Publications by authors named "Benjamin Westenberger"

2,3-Dimercaptopropane-1-sulfonate (DMPS) is a metal chelator approved in Europe for oral or intravenous use for heavy metal poisoning. Transdermally applied DMPS (TD-DMPS) is used by some alternative practitioners to treat autism, despite the absence of evidence for its efficacy. We found no literature evaluating the pharmacokinetics of the transdermal route of delivery or the ability of TD-DMPS to enhance urinary mercury elimination.

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Ion mobility spectrometry (IMS) served as a rapid, qualitative screening tool for the analysis of adulterated weight-loss products. We have previously shown that sibutramine extracted into methanol from dietary supplements can be detected at low levels (2ng) using a portable IMS spectrometer, and have adapted a similar method for the analysis of additional weight-loss product adulterants. An FDA collaborative study helped to define the limits for fluoxetine with a limit of detection of 2ng.

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The United States Public Health Service Substance Abuse and Mental Health Services Administration is alerting medical professionals that a substantial percentage of cocaine imported into the United States is adulterated with levamisole, a veterinary pharmaceutical that can cause blood cell disorders such as severe neutropenia and agranulocytosis. Levamisole HCl is the active ingredient in a number of veterinary drugs approved to treat worm infestations in animals. Levamisole HCl was also the active ingredient in a human drug for oral administration approved on June 18, 1990, as adjuvant treatment in combination with fluorouracil after surgical resection in patients with Duke's stage C colon cancer.

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In this paper we evaluate methods for standardization of Raman spectra that are required to improve spectral correlation computations between spectra measured on different instruments. Five commercially-available 785 nm Raman spectrometers from different vendors were included in the study. These spectrometers have diverse specifications and performance levels and range in size from laboratory-based instruments to field-deployable portable and handheld platforms.

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Library-based Raman spectral correlation methods are widely used in surveillance applications in multiple areas including the pharmaceutical industry, where Raman spectroscopy is commonly used in verification screening of incoming raw materials. While these spectral correlation methods are rapid and require little or no sample preparation, their sensitivity to the presence of contaminants has not been adequately evaluated. This is particularly important when dealing with pharmaceutical excipients, which are susceptible to economically motivated adulteration by substances having similar physical/chemical/spectroscopic properties.

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The transfer of a multivariate calibration model for quantitative determination of diethylene glycol (DEG) contaminant in pharmaceutical-grade glycerin between five portable Raman spectrometers was accomplished using piecewise direct standardization (PDS). The calibration set was developed using a multi-range ternary mixture design with successively reduced impurity concentration ranges. It was found that optimal selection of calibration transfer standards using the Kennard-Stone algorithm also required application of the algorithm to multiple successively reduced impurity concentration ranges.

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A high-pressure liquid chromatography-diode array detection and multi-mode ionization tandem mass spectrometry (HPLC-DAD-MMI-MS/MS) method was used to identify amino-tadalafil and rimonabant in electronic cigarette (e-cigarette) cartridges. Amino-tadalafil is a drug analogue of the commercially approved Cialis™ (i.e.

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In response to recent incidents of undeclared sibutramine, an appetite suppressant found in dietary supplements, we developed a method to detect sibutramine using hand-held ion mobility spectrometers with an analysis time of 15 s. Ion mobility spectrometry is a high-throughput and sensitive technique that has been used for illicit drug, explosive, volatile organic compound and chemical warfare detection. We evaluated a hand-held ion mobility spectrometer as a tool for the analysis of supplement extracts containing sibutramine.

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The bead sizes used in approved modified release capsules labeled for sprinkling on food was investigated to generate bead size guidelines for generic products labeled for sprinkling. The conclusions from a survey of FDA databases were corroborated with experimental data obtained by measuring the bead sizes of several reference-listed drugs on the market labeled for administration by sprinkling on food. The experimental data show that majority of the marketed products were found to have bead sizes of less than 1,500 microm (1.

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During the 2007-2008 heparin crisis, it was found that the United States Pharmacopeia (USP) testing monograph for unfractionated heparin sodium (UFH) did not detect the presence of the contaminant, oversulfated chondroitin sulfate (OSCS) in heparin. In response to this concern, new tests and specifications were developed by the Food and Drug Administration (FDA) and USP and put in place to not only detect the contaminant OSCS but also to improve assurance of quality and purity of the drug product. Additional tests were also developed to monitor the heparin supply chain for other possible economically motivated additives or impurities.

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In 2005, Palladone, an extended-release capsule, was withdrawn from the market after clinical testing showed subjects who took the product with alcohol had increased levels of drug in their blood. To better understand this phenomenon, we studied the in vitro drug release of 27 oral modified-release products in alcohol-containing media. In 40% alcoholic medium, 9 of 10 capsules and 2 of 17 tablets show accelerated drug release.

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Unlabelled: Oversulfated chondroitin sulfate (OSCS) contaminated heparin has been associated with severe anaphylactoid reaction (AR), mainly in dialysed patients. Although attributed to bradykinin (BK) released during contact system activation by OSCS, no definitive evidence exists until now for a BK release during incubation of contaminated heparin with human plasma. In this study, we investigated the kinin forming capacity of OSCS and OSCS contaminated heparin when incubated in vitro with a pool of human plasma.

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The United States Food and Drug Administration (FDA) has received numerous reports of serious adverse events, including death, in patients using fentanyl transdermal systems (FTS). To gain a better understanding of these problems, the current research focuses on the in vitro characterization of fentanyl reservoir (Duragesic) and matrix (Mylan) systems with respect to drug release and skin permeation under conditions of elevated temperature and compromised skin. In addition, different synthetic membrane barriers were evaluated to identify the one that best simulates fentanyl skin transport, and thus may be useful as a model for these systems in future studies.

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We previously published a strong-anion-exchange-high performance liquid chromatography (SAX-HPLC) method for the detection of the contaminant over sulfated chondroitin sulfate (OSCS) in heparin sodium active pharmaceutical ingredient (API). While APIs have been processed to remove impurities, crude heparins contain insoluble material, chondroitin sulfates, heparan sulfate, and proteins that may interfere with the recovery and measurement of OSCS. We examined 500MHz (1)H NMR, capillary electrophoresis (CE), and SAX-HPLC to quantify OSCS in crude heparin.

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Background: After the patent on omeprazole delayed-release capsules expired, Food and Drug Administration (FDA) approved several generic omeprazole delayed-release capsule applications. FDA has received some complaints concerning a lack of therapeutic effect of the generic omeprazole delayed-release capsules.

Aim: To investigate the quality of five different marketed generic omeprazole delayed-release capsules.

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Article Synopsis
  • The study aimed to evaluate how the age of fentanyl patches affects their stability and how well the drug penetrates the skin.
  • Drug release tests showed an increase in the amount of fentanyl in the adhesive layer over time, but the patches also lost alcohol content as they aged.
  • Despite changes in drug concentration, skin permeation rates remained stable, indicating that older patches do not deliver more drug even as they age.
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A chromatographic method was developed for the detection and quantification of the contaminant oversulfated chondroitin sulfate (OSCS) and the impurity dermatan sulfate in heparin active pharmaceutical ingredient (API). The HPLC analysis of heparin is carried out using a polymer-based strong anion exchange (SAX) column with gradient elution from 0.125 M sodium chloride to 2.

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Near infrared (NIR) reflectance and laser Raman spectra for a set of 69 heparin powder samples obtained from several foreign and domestic suppliers were measured. Both the NIR and Raman spectra of individual heparin API powder samples were correlated with sample compositions determined from response corrected relative peak areas of the capillary electropherograms of the samples using a partial least squares (PLS) regression model. Twenty-eight sample spectra were used to develop PLS models for the three major sample components; heparin, oversulfated chondroitin sulfate (OSCS) and glycosaminoglycans (GAGs).

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An attempt was made to develop a gastroretentive drug delivery system of carbamazepine using HPMC, sodium bicarbonate, and EC as matrixing agent, gas-generating agent, and floating enhancer, respectively. A simplex lattice design was applied to investigate the combined effect of 3 formulation variables (ie, amount of HPMC (), EC (), and sodium bicarbonate (). Results of multiple regression analysis indicated that low levels of and and a high level of should be used to manufacture the tablet formulation with desired in vitro floating time and dissolution.

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The objective of this study is to determine lead concentrations in a variety of widely used pharmaceutical products, and to assess the risk of lead exposure from using these products. Lead concentrations of 45 products were measured with inductively-coupled plasma mass spectrometry. Six products had lead concentrations greater than 100 parts per billion (ppb), and the highest measured concentration was 500 ppb.

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In this study, gauge repeatability and reproducibility (gauge R&R) was used to analyze variability for USP apparatus 2 dissolution measurement systems. Experiments were designed to assess the variability due to apparatus, operator, and sample tablet. Since dissolution testing is a destructive test, a nested model was used for data analysis.

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This work investigated the use of non-traditional analytical methods to evaluate the quality of a variety of pharmaceutical products purchased via internet sites from foreign sources and compared the results with those obtained from conventional quality assurance methods. Traditional analytical techniques employing HPLC for potency, content uniformity, chromatographic purity and drug release profiles were used to evaluate the quality of five selected drug products (fluoxetine hydrochloride, levothyroxine sodium, metformin hydrochloride, phenytoin sodium, and warfarin sodium). Non-traditional techniques, such as near infrared spectroscopy (NIR), NIR imaging and thermogravimetric analysis (TGA), were employed to verify the results and investigate their potential as alternative testing methods.

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Current definitions of lotions, gels, creams and ointments vary depending on literature source, market history or traditional use. This often leads to confusion when deciding which dosage form to prescribe and/or purchase. The existing classification of topical dosage forms needs to be re-examined to ensure that definitions for different dosage forms are based on consistent scientific principles and that dosage forms can be distinguished from one another.

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