Shorter and Rugged Analytical GC Method for Residual Solvents Content in Active Pharmaceutical Ingredient.

This work describes the highly selective and sensitive robust analytical method (gas chromatography) for the qualitative and quantitative analysis of commonly used residual solvents (like methanol, ethanol, acetonitrile, dichloromethane, methyl tert-butyl ether, n-hexane, 1-propanol, ethyl acetate, tetrahydrofuran, N,N-diisopropylethylamine (DIPEA) and dimethylformamide), in an active pharmaceuticals ingredients. The developed method was optimized with good resolution (>1.9 between close eluting solvents) and a shorter run time (20 min). All the solvents were separated using GC column DB-624, 30-m length, 0.32-mm diameter, 1.8-µm particle size, nitrogen as a carrier gas and recorded the signals using flame ionization detector (FID). Further, analytical method validation has been performed for the developed analytical method and the validation results demonstrated its routine application for the determination of residual solvents content by GC-head space (HS). The practical application was demonstrated by the suitable API batch analysis (having sample Con. 40 mg/mL). The present developed method has more advantages than the other methods for the qualitative and quantitative applications, such as shorter runtime, selective for multiple solvents (11 organic solvents) analysis at a time, highly sensitive at ppm levels. This GC-HS method could be used for the qualitative and quantitative determination of the residual solvents content in APIs.

Characterization and relative response factor determination of process related impurity in Naproxen by nuclear magnetic resonance spectroscopy.

In the impurity profile of naproxen around 0.6% unknown polar impurity was detected by high performance liquid chromatography (HPLC). The product ion spectrum of the impurity and Naproxen was recorded in LCMS/MS and the fragmentation pattern of the impurity was observed to be similar to the fragmentation pattern of Naproxen with only a difference of two atomic mass units. The high resolution mass spectrum (HRMS) of the impurity displayed a protonated molecular ion at m/z 229.0863, which corresponds to the pseudomolecular formula C(14)H(13)O(3)(+). Based on LC/MS/MS, HRMS, 1D and 2D NMR data, the structure of the impurity was characterized as 2-(6-methoxynaphthalen-2-yl)acrylic acid. The acrylic acid impurity was synthesized in the laboratory and co injected in HPLC to confirm the retention time. RRF of the impurity was determined by (1)H NMR method and also by conventional HPLC slope method and the RRF values are found to be 6.11 and 5.64, respectively. The values are comparable and (1)H NMR method of RRF determination is complimentary and can be effectively used as an alternative method to conventional HPLC method especially in early stages of development when availability of impurity standards is not possible.

Development and validation of GC-MS method for the determination of methyl methanesulfonate and ethyl methanesulfonate in imatinib mesylate.

A gas chromatography-mass spectrometry (GC-MS) method has been developed for the identification and determination of two carcinogenic and genotoxic mesylate esters viz. methyl methanesulfonate (MMS) and ethyl methanesulfonate (EMS) in imatinib mesylate (INM). The method was optimized based on the peak shapes and resolution of MMS and EMS. The method was validated as per International Conference of Harmonization (ICH) guidelines in terms of limits of detection (LOD), limit of quantitation (LOQ), linearity, precision, accuracy, specificity and robustness. The LOD and LOQ values were found to be 0.3 and 1.0 microg/ml, respectively. The method is linear within the range of 1-15 microg/ml for both the compounds. These mesylate esters were not found in three different batches of pure and pharmaceutical formulations of INM.