Preparation and biodistribution of [67Ga]-DTPA-gonadorelin in normal rats

Gonadorelin was successively labeled with [⁶⁷Ga]-gallium chloride after residulation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation were obtained by the addition of 1 mg of a gonadorelin to a glass tube pre-coated with DTPA-dianhydride (0.33 mg) at 25 °C with continuous mild stirring for 1 hour. Radio thin layer chromatography showed an overall radiochemical purity of >90% at optimized conditions after labeling. HPLC showed a radiochemical purity more than 95% (specific activity = 400–450 GBq/M). The stability of the radioconjugate was tested in presence of human serum at 37 °C. Preliminary in vivo studies in normal rats were performed to determine the biodistribution of the conjugate up to 48 hours. The breast and ovaries uptakes were significantly high in first 15-minute post injection which is in agreement with the other reports regarding the presence of specific GnRH receptors. This tracer can be used in detection of GnRH receptor biodistribution in various diseases and malignancies.     

Preparation and biodistribution of [111In]-rHuEpo for erythropoietin receptor imaging

Human recombinant erythropoietin (EPO) was successively labeled with [¹¹¹In]-indium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride (ccDTPA). The best results of the conjugation were obtained by the addition of 100 i.u. of an EPO pharmaceutical solution (in phosphate buffer, pH 7.5) to a glass tube pre-coated with DTPA-dianhydride (0.01 mg) at 25 °C with continuous mild stirring for 30 minutes. Radio thin layer chromatography (RTLC), instant thin layer chromatography (ITLC) and high performance liquid chromatography (HPLC) showed overall radiochemical purity of higher than 95% at optimized conditions (specific activity = 1.2–1.5 GBq/mg, labeling efficiency 80%). Preliminary in vivo studies in normal rat model was performed to determine the biodistribution of the radiotracer up to 1 hour using scarification. The high kidney uptake of the tracer was consistent with the reported EPO receptor distribution.     

Development of <Superscript>111</Superscript>In labeled insulin for receptor imaging/therapy

In order to target insulin receptors in various diabetic and insulinoma conditions, human recombinant insulin was successively labeled with [¹¹¹In]-indium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride (ccDTPA). The best results of the conjugation were obtained by addition of 0.5 mL of an insulin pharmaceutical solution (5 mg/mL, in phosphate buffer, pH 8) to a glass tube pre-coated with DTPA-dianhydride (0.01 mg) at 25 °C with continuous mild stirring for 30 minutes. Radio-thin layer chromatography (RTLC), instant thin layer chromatography (ITLC) and high performance liquid chromatography (HPLC) have shown an overall radiochemical purity of higher than 93% at optimized conditions (specific activity = 550–750 MBq/mg, radiochemical yield =81%). The white blood cell labeling capacity of the tracer was determined up to 4 hours at 37 °C. Preliminary in vivo studies in normal rat model was performed to determine the biodistribution of the radiotracer up to 48 hours. It showed a high liver and spleen uptake of the tracer which is consistent with other reported radiolabeled insulins. SPECT images have also shown high liver accumulation of the tracer.     

Quantitative estimation of riluzole in human plasma by LC-ESI-MS/MS and its application to a bioequivalence study

A novel simple, sensitive, selective, and rapid high-performance liquid chromatography coupled with tandem mass spectrometry method was developed and validated for quantification of riluzole in human plasma. The chromatography was performed by using a Zorbax-SB-C18 (4.6 × 75 mm, 3.5 μm) column , isocratic mobile phase 0.1% formic acid/acetonitrile (10:90 v/v), and an isotope-labeled internal standard (IS), [¹³C,¹⁵N₂]riluzole. The extraction of drug and internal standard was performed by liquid–liquid extraction and analyzed by MS in the multiple reaction monitoring (MRM) mode using the respective [M+H]⁺ ions, m/z 235.0/165.9 for riluzole and m/z 238.1/169.0 for the IS. The calibration curve was linear over the concentration range 0.5–500.0 ng/ml for riluzole in human plasma. The limit of quantification (LOQ) was demonstrated at 0.5 ng/ml. The within-batch and between-batch precision were 0.6–2.3% and 1.4–5.7%, and accuracy was 97.1–101.1% and 98.8–101.2% for riluzole respectively. Drug and IS were eluted within 3.0 min. The validated method was successfully applied in a bioequivalence study of riluzole in human plasma.     

Development of [<Superscript>64</Superscript>Cu]-DOTA-anti-CD20 for targeted therapy

Copper-64 was produced as a by-product of ⁵⁵Co via ⁶⁴Ni(p,n)⁶⁴Cu by 15 MeV proton bombardment of ^natNi resulting in a thick target yield of 5.31 MBq/μAh (143.5 μCi/μAh) and a radiochemical separation yield of 95% (radionuclide purity >97% after 25 hours of bombardment). Rituximab was successively labeled with [⁶⁴Cu]-CuCl₂. N-succinimidyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA-NHS) was prepared at 25 °C using DOTA and N-hydroxy succinimide (NHS) in CH₂Cl₂ followed by the addition of 1 ml of a Rituximab pharmaceutical solution. Radiolabeling was performed at 37 °C in 3 hours. Radio thin-layer chromatography showed an overall radiochemical purity of 90–95% at optimized conditions (specific activity=30 GBq/mg, labeling efficacy; 82%) using various chromatography systems. The final isotonic ⁶⁴Cu-DOTA-Rituximab complex was passed through a 0.22 μm filter and checked by gel electrophoresis for radiolysis control. Stability of the final product was checked in the formulation and in presence of human serum at 37 °C.     

Sensitive spectrophotometric determination of ascorbic acid in fruit juices and pharmaceutical formulations using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP)

A simple and very sensitive method has been developed for the determination of ascorbic acid based on the oxidation of ascorbic acid to dehydroascorbic acid by iron(III), followed by a complexation of iron(II) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol(Br-PADAP). The iron(II) complex is formed immediately, with absorption maxima at 560 and 748 nm and a molar absorptivity of 1.31 × 10⁵ l mole^–1cm^–1 and 5.69 × 10⁴ l mole^–1cm^–1, respectively. The ascorbic acid determination is possible with a linear range up to 2.4 μg ml^–1, a calibration sensitivity of 0.744 ml μg^–1 at 560 nm and 0.323 ml μg^–1 at 748 nm, and a detection limit of 15 ng ml^–1 and 44 ng ml^–1, respectively. The procedure was used for the ascorbic acid determination in several fruit juices and pharmaceutical formulations. The results demonstrated a good precision (R.S.D. < 1%) and are in agreement with those obtained with others methods. The Br-PADAP method proposed is six times more sensitive than the method using the iron(II)-1,10-phenanthroline system. Received: 7 May 1996 / Revised: 1 July 1996 / Accepted: 8 August 1996     

Multi-component analysis of tetracyclines, sulfonamides and tylosin in swine manure by liquid chromatography–tandem mass spectrometry

A multi-component method focussing on thorough sample preparation has been developed for simultaneous analysis of swine manure for three classes of antibiotic—tetracyclines, sulfonamides, and tylosin. Liquid manure was initially freeze-dried and homogenised by pulverization before extraction by pressurised liquid extraction. The extraction was performed at 75°C and 2,500 psig in three steps using two cycles with 0.2 mol L⁻¹ citric acid buffer (pH 4.7) and one cycle with a mixture of 80% methanol with 0.2 mol L⁻¹ citric acid (pH 3). After liquid–liquid extraction with heptane to remove lipids, the pH of the manure was adjusted to 3 with formic acid and the sample was vacuum-filtered through 0.6 μm glass-fibre filters. Finally the samples were pre-concentrated by tandem SPE (SAX-HLB). Recoveries were determined for manure samples spiked at three concentrations (50–5,000 μg kg⁻¹ dry matter); quantification was achieved by matrix-matched calibration. Recoveries were >70% except for oxytetracycline (42–54%), sulfadiazine (59–73%), and tylosin (9–35%) and did not vary with concentration or from day-to-day. Limits of quantification (LOQ) for all compounds, determined as a signal-to-noise ratio of 10, were in the range 10–100 μg kg⁻¹ dry matter. The suitability of the method was assessed by analysis of swine manure samples from six different pig-production sites, e.g. finishing pigs, sows, or mixed production. Residues of antibiotics were detected in all samples. The largest amounts were found for tetracyclines (up to 30 mg kg⁻¹ dry matter for the sum of CTC and ECTC). Sulfonamides were detected at concentrations up to 2 mg kg⁻¹ dry matter (SDZ); tylosin was not detected in any samples.      

Sensitive spectrophotometric determination of ascorbic acid in fruit juices and pharmaceutical formulations using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Br-PADAP)

A simple and very sensitive method has been developed for the determination of ascorbic acid based on the oxidation of ascorbic acid to dehydroascorbic acid by iron(III), followed by a complexation of iron(II) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol(Br-PADAP). The iron(II) complex is formed immediately, with absorption maxima at 560 and 748 nm and a molar absorptivity of 1.31 × 10⁵ l mole^–1cm^–1 and 5.69 × 10⁴ l mole^–1cm^–1, respectively. The ascorbic acid determination is possible with a linear range up to 2.4 μg ml^–1, a calibration sensitivity of 0.744 ml μg^–1 at 560 nm and 0.323 ml μg^–1 at 748 nm, and a detection limit of 15 ng ml^–1 and 44 ng ml^–1, respectively. The procedure was used for the ascorbic acid determination in several fruit juices and pharmaceutical formulations. The results demonstrated a good precision (R.S.D. < 1%) and are in agreement with those obtained with others methods. The Br-PADAP method proposed is six times more sensitive than the method using the iron(II)-1,10-phenanthroline system. Received: 7 May 1996 / Revised: 1 July 1996 / Accepted: 8 August 1996     

Development of <Superscript>177</Superscript>Lu-DOTA-anti-CD20 for radioimmunotherapy

Rituximab was successively labeled with ¹⁷⁷Lu-lutetium chloride. ¹⁷⁷Lu chloride was obtained by thermal neutron flux (4 × 10¹³ n cm⁻² s⁻¹) of natural Lu₂O₃ sample with a specific activity of 2.6–3 GBq/mg. The macrocyclic bifunctional chelating agent, N-succinimidyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA-NHS) was prepared at 25 °C using DOTA, N-hydroxy succinimide (NHS) in CH₂Cl₂. DOTA-rituximab was obtained by the addition of 1 mL of a rituximab pharmaceutical solution (5 mg/mL, in phosphate buffer, pH 7.8) to a glass tube pre-coated with DOTA-NHS (0.01–0.1 mg) at 25 °C with continuous mild stirring for 15 h. Radiolabeling was performed at 37 °C in 24 h. Radio-thin layer chromatography showed an overall radiochemical purity of >98% at optimized conditions (specific activity = 444 MBq/mg, labeling efficacy; 82%). The final isotonic ¹⁷⁷Lu-DOTA-rituximab complex was checked by gel electrophoresis for structure integrity control. Radio-TLC was performed to ensure that only one species was present after filtration through a 0.22 μm filter. Preliminary biodistribution studies in normal rats were carried out to determine complex distribution of the radioimmunoconjugate up to 168 h. The biodistribution data were in accordance with other antiCD20 radioimmunoconjugates already reported.     

Development of a new flow-through bulk optode for the determination of manganese(II)

A flow-through bulk optode based on the use of 1-(2-pyridylazo)-2-naphthol (PAN) immobilized in a plasticized poly(vinyl chloride) membrane entrapped in a cellulose support, in conjuntion with the flow injection analysis technique, is proposed for the determination of manganese(II). The calibration graph obtained at 570 nm was linear in the range 0.27–27.5 mg L^–1 (5 × 10^–6– 5 × 10^–4 M) Mn(II) with a detection limit of 0.18 mg L^–1. The coefficients of variation of the sensor response for 5.5 mg L^–1 of Mn(II) were ±0.22% for consecutive measurements (n = 10), ±0.48% between days (n = 5) and ±0.38% between different membranes (n = 6). The sensor was readily regenerated with the carrier acetic acid/acetate buffer of pH 4.5. The method was applied to the determination of manganese in steels, waters and lemon tree leaves. Received: 13 December 2000 / Revised: 25 January 2001 / Accepted: 26 January 2001     

Preparation and preliminary evaluation of [<Superscript>67</Superscript>Ga]-tetra phenyl porphyrin complexes as possible imaging agents

[⁶⁷Ga]labeled tetraphenyl porphyrin ([⁶⁷Ga]-TPP) was prepared using freshly prepared [⁶⁷Ga]GaCl₃ and tetraphenyl porphyrin (TPPH₂) for 30–60 min at 25 °C (radiochemical purity: >97 ± 1% ITLC, >98 ± 0.5% HPLC, specific activity: 13–14 GBq/mmol). Stability of the complex was checked in final formulation and human serum for 24 h. The partition coefficient was calculated for the compound (log P 1.89). The biodistribution of the labeled compound in vital organs of wild-type rats was studied using scarification studies and SPECT imaging up to 24 h. A detailed comparative pharmacokinetic study performed for ⁶⁷Ga cation and [⁶⁷Ga]-TPP. The complex is mostly washed out from the circulation through kidneys and can be an interesting tumor imaging/targeting agent due to low liver uptake and rapid excretion through the urinary tract.     

MSPD procedure for determining buprofezin,tetradifon, vinclozolin,and bifenthrin residues in propolis by gas chromatography–mass spectrometry

A simple and effective extraction method based on matrix solid-phase dispersion (MSPD) was developed to determine bifenthrin, buprofezin, tetradifon, and vinclozolin in propolis using gas chromatography–mass spectrometry in selected ion monitoring mode (GC–MS, SIM). Different method conditions were evaluated, for example type of solid phase (C₁₈, alumina, silica, and Florisil), the amount of solid phase and eluent (n-hexane, dichloromethane, dichloromethane–n-hexane (8:2 and 1:1, v/v) and dichloromethane–ethyl acetate (9:1, 8:2 and 7:3, v/v)). The best results were obtained using 0.5 g propolis, 1.0 g silica as dispersant sorbent, 1.0 g Florisil as clean-up sorbent, and dichloromethane–ethyl acetate (9:1, v/v) as eluting solvent. The method was validated by analysis of propolis samples fortified at different concentration levels (0.25 to 1.0 mg kg⁻¹). Average recoveries (four replicates) ranged from 67% to 175% with relative standard deviation between 5.6% and 12.1%. Detection and quantification limits ranged from 0.05 to 0.10 mg kg⁻¹ and 0.15 to 0.25 mg kg⁻¹ propolis, respectively.     

Phosphorus in biological standards and samples by thermal neutron irradiation and β-counting

A nondestructive NAA method based on the reaction ³¹P(n,γ)³²P (T _1/2 = 14.23 d) has been developed where the product nucleus, a pure β-emitter with end point energy 1.71 MeV is measured by using an end window G.M. counter and an Al filter of 27 mg·cm⁻². ³²P was identified by measuring E _β using Feather’s analysis and its half-life was found to be 15.3±0.2 days in standard reference materials (SRMs) and samples. For most reference materials (RMs) from NIST (USA) and IAEA (Vienna), our values agree within ±5% of the certified values. A variety of biological samples have also been analyzed and our values are in the range; medicinal herbs (n = 43), 0.29–5.23 mg/g; bhasmas (n = 19), 0.09–51.4 mg/g; vegetables (n = 8), 1.85–5.73 mg/g; lentils (n = 6), 2.1–5.5 mg/g; flours (n = 6), 1.3–3.3 mg/g; vegetarian diet (n = 5), 2.41–2.90 mg/g; fish (n = 43), 3.61–36.8 mg/g; human and animal milk (n = 6), 1.24–7.95 mg/g; commercial milk powders (n = 14), 2.76–11.9 mg/g; water from various sources (n = 14), 1–417 μg/l; human and animal blood (n = 9), 1.00–15.0 mg/g; cancerous and healthy breast tissue (n = 60), 1.00–8.63 mg/g; human hair (n = 43), 0.12–5.81 mg/g, where n is the number of samples analyzed. The method is simple, fast, and nondestructive and provides data within ±5% error limit with a detection limit of 0.1 mg/g.     

Purification and Characterization of a Low Molecular Weight of β-Mannanase from Penicillium occitanis Pol6

The highest β-mannanase activity was produced by Penicillium occitanis Pol6 on flour of carob seed, whereas starch-containing medium gave lower enzymes titles. The low molecular weight enzyme was purified to homogeneity by ammonium sulfate precipitation, gel filtration, and ion-exchange chromatography procedures. The purified β-mannanase (ManIII) has been identified as a glycoprotein (carbohydrate content 5%) with an apparent molecular mass of 18 kDa. It was active at 40 °C and pH 4.0. It was stable for 30 min at 70 °C and has a broad pH stability (2.0–12.0). ManIII showed K _m, V _max, and K _cat values of 17.94 mg/ml, 93.52 U/mg, and 28.13 s⁻¹ with locust bean gum as substrate, respectively. It was inhibited by mannose with a K _I of 0.610⁻³ mg/ml. ManIII was activated by CuSO₄ and CaCl₂ (2.5 mM). However, in presence of 2.5 mM Co²⁺, its activity dropped to 60% of the initial activity. Both N-terminal and internal amino acid sequences of ManIII presented no homology with mannanases of glycosides hydrolases. During incubation with locust bean gum and Ivory nut mannan, the enzyme released mainly mannotetraose, mannotriose, and mannobiose.     

Simulatenous determination of uranium and plutonium in inactive purex process solution by X-ray fluorescence

By intensity measurements of the uranium and plutoniumL _α1-lines these elements can be determined simultaneously either in aqueous or in organic Purex process solutions. Thorium was used as an internal standard. The sensitivity of the method is about 10⁵ cpm/mg U, Pu/ml and the detection limits are around 2–3 μg U, Pu/ml. The analytical range extends from 0.003 mg U, Pu/ml up to 10 mg U, Pu/ml. A time-saving routine procedure is described. Interferences detected at extreme U/Pu concentration ratios are discussed and explained.     

Source tracing of chromium-, manganese-, nickel- and zinc-containing particles (PM<Subscript>10</Subscript>) by micro-PIXE spectrum

Due to the interesting anti-proliferative properties of gallium-thiosemicarbazone complexes, the production of [⁶⁷Ga]labeled 2-acetylpyridine 4,4-dimethyl thiosemicarbazone (APTSM₂) was investigated. The freshly prepared [⁶⁷Ga]GaCl₃ was mixed with 2-acetylpyridine 4,4-dimethyl thiosemicarbazone for 60 minutes at 90 °C to yield [⁶⁷Ga]APTSM₂ with a radiochemical yield of more than 98%. Radio-thin-layer-chromatography (RTLC) showed a radiochemical purity of more than 99%. A specific activity of about 370–740 MBq/mmol (10–20 Ci/mmol) was obtained. The stability of the final product was checked in the absence and presence of human serum at 37 °C. The partition coefficient of the final complex was also determined. The biodistribution of the labeled compound in normal rats was compared with that of free Ga³⁺ cation up to 22 hours.     

Preparation and characterization of self-assembled nanoparticles based on glycol chitosan bearing adriamycin

An anthracycline drug, adriamycin, was chemically conjugated onto the backbone of glycol chitosan via an acid-labile cis-aconityl linkage. The physicochemical characteristics of the glycol chitosan–adriamycin (GC–ADR) conjugates were investigated by dynamic light scattering, atomic force microscopy, and fluorescence spectroscopy. The GC–ADR conjugates were capable of forming nano-sized self-aggregates in an aqueous medium, when the adriamycin content in the conjugate was in the range of 2.0–5.0 wt.%. The self-aggregates were spherical in shape, and had mean diameters of 238–304 nm, depending on the adriamycin content. The critical aggregation concentrations of the conjugates, estimated by the fluorescence quenching method, were as low as 1.0–2.5×10⁻² mg/ml. The size of self-aggregates was not affected by the polymer concentration in the range from 50 to 2,000 μg/ml, and was maintained up to 8 days in phosphate-buffered saline (pH 7.4), indicating high colloidal stability. The release of adriamycin from self-aggregates was significantly dependent on the pH of the medium due to the cis-aconityl linkage; e.g., the amount of adriamycin released for 4 days was 7.3±0.3% at pH 7, whereas it was 29.3±1.9% at pH 4. The cell viability results demonstrated that free adriamycin shows more potent cytotoxicity than the conjugates, primarily attributed to the sustained release of adriamycin from self-aggregates. In conclusion, the self-aggregates, formed by GC–ADR conjugates, might be useful for the site-specific delivery of adriamycin in a sustained manner.     

Study of the voltammetric behaviour of metam and its application to an amperometric flow system

The electrochemical behaviour of the pesticide metam (MT) at a glassy carbon working electrode (GCE) and at a hanging mercury drop electrode (HMDE) was investigated. Different voltammetric techniques, including cyclic voltammetry (CV) and square wave voltammetry (SWV), were used. An anodic peak (independent of pH) at +1.46 V vs AgCl/Ag was observed in MT aqueous solution using the GCE. SWV calibration curves were plotted under optimized conditions (pH 2.5 and frequency 50 Hz), which showed a linear response for 17–29 mg L⁻¹. Electrochemical reduction was also explored, using the HMDE. A well defined cathodic peak was recorded at −0.72 V vs AgCl/Ag, dependent on pH. After optimizing the operating conditions (pH 10.1, frequency 150 Hz, potential deposition −0.20 V for 10 s), calibration curves was measured in the concentration range 2.5×10⁻¹ to 1.0 mg L⁻¹ using SWV. The electrochemical behaviour of this compound facilitated the development of a flow injection analysis (FIA) system with amperometric detection for the quantification of MT in commercial formulations and spiked water samples. An assessment of the optimal FIA conditions indicated that the best analytical results were obtained at a potential of +1.30 V, an injection volume of 207 μL and an overall flow rate of 2.4 ml min⁻¹. Real samples were analysed via calibration curves over the concentration range 1.3×10⁻² to 1.3 mg L⁻¹. Recoveries from the real samples (spiked waters and commercial formulations) were between 97.4 and 105.5%. The precision of the proposed method was evaluated by assessing the relative standard deviation (RSD %) of ten consecutive determinations of one sample (1.0 mg L⁻¹), and the value obtained was 1.5%.     

Spectrophotometric determination of nitrite in natural waters using diazotization-coupling method with column preconcentration on naphthalene supported with ion-pair of tetradecyldimethylbenzyl-ammonium and iodide

A column preconcentration method has been established for the spectrophotometric determination of traces of nitrite using diazotization and coupling on an naphthalene-tetradecyldimethylbenzylammonium (TDBA)-iodide (I) adsorbent. Nitrite ion reacts with sulfanilic acid (SA) in the pH range 1.8–3.0 for the SA-1-naphthol system and in the pH range 2.3–3.2 for the SA-1-naphthylamine-4-sulfonate system (SA-NAS system) in hydrochloric acid medium to form water-soluble colourless diazonium cations. These cations were coupled with 1-naphthol in the pH range 1.6–4.6 and with NAS in the pH range 2.6–5.0 to be retained on naphthalene-TDBA-I packed in a column. The solid mass was dissolved from the column with 5 mL of dimethylformamide (DMF) and the absorbance measured at 418 nm for the SA-1-naphthol system and at 485 nm for the SA-NAS system. The calibration curve was linear over the concentration range 0.02–0.87 mg/L for SA-1-naphthol and 0.02–0.80 mg/L in the sample for SA-NAS. The molar absorptivity was calculated to be 1.70 × l0⁴ Lmol⁻¹ cm⁻¹ for SA-1-naphthol and 1.66 × l0⁴ L mol⁻¹ cm⁻¹ for SA-NAS. The detection limits were found to be 0.014 and 0.016 mg/L for SA-1-naphthol and SA-NAS, respectively. The preconcentration factors were 8 and 6 for SA-1-naphthol and SA-NAS, respectively. Replicate determinations of seven sample solutions containing 6.6 ug of nitrite for SA-1-naphthol and 5.3 ug of nitrite for SA-NAS gave mean absorbances of 0.486 and 0.382 with relative standard deviations of 0.49 and 0.58%, respectively. Interferences due to various foreign ions have been studied and the method has been applied to the determination of 27–65 μg/L levels of nitrite in natural waters. The recovery and relative standard deviation for water samples were 98–102% and 0.49–0.58% for both systems. Presented at the 29th Colloquium Spectroscopicum Internationale, Leipzig, Germany, 27 August –1 September 1995     

Rapid HPLC method for acetyl starch determination in blood

Summary Colloidal plasma substitutes of chemically modified starch are used in surgery and in emergency medicine. Acetyl starch (ACS) is a new plasma substitute based on an amylopectin acetic ester. Metabolic cleavage of the ACS ester substituents leads to improved degradation and elimination of infused polymer. To determine the metabolic fate of ACS a rapid LC-method for ACS quantitiation in blood samples was needed. For this purpose a size-exclusion chromatography (SEC) system with improved sensitivity is outlined using a refractive index detector. The limit of detection is 0.005 mg mL⁻¹. From 0.10–5.00 mg mL⁻¹ a linear relationship (correlation coefficient R=0,9999) between the RI signal and ACS concentration is obtained. Recoveries of ACS from blood plasma range 102.3–107.7% for ACS 200/0.5 (range 0.20–7.94 mg mL⁻¹) and 103.0–111.4% for ACS 200/0.7 (range 0.19–9.33 mg mL⁻¹). Only small differences between runs are obtained. In the inter assay test coeficients of variation of 1.8% and of 2.6% respectively are obtained for ACS 200/0.5 and ACS 200/0.7.