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Here we report results from the analyses by enzymatic digestion and reversed-phase ion-pairing liquid chromatography mass spectrometry (RPIP-LC-MS) of active pharmaceutical ingredient (API) unfractionated heparins (UFHs) from six different manufacturers and one USP standard sample. We employed a reverse phase ion-pairing chromatography method using a [C.sub.18] column and hexylamine as the ion-pairing reagent with acetonitrile gradient elution to separate disaccharides generated from the digestion of the heparins by lyase I and III (E.C. 4.2.2.7 and 4.2.2.8) before introduction into an ion-trap mass spectrometer by an electrospray ionization (ESI) interface. Extracted ion chromatograms (EICs) were used to determine the relative abundance of the disaccharides by mass spectrometry. Eight disaccharides were observed and a similar composition profile was observed from digests of 20 UFH samples. The compositional profile determined from these experiments provides a measure of the norm and range of variation in 'good' heparin to which future preparations can be compared. Furthermore, the profile obtained in the RPIP-LC-MS assay is sensitive to the presence of the contaminant, oversulfated chow droitin sulfate A (OSCS), in heparin. 10.1021/ac102301j

A study was conducted to determine whether contaminated heparin containing oversulphated chondroitin sulphate (OSCS) was responsible for adverse clinical events in patients administered this during dialysis. Results indicated that there was a connection between the two and suggested further and quick research.

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Explaining aspects of form and colour themes in Iranian art has special importance. In fact, colour and form are the links between plural elements of Iranian art and this issue is well manifested in Iranian hand-woven rugs, or Gabbeh. The Iranian weaver transforms the traditional geometry of picture into a pattern by applying a colour formula in which form and colourhave special significance. Such form of array of work produces a modern method of presentation, the visual equivalent of which can be seen in various forms of modern art especially post-painterly abstraction; this essay tries to find the position of art of Gabbeh-weaving art as one of the most important contemporary visual kinds, the main question is: is there a similarity between aesthetic signs (geometric form and colour) in Iranian Gabbeh-weaving and post-painterly abstraction? One shall implement a descriptive-analytical method, rely on information derived from library books and references and collected field-data, aiming at studying some common aspects of the specific samples. The result of comparison and studies show that: 1. Iranian Gabbeh-weaving has discovered an exactly calculated organization of various forms, withdissimilar patterns of images; a system of relations of colour and images which it logically presents through colourful yarns. 2. Visual cues used in Iranian Gabbeh-weaving and post-painterly abstraction are similarly used regardless of time and space. 3. Visual cues, such as colour and geometric form, were first manifested in the art of Iranian Gabbeh-weaving before being seen in modern art aesthetics. [ABSTRACT FROM AUTHOR]

We evaluated polyacrylamide gel electrophoresis (PAGE) and size exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALLS) approaches to determine weight-average molecular weight ( M) and polydispersity ( PD) of heparins. A set of unfractionated heparin sodium (UFH) and low-molecular-weight heparin (LMWH) samples obtained from nine manufacturers which supply the US market were assessed. For SEC-MALLS, we measured values for water content, refractive index increment ( dn/ dc), and the second virial coefficient ( A) for each sample prior to molecular weight assessment. For UFH, a mean ± standard deviation value for M of 16,773 ± 797 was observed with a range of 15,620 to 18,363 ( n = 20, run in triplicate). For LMWHs by SEC-MALLS, we measured mean M values for dalteparin, tinzaparin, and enoxaparin of 6,717 ± 71 ( n = 4), 6,670 ± 417 ( n = 3), and 3,959 ± 145 ( n = 3), respectively. PAGE analysis of the same UFH, dalteparin, tinzaparin, and enoxaparin samples showed values of 16,135 ± 643 ( n = 20), 5,845 ± 45 ( n = 4), 6,049 ± 95 ( n = 3), and 4,772 ± 69 ( n = 3), respectively. These orthogonal measurements are the first M results obtained with a large heparin sample set on product being marketed after the heparin crisis of 2008 changed the level of scrutiny of this drug class. In this study, we compare our new data set to samples analyzed over 10 years earlier. In addition, we found that the PAGE analysis of heparinase digested UFH and neat LMWH samples yield characteristic patterns that provide a facile approach for identification and assessment of drug quality and uniformity. [ABSTRACT FROM AUTHOR]

Heparin, a widely used anticoagulant primarily extracted from animal sources, contains varying amounts of galactosamine impurities. Currently, the United States Pharmacopeia (USP) monograph for heparin purity specifies that the weight percent of galactosamine (%Gal) may not exceed 1%. In the present study, multivariate regression (MVR) analysis of H NMR spectral data obtained from heparin samples was employed to build quantitative models for the prediction of %Gal. MVR analysis was conducted using four separate methods: multiple linear regression, ridge regression, partial least squares regression, and support vector regression (SVR). Genetic algorithms and stepwise selection methods were applied for variable selection. In each case, two separate prediction models were constructed: a global model based on dataset A which contained the full range (0-10%) of galactosamine in the samples and a local model based on the subset dataset B for which the galactosamine level (0-2%) spanned the 1% USP limit. All four regression methods performed equally well for dataset A with low prediction errors under optimal conditions, whereas SVR was clearly superior among the four methods for dataset B. The results from this study show that H NMR spectroscopy, already a USP requirement for the screening of contaminants in heparin, may offer utility as a rapid method for quantitative determination of %Gal in heparin samples when used in conjunction with MVR approaches. [ABSTRACT FROM AUTHOR]

Abstract: Heparin is a naturally produced, heterogeneous compound consisting of variably sulfated and acetylated repeating disaccharide units. The structural complexity of heparin complicates efforts to assess the purity of the compound, especially when differentiating between similar glycosaminoglycans. Recently, heparin sodium contaminated with oversulfated chondroitin sulfate A (OSCS) has been associated with a rapid and acute onset of an anaphylactic reaction. In addition, naturally occurring dermatan sulfate (DS) was found to be present in these and other heparin samples as an impurity due to incomplete purification. The present study was undertaken to determine whether chemometric analysis of these NMR spectral data would be useful for discrimination between USP-grade samples of heparin sodium API and those deemed unacceptable based on their levels of DS, OSCS, or both. Several multivariate chemometric methods for clustering and classification were evaluated; specifically, principal components analysis (PCA), partial least squares discriminant analysis (PLS-DA), linear discriminant analysis (LDA), and the k-nearest-neighbor (kNN) method. Data dimension reduction and variable selection techniques, implemented to avoid over-fitting the training set data, markedly improved the performance of the classification models. Under optimal conditions, a perfect classification (100% success rate) was attained on external test sets for the Heparin vs OSCS model. The predictive rates for the Heparin vs DS, Heparin vs [DS + OSCS], and Heparin vs DS vs OSCS models were 89%, 93%, and 90%, respectively. In most cases, misclassifications can be ascribed to the similarity in NMR chemical shifts of heparin and DS. Among the chemometric methods evaluated in this study, we found that the LDA models were superior to the PLS-DA and kNN models for classification. Taken together, the present results demonstrate the utility of chemometric methods when applied in combination with 1H NMR spectral analysis for evaluating the quality of heparin APIs. [Copyright &y& Elsevier]

To differentiate heparin samples with varying amounts of dermatan sulfate (DS) impurities and oversulfated chondroitin sulfate (OSCS) contaminants, proton NMR spectral data for heparin sodium active pharmaceutical ingredient samples from different manufacturers were analyzed using multivariate chemometric techniques. A total of 168 samples were divided into three groups: (a) Heparin, [DS] ≤ 1.0% and [OSCS] = 0%; (b) DS, [DS] > 1.0% and [OSCS] = 0%; (c) OSCS, [OSCS] > 0% with any content of DS. The chemometric models were constructed and validated using two well-established methods: soft independent modeling of class analogy (SIMCA) and unequal class modeling (UNEQ). While SIMCA modeling was conducted using the entire set of variables extracted from the NMR spectral data, UNEQ modeling was combined with variable reduction using stepwise linear discriminant analysis to comply with the requirement that the number of samples per class exceed the number of variables in the model by at least 3-fold. Comparison of the results from these two modeling approaches revealed that UNEQ had greater sensitivity (fewer false positives) while SIMCA had greater specificity (fewer false negatives). For Heparin, DS, and OSCS, respectively, the sensitivity was 78% (56/72), 74% (37/50), and 85% (39/46) from SIMCA modeling and 88% (63/72), 90% (45/50), and 91% (42/46) from UNEQ modeling. Importantly, the specificity of both the SIMCA and UNEQ models was 100% (46/46) for Heparin with respect to OSCS; no OSCS-containing sample was misclassified as Heparin. The specificity of the SIMCA model (45/50, or 90%) was superior to that of the UNEQ model (27/50, or 54%) for Heparin with respect to DS samples. However, the overall prediction ability of the UNEQ model (85%) was notably better than that of the SIMCA model (76%) for the Heparin vs DS vs OSCS classes. The models were challenged with blends of heparin spiked with nonsulfated, partially sulfated, or fully oversulfated chondroitin sulfate A, dermatan sulfate, or heparan sulfate at the 1.0, 5.0, and 10.0 wt % levels. The results from the present study indicate that the combination of (1)H NMR spectral data and class modeling techniques (viz., SIMCA and UNEQ) represents a promising strategy for assessing the quality of commercial heparin samples with respect to impurities and contaminants. The methodologies show utility for applications beyond heparin to other complex products.