Tarek Saied Belal

The current work offers a rigorous way for the microwave‐assisted synthesis of N and S doped carbon quantum dots (QDs). The latter are deemed highly sensitive and selective fluorescence sensors that were widely investigated in pharmaceutical analysis. Quenching of luminescence of the prepared QDs in lab fabricated sensor at λ emission = 418 nm after excitation at 370 nm was implemented to quantify the anti‐HCV drug Ledipasvir (LDP). LDP showed a linear response within the dynamic range of 1–40 μM. The calculated LDP detection and quantification limits were 313.06 and 948.67 nM, respectively. Besides the analysis of LDP in bulk and commercial dosage form, the scope of application extended to evaluate the effect of the nutraceutical silymarin (liver support) on the excretion of LDP in rat feces. The compliance with the green and white analytical chemistry fundamentals is comprehensively investigated and compared with selected versatile reported procedures. Numerous prevalent metrics, namely, analytical eco‐scale, AGREE, RGB12, RGB fast, BAGI, and complex GAPI, were employed. Our developed fluorometric procedure demonstrated great sensitivity, selectivity, and functionality that outperformed other sophisticated platforms. Thus, the utility of the depicted procedure in pharmaceutical analysis and studying pharmacokinetics aspects is profoundly proven.

Herein, a novel spectrofluorometric sensor is proposed for the sensitive analysis of two nonfluorescent mucolytic drugs, namely, acetylcysteine (ACT) and carbocisteine (CST), utilizing the newly synthesized 2‐[(2‐hydroxyethyl)‐(2,8,10‐trimethylpyrido[2′,3′:3,4]pyrazolo[1,5‐a]pyrimidin‐4‐yl)‐amino]‐ethanol as a fluorescence probe (Flu. Probe). This fluorophore exhibits fluorescence emission at 445 nm upon excitation at 275 nm. The addition of increasing concentrations of each drug resulted in quantitative quenching of the Flu. Probe's fluorescence. Investigation into the quenching mechanism revealed that static quenching is the primary contributing factor for both drugs. The spectroscopic characteristics of the Flu. Probe in the presence of ACT and CST were analyzed using DFT and TD‐B3LYP calculations, revealing typical π → π* transitions, attributed to stable hydrogen‐bonding structures. The developed method was validated in accordance with ICH Q2(R1) guidelines. Linear responses for ACT and CST were observed over concentration ranges 0.125–2.25 and 0.125–3.0 μg/mL, respectively, with detection limits (LODs) 31.97 and 37.14 ng/mL. The proposed spectrofluorometric platform was successfully applied to the analysis of ACT and CST in pharmaceutical dosage forms and spiked urine, within concentration ranges 0.25–2.25 and 0.25–2.50 μg/mL and LODs = 80.21 and 71.48 ng/mL, respectively. Finally, the greenness of the proposed protocol was evaluated employing GAPI, hexagon, and AGREE approaches.

Plaque psoriasis is a common, long-lasting illness that affects the immune system and causes significant negative impacts on a patient’s physical health, well-being, and ability to work effectively. Deucravacitinib (DEU) is the first oral medication used in the treatment of plaque psoriasis, a chronic skin condition that causes red, scaly patches on the skin. DEU is a type of medication called an oral Janus kinase (JAK) inhibitor, which works by blocking specific enzymes that play a role in the inflammation and immune response associated with psoriasis. Therefore, a quick, easy, novel, reliable, sensitive, and straightforward liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach was used to analyze DEU in plasma samples. The LC-MS/MS method for the determination of DEU in human plasma was based on using trimethoprim as an internal standard (IS). The separation of DEU and IS was carried out via liquid–liquid extraction (LLE). The extract was then subjected to the chromatographic system separation using the ACE-C18 column (4.6 × 100 mm, 5 µm). The mobile phase employed consisted of methanol and a solution of 2 mM ammonium formate (80:20 v/v, respectively). The flow rate used was set at 0.9 mL min⁻¹. The creative strategy was performed by running an ABSCIEX API 4000 mass spectrometer with an electron spray ionization source in multiple reaction monitoring (MRM) mode. The ion transitions m/z 426.3 → 358.2 were used for DEU quantitation, while the ion transitions m/z 291.1 → 261.1 were used for trimethoprim quantitation. The accuracy, precision, linearity, recovery, and selectivity of DEU were deemed acceptable when validated for a concentration range between 0.500 and 601.050 ng/mL, utilizing a weighting factor of 1/x².

Plaque psoriasis is a common, long-lasting illness that affects the immune system and causes significant negative impacts on a patient's physical health, well-being, and ability to work effectively. Deucravacitinib (DEU) is the first oral medication used in the treatment of plaque psoriasis, a chronic skin condition that causes red, scaly patches on the skin. DEU is a type of medication called an oral Janus kinase (JAK) inhibitor, which works by blocking specific enzymes that play a role in the inflammation and immune response associated with psoriasis. Therefore, a quick, easy, novel, reliable, sensitive, and straightforward Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) approach was used to analyse DEU in plasma samples. The LC-MS/MS method for the determination of DEU in human plasma was based on using trimethoprim as an internal standard (IS). The separation of DEU and IS was carried out via liquid-liquid extraction (LLE). The isolated substances were then subjected to the chromatographic system using the ACE-C18 column (4.6x100 mm, 5 µm). The mobile phase employed consisted of methanol and a solution of 2 mM ammonium formate (80:20 v/v, respectively). The flow rate used was set at 0.9 mL min-1. The creative strategy was performed by running an ABSCIEX API 4000 mass spectrometer with an electron spray ionization source in Multiple Reaction Monitoring (MRM) modes. The ion transitions m/z 426.3  358.2 was used for DEU quantitation, while the ion transitions m/z 291.1  261.1 was used for trimethoprim quantitation. The accuracy, precision, linearity, recovery, and selectivity of DEU were deemed acceptable when validated for a concentration range between 0.500 to 601.050 ng/mL, utilizing a weighting factor of 1/x2.

Background: Careful review of the scientific databases revealed that no stability-indicating analytical method is available for the binary mixture of allopurinol (ALO) and thioctic acid (THA). Objective: A comprehensive stability-indicating HPLC-DAD procedure has been executed for concurrent analysis of ALO and THA. Method: Successful chromatographic separation of the cited drugs was reached using a Durashell C18 column (4.6 × 250 mm, 5 µm particle size). The mobile phase consisted of a mixture of acidified water (pH 4.0) using phosphoric acid and acetonitrile pumped in gradient elution mode. For quantification of ALO and THA, their respective peak areas were recorded at 249 and 210 nm. A systematic validation of analytical performance was investigated in terms of system suitability, linearity, ranges, precision, accuracy, specificity, robustness, detection, and quantification limits. Results: ALO and THA peaks emerged at retention times 4.26 and 8.15 min, respectively. Linear ranges for ALO and THA were 5–100 and 10–400 µg/mL, respectively, with correlation coefficient values exceeding 0.9999. Both drugs were exposed to conditions of neutral, acidic, and alkaline hydrolysis, oxidation, and thermal decomposition. Stability-indicating features have been demonstrated by resolution of the drugs from their forced degradation peaks. For verification of peak identity and purity, the diode-array detector (DAD) was used. In addition, degradation pathways for the cited drugs were postulated. Furthermore, separation of both analytes from about 13 medicinal compounds of different therapeutic classes disclosed optimum specificity of the proposed method. Conclusions: Advantageous application of the validated HPLC method for the concurrent analysis of ALO/THA in their tablet dosage form was accomplished. Highlights: So far, the described HPLC-DAD method is considered the first detailed stability-indicating analytical study for this pharmaceutical mixture.

The present work deals with the optimization, validation and application of a versatile HPLC–DAD method for concurrent estimation of nine antimicrobials and proton pump inhibitors, namely amoxicillin (AMX), doxycycline (DOX), furazolidone (FRZ), lansoprazole (LNS), levofloxacin (LVF), metronidazole (MTZ), omeprazole (OMZ), pantoprazole (PNZ) and tinidazole (TNZ). The selected nine drugs are frequently included in various treatment regimens of Helicobacter pylori infection. Successful separation was accomplished using the analytical column Agilent Zorbax Eclipse plus-C18 (250 × 4.6 mm, 5 µm particle size) and a mobile phase prepared from phosphate buffer pH 5 and acetonitrile pumped at a flow rate 1 mL/min using a gradient elution program. The gradient elution started with buffer/acetonitrile ratio 90:10, then it was altered in 15 min to reach 40:60 by volume. Quantification of the analytes was based on measuring peak areas of AMX at 230 nm, LVF, LNS and PNZ at 290 nm, OMZ at 300 nm, MTZ and TNZ at 320 nm, and DOX and FRZ at 360 nm. The separated compounds eluted at retention times 5.68, 6.43, 7.82, 8.84, 9.42, 10.75, 12.82, 13.74 and 14.90 min for AMX, MTZ, LVF, TNZ, DOX, FRZ, OMZ, PNZ and LNS respectively. Validation of the proposed HPLC procedure was carefully studied according to the ICH items: ranges, precision, accuracy, linearity, robustness and limits of detection and quantitation. The linear dynamic ranges were 5–100, 5–50, 2–40, 10–100, 10–100, 5–50, 2.5–30, 3–30 and 2–30 µg/mL for AMX, MTZ, LVF, TNZ, DOX, FRZ, OMZ, PNZ and LNS, respectively with correlation coefficients > 0.9993. Application fields of the validated method included analysis of laboratory-prepared binary dosage forms along with analysis of several ternary mixtures in spiked simulated intestinal fluid.