A novel, stability-indicating, reversed-phase ultra-performance liquid chromatographic (RP-UPLC) method was developed for the determination of pure drotaverine hydrochloride and ibuprofen in the presence of their impurities and degradation products. The method was developed using a Waters UPLC BEH C18, 100 × 2.1 mm, 1.7 µm column with a flow rate of 0.3 mL/min and detector wavelength at 210 nm....

most versatile and sensitive tools for micro-chemical studies of biological material. Since the publication of Volume I, which covers this topic very briefly, many advances have been made both in the development of new procedures and in the adaptation of existing ones to the micro-chemical level. Although the latter deficit is recognized by Dr. Glick in the preface to Volume II, it is unfortuna...

Binders are important ingredients of solid oral dosage formulations (SODFs). The structure and function of binders play an important role in dosages’ shape and size, delivery, and stability of drug products. The stability of active ingredients depends on external factors, e.g. exposure to heat, oxygen and humidity but also on internal factors, e.g. the impurities such as peroxides, aldehydes, h...

Nevirapine (Viramune), a dipyridiodiazepinone, is a potent and highly specific nonnucleoside inhibitor of HIV-1 reverse transcriptase. This paper describes the validation of a specific, sensitive, and stability-indicating high-performance liquid chromatography method for the assay and determination of related organic impurities in nevirapine drug substance. This method uses a Supelcosil LC-ABZ ...

High performance liquid chromatography tandem mass spectrometry (HPLC MS) has been widely used for β-lactam antibiotics determination. However, its application to identify impurities of these frequently used drugs is not sufficient at present. In this job, characteristic profiles of the collision induced dissociation (CID) spectra of both β-lactams and ring-opened β-lactams were extracted from ...

Impurities enter the electrolyte mainly from the consumable carbon anode and aluminium oxide. Important impurity elements are iron, silicon, phosphorus and sulfur. Metallic impurities such as iron and silicon tend to codeposit at the cathode, while dissolved phosphorus and sulfur species also affect the current efficiency for aluminium production. In modern industrial cells more impurities end ...

In 2008, heparin (active pharmaceutical ingredient, API) lots were associated with anaphylactoid-type reactions. Oversulfated chondroitin sulfate (OSCS), a semi-synthetic glycosaminoglycan (GAG), was identified as a contaminant and dermatan sulfate (DS) as an impurity. While DS has no known toxicity, OSCS was toxic leading to patient deaths. Heparins, prepared before these adverse reactions, ne...

The critical behaviour of thin films containing quenched random impurities and inhomogeneities is investigated by the renormalization–group method to the one–loop order within the framework of the n–component φ–model.The finite–size crossover in impure films has been consdered on the basis of the fundamental relationship between the effective dimensionality Deff and the characteristic lengths o...

We present first-principles density-functional calculations for the structural, electronic, and magnetic properties of substitutional 3d transition metal (TM) impurities in two-dimensional black and blue phosphorenes. We find that the magnetic properties of such substitutional impurities can be understood in terms of a simple model based on the Hund's rule. The TM-doped black phosphorenes with ...

The quantitative analysis method for volatile impurities in diallyldimethylammonium chloride (DADMAC) monomer solution was established in this paper. The volatile impurities were quantitatively analyzed with trichloromethane as extraction solvent and n-hexane as internal standard by using gas chromatography (GC) coupled with solvent extraction, and the chromatographic conditions, quantitative m...