Search Results
Abstract
The article gives a brief survey of the chequered critical history of Blake reception, from the beginning to our day. Four major trends are outlined: 1. detection of basic documents 2. appropriation and interpretation 3. professionalisation of Blake studies; assimilation of the oeuvre into the canon of the mainstream of English literature 4. rediscovery of "dangerous" Blake; defacing the monument erected by previous scholars. As Blake's work is peculiarly available, and simultaneously peculiarly resistant, to recent changes to critical awareness, special attention is paid to three of the most distinctive tendencies and debates that define the past two decades of Blake scholarship: deconstruction, new-historicism and feminist argument.
In October 2012 the workshop entitled “Reading Past and Present Landscapes in Central Europe” was held in Hungary. During the workshop, which was focused on exchanging ideas and experience concerning remote sensing methods of detection and registering archaeological sites, a large Roman site near the village of Sárbogárd in Nagyhörcsökpuszta was detected. The area of the site, its location, and the finds suggest that it could have played an important role in the region. This paper presents the results obtained from geophysical prospection and field walking, as well as the results of pottery analysis.
Summary
A stability-indicating gradient reverse-phase liquid chromatographic method was developed for the quantitative determination of process-related impurities and forced degradation products of oxcarbazepine in pharmaceutical formulation. The method was developed by using Inertsil cyano (250 × 4.6 mm) 5 μm column with mobile phase containing a gradient mixture of solvent A (0.01 M sodium dihydrogen phosphate, pH adjusted to 2.7 with orthophosphoric acid and acetonitrile in the ratio of 80:20 v/v) and B (50:40:10 v/v/v mixture of acetonitrile, water, and methanol). The flow rate of mobile phase was 1.0 mL min−1. Column temperature was maintained at 25°C and detection wavelength at 220 nm. Developed reverse-phase high-performance liquid chromatography (RP-HPLC) method can adequately separate and quantitate five impurities of oxcarbazepine, namely imp-A, imp-B, imp-C, imp-D, and imp-E. Oxcarbazepine was subjected to the stress conditions of oxidative, acid, base, hydrolytic, thermal, and photolytic degradation. Oxcarbazepine was found to degrade significantly in acid, base, and oxidative stress conditions. The degradation products were well resolved from oxcarbazepine and its impurities. The developed method was validated as per International Conference on Harmonization (ICH) guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, and robustness.
Summary
In this research paper we describe validated high-performance liquid chromatographic (HPLC) and high-performance thin-layer chromatographic (HPTLC) methods for simultaneous analysis of tamsulosin hydrochloride and dutasteride in tablet formulations. HPLC was performed on a C18 column with 85:15 (υ/υ) methanol-0.02 m ammonium acetate buffer (pH 9.5, adjusted with triethylamine) as mobile phase. HPTLC was performed on aluminium foil-backed silica gel G60F254 layers with toluene-methanol-triethylamine 9:1.5:1 (υ/υ/υ) as mobile phase. In HPLC, quantification was achieved by photo diode-array (PDA) detection at 274 nm over the concentration range 1–20 μg mL−1 for both; mean recovery was 98.18 ± 0.698 and 99.94 ± 0.611% for TAM and DUTA, respectively. In HPTLC, quantification was achieved by UV detection at 280 nm over the concentration range 200–2000 ng per band for both; mean recovery was 99.66 ± 0.892 and 100.05 ± 1.012% for TAM and DUTA, respectively. These methods are simple, precise, and sensitive, and are suitable for simultaneous analysis of TAM and DUTA in tablet formulations.
Summary
A stability-indicating reversed-phase high-performance liquid chromatographic method has been developed for analysis of gemifloxacin in tablet formulations. When the drug was subjected to forced degradation under acidic, basic, thermal, oxidative, and photolytic conditions, the degradation products produced were successfully separated on a 250 mm × 4.6 mm, 5-μm particle, C18 column with ammonium acetate buffer (pH 2.7; 0.05 m)-acetonitrile 70:30 (υ/υ) as mobile phase at a flow rate of 0.7 mL min−1. Diode-array detection was performed at 272 nm. The method was validated in accordance with ICH guidelines. Response was a linear function of concentration over the range 0.256–128 μg mL−1 (correlation coefficient 0.9990). The limits of detection and quantification were 10 and 30 ng mL−1, respectively. Separation of gemifloxacin from its stress-induced degradation products and excipients was adequate; resolution was >1.5 within 11 min. The purity index for the gemifloxacin peak after all types of stress was >0.999, indicating complete separation of the analyte peak from the degradation products. The method can therefore be regarded as stability-indicating. It is rapid, and suitable for purity and assay determination not only for routine quality control but also in stability studies.
Summary
A simple isocratic HPLC-UV assay for measurement of total and free melphalan concentrations in human plasma is described. Samples were prepared by methanol precipitation (total melphalan assay) and ultrafiltration (free melphalan assay). On a 25 cm × 4.6 mm C18 column with 0.016 m mixed soldium phosphate citrate buffer (pH 3.75)-acetonitrile 87:13 as mobile phase, at a flow rate of 1 mL min−1, the retention time of melphalan was 11.5 min. Detection was at 254 nm. For total melphalan assay response was a linear function of concentration up to 40 μg mL−1, with excellent interday precision (<6% for 0.5–40 μg mL−1 melphalan), accuracy (<2% deviation from the true concentration), and recovery (91–110%). For free melphalan assay response was a linear function of concentration up to 2.5 μg mL−1, with good precision (<11% for 0.7–2.5 μg mL−1 melphalan) and recovery (89–93%). Detection limits were 0.1 μg mL−1 and 0.05 μg mL−1 for total and free melphalan assays, respectively. The assays were clinically applied in a study of myeloma patients.
Summary
Dispersive liquid-liquid microextraction in combination with an in situ derivatization is suggested for parabens sampling and preconcentration. The derivatization was carried out with acetic anhydride under alkaline conditions maintained using di-potassium hydrogen phosphate. The effects of an extraction solvent type, extraction and disperser solvents volume, extraction time, and ionic strength of the solution on the extraction efficiency were investigated. Chlorobenzene containing n-hexadecane as internal standard was used as an extracting solvent and acetone was used as a disperser solvent. The calibration graphs were linear up to 10 mg mL−1, correlation coefficients were 0.997–0.999, enrichment factors were from 70 for methylparaben to 210 for butylparaben, and detection limits were 22, 4.2, 3.3, and 2.5 µg L−1 for methylparaben, ethylparaben, propylparaben, and butylparaben, respectively. Repeatabilities of the results were acceptable with relative standard deviations up to 11%. A possibility to apply the proposed method for parabens determination in water samples was demonstrated.
Summary
An isocratic reversed-phase high-performance liquid chromatographic (RPHPLC) method for analysis of irinotecan HCl has been developed and validated. Separation was achieved on a C18 column with potassium dihydrogen phosphate buffer (pH adjusted to 3.5 with orthophosphoric acid)-acetonitrile-methanol 55:25:20 (v/v) as mobile phase at a flow rate of 1.0 mL min−1. UV detection was performed at 254 nm. The method is simple, sensitive, rapid, and selective, and linear over the range 30–70 μg mL−1 for assay of irinotecan HCl. The precision of the assay method was below 1.0% RSD. Mean recovery was in the range 98.0–102.0%. Recovery of the active pharmaceutical ingredient from dosage forms ranged from 99.0 to 101.0. The method is useful for quality control in bulk manufacture and of the pharmaceutical formulation.
Summary
This paper reports development and validation of a new microemulsion liquid chromatographic (MELC) method for rapid screening of simvastatin and simvastatin acid in human plasma. Plasma samples were injected directly into the HPLC system after appropriate sample dilution with mobile phase. Separations were performed on a 4.6 mm × 150 mm, 5-μm particle, C18 column, with UV detection at 238 nm. The mobile phase was 0.5% (w/υ) diisopropyl ether, 1.0% (w/υ) sodium dodecylsulphate (SDS), 4.0% (w/v) n-butanol, and 94.5% (w/w) aqueous 25 mM disodium hydrogen phosphate, pH 7.0, at a flow rate of 1 mL min−1. The method was evaluated according to criteria stated in FDA bioanalytical method validation guidance. The unique approach applied in this paper enables direct analysis of simvastatin and simvastatin acid, so the method can be used to obtain reliable results in a rapid and simple way.
Summary
A simple, rapid, precise, and accurate, stability-indicating reversed phase high performance liquid chromatographic method was developed and validated for simultaneous determination of metformin HCl and repaglinide. The chromatographic separation was achieved on YMC Pack AM ODS (5 μm, 250 mm length × 4.6 mm i.d.) column at a detector wavelength of 210 nm, using an isocratic mobile phase consisting of methanol and 10 mM potassium dihydrogen phosphate buffer (pH 2.5) in a ratio of 70:30 v/v at a flow rate of 1 mL min−1. The retention times for metformin and repaglinide were found to be 2.6 and 11.3 min, respectively. The drugs were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Validation of the method was carried out as per International Conference on Harmonization (ICH) guidelines. Linearity was established for metformin and repaglinide in the range of 5–200 μg mL−1 and 1–200 μg mL−1, respectively. The limits of detection were 0.3 μg mL−1 and 0.13 μg mL−1 for metformin and repaglinide, respectively. The method was found to be specific and stability-indicating as no interfering peaks of degradants and excipients were observed. The proposed method is hence suitable for application in quality-control laboratories for quantitative analysis of both the drugs individually and in combination, since it is simple and rapid with good accuracy and precision.
