Synthesis and antimicrobial activity of some new N-acyl substituted phenothiazines.

A series of 2-substituted N-acylphenothiazines were synthesized by using imides, N-carboxymethyl imides and the structures of these newly synthesized compounds were confirmed by spectral and elemental analyses. All new compounds were tested for their antibacterial and antifungal activities. Some compounds showed promising antibacterial and antifungal activities.

Identification and characterization of process related impurities in chloroquine and hydroxychloroquine by LC/IT/MS, LC/TOF/MS and NMR.

The focus of this study is identification and characterization of major unknown impurities in chloroquine (CQ) and hydroxychloroquine (HCQ) bulk drug samples using liquid chromatography/ion trap mass spectrometry (LC/IT/MS) and liquid chromatography/time of flight mass spectrometry (LC/TOF/MS). The newly developed LC/MS method was employed for the analysis of both the drugs. The analysis revealed the presence of two impurities in each of the drugs.

Investigation of amodiaquine bulk drug impurities by liquid chromatography/ion trap mass spectrometry.

Three unknown impurities in an amodiaquine bulk drug sample were detected by reversed-phase high-performance liquid chromatography with ultraviolet detection (HPLC/UV). A liquid chromatography/tandem mass spectrometry (LC/MS(n)) method is described for the investigation of these impurities. Mass spectral data were acquired on an LCQ ion trap mass analyzer equipped with an electrospray ionization (ESI) source operated in positive ion mode.

Simultaneous determination of metoprolol succinate and amlodipine besylate in pharmaceutical dosage form by HPLC.

A simple, precise, specific and accurate reverse phase HPLC method has been developed for the simultaneous determination of metoprolol succinate (MS) and amlodipine besylate (AB) in tablet dosage form. The chromatographic separation was achieved on Hypersil BDS cyano (250 mm x 4.6 mm, 5 microm) column using PDA detector.

Development and validation of UPLC method for determination of primaquine phosphate and its impurities.

With the objective of reducing analysis time and maintaining good efficiency, there has been substantial focus on high-speed chromatographic separations. Recently, commercially available ultra-performance liquid chromatography (UPLC) has proven to be one of the most promising developments in the area of fast chromatographic separations. In this work, a new isocratic reverse phase chromatographic method was developed using UPLC for primaquine phosphate bulk drug.

Isolation and structural identification of an impurity in fluconazole bulk drug substance.

Four impurities in fluconazole API sample obtained from a recently proposed synthetic process were detected by HPLC. One of the impurities was unknown having not been reported previously. This less polar unknown impurity was isolated from the crude sample of fluconazole bulk drug using semi-preparative HPLC.

Characterization and quantitative determination of impurities in piperaquine phosphate by HPLC and LC/MS/MS.

Four impurities in piperaquine phosphate bulk drug substance were detected by a newly developed gradient reverse phase high performance liquid chromatographic (HPLC) method. These impurities were identified by LC/MS/MS. The structures of impurities were confirmed by spectroscopic studies (NMR and IR) conducted using synthesized authentic compounds.

Preparative isolation and structural elucidation of impurities in fluconazole by LC/MS/MS.

Three impurities were detected in the LC/MS analysis of fluconazole bulk drug substance. Two of the impurities were unknowns having not been reported previously. Structural assignment of these impurities was carried out by LC/MS/MS using electrospray ionization source and an ion trap mass analyzer.

Application of GC-EI-MS for the identification and investigation of positional isomer in primaquine, an antimalarial drug.

A major impurity associated with primaquine drug samples obtained from European Pharmacopoeia (EP) and other commercial sources was detected and identified using HPLC, photo diode array (PDA), LC-MS/MS and gas chromatograph-electron impact-mass spectrometer (GC-EI-MS). PDA and LC-ESI-MS/MS data provided an evidence for it being isomeric in nature. However, spectral data obtained from the newly developed GC-EI-MS method has been utilised for structural elucidation and found to be conclusive to characterize this impurity as positional isomer, i.