Linagliptin is a highly specific, long‐acting inhibitor that is used as an orally administrable agent for type‐2 diabetes treatment. Because only the R‐enantiomer is of clinical use, we developed a ...capillary electrophoresis method for the determination of the enantiomeric impurity of this compound. Carboxymethyl‐β‐cyclodextrin was selected as the chiral selector for the separation of linagliptin enantiomers. Design of experiments and desirability functions were used for the analytical optimization, which was focused on understanding and improving the electrophoretic process. The effects of significant parameters (background electrolyte concentration and pH, cyclodextrin concentration, temperature, and voltage) were thoroughly investigated. The complete separation of linagliptin and its enantiomeric impurity with baseline resolution was achieved within 10 min on an uncoated fused‐silica capillary (50 μm inner diameter, 365 μm outer diameter, 64.5/56 cm in total/ effective length) maintained at 25°C, under an applied voltage of 28.0 kV. The background electrolyte contained 70 mM sodium acetate and 4.7 mM carboxymethyl‐β‐cyclodextrin, and the pH was adjusted to 6.10. The method was validated, and a limit of quantitation of 0.05% for the impurity was estimated.
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A simple and reliable high‐performance liquid chromatography method was developed to determine the enantiomeric impurity of tenofovir disoproxil fumarate, an orally bioavailable prodrug of tenofovir, ...commonly used for the treatment of human immunodeficiency virus and hepatitis B. Tenofovir disoproxil and its enantiomer, were completely separated on a Chiralpak IC column (3 μm, 100 × 4.6 mm, i.d.). The chiral separation was achieved using a mobile phase containing n‐hexane, ethanol, methanol, and triethylamine 65/25/10/0.1 (v/v/v/v) at a flow rate of 0.6 mL/min. Ideally, the reversal of enantiomer elution order was achieved on the Chiralpak IC column, to allow the elution of the minor enantiomeric impurity before the major component. Moreover, the proposed method was able to discriminate the active ingredient from the related substances available in the tenofovir disoproxil fumarate raw materials. These compounds were isolated and structurally elucidated by MS and nuclear magnetic resonance. Based on the spectral data, the structures of related substances were confirmed as tenofovir isoproxil monoester and fumaric acid. The high‐performance liquid chromatography method was optimized by the design of experiment approach and successfully validated following the International Conference on Harmonization guideline. Proposed method was effectively applied for the quantification of enantiomeric impurity in tenofovir disoproxil fumarate raw materials.
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A simple, cost‐effective, and greener HPLC method was investigated to determine 14 β‐lactams. To achieve this, various strategies were implemented such as the use of an aqueous mobile phase, ionic ...liquids, or an alternative organic solvent. Preliminary experiments were conducted using “one‐factor‐at‐a‐time” to identify the significant factors affecting chromatographic performance. The experimental design (central composite design) was then applied to thoroughly examine the effects of the key factors and exploit them to achieve optimal HPLC condition. The developed method was less hazardous and improved the retention and peak shape, compared with other conventional methods. The optimized assay condition was validated according to the ICH guidelines and effectively applied for the quantification of some β‐lactams in various formulations. These results imply that this novel HPLC method can be employed for routine analyses of some β‐lactams in pure drug and commercial formulations.
Combination of Green analytical chemistry and Experimental design in the determination of β‐lactams.
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The study assesses the impact of tariffs on Vietnam's trade in the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP). Research data was conducted between 2001 and 2018 on ...the official website of the Uncomtrade and the World Bank. This paper uses the gravity model to estimate the relationship between data series and considers the impact of factors on Vietnam's trade with CPTPP countries. The results have proven that tariff reductions have a positive effect on Vietnam's trade. Besides, the trade openness of Vietnam and CPTPP countries has positive impacts on Vietnam's trade. The study also shows that Real Effective Exchange Rate (REER) between Vietnam's and CPTPP countries' currencies has no strong effect on Vietnam's trade. Based on these findings, the article also suggests a number of policies to promote Vietnam's trade in future. In order to support businesses to better utilize opportunities and promote exports to CPTPP countries, the government of Vietnam should: (1) focus on reducing costs and time to participate in the market for production and business investors; (2) improve business investment environment to mobilize resources for production; and (3) continue to organize information campaigns to raise businesses' awareness of how to take advantage of CPTPP preferences.
The study assesses the impact of trade liberalization factors on changes in customs revenues in Vietnam. Research data was conducted between 2002 and 2017 on the official website of the Government's ...Web Portal and The World Bank. This paper uses the vector error correction model to estimate the short-term and long term relationship between data series. The results have proven that tariff reductions have a positive effect on short-term and long-term customs revenues in Vietnam. However, the implementation of other international commitments on trade liberalization has positive short-term and long-term negative impacts on customs revenues in Vietnam. The study's results also show that exchange rate has no effect on changes in customs revenues in the short term but it has a strong impact on increasing customs revenues in the long run. Based on these findings, the article also suggests a number of policies to ensure customs revenues in Vietnam in future. In order to ensure customs revenues, the government of Vietnam should: (1) having some policy to improve the efficiency of customs management in Vietnam; (2) Building appropriate VND exchange rate policy; (3) Establishing reasonable non - tariff barriers to prevent fraud and ovations cause losses in customs revenues.
A simple, specific, and economical LC-MS/MS method was investigated for the screening of 43 prescribed antihypertensive and related drugs in human urine. The urine samples were simply prepared by ...diluting and mixing with internal standard before directly introduced to the LC-MS/MS system, which is fast, straightforward, and cost-effective. Fractional factorial, Box-Behnken, and I-optimal design were applied to screen and optimize the mass spectrometric and chromatographic factors. The analysis was carried out on a triple quadrupole mass spectrometer system utilizing multiple reaction monitoring with positive and negative electrospray ionization method. Chromatographic separation was performed on a Thermo Scientific Accucore RP-MS column (50 × 3.0 mm ID., 2.6 ㎛) using two separate gradient elution programs established with the same mobile phases. Chromatographic separation was performed within 12 min. The optimal method was validated based on FDA guideline. The results indicated that the assay was specific, reproducible, and sensitive with the limit of detection from 0.1 to 50.0 ㎍/L. The method was linear for all analytes with coefficient of determination ranging from 0.9870 to 0.9981. The intra-assay precision was from 1.44 to 19.87% and the inter-assay precision was between 2.69 and 18.54% with the recovery rate ranges from 84.54 to 119.78% for all drugs measured. All analytes in urine samples were stable for 24 h at 25℃, and for 2 weeks at -60℃. The developed method improves on currently existing methods by including larger number of cardiovascular medications and better sensitivity of 12 analytes.
The study assesses the impact of tariffs on Vietnam’s trade in the Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP). Research data was conducted between 2001 and 2018 on ...the official website of the Uncomtrade and the World Bank. This paper uses the gravity model to estimate the relationship between data series and considers the impact of factors on Vietnam’s trade with CPTPP countries. The results have proven that tariff reductions have a positive effect on Vietnam’s trade. Besides, the trade openness of Vietnam and CPTPP countries has positive impacts on Vietnam’s trade. The study also shows that Real Effective Exchange Rate (REER) between Vietnam’s and CPTPP countries’ currencies has no strong effect on Vietnam’s trade. Based on these findings, the article also suggests a number of policies to promote Vietnam’s trade in future. In order to support businesses to better utilize opportunities and promote exports to CPTPP countries, the government of Vietnam should: (1) focus on reducing costs and time to participate in the market for production and business investors; (2) improve business investment environment to mobilize resources for production; and (3) continue to organize information campaigns to raise businesses’ awareness of how to take advantage of CPTPP preferences. KCI Citation Count: 0
The study assesses the impact of trade liberalization factors on changes in customs revenues in Vietnam. Research data was conducted between 2002 and 2017 on the official website of the Government’s ...Web Portal and The World Bank. This paper uses the vector error correction model to estimate the short-term and long term relationship between data series. The results have proven that tariff reductions have a positive effect on short-term and long-term customs revenues in Vietnam. However, the implementation of other international commitments on trade liberalization has positive short-term and long-term negative impacts on customs revenues in Vietnam. The study’s results also show that exchange rate has no effect on changes in customs revenues in the short term but it has a strong impact on increasing customs revenues in the long run. Based on these findings, the article also suggests a number of policies to ensure customs revenues in Vietnam in future. In order to ensure customs revenues, the government of Vietnam should: (1) having some policy to improve the efficiency of customs management in Vietnam; (2) Building appropriate VND exchange rate policy; (3) Establishing reasonable non – tariff barriers to prevent fraud and ovations cause losses in customs revenues.
There is still limited research studying multilevel factors influencing talent management (TM) practices in general and TM practices in the Vietnamese banking sector, particularly within the Covid ...pandemic context. Considering this gap, this article has three research objectives: developing a conceptual framework about multilevel contextual factors affecting TM within the studied sector, assessing the framework's suitability and applicability, and proposing a TM model and toolkit for bank leaders to improve TM strategic planning. The study employed the qualitative research method and semi-structured interviews with bank managers from different types of banks. The conceptual framework formulated in this study indicates a progression in examining factors influencing TM practices in developing countries. All the interviewees revealed their interest in studying the framework and their agreement with the arrangement of the relevant factors in the framework. As per the suggestion from the interviewees about the need to develop a TM model or guideline to execute TM practices, this paper also provides a suggested TM model with specific steps and an industry toolkit used for TM strategic planning and decision-making process based on the proposed framework. The model's steps, indicating explicit recommendations for bank managers to enhance TM effectiveness, are arranged in accordance with the process included in the proposed framework's TM flow. Besides, the reflection questions in the toolkit are helpful for managers to improve their critical thinking about their actual TM flow. The transformation from the framework to the toolkit can be viewed as how theoretical contribution can lead to managerial implications. This study contributes to the progress of contemporary TM literature during historical events in unstable business environments. It can be seen as a contribution to the applications of TM literature in practice.
This study focuses on the optimization of isoflavones extraction from soybeans cultivated in Quangnam province, Vietnam, using aqueous ethanol solvent extraction. The total isoflavone concentration ...was determined with six isoflavone standards including daidzin, glycitin, genistin, daidzein, glycitein, and genistein by Reversed Phase HPLC method. The effects of temperature, extraction time, and ratio of solvent to material on the extracted isoflavone content were investigated for use in the experimental planning method with full element 23 and optimization using the Box‐Wilson model. The results of the optimization showed that the optimal conditions of isoflavones extraction from soybeans using ethanol 80% was in temperature of 72.5°C, extraction time of 67.5 min, and solvent to dry soybean ratio of 26.5/1 (ml/g). The maximum amount of isoflavone content obtained from this extraction condition was 1,932.44 µg/g dry matter.
Practical applications
The extraction of isoflavones from soybeans involves the interaction between various factors including solvent concentration, temperature, extraction time, and ratio of solvent to material. There is a need to study the combined effect of these factors to optimize the extraction conditions within a minimum number of experiments. Hence, this work applies the full factorial design to study the effects of several factors on one or more responses to achieve the optimum extraction condition. This research work is important to obtain the most efficient extraction conditions for isoflavones production without consuming too much efforts on the experimentation. The results attain from this work can contribute to the extension of efficient isoflavones extraction in industrial scale.
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