Parenteral Solutions Research Articles

Chilaiditi?s syndrome in a 9-year-old girl with hepato-diaphragmatic interposition of the colon: a short report

Chilaiditi’s syndrome is an infrequent condition with radiological evidence of symptomatic colonic interposition between the liver and diaphragm. We report on a 9-year-old girl suffering from this rare syndrome and on the predisposing factors of diaphragmatic eventration and constipation which would also appear to be rare and may never have been reported previously for children. A 9-year-old girl was admitted to our hospital complaining of a 4-day history of epigastric pain, constipation, and nausea without preceding trauma. The patient was haemodynamically stable and had a low-grade fever. Upon examination, slightly decreased breath sounds were noted at the right lung base, compared with the left. Tympany and hyperactive bowel sounds were present in the right abdomen, which was diffusely tender off and on without rebound. There was no hyperleukocytosis and there were no other abnormalities apparent upon clinical examination. On an X-ray film, the colon was found between the right liver surface and the diaphragm (Fig. 1A,B). The patient passed a lot of gas and hard dry stools with the help of an enema; however, the symptoms did not resolve until after nasogastric decompression and parenteral electrolyte solution administration over the subsequent 5 days. The incidence of Chilaiditi’s syndrome in the general population ranges from 0.025% to 0.28% and seems to increase with age [5]. The sex ratio is 4:1, male to female [2]. The syndrome is usually of little clinical significance, but nausea, vomiting, anorexia, constipation, right upper quadrant pain, and epigastric pain have been described [2,5]. Aetiologically, Chilaiditi’s syndrome has been attributed to either intestinal factors, diaphragmatic factors, hepatic factors, an enlarged lower thoracic outlet or elevated intra-abdominal pressure [2, 4,5]. In this patient, constipation is likely a significant contributor to colonic mobility, given its reported association with colonic elongation. Furthermore, diaphragmatic eventration provides a larger potential suprahepatic space which could lead to colonic interposition [4]. The ascent of the distended colon is such that it can protrude into the subphrenic space with frequently consequent infero-medial displacement of the liver [6]. Our patient, however, presented with an upward and medial displacement of the liver, associated with diaphragmatic eventration.

A Cluster of Nosocomial Klebsiella oxytoca Bloodstream Infections in a University Hospital

On February 19, 2003, four patients (patients 1-4) in the neurology ward underwent cranial magnetic resonance angiography (MRA) and developed fever within 1 hour afterward. Klebsiella oxytoca was isolated from blood cultures of patients 1 through 3. To identify the source of this cluster of nosocomial K. oxytoca bloodstream infections. Outbreak investigation. A 1,000-bed university hospital. The infection control team reviewed patient charts and interviewed nursing staff about the preparation and administration of parenteral fluids. The procedure of cranial MRA was observed. Arbitrarily primed polymerase chain reaction (AP-PCR) was performed to show the clonal relationship among these three strains. AP-PCR revealed that three K. oxytoca isolates had the same molecular profile. Cranial MRA was found to be the only common source among these patients. During MRA, before injection of the contrast medium, normal saline solution was infused to check the functioning of the intravenous catheter. Use of the solution for multiple patients was routine, but the access diaphragm of the bottle was not cleansed. The bottle of normal saline solution used on February 19 had already been discarded and the culture sample taken from the solution on the day of observation was sterile. We speculate that normal saline solution became contaminated during manipulation and that successive uses might have been responsible for this cluster. Poor aseptic techniques employed during successive uses appear to be the most likely route of contamination. Use of parenteral solutions for multiple patients was discontinued.

Amino Acid Needs for Early Growth and Development

Few data exist on amino acid needs in infants and children, mainly because until recently, amino acid requirements were determined using nitrogen balance. The advent of the indicator amino acid oxidation (IAAO) method permits studies to be conducted with minimal adaptation to the test amino acid. In light of the very limited data available for human infants, toddlers, and children, it was proposed that a factorial approach should be used to estimate their essential amino acid requirements. Using amino acid oxidation techniques, dietary essential amino acid requirements in adults have been nearly completed. Data on changes in total body potassium are now available for infants and children. From these data it is possible to calculate protein deposition during growth, and hence, it is now possible to estimate the amino acid requirements in children using a factorial model. However, there has been no independent verification of the model. Recently we determined total branched chain-amino acid requirements for young adults and children, and we can provide data to support the validity of the factorial model. IAAO has been used on children with liver disease as young as 3 y. The minimally invasive IAAO model opens the door for determination of dietary essential amino acid requirements in infants and children during health and disease. For study of preterm neonates, we used a piglet model to show that the amino acid needs for parenteral feeding are markedly reduced for several essential amino acids; this suggests that current commercial total parenteral nutrition amino acid solutions are less than ideal.

Artificial Nutrition Support in Intestinal Failure: Principles and Practice of Parenteral Feeding

Patients with intestinal failure are at risk for malnutrition and its associated adverse consequences. In many of these patients it is not possible to feed via the gastrointestinal tract, and nutrients must be provided directly into the bloodstream. For some patients with irreversible intestinal failure, this is a lifelong requirement. Parenteral nutrient solutions may be tailored specifically to individual requirements and are usually administered directly into a central vein using an indwelling catheter. Serious complications related to both the indwelling catheter and metabolic consequences of the nutritional support may occur. A team approach to the provision and monitoring of parenteral nutrition in intestinal failure produces the best results.

A Standardized Approach to Pediatric Parenteral Medication Delivery

Delivering medications safely to hospitalized pediatric patients presents a significant challenge. Current JCAHO standards require safe medication practices, including the standardization of parenteral medications and solutions. Our institution convened a pediatric process improvement team (consisting of pharmacists, nurses, physicians, and administrators) to address deficiencies in our medication use process. This article describes the standardized parenteral medication processes that this committee ultimately endorsed. The new system was designed to control, simplify, and standardize each major step in the medication use process, from prescribing through administration. The system involved defining and standardizing prescribing practices, which then allowed for reduced variability and the preplanning of drug preparation and administration processes. To ease transition and simplify implementation, three phases of the process were introduced in a step-by-step manner: phase 1, continuous infusions; phase 2, intermittent IV doses; and phase 3, bulk IV fluids. Time to implementation included 6 months of preparation prior to phases 1 and 2 and approximately another year to phase 3. The standardized pediatric parenteral medication process has resulted in improved patient safety and operational efficiency. It has also eliminated the “Rule of six” method of drug preparation and administration.

Gran method for end point anticipation in monosegmented flow titration

An automatic potentiometric monosegmented flow titration procedure based on Gran linearisation approach has been developed. The controlling program can estimate the end point of the titration after the addition of three or four aliquots of titrant. Alternatively, the end point can be determined by the second derivative procedure. In this case, additional volumes of titrant are added until the vicinity of the end point and three points before and after the stoichiometric point are used for end point calculation. The performance of the system was assessed by the determination of chloride in isotonic beverages and parenteral solutions. The system employs a tubular Ag2S/AgCl indicator electrode. A typical titration, performed according to the IUPAC definition, requires only 60 mL of sample and about the same volume of titrant (AgNO3) solution. A complete titration can be carried out in 1 - 5 min. The accuracy and precision (relative standard deviation of ten replicates) are 2% and 1% for the Gran and 1% and 0.5% for the Gran/derivative end point determination procedures, respectively. The proposed system reduces the time to perform a titration, ensuring low sample and reagent consumption, and full automatic sampling and titrant addition in a calibration-free titration protocol.

Flow and injection characteristics of pharmaceutical parenteral formulations using a micro-capillary rheometer

A micro-capillary rheometer consisted of a fine needle with an internal diameter of 347 μm attached to a 1 ml removable-needle syringe within an Instron device that operated in compression mode to provide various crosshead speeds ranging from 150 to 950 mm min −1 covering typical clinical injection rates, and that determined the resulting force on the plunger. The crosshead speed and the resulting force were used to calculate the shear rate and the shear stress respectively. These were used in standard capillary flow expressions together with an independent measurement of the wall frictional force and allowed the viscosity of parenteral Newtonian solutions and non-Newtonian suspensions to be measured quantitatively and their rheological behaviour in needles of clinical dimensions to be established. Commercial pharmaceutical parenteral formulations consisting of three oil-based solutions and three aqueous suspensions were chosen for this study. The net injection forces were also obtained and it was shown that both the oil-based solutions and the aqueous suspensions covered similar ranges. The viscosities for the parenteral solutions were determined from the slope of the linear regression ( R 2>0.97) between shear stress and shear rate and ranged between 0.029 and 0.060 Pa s. For the aqueous suspensions examined, viscosities decreased from low shear rate to high shear rate, following a power-law model and indicating a pseudo plastic behaviour. Standardisation of the micro-capillary rheometer with Newtonian silicone oils calibrated with a Rheometrics Fluids Spectrometer showed viscosity values consistent between the rotational flow measurements and capillary flow measurements which were within 5% and showed very high degrees of reproducibility between replicate samples. This degree of reproducibility allowed differences in the contribution of the wall frictional force to the required plunger force for both the oil-based and aqueous parenteral formulations to be determined reliably. The wall frictional force values for all formulations were similar (0.6–1.6 N) but the frictional forces of aqueous systems were found to decline significantly with plunger speed. The micro-capillary rheometer has been used to evaluate the impact of concentration changes due to sedimentation on the injectability of one of the aqueous suspensions, where it was shown that not only the viscosity increased but the shear thinning behaviour ceased at higher shear rates. The micro-capillary rheometer which was able to operate in clinical shear rate ranges has been shown to detect deteriorations in the injectable rheology of suspensions, which in the case here was due to pre-injection sedimentation.

Dietary Cysteine Reduces the Methionine Requirement by an Equal Proportion in Both Parenterally and Enterally Fed Piglets

The sulfur amino acids (SAA), methionine and cysteine, are normally supplied in a 50:50 ratio in the oral diet of pigs. In contrast, cysteine is not included in any appreciable amounts in parenteral solutions due to its instability in solution. Cysteine can replace part of the methionine requirement, but is not required when methionine is supplied at a level that meets the entire SAA requirement. However, the role of the gut on cysteine sparing has not been investigated. In the present study, the enteral and parenteral methionine requirement was determined, with excess dietary cysteine, by using the indicator amino acid oxidation (IAAO) technique. Piglets [n = 28, 2 d, 1.65 +/- 0.014 kg (SE)] were fed elemental diets containing adequate energy, phenylalanine and excess tyrosine, with varied methionine concentrations and excess cysteine [0.55 g/(kg. d)]. Diets were infused continuously via intravenous (parenteral) or gastric (enteral) catheters. Phenylalanine oxidation was determined during a primed, constant infusion of L-[1-(14)C]-phenylalanine, by measuring expired (14)CO(2) and plasma specific radioactivity (SRA) of phenylalanine. For both the parenteral and enteral groups, phenylalanine oxidation (% of dose) decreased linearly (P < 0.01) as methionine intake increased and then became low and unchanging. Using breakpoint analysis, the methionine requirement was estimated to be 0.25 and 0.18 g/(kg. d) for enteral and parenteral feeding, respectively. These data show that the parenteral methionine requirement is approximately 70% of the enteral requirement when measured in the presence of excess dietary cysteine (P < 0.05). A comparison with our previous studies in which methionine was the only source of sulfur amino acids shows that the addition of dietary cysteine reduces the methionine requirement by approximately 40% in both enterally and parenterally fed neonatal piglets. Therefore, dietary cysteine is equally effective in sparing dietary methionine whether fed enterally or parenterally.

Dose Response of Milk Fat to Intravenous Administration of the trans-10, cis-12 Isomer of Conjugated Linoleic Acid

Intravenous infusion of conjugated linoleic acid (CLA) was evaluated as a simpler method than abomasal infusion and the feeding of calcium salts to examine milk fat depression. The objectives were to determine the dose-dependent response of milk fat and plasma metabolites to intravenous administration of the trans-10, cis-12 isomer of CLA, an isomer identified to possess an inhibitory effect on milk fat synthesis. Four multiparous Holstein cows averaging 123±30 d in milk were randomly assigned to treatments in a 4×4 Latin square design. Catheters were inserted into the jugular vein for infusions and blood sampling. Treatments consisted of intravenous infusions of 0, 2, 4, and 6 g/d CLA (>95% trans-10, cis-12 CLA). Infusates contained 72 g/d of a parenteral solution, saline, and CLA to 90ml. Periods were of 5 d duration with a 7 d wash out. Milk was sampled at each milking and analyzed for fat, protein, and fatty acids. Blood samples were obtained on the last day of each period. Dry matter intake (22.4±2.4 kg/d), milk yield (28.5±3.3 kg/d), and protein percent (3.26±0.08%) of cows were not affected by treatment. However, milk fat percentage was reduced linearly with increasing doses of CLA. Milk fat percentage was 4.17, 3.53, 3.29, and 2.92% on d 5 for treatments 0, 2, 4, and 6 g/d CLA, respectively. Concentrations (4.2 mg/g of fat) of cis-9, trans-11 CLA in milk fat were not affected by treatment. However, an increase in the trans-10, cis-12 CLA content of milk fat was observed. Milk fat contained 0.00, 0.02, 0.06, and 0.10mg of trans-10, cis-12 CLA per g of fat (SEM = 0.065) for treatments 0, 2, 4, and 6 g/d CLA, respectively. Plasma NEFA concentration increased linearly with the dose of the trans-10, cis-12 CLA. Intravenous infusion of the trans-10, cis-12 isomer of CLA depressed milk fat in a linear manner over the range of infusion studied and, therefore, is an alternative to abomasal infusion.

Preparation and in-vitro release rate of fentanyl–cyclodextrin complexes for prolonged action in epidural analgesia

Fentanyl was complexed with cyclodextrin derivatives with the intention to obtain parenteral solutions able to provide prolonged analgesia following epidural administration. Three cylodextrins (CDs) suitable for parenteral use were used: hydroxypropyl-β-cyclodextrin (HP-β-CD), sulfobutylether-β-cyclodextrin (SBE-7-β-CD), and maltosyl-β-cyclodextrin (malt-β-CD). Analysis of fentanyl was done with HPLC-UV. The inclusion capacity of HP-β-CD was determined from phase-solubility diagrams at pH 6.5, 7.2 and 8.0, and those of SBE-7-β-CD and of malt-β-CD at pH 8.0. Solubility of fentanyl increased linearly (i) as a function of the CD concentration, and (ii) with decreasing pH. Complexation was highest with HP-β-CD and malt-β-CD, much higher than with SBE-7-β-CD, with stability constants at pH 8.0 of 801, 729 and 1309 M −1, respectively. The CD concentration was calculated to obtain a fentanyl–CD formulation, with the desired amount free fentanyl as loading dose in solution and the rest complexed with CD, as reservoir for prolonged action. A suitable membrane and a release-rate apparatus were selected for in-vitro release-rate studies. Best results were obtained with Spectrapor membranes and a home-made release-rate apparatus. Release rate was evaluated in static and dynamic conditions. For both modes, the release rate of fentanyl decreased as a function of CD concentration, due to complex formation of fentanyl, which suggests the possibility to provide prolonged pharmacodynamic effects in vivo.

Long-term stabilization of recombinant human interferon α 2b in aqueous solution without serum albumin

The development of parenteral solution dosage forms of interferon α 2 (rhIFN-α2) without human albumin may significantly diminish the problem of forming highly immunogenic rhIFN-α2b aggregates and the potential risk of blood-transmitted diseases caused by infectious viruses and often living pathogens that may be present in the plasma. With this purpose, we evaluated the compatibility of type I borosilicate glass vials and chlorobutyl stoppers with rhIFN-α2b in an aqueous solution. At the same time, we carried out a targeted formulation screen at 37 °C of single or combined (e.g. polysorbate 80, EDTA Na 2, PEG 400) potentially stabilizing excipients. Quantified biochemical results from 12 independent batches of rhIFN-α2b in a polysorbate/benzyl alcohol-based vehicle formulated at pH 7.4 were all found within the limits established by the World Health Organization for this cytokine. Real-time storage data confirmed the excellent biochemical long-term (30 months) stability of rhIFN-α2b in this aqueous solution formulation. Analyses were performed at intervals throughout the time period using reverse-phase high-performance liquid chromatography, a sandwich-type enzyme-linked immunosorbent assay, and antiviral activity as stability-indicating assays. Furthermore, both the physical stability (color, odor, appearance, pH, and absence of particulate material) and the sterility of this formulation were maintained under the proposed shelf conditions.

Improvement of cefpodoxime proxetil oral absorption in rats by an oil-in-water submicron emulsion

Absolute bioavailability of cefpodoxime proxetil is both limited by its low solubility in aqueous solution and its intraluminal hydrolysis. The oil-in-water submicron emulsion was proven to be effective in protecting the prodrug from the enzymatic attack in rabbit intestinal washings. The aim of the study was to perform a pharmacokinetic study in conscious rats to confirm o/w submicron superiority in comparison to other oral formulations (hydro-alcoholic solution, suspension and coarse emulsion). The pharmacokinetic study was performed in conscious rats implanted with permanent aortic catheters. A parenteral solution of cefpodoxime was injected via this catheter, and oral formulations were administered orally. The cefpodoxime plasma level was performed by a HPLC validated method. The pharmacokinetic parameters, t 1/2, C max, t max, AUC and absolute bioavailability ( F) were determined with a non-compartmental analysis. The results show a significant increase of F for submicron emulsion (97.4%) between the other oral formulations. No significant difference of F was found between the other oral formulations, even with the coarse o/w emulsion. The o/w submicron emulsion made the enhancement of the absolute bioavailability of cefpodoxime proxetil possible. This benefit could be explained by the low droplet size of the submicron emulsion which improve the absorption process of the prodrug.

A Chryseobacterium meningosepticum outbreak in a neonatal ward.

To report epidemiologic, bacteriologic, and clinical features of a Chryseobacterium meningosepticum outbreak. Outbreak investigation. A neonatal intensive care unit (NICU) of a referral teaching hospital. During 2 weeks in September 2001, four neonates in the NICU developed sepsis and underwent laboratory investigation. Multiple samples were obtained for cultures from endotracheal tubes, mechanical ventilators and humidifier boxes, infant incubators, parenteral and antiseptic solutions, feeding bottles, sinks, faucets, doors, and healthcare workers. C. meningosepticum was isolated from the blood cultures of four patients. The first isolate was identified 5 days after the death of the index case. Although all isolates were ciprofloxacin susceptible in vitro, the remaining three patients did not respond to ciprofloxacin therapy given for 6 or 7 days. Therapy was switched to vancomycin and rifainpin and all three patients survived, with one having a complication (hydrocephalus). Environmental surveillance revealed C. meningosepticum in the stock lipid solution as the source of the epidemic. The outbreak was controlled after discontinuation of intravenous lipid solution, restriction of further neonatal admissions, and thorough disinfection of the unit and its equipment. Early identification of an epidemic and its source is important in avoiding morbidity and mortality. A contaminated lipid stock bottle was the source of this outbreak associated with multiple cases and one death.

Uso da flunixina meglumina tópica no tratamento de uveítes em cães

Este trabalho teve por objetivo comparar o efeito (uso tópico) da flunixina meglumina e da dexametasona no controle da uveíte anterior em cães, por meio de avaliação clínica e pela dosagem de proteínas no humor aquoso. Foram utilizados 17 cães portadores de uveíte anterior de diversas etiologias. Os animais, divididos em dois grupos, foram tratados durante 15 dias. Observou-se maior eficácia da flunixina meglumina na cura clínica das uveítes e na redução significativa da concentração de proteínas no humor aquoso em relação à dexametasona. Concluiu-se que a preparação comercial de uso parenteral pode ser utilizada como colírio no tratamento de doenças inflamatórias da úvea.

Preparation of Parenteral Solutions–How Far We May Deviate From the Regulations?

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On-line preconcentration and determination of chromium in parenteral solutions by flow injection—flame atomic absorption spectrometry

An on-line chromium preconcentration and determination system implemented with flame atomic absorption spectrometry (FAAS) associated to flow injection (FI) was studied. For the retention of chromium, 4-(2-Thiazolylazo)-resorcinol (TAR) and Amberlite XAD-16 were used, at pH 5.0. The Cr–TAR complex was removed from the micro-column with ethanol. An enrichment factor of 50 was obtained for the preconcentration of 50 ml of sample solution. The detection limit value for the preconcentration of 50 ml of aqueous solution of Cr was 20 ng l −1. The precision for ten replicate determinations at the 5 μg l −1 Cr levels was 2.9% relative standard deviation (RSD), calculated from the peak heights obtained. The calibration graph using the preconcentration system for chromium was linear with a correlation coefficient of 0.9997 at levels near the detection limits up to at least 100 μg l −1. The method was successfully applied to the determination of chromium in parenteral solution samples.

STEPWISE DETERMINATION OF ALUMINUM AND CHROMIUM IN WATER AND BIOMEDICAL SAMPLES BY HPLC-UV, BASED ON THEIR DIFFERENT KINETICS WITH 8-HYDROXYQUINOLINE

ABSTRACT A reversed-phase high performance liquid chromatographic (RP-HPLC) method, with spectrophotometric detection for determination of trace amounts of aluminum (Al) and chromium (Cr) in water and biomedical samples, has been developed using 8-hydroxylquinoline (8-HQ) as a precolumn reagent based on the differential chelation kinetics of these two ions. The analysis is achieved with a Spherisorb ODS 2 column, with an eluent consisting of 4.0 mmol L−1 acetate buffer (pH 6.0) and 3.2 mmol L−1 8-HQ in 57% (v/v) methanol–water, at a flow rate of 1.0 mL min−1. On the basis of the fact that the peaks of Al and Cr chelates appear at the same retention time, the procedure is divided into two stages: 1. (1) determining Al concentration by peak area after precolumn chelation at ambient temperature; 2. (2) measuring total peak area of Al and Cr after reaction at 90°C for 30 min, and the concentration of Cr being determined by the difference between Al peak area and the total area. The response of both Al and Cr is linear from 0.002 to 0.6 µg mL−1 with a detection limit of 0.001 µg mL−1. The analysis is free from interference from common ions except 10-fold excess of cobalt. The values obtained by this method are in good agreement with those of ICP-AES or GF-AAS. The proposed method has been successfully applied to the direct determination of Al and indirect determination of Cr in natural water, serum, synthetic renal dialysate, parenteral solution, and pharmaceutical-grade organic acid with the recoveries of over 90%.

Contribution of the raw material to the aluminum contamination in parenterals.

The extent of aluminum contamination in parenteral nutrition solutions was measured in 35 different commercial products, including amino acids, electrolytes, glucose, lipids, vitamins trace elements, and albumin. The extent of aluminum contamination in substances used as raw material for preparation of parenterals was also measured. Chemicals from different manufacturers and of different quality grades were analyzed individually. The measurements were done by atomic absorption spectrometry. The results showed that the same product might have different aluminum content depending on the manufacturer, either for commercial formulations or substances. The highest contaminated chemicals included cystine, NaOH, vitamin C, biotin, gluconate, and Fe and Cr salts. The lowest contaminated chemicals included lipids, apolar amino acids, glucose, HCI, acetic acid, KCl, NaCl, and heparin. Among commercial products, the major contamination rates appeared in calcium gluconate, followed by trace elements, some vitamins, bicarbonate, phosphates salts, and heparin. Comparing the aluminum in commercial products and substances, it can be concluded that the contamination may occur in parenterals because aluminum is present naturally in the chemicals. However, when the composition and concentration of the parenteral solution are considered, the contamination of calcium gluconate, trace elements, some vitamins, phosphates, bicarbonate, and heparin cannot be related only to the raw substances. The aluminum level present in these commercial formulations is too high to come only from the substances; therefore, it is possible that one of the steps of the manufacturing procedure is responsible for elevating the contamination of these products.

Assessment of trace aluminium content in parenteral solutions by combined cloud point preconcentration—flow injection inductively coupled plasma optical emission spectrometry

A micelle-mediated phase separation without added chelating agents to preconcentrate trace levels of aluminium in parenteral solutions as a prior step to its determination by flow injection inductively coupled plasma optical emission spectrometry has been developed. The enrichment step is based on the cloud point extraction of aluminium with the non-ionic surfactant polyethyleneglycolmono- p-nonylphenylether (PONPE 7.5). The chemical variables affecting the sensitivity of the extractive-spectrometric procedure were studied in detail. After optimization, a preconcentration factor of 200 and a %E higher than 99.9 were achieved. The detection limit (DL) value of aluminium for the preconcentration of 50 ml of parenteral solution was 0.25 μg l −1. The calibration graph using the preconcentration system for aluminium was linear with a correlation coefficient of 0.9997 at levels near the DLs up to at least 200 μg l −1. The developed hyphenated assay, which thoroughly satisfies the typical requirements for pharmaceutical control processes, is appropriate to monitor the aluminium concentration in parenteral nutrition.

Cloud point extraction of vanadium in parenteral solutions using a nonionic surfactant (PONPE 5.0) and determination by flow injection-inductively coupled plasma optical emission spectrometry

A preconcentration and determination methodology for vanadium at trace levels in parenteral solutions was developed. Cloud point extraction was successfully employed for the preconcentration of vanadium prior to inductively coupled plasma atomic optical emission spectrometry (ICP-OES) coupled to a flow injection (FI) system. The vanadium was extracted as vanadium-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol [V-(5-Br-PADAP)] complex, at pH 3.7 mediated by micelles of the nonionic surfactant polyoxyethylene (5.0) nonylphenol (PONPE 5.0). The extracted surfactant-rich phase (100 μl) was mixed with 100 μl of ethanol and this final volume injected into ICP-OES for the vanadium determination. Under these conditions, the 50 ml sample solution preconcentration allowed raising an enrichment factor of 250-fold; however, it was possible to obtain a theoretical enrichment factor of 500-fold. The lower limit of detection (LOD) obtained under the optimal conditions was 16 ng l −1. The precision for 10 replicate determinations at the 2.0 μg l −1 V level was 2.3% relative standard deviation (RSD), calculated with the peak heights. The calibration graph using the preconcentration system for vanadium was linear with a correlation coefficient of 0.9996 at levels near the detection limits up to at least 50 μg l −1. The method was successfully applied to the determination of vanadium in parenteral solution samples.