Development and Validation of a Fast Procedure To Analyze Amoxicillin in River Waters by Direct-Injection LC–MS/MS

Due to the increasing demands on improved fuel economy and stringent government regulations on tailpipe emissions, many automotive industries and research institutes have been looking for alternative solutions, such as diesel engines, hybrid-electric vehicles, and fuel cell technologies, over conventional port fuel injection (PFI) gasoline engines to meet the demands. On the other hand, many people in the automotive community also realize that there are still a lot of room for improvements in gasoline engine technologies, such as utilizing direct injection and/or variable valve actuation. In order to fully realize the potential benefits of such advanced technologies in gasoline engines, a well-coordinated complex control system design is essential. This paper describes the development and validation of a control-oriented mean-value model for a spark-ignition direct-injection (SIDI) engine to assist and accelerate such coordinated control system design and calibration processes via use of an engine model. The performance and accuracy of the dynamic engine model are evaluated and validated against a set of data for an engine running on a transient driving cycle.

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Development and validation of gas chromatography methods for the control of volatile impurities in the pharmaceutical substance dutasteride

10.7287/peerj.preprints.1836v1 ◽

2016 ◽

Author(s):

Aleksandra Groman ◽

Elżbieta U. Stolarczyk ◽

Marta Jatczak ◽

Elżbieta Lipiec-Abramska

Keyword(s):

Gas Chromatography ◽

Carbon Tetrachloride ◽

Direct Injection ◽

Test Procedure ◽

Active Pharmaceutical Ingredient ◽

Experimental Conditions ◽

Limit Test ◽

Development And Validation ◽

Optimization Of Experimental Conditions ◽

Volatile Impurities

Dutasteride, N-[2,5-Bis(trifluoromethyl)phenyl]-3-oxo-4-aza-5α-androst-1-ene-17β-carboxamide, is an active pharmaceutical ingredient (API) which inhibits the conversion of testosterone to dihydrotestosterone. Dutasteride as a 5-reductase inhibitor is useful for the treatment of benign prostatic hyperplasia (BPH) and prostate cancer. Because of a large variety of solvents and reagents used in the synthesis, it was necessary to develop new, sensitive and selective gas chromatography (GC) methods. The optimization of the methods consisted in selecting different types of sample injection and detection as well as optimization of experimental conditions that allowed to meet the appropriate range (10-120% of the specification limit) and suitable detection limits (LOD) of compounds. Significant differences in the volatility of these compounds forced the division into volatile solvents (methanol, acetonitrile, dichloromethane, ethyl acetate, heptane and toluene) analyzed with the use of the gas chromatography with headspace (GC-HS) and less volatile compounds (pyridine, dimethylformamide, 1,4-dioxane, acetic acid, ethylene glycol, 4-dimethylaminopyridine) analyzed with the use of gas chromatography with direct injection (GC-FID). Benzene, carbon tetrachloride and 1,2-dichloroethane are potential contaminants of toluene and dichloromethane, thus the control of these solvents was a limit test procedure. Due to the low specification limits for benzene (2 ppm), carbon tetrachloride (4 ppm) and 1,2-dichloroethane (5 ppm) it was neccesery to use gas chromatography with mass spectrometry detection (GC-MS). All three new methods were validated according to the requirements of the ICH (International Conference on Harmonization) validation guideline Q2R1 and the guideline for residual solvents Q3C. Specificity, precision, accuracy, linearity, limits of detection and quantitation and robustness were determined and the results meeting the acceptance criteria were obtained.

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Comparative analysis of odorous volatile organic compounds between direct injection and solid-phase microextraction: Development and validation of a gas chromatography–mass spectrometry-based methodology

Journal of Chromatography A ◽

10.1016/j.chroma.2009.05.022 ◽

2009 ◽

Vol 1216 (28) ◽

pp. 5436-5444 ◽

Cited By ~ 13

Author(s):

Sudhir Kumar Pandey ◽

Ki-Hyun Kim

Keyword(s):

Mass Spectrometry ◽

Gas Chromatography ◽

Comparative Analysis ◽

Organic Compounds ◽

Solid Phase Microextraction ◽

Solid Phase ◽

Direct Injection ◽

Gas Chromatography Mass Spectrometry ◽

Volatile Organic ◽

Development And Validation

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Development and validation of a column-switching high-performance liquid chromatographic method for the determination of sanfetrinem in rat and dog plasma by direct injection

Journal of Chromatography B Biomedical Sciences and Applications ◽

10.1016/s0378-4347(00)00533-8 ◽

2001 ◽

Vol 752 (1) ◽

pp. 133-139 ◽

Cited By ~ 9

Author(s):

C De Nardi ◽

L Ferrari ◽

E Nardin ◽

A Ruffo ◽

S Braggio

Keyword(s):

High Performance ◽

Chromatographic Method ◽

Direct Injection ◽

High Performance Liquid Chromatographic ◽

Column Switching ◽

Dog Plasma ◽

Liquid Chromatographic Method ◽

Development And Validation ◽

Liquid Chromatographic

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Development and validation of gas chromatography methods for the control of volatile impurities in the pharmaceutical substance dutasteride

10.7287/peerj.preprints.1836 ◽

2016 ◽

Author(s):

Aleksandra Groman ◽

Elżbieta U. Stolarczyk ◽

Marta Jatczak ◽

Elżbieta Lipiec-Abramska

Keyword(s):

Gas Chromatography ◽

Carbon Tetrachloride ◽

Direct Injection ◽

Test Procedure ◽

Active Pharmaceutical Ingredient ◽

Experimental Conditions ◽

Limit Test ◽

Development And Validation ◽

Optimization Of Experimental Conditions ◽

Volatile Impurities

Dutasteride, N-[2,5-Bis(trifluoromethyl)phenyl]-3-oxo-4-aza-5α-androst-1-ene-17β-carboxamide, is an active pharmaceutical ingredient (API) which inhibits the conversion of testosterone to dihydrotestosterone. Dutasteride as a 5-reductase inhibitor is useful for the treatment of benign prostatic hyperplasia (BPH) and prostate cancer. Because of a large variety of solvents and reagents used in the synthesis, it was necessary to develop new, sensitive and selective gas chromatography (GC) methods. The optimization of the methods consisted in selecting different types of sample injection and detection as well as optimization of experimental conditions that allowed to meet the appropriate range (10-120% of the specification limit) and suitable detection limits (LOD) of compounds. Significant differences in the volatility of these compounds forced the division into volatile solvents (methanol, acetonitrile, dichloromethane, ethyl acetate, heptane and toluene) analyzed with the use of the gas chromatography with headspace (GC-HS) and less volatile compounds (pyridine, dimethylformamide, 1,4-dioxane, acetic acid, ethylene glycol, 4-dimethylaminopyridine) analyzed with the use of gas chromatography with direct injection (GC-FID). Benzene, carbon tetrachloride and 1,2-dichloroethane are potential contaminants of toluene and dichloromethane, thus the control of these solvents was a limit test procedure. Due to the low specification limits for benzene (2 ppm), carbon tetrachloride (4 ppm) and 1,2-dichloroethane (5 ppm) it was neccesery to use gas chromatography with mass spectrometry detection (GC-MS). All three new methods were validated according to the requirements of the ICH (International Conference on Harmonization) validation guideline Q2R1 and the guideline for residual solvents Q3C. Specificity, precision, accuracy, linearity, limits of detection and quantitation and robustness were determined and the results meeting the acceptance criteria were obtained.

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Ultrastructure of melanocyte-keratinocyte interactions and pigment transfer in vitro

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084120 ◽

1978 ◽

Vol 36 (2) ◽

pp. 650-651

Author(s):

Raul I. Garcia ◽

Evelyn A. Flynn ◽

George Szabo

Keyword(s):

Direct Injection ◽

Skin Pigmentation ◽

Freeze Fracture ◽

Pigment Granule ◽

Time Lapse ◽

Ultrastructural Level ◽

Lanthanum Tracer ◽

A Cell

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.

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