 21st and 28th day after irradiation. In order to estimate the radioprotective effects of fullerenol and amifostine on other rat tissue, the animals were sacrificed on the 7th and 28th day after irradiation and their main organs (lung, heart, liver, kidney, small intestine and spleen) were taken for histopathological analysis. In the experiment in which the general radioprotective efficacy of fullerenol and amifostine was examined, fullerenol given in a dose of 100mg/kg produced better protection than given in a dose of 10mg/kg. This effect was comparable to that of amifostine. The results of hematological investigations showed that fullerenol better than amifostine prevented radiation-induced reduction in the white cell count (granulocytes and lymphocytes), particularly in the first 7 days after irradiation. Pathohistology examinations revealed better radioprotective effects of fullerenol compared to those of amifostine on the spleen, small intestine and lung, while amifostine had better radioprotective effects than fullerenol in protection of the heart, liver and kidney. These results confirm satisfactory radioprotective efficacy of fullerenol and encourage further investigations as a potential radioprotector.     

Design,synthesis and preclinical evaluations of (s)-2-((s)-1-benzyl-2,5-dioxopyrrolidin-3-yl)-3-(4-isopropylphenyl)-2-methylpropanal (succ-5) as cardioprotective,hepatoprotective and lipid lowering molecule. in-vivo and in-silico approaches

In this study, the newly synthesized compound (Succ-5) was analyzed through spectral methods, seen for potential receptor targets via molecular docking, and pre-clinically evaluated for therapeutic effects and safety profile using biochemical and histopathological techniques. The biochemical analysis included assessment of cardiac biomarkers, hepatic enzymes, and lipid profiles, while histopathology included evaluation of cardiac and liver tissues. The toxic dose was determined pre-clinically, followed by dividing albino rats into five treatment groups (each having n = 6). The control group received oral saline for eight days. The 5-FU (5-Fluorouracil) group received oral saline for 8 days and 5-FU (150 mg/kg I.P.) on day 5. The atenolol group was administered with atenolol (20 mg/kg) for 8 days and 5-FU (150 mg/kg I.P.) on day 5. Two groups of rats were administered with the test compound (Succ-5) at doses of 5 mg/kg I.P and 10 mg/kg I.P (for 8-days), followed by 5-FU (150 mg/kg I.P.) on day 5. Elevated serum levels of CK-MB (creatinine kinase myocardial band), cTnI (troponin I), LDH (lactate dehydrogenase), lipid profile, and selected liver enzymes including ALP (alkaline phosphatase), ALT (alanine transaminase), AST (aspartate aminotransferase), BT (bilirubin total) and BD (direct bilirubin) were associated with 5-FU toxicity. After administration of the test compound at the mentioned doses, these biomarkers significantly decreased. Likewise, histological examination revealed 5-FU damaged the heart and hepatic tissues, which were also considerably recovered following administration of the test compound. Immunohistochemistry of heart tissue also revealed the low expression of COX-2 and TNF-α in Succ-5 treated groups compared to toxic group. Dose-response evaluation showed that a dose of 10 mg/kg provided better results than 5 mg/kg. The analysis of binding energy values computed via docking simulations showed that Succ-5 interacts with the human beta2-adrenergic G protein-coupled receptor with a slightly stronger affinity than calcium channel T-type. In conclusion, the histological and biochemical findings revealed that the test compound had significant cardioprotective, hepatoprotective, and lipolytic effects in the 5-FU-induced toxicity.     

Application of accelerator mass spectrometry to macromolecules: preclinical pharmacokinetic studies on a polybisphosphonate

Data on the use of accelerator mass spectrometry (AMS) in conjunction with in vivo studies of macromolecular drugs are scarce. The present study shows the versatility of this technique when investigating the pharmacokinetics (PK) of a macromolecular drug candidate, a polybisphosphonate conjugate (ODX). The aforementioned is a polymer (molecular weight ~30 kDa) constituting a carbohydrate backbone with covalently linked ligands (aldendronate and aminoguanidine) and is intended for treatment of osteoporosis and the therapy of bone metastasis from prostate cancer. The conjugate is prepared through partial oxidation of the carbohydrate and sequential coupling of the ligands by reductive amination. ¹⁴ C was incorporated in the conjugate by means of coupling a commercially available ¹⁴ C‐lysine in the conjugation sequence. Fifteen rats were injected intravenously with ¹⁴ C‐labelled ODX (150 µg, 14 Bq/rat) and blood samples were collected at 1, 2, 4, 6, and 24 h post‐injection (3 rats/time point). Liver, spleen and kidney samples were collected at 4 and 24 h post‐injection. Blood from each time point (triplicate) were collected for AMS measurement determining the isotopic ratio (¹⁴ C/¹² C) and consequently the drug concentration in blood. ODX showed a transient presence in blood circulation; 93% of the total dose was cleared from the circulation within 1 h. The half‐life after 1 h was estimated to be about 3 h; 0.7% of the administered ¹⁴ C dose of ODX remained in circulation after 24 h. The major ¹⁴ C accumulation was in the liver, the spleen and the kidneys indicating the probable route of metabolism and excretion. This study demonstrates the versatility of AMS for pharmacological in vivo studies of macromolecules. Labelling with ¹⁴ C is relatively simple, inexpensive and the method requires minimal radioactivity, eliminating the need for radioprotection precautions in contrast to methods using scintillation counting. Copyright © 2011 John Wiley & Sons, Ltd.     

PEG-m-THPC-mediated photodynamic effects on normal rat tissues

Photodynamic therapy (PDT) of malignancies uses light to activate a photosensitizer preferentially accumulated in cancer cells. The first pegylated photosensitizer, tetrakis-(m-methoxypolyethylene glycol) derivative of 7,8-dihydro-5,10,15,20-tetrakis(3-hydroxyphenyl)-21-23-[H]-porphyrin (PEG-m-THPC), was evaluated in non-tumor-bearing rats. The aim of this study was to assess the photodynamic threshold for damage and its sequelae in normal rat tissue. Thirty-five Fischer rats were sensitized with 3, 9 or 30 mg/kg body weight PEG-m-THPC. Colon, vagina and perineum were irradiated with laser light of 652 nm wavelength and an optical dose of 50, 150 or 450 J/cm fiber length. Temperature in the pelvis was measured during PDT. Three days following PDT the effect on skin, vagina, colon, striated muscle, connective tissue, nerves and blood vessels was assessed by histology. The healing of the above-mentioned tissues was assessed on two rats 3 and 8 weeks after PDT using 9 mg/kg PEG-m-THPC activated with 450 J/cm laser light. No dark toxicity was observed. PDT using 30 mg/kg PEG-m-THPC induced severe necrosis irrespective of the optical dose. Body weight of 9 or 3 mg/kg activated with less than 450 J/cm induced moderate or no damage. No substantial increase in body temperature was seen during PDT. Tissues with severe PDT-induced damage seem to have a good tendency to regenerate. We conclude that within the dose required for tumor treatment PEG-m-THPC is a safe photosensitizer with promising properties. PDT of the colon mucosa below 9 mg/kg PEG-m-THPC and 150 J/cm seems to be safe. All other tissues can be exposed to 9 mg/kg PEG-m-THPC activated with less than 450 J/cm laser light with little side effects.     

In vivo radioprotective effects of Nigella sativa L oil and reduced glutathione against irradiation-induced oxidative injury and number of peripheral blood lymphocytes in rats

Radiotherapy is one of the most common therapies for treating human cancers. Several studies have indicated that irradiation induces reactive oxygen species (ROS), which play an important role in radiation damage of the cell. It has been shown that Nigella sativa L. (NS) and reduced glutathione (GSH) have both an antiperoxidative effect on different tissues and a scavenger effect on ROS. The purpose of this study was to determine the antioxidant and radio-protective roles of NS and GSH against irradiation-induced oxidative injury in an experimental model. The NS group was administrated NS (1 mL/kg body weight), the GSH group was injected GSH (150 mg/kg body weight) and the control group was given physiologic saline solution (1 mL/kg body weight) for 30 consecutive days before exposure to a single dose of 6 Gy of radiation. Animals were sacrificed after irradiation. Malondialdehyde, nitrate, nitrite (oxidative stress markers) and ascorbic acid, retinol, beta-carotene, GSH and ceruloplasmin (nonenzymatic antioxidant markers) levels and peripheral blood lymphocytes were measured in all groups. There were statistically significant differences between the groups for all parameters (P < 0.05). Whole-body irradiation caused a significant increase in blood malondialdehyde, nitrate and nitrite levels. The blood oxidative stress marker levels in irradiated rats that were pretreated with NS and GSH were significantly decreased; however, non-enzymatic antioxidant levels were significantly increased. Also, our results suggest that NS and GSH administration prior to irradiation prevent the number of alpha-naphthyl acetate esterase peripheral blood T lymphocytes from declining. These results clearly show that NS and GSH treatment significantly antagonize the effects of radiation. Therefore, NS and GSH may be a beneficial agent in protection against ionizing radiation-related tissue injury.     

Examination of the in vitro degradation of [14C] pentaerythritol tetranitrate in rat and human blood with an improved thin-layer radiochromatographic procedure

Improvements were made on a reported thin-layer radiochromatographic assay for the determination of [14C]pentaerythritol tetranitrate (PETN) and its metabolites in whole blood, using methanol instead of dioxane as the extracting solvent. Recovery of total radioactivity for the entire work-up procedure was greater than 90%, and the distribution of PETN and its metabolites in degraded blood samples was found to be reproducible. This modified method appeared simpler and yielded better recovery of radioactivity than the literature method. In vitro metabolism of [14C]PETN in rat and human blood was examined by incubation of the drug with fresh blood at 37 degrees C for 60 min. In rat blood, the half-life of PETN degradation was about 15 min producing the trinitrate, dinitrate and mononitrate metabolites. Human blood was also capable of degrading PETN in vitro, but at a lower rate than rat blood, yielding only the trinitrate metabolite in quantifiable amounts during the incubation period. Equilibrium of PETN between plasma and red blood cells was observed within 1 min after PETN addition to both rat and human blood. The apparent plasma/red blood cells partition ratios of PETN were 1.1 and 1.7 for rat and human blood, respectively. PETN degradation was approximately ten times slower in rat plasma than in rat blood, suggesting that enzymes in erythrocytes are important for PETN metabolism in rat whole blood.     

Solvent effect on infrared spectra of methyl methacrylate in CCl4/C6H14, CHCl3/C6H14 and C2H5OH/C6H14 binary solvent systems

Research of methyl methacrylate (MMA) in three kinds of binary solvent systems (CCl4/C6H14, CHCl3/C6H14 and C2H5OH/C6H14) on the infrared (IR) spectra was reported. Two types of carbonyl stretching vibration bands for MMA in CHCl3/C6H14 or C2H5OH/C6H14 mixtures were found with the changing of the mole fraction of CHCl3 (XCHCl3) or C2H5OH (XC2H5OH). The carbonyl stretching vibration bands at lower frequencies in the above two mixtures were attributed to the formation of hydrogen bonding between MMA and CHCl3 or C2H5OH. While in CCl4/C6H14 mixtures there was only one type of carbonyl stretching vibration band of MMA. Good linear correlations between the frequencies of C=O or C=C stretching vibration band of MMA and XCCl4, XCHCl3 or XC2H5OH were found, respectively. The solute-solvent interactions in the three different binary solvent systems were discussed in detail.     

Synthesis and biodistribution of bowman-birk soybean protease inhibitor conjugate with amphiphilic polyester

The modification of Bowman-Birk soybean protease inhibitor (BBI) with the monoaldehyde derivative of block copolymer of ethylene oxide and propylene oxide (PE),M _r 2000 is described. The conjugate contains five covalently bound polymer chains per protein molecule, and retains the ability to inhibit trypsin and chymotrypsinlike proteinases. The distribution of native BBI and the BBI-PE conjugate was examined in mice. After iv injection of [¹²⁵I]BBI and [¹²⁵I]BBIPE, both inhibitors distributed very rapidly to the liver, kidney, and lungs, and more slowly to the brain. At the same time-points (up to 24 h), radioactivity in the blood and organs of mice injected with modified inhibitor was higher than that of the native inhibitor. The blood concentration time profile following iv administration of two BBI preparations at a dose 3 mg/kg was reasonable well described by a two-compartment open model with first-order elimination kinetics. The total clearance of BBI-PE decreased by a factor of 8, body mean residence time increased by a factor of 5 in comparison with BBI. A physiological pharmacokinetic model was developed to describe the tissue-to-blood distribution of two inhibitors. One-compartment physiological organ model (flow limited) was used to describe of timecourse profiles of BBI concentration in organs. A two-compartment physiological organ model (membrane limited) was used to predict tissue-to-blood distribution of conjugated BBI in some organs of mice (liver, lungs). The predicted concentration curves of BBI and BBI-PE in blood and organs in mice (with the exception of kidney) showed good agreement with the observed values.