Molecules

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8 pages, 238 KiB

Open AccessArticle

The Development of New Methodology for Determination of Vincristine (VCR) in Human Serum Using LC-MS/MS-Based Method for Medical Diagnostics

by Kamil Jurowski, Łukasz Paprotny, Marcin Zakrzewski, Dorota Wianowska, Joanna Kasprzyk-Pochopień, Małgorzata Herman, Katarzyna Madej, Wojciech Piekoszewski and Tomasz Kubrak

Molecules 2022, 27(22), 7945; https://doi.org/10.3390/molecules27227945 - 16 Nov 2022

Cited by 1 | Viewed by 1879

Abstract

In this article, we have presented the development and validation of a rapid and sensitive reversed-phase liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for the determination of vincristine (VCR) in patient serum samples. Chromatographic separation was achieved on a Kinetex^® (Singapore) [...] Read more.

In this article, we have presented the development and validation of a rapid and sensitive reversed-phase liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for the determination of vincristine (VCR) in patient serum samples. Chromatographic separation was achieved on a Kinetex^® (Singapore) column using a mobile phase consisting of 25 mM acetic acid and 0.3% formic acid (A) and methanol (B) in a gradient elution mode at a flow rate of 0.3 mL/min. The VCR and internal standard (vinblastine) were monitored using the multiple reaction monitoring mode under positive electrospray ionization. The lower limit of quantification (LLOQ) was 0.67 ng/mL, and the upper limit of quantification (ULOQ) was 250 ng/mL for VCR. The calculated values of LOD and LOQ for VCR were 0.075 and 0.228 ng/mL, respectively. The calibration curve was linear over the VCR concentration range of 1.0–250 ng/mL in serum. The intra- and inter-day precision and precision were within the generally accepted criteria for the bioanalytical method (<15%). The method was successfully applied to the analysis of serum samples in clinical practice. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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11 pages, 1663 KiB

Open AccessArticle

Rapid Capillary Electrophoresis Method for Simultaneous Determination of Abemaciclib, Ribociclib, and Palbociclib in Pharmaceutical Dosage Forms: A Green Approach

by Zvonimir Mlinarić, Lu Turković, Iva Begović, Biljana Nigović and Miranda Sertić

Molecules 2022, 27(21), 7603; https://doi.org/10.3390/molecules27217603 - 6 Nov 2022

Cited by 11 | Viewed by 2458

Abstract

Advances in the treatment of HR+/HER2- breast cancer phenotype have been made with the introduction of abemaciclib, ribociclib, and palbociclib, inhibitors of cyclin D dependent kinases 4 and 6 (CDK4/6). Here, a novel, fast, cheap, and green CE method for the simultaneous determination [...] Read more.

Advances in the treatment of HR+/HER2- breast cancer phenotype have been made with the introduction of abemaciclib, ribociclib, and palbociclib, inhibitors of cyclin D dependent kinases 4 and 6 (CDK4/6). Here, a novel, fast, cheap, and green CE method for the simultaneous determination of these three CDK4/6 inhibitors in less than 4 min is proposed for the first time. Separation was achieved by capillary zone electrophoresis in an acidic medium, in accordance with the structures of the analytes and their pKa values. The optimal pH of the running buffer was found to be 2.9. The optimal method conditions were 27.5 kV separation voltage, 30 °C, 5 s injection time under 50 mbar pressure, and 50 mM phosphate background buffer with benzimidazole as an internal standard. The developed method was validated with respect to robustness, selectivity, accuracy, precision, linearity, and limits of detection. The method was shown to be linear in the range of 10 to 100 µg mL⁻¹ with correlation coefficients higher than 0.9981. A greenness assessment of the proposed method was performed, and the method was shown to be green. The validated method was successfully applied to pharmaceutical dosage forms of all CDK4/6 inhibitors. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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15 pages, 1746 KiB

Open AccessArticle

Development and Optimization of a New UPLC-UV/MS Method through DoE and MLR for Detecting Substandard Drug Products to Treat Tuberculosis

by Javier Suárez-González, Amor R. Cáceres-Pérez, Alexis Oliva, Ana Santoveña-Estévez and José B. Fariña

Molecules 2022, 27(20), 7141; https://doi.org/10.3390/molecules27207141 - 21 Oct 2022

Viewed by 2863

Abstract

Drug products used for treating tuberculosis are one of the most widely reported medicines to be classified as falsified or substandard in low- and middle-income countries, representing a major hazard to health. The aim of this study was, firstly, to develop an ultra-performance [...] Read more.

Drug products used for treating tuberculosis are one of the most widely reported medicines to be classified as falsified or substandard in low- and middle-income countries, representing a major hazard to health. The aim of this study was, firstly, to develop an ultra-performance liquid chromatography (UPLC) method which is able to analyze fixed combination tablets with up to four active pharmaceutical ingredients, including isoniazid, pyrazinamide, rifampicin, and ethambutol. Secondly, we aimed to optimize it through the design of experiments and multi-linear regression based on a central composite design and to validate it according to the guidelines of the International Conference on Harmonization. The application of this tools enabled the identification of the influential factors (flow rate, formic acid, and temperature) and their effects on the studied responses (retention factor and percentage for each drug) as part of the quality by design approach. The method proved to be to be linear in the range from 5.0 to 15 µg/mL for isoniazid, pyrazinamide, and rifampicin, being precise (<1%) and accurate (97–101%). In addition, the method validated for ethambutol proved to be linear from 1.4 to 4.2 µg/mL, as well as precise (0.54%) and accurate (97.3%). The method was stability indicated for all the active pharmaceutical ingredients studied and was able to detect two substandard formulations sampled on the African market. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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9 pages, 965 KiB

Open AccessArticle

Simultaneous Quantification of Opioids in Blood and Urine by Gas Chromatography-Mass Spectrometer with Modified Dispersive Solid-Phase Extraction Technique

by Sara Yasien, Ejaz Ali, Mohsin Javed, Muhammad Muntazir Iqbal, Shahid Iqbal, Hamad Alrbyawi, Samar O. Aljazzar, Eslam B. Elkaeed, Ayed A. Dera, Rami Adel Pashameah, Eman Alzahrani and Abd-ElAziem Farouk

Molecules 2022, 27(19), 6761; https://doi.org/10.3390/molecules27196761 - 10 Oct 2022

Cited by 8 | Viewed by 2940

Abstract

Common methodologies such as liquid-liquid extraction and solid-phase extraction are applied for the extraction of opioids from biological specimens i.e., blood and urine. Techniques including LC-MS/LC-MSMS, GC-MS, etc. are used for qualitative or quantitative determination of opioids. The goal of the present work [...] Read more.

Common methodologies such as liquid-liquid extraction and solid-phase extraction are applied for the extraction of opioids from biological specimens i.e., blood and urine. Techniques including LC-MS/LC-MSMS, GC-MS, etc. are used for qualitative or quantitative determination of opioids. The goal of the present work is to design a green, economic, rugged, and simple extraction technique for famous opioids in human blood and urine and their simultaneous quantification by GC-MS equipped with an inert plus electron impact (EI) ionization source at SIM mode to produce reproducible and efficient results. Morphine, codeine, 6-acetylmorphine, nalbuphine, tramadol and dextromethorphan were selected as target opioids. Anhydrous Epsom salt was applied for dSPE of opioids from blood and urine into acetonitrile extraction solvent with the addition of sodium phosphate buffer (pH 6) and n-hexane was added to remove non-polar interfering species from samples. BSTFA was used as a derivatizing agent for GC-MS. Following method validation, the LOD/LLOQ and ULOQ were determined for morphine, codeine, nal-buphine, tramadol, and dextromethorphan at 10 ng/mL and 1500 ng/mL, respectively, while the LOD/LLOQ and ULOQ were determined for 6-acetylmorphine at 5 ng/mL and 150 ng/mL, respectively. This method was applied to real blood and urine samples of opioid abusers and the results were found to be reproducible with true quantification. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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16 pages, 6857 KiB

Open AccessArticle

Simultaneous Estimation of Escitalopram and Clonazepam in Tablet Dosage Forms Using HPLC-DAD Method and Optimization of Chromatographic Conditions by Box-Behnken Design

by Ahmed I. Foudah, Sultan Alshehri, Faiyaz Shakeel, Mohammed H. Alqarni, Tariq M. Aljarba and Prawez Alam

Molecules 2022, 27(13), 4209; https://doi.org/10.3390/molecules27134209 - 30 Jun 2022

Cited by 8 | Viewed by 2305

Abstract

The study aimed to develop a new reverse-phase high-performance liquid chromatography (RP-HPLC) method with diode array detection (DAD) detection for simultaneous estimation of escitalopram (EST) and clonazepam (CZP) in tablet dosage forms with a quality by design (QbD) approach. The chromatographic conditions were [...] Read more.

The study aimed to develop a new reverse-phase high-performance liquid chromatography (RP-HPLC) method with diode array detection (DAD) detection for simultaneous estimation of escitalopram (EST) and clonazepam (CZP) in tablet dosage forms with a quality by design (QbD) approach. The chromatographic conditions were optimized by Box-Behnken design (BBD) and developed method was validated for the linearity, system suitability, accuracy, precision, robustness, sensitivity, and solution stability according to International Council for Harmonization (ICH) guidelines. EST and CZP standard drugs peaks were separated at retention times of 2.668 and 5.046 min by C-18 column with dimension of 4.6 × 100 mm length and particle size packing 2.5 µm. The mobile phase was methanol: 0.1% orthophosphoric acid (OPA) (25:75, v/v), with a flow rate of 0.7 mL/min at temperature of 26 °C. The sample volume injected was 20 µL and peaks were detected at 239 nm. Using the standard calibration curve, the % assay of marketed tablet was founded 98.89 and 98.76 for EST and CZP, respectively. The proposed RP-HPLC method was able to detect EST and CZP in the presence of their degradation products, indicating the stability-indicating property of the developed RP-HPLC method. The validation parameter’s results in terms of linearity, system suitability, accuracy, precision, robustness, sensitivity, and solution stability were in an acceptable range as per the ICH guidelines. The newly developed RP-HPLC method with QbD application is simple, accurate, time-saving, and economic. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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14 pages, 2135 KiB

Open AccessArticle

Development and Validation of an HPLC-UV Method for the Quantification of 4′-Hydroxydiclofenac Using Salicylic Acid: Future Applications for Measurement of In Vitro Drug–Drug Interaction in Rat Liver Microsomes

by Hassan Salhab and James Barker

Molecules 2022, 27(11), 3587; https://doi.org/10.3390/molecules27113587 - 2 Jun 2022

Cited by 1 | Viewed by 3443

Abstract

Salicylic acid is a key compound in nonsteroidal anti-inflammatory drugs that has been recently used for preventing the risk of hospitalization and death among COVID-19 patients and in preventing colorectal cancer (CRC) by suppressing two key proteins. Understanding drug–drug interaction pathways prevent the [...] Read more.

Salicylic acid is a key compound in nonsteroidal anti-inflammatory drugs that has been recently used for preventing the risk of hospitalization and death among COVID-19 patients and in preventing colorectal cancer (CRC) by suppressing two key proteins. Understanding drug–drug interaction pathways prevent the occurrence of adverse drug reactions in clinical trials. Drug–drug interactions can result in the variation of the pharmacodynamics and pharmacokinetic of the drug. Inhibition of the Cytochrome P450 enzyme activity leads to the withdrawal of the drug from the market. The aim of this paper was to develop and validate an HPLC-UV method for the quantification of 4′-hydroxydiclofenac as a CYP2C9 metabolite using salicylic acid as an inhibitor in rat liver microsomes. A CYP2C9 assay was developed and validated on the reversed phase C₁₈ column (SUPELCO 25 cm × 4.6 mm × 5 µm) using a low-pressure gradient elution programming at T = 30 °C, a wavelength of 282 nm, and a flow rate of 1 mL/min. 4′-hydroxydiclofenac demonstrated a good linearity (R² > 0.99), good reproducibility, low detection, and quantitation limit, and the inter and intra-day precision met the ICH guidelines (<15%). 4′-hydroxydiclofenac was stable for three days and showed an acceptable accuracy and recovery (80–120%) within the ICH guidelines in a rat liver microsome sample. This method will be beneficial for future applications of the in vitro inhibitory effect of salicylic acid on the CYP2C9 enzyme activity in rat microsomes and the in vivo administration of salicylic acid in clinical trials. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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17 pages, 2814 KiB

Open AccessArticle

An Experimental Design Approach to Quantitative Expression for Quality Control of a Multicomponent Antidiabetic Formulation by the HILIC Method

by Mahesh Attimarad, Katharigatta Narayanaswamy Venugopala, Muhammad S. Chohan, Marysheela David, Efren II Plaza Molina, Nagaraja Sreeharsha, Anroop Balachandran Nair, Christophe Tratrat, Abdulrahman Ibrahim Altaysan and Abdulmalek Ahmed Balgoname

Molecules 2022, 27(10), 3135; https://doi.org/10.3390/molecules27103135 - 13 May 2022

Cited by 13 | Viewed by 2402

Abstract

A rapid and reproducible hydrophilic liquid chromatography (HILIC) process was established for concomitant determination of remogliflozin etabonate (RE), vildagliptin (VD), and metformin (MF) in a formulation. A face-centered central composite experimental design was employed to optimize and predict the chromatographic condition by statistically [...] Read more.

A rapid and reproducible hydrophilic liquid chromatography (HILIC) process was established for concomitant determination of remogliflozin etabonate (RE), vildagliptin (VD), and metformin (MF) in a formulation. A face-centered central composite experimental design was employed to optimize and predict the chromatographic condition by statistically studying the surface response model and design space with desirability close to one. A HILIC column with a simple mobile phase of acetonitrile (65% v/v) and 20 mM phosphate buffer (35% v/v, pH 6, controlled with orthophosphoric acid) was used to separate RE, VD, and MF. RE, VD, and MF were separated in 3.6 min using an isocratic mode mobile phase flow at a flow rate of 1.4 mL at room temperature, and the analytes were examined by recording the absorption at 210 nm. The developed HILIC method was thoroughly validated for all parameters recommended by ICH, and linearity was observed in the ranges 20–150 µg/mL, 10–75 µg/mL, and 50–750 µg/mL for RE, VD, and MF, respectively, along with excellent regression coefficients (r² > 0.999). The calculated percentage relative deviation and relative error ascertained the precision and accuracy of the method. The selectivity and accuracy were further confirmed by the high percentage recovery of added standard drugs to the formulation using the standard addition technique. The robustness of the HILIC processes was confirmed by developing a half-normal probability plot and Pareto chart, as the slight variation of a single factor had no significant influence on the assay outcomes. Utilization of the optimized HILIC procedure for concurrent quantification of RE, VD, and MF in solid dosage forms showed accurate and reproducible results. Hence, the fast HILIC method can be regularly employed for the quality assurance of pharmaceutical preparations comprising RE, VD, and MF. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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14 pages, 2739 KiB

Open AccessArticle

Application of Transmission Raman Spectroscopy in Combination with Partial Least-Squares (PLS) for the Fast Quantification of Paracetamol

by Xuejia Zhao, Ning Wang, Minghui Zhu, Xiaodan Qiu, Shengnan Sun, Yitong Liu, Ting Zhao, Jing Yao and Guangzhi Shan

Molecules 2022, 27(5), 1707; https://doi.org/10.3390/molecules27051707 - 5 Mar 2022

Cited by 8 | Viewed by 2775

Abstract

In recent years, transmission Raman spectroscopy (TRS) has emerged as a potent new tool for rapid, nondestructive quantitation in pharmaceutical manufacturing. In order to expand the applicability of TRS and enhance its use in product quality monitoring during drug production, we aimed, in [...] Read more.

In recent years, transmission Raman spectroscopy (TRS) has emerged as a potent new tool for rapid, nondestructive quantitation in pharmaceutical manufacturing. In order to expand the applicability of TRS and enhance its use in product quality monitoring during drug production, we aimed, in the present study, to apply partial least-squares (PLS) approaches to build a model consisting of 150 handmade tablets and covering 15 levels through the use of a multifactor orthogonal design of experiment (DOE), which was used to predict concentrations of validation tablets made by hand. The difference between results according to HPLC and TRS were negligible. The model was used to predict the active pharmaceutical ingredient (API) content in four random commercial paracetamol tablets, and corrected with the spectra of the commercial tablets to obtain four corresponding models. The results show that the content relative error in the model’s predictions after correction with commercially available tablets was significantly lower than that before correction. The corrected model was used to make predictions for 20 tablets from the brand Panadol. Compared with the HPLC results, the prediction relative error was basically less than 4.00%, and the relative standard deviation (RSD) of the content was 0.86%. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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13 pages, 1731 KiB

Open AccessArticle

Development of Improved High-Performance Liquid Chromatography Method for the Determination of Residual Caprylic Acid in Formulations of Human Immunoglobulins

by Adela Štimac, Tihana Kurtović, Nediljko Pavlović and Beata Halassy

Molecules 2022, 27(5), 1665; https://doi.org/10.3390/molecules27051665 - 3 Mar 2022

Cited by 2 | Viewed by 2435

Abstract

Quality control of human immunoglobulin formulations produced by caprylic acid precipitation necessitates a simple, rapid, and accurate method for determination of residual caprylic acid. A high-performance liquid chromatography method for that purpose was developed and validated. The method involves depletion of immunoglobulins, the [...] Read more.

Quality control of human immunoglobulin formulations produced by caprylic acid precipitation necessitates a simple, rapid, and accurate method for determination of residual caprylic acid. A high-performance liquid chromatography method for that purpose was developed and validated. The method involves depletion of immunoglobulins, the major interfering components that produce high background noise, by precipitation with acetonitrile (1:1, v/v). Chromatographic analysis of caprylic acid, preserved in supernatant with no loss, was performed using a reverse-phase C18 column (2.1 × 150 mm, 3 μm) as a stationary phase and water with 0.05% TFA–acetonitrile (50:50, v/v) as a mobile phase at a flow rate of 0.2 mL/min and run time of 10 min. The developed method was successfully validated according to the ICH guidelines. The validation parameters confirmed that method was linear, accurate, precise, specific, and able to provide excellent separation of peaks corresponding to caprylic acid and the fraction of remaining immunoglobulins. Furthermore, a 2⁴⁻¹ fractional factorial design was applied in order to test the robustness of developed method. As such, the method is highly suitable for the quantification of residual caprylic acid in formulations of human immunoglobulins for therapeutic use, as demonstrated on samples produced by fractionation of convalescent anti-SARS-CoV-2 human plasma at a laboratory scale. The obtained results confirmed that the method is convenient for routine quality control. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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10 pages, 2835 KiB

Open AccessArticle

LC–MS³ Strategy for Quantification of Carbamazepine in Human Plasma and Its Application in Therapeutic Drug Monitoring

by Dongxiao Ma, Zhengchao Ji, Haiwei Cao, Jing Huang, Lei Zeng and Lei Yin

Molecules 2022, 27(4), 1224; https://doi.org/10.3390/molecules27041224 - 11 Feb 2022

Cited by 11 | Viewed by 2549

Abstract

This study developed a detection method based on the strategy of HPLC/MS³ and verified its suitability by quantifying carbamazepine in human plasma. The high-performance liquid chromatography–tandem mass spectrometry (HPLC/MS³) system was performed using a Shimadzu UFLC XR liquid chromatography and [...] Read more.

This study developed a detection method based on the strategy of HPLC/MS³ and verified its suitability by quantifying carbamazepine in human plasma. The high-performance liquid chromatography–tandem mass spectrometry (HPLC/MS³) system was performed using a Shimadzu UFLC XR liquid chromatography and a SCIEX QTRAP^® 5500 linear ion trap triple quadrupole mass spectrometer. The specific operation was as follows: the sample protein was firstly precipitated using methanol, then carbamazepine and carbamazepine-D₂N¹⁵ were separated on an ACQUITY UPLC HSS T3 column using the gradient elution with solvent A (0.1% formic acid) and solvent B (0.1% formic acid in acetonitrile) at a flow rate of 0.25 mL/min. Each sample was run for 7 min. This method was validated for various parameters including accuracy, precision, selectivity, linearity, LLOQ, etc. Only 5 μL of sample plasma could obtain the result of LLOD 0.5 µg/mL. The intra-day and inter-day precision was <8.23%, and accuracy was between −1.74% and 2.92%. This method was successfully used for monitoring the blood concentration of epilepsy patients after carbamazepine treatment. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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11 pages, 1385 KiB

Open AccessArticle

Development and Validation of Stability-Indicating Assay Method for a Novel Oxazolidinone (PH-192) with Anticonvulsant Activity by Using UHPLC-QToF-MS

by Naser F. Al-Tannak, Oludotun A. Phillips, Husein J. Kamal and Ahmed Hemdan

Molecules 2022, 27(3), 1090; https://doi.org/10.3390/molecules27031090 - 6 Feb 2022

Viewed by 1963

Abstract

The treatment of seizure disorders with currently available pharmacotherapeutic agents is not optimal due to the failure of some patients to respond, coupled with occurrences of side effects. There is therefore a need for research into the development of new chemical entities as [...] Read more.

The treatment of seizure disorders with currently available pharmacotherapeutic agents is not optimal due to the failure of some patients to respond, coupled with occurrences of side effects. There is therefore a need for research into the development of new chemical entities as potential anticonvulsant agents, which are different structurally from the existing class of drugs. We recently identified a novel triazolyl-oxazolidinone derivative, PH-192, as a potential anticonvulsant agent. PH-192 demonstrated protection comparable to phenytoin against both chemically- and electrically-induced seizures in rodents with little or no central nervous system side effects. However, PH-192 did not exhibit protection beyond 30 min; therefore, we decide to investigate a stability-indicating assay of PH-192 in plasma and other solutions. A reliable and validated analytical method was developed to investigate the stability of PH-192 for 90 min in human plasma, acidic, basic, and oxidative conditions, using a Waters Acquity ultra high-performance liquid chromatography (UHPLC) system with a quaternary Solvent Manager (H-Class). A simple extraction method indicated that PH-192 was stable in human plasma after 90 min at 37 °C, with more than 90% successfully recovered. Moreover, stress stability studies were performed, and degradants were identified using LC-QToF-MS under acidic, basic, and oxidative simulated conditions. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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12 pages, 1035 KiB

Open AccessArticle

Quantitative Analysis of Abamectin, Albendazole, Levamisole HCl and Closantel in Q-DRENCH Oral Suspension Using a Stability-Indicating HPLC-DAD Method

by Hazim M. Ali, Mohammed Gamal, Mohammed M. Ghoneim and Lobna Mohammed Abd Elhalim

Molecules 2022, 27(3), 764; https://doi.org/10.3390/molecules27030764 - 24 Jan 2022

Cited by 13 | Viewed by 3713

Abstract

Combination therapy of many anthelmintic drugs has been used to achieve fast animal curing. Q-DRENCH is an oral suspension, containing four different active drugs against GIT worms in sheep, commonly used in Australia and New Zeeland. The anti-parasitic drugs are Albendazole (ALB), Levamisole [...] Read more.

Combination therapy of many anthelmintic drugs has been used to achieve fast animal curing. Q-DRENCH is an oral suspension, containing four different active drugs against GIT worms in sheep, commonly used in Australia and New Zeeland. The anti-parasitic drugs are Albendazole (ALB), Levamisole HCl (LEV), Abamectin (ABA), and Closantel (CLO). The main purpose of this study is to present a new simultaneous stability-indicting HPLC-DAD method for the analysis of the four drugs. The recommended liquid system was 1 mL of Triethylamine/L water, adjusting the pH to 3.5 by glacial acetic acid: acetonitrile solvent (20:80, v/v). Isocratic elusion achieved the desired results of separation at a 2 mL/min flow rate using Zorbax C-18 as a stationary phase. Detection was performed at 210 nm. The linearity ranges were 15.15 to 93.75 μg/mL for ALB, 25 to 150 μg/mL for LEV, 30 to 150 μg/mL for ABA, and 11.7 to 140.63 μg/mL for CLO. Moreover, the final greenness score was 0.62 using the AGREE tool, which reflects the eco-friendly nature. Moreover, the four drugs were determined successfully in the presence of their stressful degradation products. This work presents the first chromatographic method for simultaneous analysis for Q-DRENCH oral suspension drugs in the presence of their stressful degradation products. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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16 pages, 781 KiB

Open AccessArticle

Use of TLC-Densitometric Method for Determination of Valproic Acid in Capsules

by Wioletta Parys and Alina Pyka-Pająk

Molecules 2022, 27(3), 752; https://doi.org/10.3390/molecules27030752 - 24 Jan 2022

Cited by 1 | Viewed by 3067

Abstract

Determination of valproic acid in the drug was carried out on the aluminum silica gel 60F₂₅₄ plates and using acetone–water–chloroform–ethanol–ammonia at a volume ratio of 30:1:8:5:11 as the mobile phase, respectively. Two methods of detection of valproic acid were used. The first [...] Read more.

Determination of valproic acid in the drug was carried out on the aluminum silica gel 60F₂₅₄ plates and using acetone–water–chloroform–ethanol–ammonia at a volume ratio of 30:1:8:5:11 as the mobile phase, respectively. Two methods of detection of valproic acid were used. The first was a 2% aqueous CuSO₄×5H₂O solution, and the second was a 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system. The applied TLC-densitometric method is selective, linear, accurate, precise, and robust, regardless of the visualizing reagent used for the determination of valproic acid in Convulex capsules. It has low limits of detection (LOD) and limits of quantification (LOQ), which are equal to 5.8 μg/spot and 17.4 μg/spot using a 2% aqueous CuSO₄×5H₂O solution as visualizing agent and also 0.32 μg/spot and 0.97 μg/spot using a 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system as visualizing reagent, respectively. The described analytical method can additionally be used to study the identity of valproic acid in a pharmaceutical preparation. The linearity range was found to be 20.00–80.00 μg/spot and 1.00–2.00 μg/spot for valproic acid detected on chromatographic plates using a 2% aqueous CuSO₄×5H₂O solution and the 2′,7′-dichlorofluorescein-aluminum chloride-iron (III) chloride system, respectively. A coefficient of variation that was less than 3% confirms the satisfactory accuracy and precision of the proposed method. The results of the assay of valproic acid equal 96.2% and 97.0% in relation to the label claim that valproic acid fulfill pharmacopoeial requirements. The developed TLC-densitometric method can be suitable for the routine analysis of valproic acid in pharmaceutical formulations. The proposed TLC-densitometry may be an alternative method to the modern high-performance liquid chromatography and square wave voltammetry in the control of above-mentioned substances, and it can be applied when other analytical techniques is not affordable in the laboratory. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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13 pages, 3092 KiB

Open AccessArticle

A Solvent-Mediated Excited-State Intermolecular Proton Transfer Fluorescent Probe for Fe³⁺ Sensing and Cell Imaging

by You Qian, Fuchun Gong, Jiguang Li, Pan Ma, Hanming Zhu, Lingzhi He and Jiaoyun Xia

Molecules 2022, 27(2), 516; https://doi.org/10.3390/molecules27020516 - 14 Jan 2022

Cited by 7 | Viewed by 2174

Abstract

Constructing excited-state intermolecular proton transfer (ESIPT-e) fluorophores represents significant challenges due to the harsh requirement of bearing a proton donor-acceptor (D-A) system and their matching proton donating-accepting ability in the same molecule. Herein, we synthesized a new-type ESIPT-e fluorophor (2-APC) using the “four-component [...] Read more.

Constructing excited-state intermolecular proton transfer (ESIPT-e) fluorophores represents significant challenges due to the harsh requirement of bearing a proton donor-acceptor (D-A) system and their matching proton donating-accepting ability in the same molecule. Herein, we synthesized a new-type ESIPT-e fluorophor (2-APC) using the “four-component one-pot” reaction. By the installing of a cyano-group on pyridine scaffold, the proton donating ability of -NH₂ was greatly enhanced, enabling 2-APC to undergo ESIPT-e process. Surprisingly, 2-APC exhibited dual-emissions in protic solvents ethanol and normal fluorescence in aprotic solvents, which is vastly different from that of conventional ESIPT-a dyes. The ESIPT emission can be obviously suppressed by Fe³⁺ due to the coordination reaction of Fe³⁺ with the A-D system in 2-APC. From this basis, a highly sensitive and selective method was established using 2-APC as a fluorescent probe, which offers the sensitive detection of Fe³⁺ ranging from 0 to 13 μM with the detection limit of 7.5 nM. The recovery study of spiked Fe³⁺ measured by the probe showed satisfactory results (97.2103.4%) with the reasonable RSD ranging from 3.1 to 3.8%. Moreover, 2-APC can also exhibit aggregation-induced effect in poor solvent or solid-state, eliciting strong red fluorescence. 2-APC was also applied to cell-imaging, exhibiting good cell-permeability, biocompatibility and color rendering. This multi-mode emission of 2-APC is significant departure from that of conventional extended p-conjugated systems and ESIPT dyes based on a flat and rigid molecular design. The “one-pot synthesis” strategy for the construction of ESIPT molecules pioneered a new route to achieve tricolor-emissive fluorophores. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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