Therapeutic drug monitoring of six contraindicated/co-administered drugs by simple and green RP-HPLC-PDA; application to spiked human plasma

Therapeutic drug monitoring is an important clinical testing of the drugs to monitor their concentrations in plasma in order to guarantee their optimal impact, and to avoid any side effects resulting from drug-drug interactions. A green reversed-phase high-performance liquid chromatographic method using a photodiode array detector (RP-HPLC-PDA) was developed for the simultaneous determination of three carbapenem antibiotics (Imipenem, ertapenem, and meropenem) with the co-formulated drug (cilastatin) and contraindicated drugs (probenecid and warfarin) in spiked human plasma. The separation was achieved at 25 °C using a gradient elution of a mixture of mobile phase A: methanol and mobile phase B: phosphate buffer (pH 3.0). The photodiode array detector was adjusted at 220 nm. Bioanalytical method validation was carried out as per the FDA guidelines, and the method showed good linearity ranges for the six drugs that included their Cmax levels along with low limits of quantification. Based on the results, the method was found to be accurate and precise; with high % recovery and good % RSD, respectively. The method was successfully applied to spiked human plasma, signifying a good potential to be implemented in future TDM studies of these drugs when co-administered together.

Potentiometric detection of apomorphine in human plasma using a 3D printed sensor

Apomorphine is a dopamine agonist that is used for the management of Parkinson's disease and has been proven to effectively decrease the off-time duration, where the symptoms recur, in Parkinson's disease patients. This paper describes the design and fabrication of the first potentiometric sensor for the determination of apomorphine in bulk and human plasma samples. The fabrication protocol involves stereolithographic 3D printing, which is a unique tool for the rapid fabrication of low-cost sensors. The solid-contact apomorphine ion-selective electrode combines a carbon-mesh/thermoplastic composite as the ion-to-electron transducer and a 3D printed ion-selective membrane, doped with the ionophore calix[6]arene. The sensor selectively measures apomorphine in the presence of other biologically present cations - sodium, potassium, magnesium, and calcium - as well as the commonly prescribed Parkinson's pharmaceutical, levodopa (L-Dopa). The sensor demonstrated a linear, Nernstian response, with a slope of 58.8 mV/decade over the range of 5.0 mM-9.8 μM, which covers the biologically (and pharmaceutically) relevant ranges, with a limit of detection of 2.51 μM. Moreover, the apomorphine sensor exhibited good stability (minimal drift of just 188 μV/hour over 10 h) and a shelf-life of almost 4 weeks. Experiments performed in the presence of albumin, the main plasma protein to which apomorphine binds, demonstrate that the sensor responds selectively to free-apomorphine (i.e., not bound or complexed forms). The utility of the sensor was confirmed through the successful determination of apomorphine in spiked human plasma samples.

A probe of new molecularly imprinted solid-phase extraction coupled with HPLC-DAD and atomic absorption spectrophotometry for quantification of tetracycline HCl, metronidazole and bismuth subcitrate in combination with their official impurities: Application in dosage form and human plasma

The integration of molecular imprinting technique with chromatographic one has a great impact on the assay's selectivity and sensitivity. Herein, a molecularly imprinted solid-phase extraction associated with high performance liquid chromatography (MISPE-HPLC) was employed for simultaneous determination of the co-formulated drugs; tetracycline hydrochloride (TET) and metronidazole (MET), in plasma and in their anti-H-pylori drug for the first time. Two sorts of molecularly imprinted polymers (MIPs) were fabricated using TET and MET as the template molecules, while ethylene glycol dimethacrylate and methacrylic acid were used as a cross-linker and a monomer, respectively. The synthesized MIPs were identified using different techniques. The adsorption-desorption capability of each template was investigated towards its corresponding MIP. The extraction conditions of MISPE was optimized with respect to TET/MIP and MET/MIP sorbent. Bismuth subcitrate (BSC), the third co-formulated drug was analyzed in spiked human plasma using an atomic absorption spectrometric (AAS) method. The performance of the developed methods was assured as per ICH guidelines for analyzing the studied drugs in their pharmaceutical dosage form along with two of their official impurities. In addition, bioanalytical method validation was conducted where linearity was achieved at 2.0-40.0 μg mL-1, 2.0-40.0 μg mL-1 and 5.0-80.0 μg mL-1 for TET, MET and BSC, respectively.

Stability-indicating UPLC assay coupled with mass spectrometry for the analysis of vilanterol degradation products in human urine

Vilanterol is a once-daily dose inhaler prescribed for asthma and chronic obstructive pulmonary disease. This study involved an investigation of vilanterol stability under acidic, basic, oxidative, thermal, and photolytic stress conditions. UPLC method was developed and validated for the analysis of vilanterol with its degradants. The drug was stable under photolytic and thermal stress conditions and degraded under acidic, basic, and oxidative stress conditions. Degradation kinetics was performed for acidic, basic and oxidative stress conditions. Kinetics parameters, K, half-life time (t1/2) and shelf-life time (t90) were assessed, and the degradation followed first order reaction. The method was linear from 0.10 to 100.00 µg mL-1 with accuracy, inter-day and intra-day precision from 99.45 to 100.02%, 0.391-0.694 and 0.041-0.345, respectively. Mass spectrometry was employed to elucidate the structure of the degradants, and the results revealed that certain degradation products were comparable to vilanterol metabolites. The World Anti-Doping Agency has prohibited the presence of vilanterol and its metabolites in athletes' urine except for exercise bronchoconstriction with limited dose. So, quantification of vilanterol in the presence of its degradants was performed in human urine. The results revealed that the method was linear in range of 1.00 to 100.00 µg mL-1. Samples collection and experimental protocol was performed according to the guidelines of the Research Ethics Committee of the Faculty of Pharmacy, the British University in Egypt with approval No. CH-2305.

Stability and Biosimilarity Assessment of Bevacizumab Monoclonal Antibody; Orthogonal Testing Protocol Coupled With Peptide Mapping-Principal Component Analysis

BACKGROUND

Biologics are essential in cancer treatment because they stimulate the body's natural response to fight cancer, but they are expensive. Biosimilars are more affordable compared to patent biologicals, but it must be verified that they are as effective as their innovators. Characterization of biosimilars and assessment of interchangeability requires many data points for verification.

OBJECTIVE

The proposed study provides a quality assessment of two new bevacizumab (BVZ) biosimilars, produced by Amgen and Biocad, Inc., through the development and greenness assessment of an orthogonal testing protocol and purity indicating assay, including size-exclusion (SE-HPLC), reversed-phase (RP-HPLC), and cation exchange chromatography (CEX-HPLC) in addition to dynamic light scattering (DLS) and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE).

METHODS

SE-HPLC method was performed and validated to screen the BVZ monomer and its aggregates and/or fragments. Peak purity and system suitability parameters were calculated. Results indicate that the orthogonal protocol is a useful tool for assessing monoclonal antibody stability. It is a key criterion for biosimilarity assessment. DLS and SDS-PAGE results were compared to each other to reveal close retention times and banding patterns between BVZ innovator and its biosimilars. These results showed that Avastin® and the investigated biosimilars have the same profile in terms of peak area of related compounds within the acceptance limit and apparent molecular weight, and the SDS-PAGE technique was found to be the most eco-friendly technique among others.

CONCLUSIONS

The results obtained highlighted the importance of assessing similarities and differences in ensuring the biosimilarity and interchangeability of the studied products.

HIGHLIGHTS

BVZ is one of the essential monoclonal antibodies in the treatment of colorectal cancer (CRC). BVZ biosimilars were evaluated by developing an orthogonal testing protocol and a purity-indicating assay. The size-exclusion (SE)-HPLC method was applied and validated to monitor the BVZ monomer and its aggregates. The results demonstrated the importance of assessing the stability and biosimilarity of BVZ.

Expeditive Chromatographic Methods for Quantification of Solifenacin Succinate along with its Official Impurity as the Possible Acid Degradation Product

Two selective stability-indicating procedures were adopted for the quantification of Solifenacin succinate (SOL) along with its acid degradant, in its powder form or in pharmaceutical tablet. Under stress conditions, the acid degradation pathway of SOL was investigated, its official impurity (SOL imp-A) was obtained as the possible acid degradation product, also. A densitometric technique based on the separation of SOL from SOL imp-A employing HPTLC plates prelaminated with silica gel 60 F254 as the stationary phase and a developing solution containing methanol:chloroform:ammonia (8:1:1, v/v/v) and UV scanning of the developed bands at 220 nm. Linear regression analysis data for the calibration plot of SOL showed perfect linear relationships throughout the range of concentration 10-60 μg/band. A reversed phase C18 analytical column (4.6 × 250 mm, 5 μm) was also used to separate the mixture at a flow rate of 1 mL/min, using acetonitrile:0.05 M phosphate buffer (70:30, v/v) as the mobile phase and phosphoric acid to set pH = 3.5. Quantification was obtained at 220 nm using peak area and linear calibration curve across a concentration range of 10-70 μg/mL. The recommended procedures were applied to the existing dosage form, and they generated satisfactory results.

Development and Validation of Green Chromatographic Approaches for Simultaneous Determination of Aspirin, Rosuvastatin and Clopidogrel in their Tertiary Mixture

Reduction of environmental pollution sources is the main target of green chemistry; it is applied across the life cycle of a chemical product. Scientists try to switch to eco-friendly practices to diminish the negative impact of chemicals and solvents on the environment. Analytical chemistry is one of the main fields that mounted green chemistry approach. In this work, sensitive and selective green chromatographic methods with UV detection are described for the simultaneous determination of aspirin, rosuvastatin and clopidogrel. The first proposed method is an RP-HPLC one, which was described and successfully validated for the simultaneous separation and determination of the three components on Prontosil Hyperchom C18 (250 × 4.6 mm, 5 μm) column using an isocratic elution. The second method was a TLC spectrodensitometry in which the three components were separated, identified and quantified. The drugs were applied on silica gel plates, and developed using n-heptane: acetone: glacial acetic acid (60:40:0.4, by volume). The three drugs resolved bands were quantified by spectrodensitometric scanning at 240 nm. Both methods were validated according to ICH, statistically compared to the official methods with full greenness investigation to confirm that the proposed methods are viable alternatives for quality assessment of this combination.

Application of multivariate chemometrics tools for spectrophotometric determination of naphazoline HCl, pheniramine maleate and three official impurities in their eye drops

This work is concerned with exploiting the power of chemometrics in the assay and purity determination of naphazoline HCl (NZ) and pheniramine maleate (PN) in their combined eye drops. Partial least squares (PLS) and artificial neural network (ANN) were the chosen models for that purpose where three selected official impurities, namely; NZ impurity B and PN impurities A and B, were successfully determined. The quantitative determinations of studied components were assessed by percentage recoveries, standard errors of prediction as well as root mean square errors of prediction. The developed models were constructed in the ranges of 5.0-13.0 μg mL-1 for NZ, 10.0-60.0 μg mL-1 for PN, 1.0-5.0 μg mL-1 for NZ impurity B and 2.0-14.0 μg mL-1 for two PN impurities. The proposed models could determine NZ and PN with respective detection limits of 0.447 and 1.750 μg mL-1 for PLS, and 0.494 and 2.093 μg mL-1 for ANN. The two established models were compared favorably with official methods where no significant difference observed.

Green chromatographic methods for determination of co-formulated lidocaine hydrochloride and miconazole nitrate along with an endocrine disruptor preservative and potential impurity

Recently, green analytical chemistry (GAC) is a key issue towards the idea of sustainability, the analytical community is focused on developing analytical methods that incorporate green chemistry principles to minimize adverse impacts on the environment and humans. Herein, we present 2 sustainable, selective, and validated chromatographic methods. Initially, lidocaine hydrochloride (LDC) and miconazole nitrate (MIC) with two preservatives; methyl paraben (MTP) and saccharin sodium (SAC) were chromatographed via TLC-densitometric method which employed ethyl acetate: methanol: formic acid (9:1:0.1, by volume) as the mobile phase with UV detection at 220.0 nm, good correlation was obtained in the range of 0.3-3.0 µg/band for MIC and LDC. Following that, RP-HPLC was successfully applied for separating quinary mixture of LDC, MIC, MTP, SAC along with LDC impurity; dimethyl aniline (DMA) using C18 column, and a gradient green mobile phase composed of methanol and phosphate buffer (pH 6.0) in different ratios with a flow rate 1.5 mL/min and UV detection at 210.0 nm, linearity ranges from 1.00 to 100.00 µg/mL for MIC, 2.00-100.00 µg/mL for LDC and 1.00--20.00 µg/mL for MTP and DMA. No records to date regarding the determination of the two drugs, besides MTP and DMA. The proposed methods were validated according to the ICH guidelines and applied successfully to the analysis of the compounds. The methods' results were statistically compared to those obtained by applying the reported one, indicating no significant difference regarding both accuracy and precision. The methods' greenness profiles have been assessed and compared with those of the reported method using different assessment tools.

Molecular imprinted polymer-based potentiometric approach for the assay of the co-formulated tetracycline HCl, metronidazole and bismuth subcitrate in capsules and spiked human plasma

BACKGROUND

An anti-H-pylori co-formulated mixture of tetracycline HCl (TET), metronidazole (MET), and bismuth subcitrate (BSC) is recently available. Only two chromatographic and spectrophotometric methods are reported for determining those drugs simultaneously where the effect of impurities that could be present as well as the biological fluids matrix influence do not be taken into consideration. There is a need to develop an easy-to-use potentiometric technique for analysis of TET, MET, and BSC in their co-formulated capsules, in presence of some official impurities and in spiked human plasma.

RESULTS

Three carbon paste electrodes (CPEs) were fabricated for this purpose. Being a solid contact ion-selective electrode, CPE suffers from the creation of a water layer affecting its stability and reproducibility. Besides, it has a common problem in differentiation between two drugs carrying the same charge (positively charged TET and MET). Water layer formation was prevented through inserting polyaniline nanoparticles (≈10.0 nm diameter) between solid contact and ion-sensing membrane in the three proposed sensors. TET and MET interference was overcome by synthesizing a corresponding molecular imprinted polymer (MIP) for each drug. The synthesized MIPs were inserted in equivalent sensing membranes and characterized using several techniques. The suggested MIPs have a noticeable enhanced sensitivity in potentiometric determination. The obtained LODs were 5.88 × 10-8, 5.19 × 10-7, and 1.73 × 10-6 M for TET, MET and BSC proposed CPEs, respectively, with corresponding slopes of 57.37, 56.20, and -57.40 mV decade-1.

SIGNIFICANCE

The proposed potentiometric method makes the detection of the three cited drugs simple, fast, and feasible. This approach is the first for determining three drugs potentiometrically in one combined formulation. The obtained results were compared favorably with previously reported potentiometric methods.

Smart chemometrics-assisted spectrophotometric methods for efficient resolution and simultaneous determination of paracetamol, caffeine, drotaverine HCl along with three of their corresponding related impurities

Three novel, simple and accurate multivariate spectrophotometric assisted mathematical techniques were developed for determination of paracetamol, caffeine, drotaverine HCl and their related impurities. The used multivariate algorithms are principal component regression (PCR), partial least squares (PLS), and synergy intervals partial least squares (siPLS). Linearity of the suggested methods was found to be (1.00-14.60, 1.40-7.00, 1.40-3.80, 1.00-3.00, 1.50-3.50 and 2.50-4.50 µg/mL) for paracetamol, caffeine, drotaverine HCl, and their related impurities; p-aminophenol, theophylline and homoveratric acid, correspondingly. The presented methods were effectively implemented in the determination of the cited compounds in their laboratory prepared mixtures. Commercially available tablet preparation was also analyzed using the applied methods where no impurities were detected and without interference from tablet additives. Moreover, statistical analysis did not reveal any noticeable differences between the obtained results and those acquired from the reported method in terms of accuracy and precision. The developed multivariate algorithms were validated by means of internal and external validation sets. The obtained results showed the siPLS algorithm's superiority to PCR and PLS according to the values of correlation coefficient values (r) and the lowest root mean square error of prediction (RMSEP). The combination of four subintervals [10, 12, 14, and 17] produced the highest efficiency model. Furthermore, these methods may be an applicable substitute to HPLC ones in quality control laboratories during rush of analyses where several samples have to be analyzed in a short time.

Spectrophotometric determination of favipiravir in presence of its acid hydrolysis product

Favipiravir (FAV) has been approved as an antiviral drug used in pandemic corona virus to treat covid-19. It has an amide moiety susceptible to hydrolysis and degradation in acid medium. Therefore, four simple, sensitive, and accurate stability indicating spectrophotometric methods have been developed for the determination of FAV in presence of its acid induced degradation product. The first method describes direct determination of FAV at 323 nm. Dual wavelength method was the second developed one for FAV quantitation by recording the absorbance difference at 322.7 and 270 nm. The third method involves using first derivative peak to peak amplitude at 338.0 and 308.0 nm, while difference spectrophotometry was the fourth suggested method, and it was based on recording the spectral changes at 361.3 nm as pH changes. The obtained calibration curves were linear over 4.0-22.0 µg/mL. Accuracy of the suggested procedures ranged from 99.11 to100.06, while precision results were from 0.80 to1.68. The developed methods were used to determine FAV in pure powdered form, laboratory-prepared mixtures with their degradation product, and pharmaceutical formulation without interference from its acidic degradation product.The greenness was assessed based on GAPI and ACREE metric and was found to be compatible and in reconciliation with green analytical chemistry concepts.

Design of Experiment-Based Green UPLC-DAD Method for the Simultaneous Determination of Indacaterol, Glycopyrronium and Mometasone in their Combined Dosage Form and Spiked Human Plasma

Indacaterol, is an ultra-long-acting β2 agonist, glycopyrronium is a long-acting muscarinic-antagonist and mometasone is a synthetic corticosteroid. They were used recently in combination for the treatment of severe asthma symptoms and chronic obstructive pulmonary disease. In this work, it was the first time to develop a green and environment friendly ultra-performance liquid chromatographic method using design expert program for the analysis of the three drugs in their combined dosage form. Also, the method was bioanalytically validated for the analysis of the three drugs in spiked human plasma samples. The method was linear in range from 0.50 to 100.0 μg mL-1 for indacaterol and mometasone and from 1.0 to 150.0 μg mL-1 for glycopyrronium. It showed high accuracy where, the % recovery for indacaterol, glycopyrronium and mometasone in plasma were ranged from 94.27 to 97.86%, 96.43 to 98.75% and 96.86 to 98.43%, respectively. Also, it was precise where, the % relative standard deviation for the inter-day precision was ranged from 2.571 to 3.484%, 3.180 to 4.123% and 3.150 to 3.984% and the intra-day precision was ranged from 2.351 to 3.125%, 2.512 to 3.544% and 2.961 to 3.983% for indacaterol, glycopyrronium and mometasone, respectively. The limit of detection and the limit of quantification for indacaterol and mometasone were 0.03 and 0.10 μg mL-1 while for glycopyrronium, they were 0.16 and 0.50 μg mL-1.

HIGHLIGHTS

A reversed-phase-high performance liquid chromatography method for simultaneous determination of paracetamol, caffeine, drotaverine HCl and their related impurities with dissolution profiling of their tablets and greenness profile assessment

A sensitive, specific and eco-friendly reversed-phase-HPLC method was developed and validated for the determination of paracetamol, caffeine and drotaverine HCl along with their related impurities. The separation was accomplished using an X-bridge C₁₈ column (5 μm; 250 mm × 4.6 mm inner diameter) and a green mobile phase consisting of methanol and 0.02 M phosphate buffer at pH 5.0 in the gradient elution mode. The detector used was a diode array detector. The proposed method was validated in accordance with the International Conference on Harmonisation guidelines. Linear regressions were found in the range of 1-100, 1-100, 2-60, 1-20, 0.50-30 and 1-15 μg/mL for paracetamol, caffeine, drotaverine HCl, p-aminophenol, theophylline and 3,4-dimethoxyphenylacetic acid, respectively. The suggested method was successfully applied for the determination of the studied drugs in their tablet dosage form without interference from any excipients. No discernible difference was found between the obtained results and official or reported methods, statistically, in terms of both accuracy and precision. Dissolution profiling of the studied tablet was also performed using the suggested procedure. Moreover, the greenness profile was assessed using three different tools, namely, the National Environmental Methods Index, the Analytical Eco-Scale and the Analytical GREEnness Metric Approach. The acquired results assert the agreement of the assay with green chemistry principles.

Comparative Chemometric Manipulations of UV-Spectrophotometric Data for the Efficient Resolution and Determination of Overlapping Signals of Cyclizine and Its Impurities in Its Pharmaceutical Preparations

BACKGROUND

Cyclizine (CYZ), a commonly used antiemetic drug, has two pharmacopeial toxic impurities, 1-methylpiperazine (MPZ) and diphenylmethanol (DPM). When CYZ parenteral formulations are administered intravenously, both impurities are poisonous, toxic, and harmful to the human body.

OBJECTIVE

Cyclizine was determined along with its hazardous impurities MPZ and DPM by green multivariate calibration using UV-spectroscopic data.

METHODS

Three multivariate algorithms were used to resolve and quantify overlapped spectral signals: principal component regression (PCR), partial least squares (PLS), and synergistic intervals partial least squares (siPLS). A concentration set containing 16 distinct combinations of CYZ, MPZ, and DPM was randomly prepared, and the absorbance values of the concentration set were determined using the 376 point-wavelength set with an interval of 0.2 nm between 200 and 275 nm.

RESULTS

Good linear correlations were established for CYZ, MPZ, and DPM in the concentration ranges of 5.00-25.0, 0.50-2.50, and 0.50-2.50 µg/mL, respectively. The ideal spectral range and associated combinations were chosen based on the lowest root mean error of prediction (RMSEP) and correlation coefficient values (r). The siPLS approach performed better than the PCR and PLS models. The combination of four subintervals, 1, 3, 4, and 7, demonstrated the greatest effect, with RMSEP values of 0.0272, 0.0053, and 0.0315 for CYZ, MPZ, and DPM, respectively, and correlation coefficients of 0.9991, 0.9999, and 0.9997, in order. Various assessment tools were used to evaluate and measure the greenness profile of the established methods. The proposed methods were validated using internal and external validation sets.

CONCLUSIONS

The three methods were effectively used to determine CYZ in its pure form and parenteral formulations, as well as its toxic impurities. The acquired results were compared statistically to those obtained using the reported HPLC method.

HIGHLIGHTS

Cyclizine and its toxic impurities can be determined spectrophotometrically by using the three developed chemometric models.

Univariate and Multivariate Determination of Dapagliflozin and Saxagliptin in bulk and Dosage Form

Background

Dapagliflozin is a sodium glucose cotransporter-II inhibitor while Saxagliptin is a dipeptidyl peptidase-4 inhibitor. Both are used to manage Type II diabetes mellitus.

Objective

The aim of this work is to develop four simple, accurate and precise UV-spectrophotometric methods, three univariate and one multivariate, were developed for the estimation of dapagliflozin and saxagliptin in their pure and marketed dosage forms.

Method

Method (A) is based on the ratio difference method; Method (B) is ratio subtraction with constant multiplication; while Method (C) is second derivative method and Method (D) is Partial least square.

Results

The calibration curves for dapagliflozin and saxagliptin were linear within the concentration range of 2.50–50.0 μg/mL and 5.0–60.0 μg/mL, respectively. The specificity of the proposed methods was studied by analyzing different laboratory prepared mixtures and their combined pharmaceutical dosage form. According to the ICH guidelines, the three proposed methods were validated regarding the accuracy, precision and specificity. Method (D) is Partial least square that was employed for the determination of the same mixture in wavelength range of 205–300 nm. A statistical comparison was performed between the results of the proposed methods and those of a reported spectrophotometric method and there was not any statistically significant difference detected at 95% confidence limit regarding both precision and accuracy.

Conclusion

Four accurate, specific, and precise UV-spectrophotometric methods for dapagliflozin and saxagliptin testing and estimation were successfully utilized and validated.

Highlights

The examined methods are simple and do not involve sophisticated and expensive instruments and could be effectively employed in quality control laboratories for routine examination of the investigated drugs in their pure powdered or combined pharmaceutical formulations.

Eco-friendly resolution of spectrally overlapping signals of a combined triple-action over-the-counter pharmaceutical formulation for symptomatic management of COVID-19 pandemic: application to content uniformity testing

Currently, all researchers are concentrating their efforts on countering the COVID-19 pandemic. The majority of patients are managed at home, according to recent statistics. An OTC triple action combination comprising paracetamol (PAR), aspirin (ASP), and diphenhydramine (DIPH) is commonly given for pain relief, fever control, and as a night-time sleep aid. This combination is currently recommended for COVID-19 patients as part of symptomatic treatment and management. In this work, three smart, simple, accurate, eco-friendly, and cost-effective spectrophotometric methods are developed for simultaneous determination of PAR, ASP, and DIPH in their combined over-the-counter caplet dosage form without any prior separation steps. The first method is the first derivative spectrophotometry (D¹) which determined PAR at 259.7 nm. The second one is the dual-wavelength in ratio spectra (DWRS) for determination of ASP at 214.1 and 220.1 nm after using 10.0 μg/mL of PAR as a divisor, where PAR was a constant, and the wavelengths difference equal to zero for DIPH. The third method is the double divisor-ratio difference spectrophotometric one (DD-RD) which was based on using the sum of 15.0 µg/mL of each of PAR and ASP as a double divisor, and the difference in amplitudes was measured at two wavelengths ∆P_{(214.5–226.0)} for determination of DIPH. The developed methods have been validated as per ICH guidelines. Furthermore, the three suggested methods were employed successfully to assay marketed pharmaceutical formulation and to investigate the content uniformity of the dosage units in accordance with the United States Pharmacopeia's guidelines. Finally, the greenness profile of the proposed methods was assessed and compared with the reported method using the analytical eco-scale system, national environmental method index (NEMI), green analytical procedure index (GAPI), and analytical greenness (AGREE) metric. The results from the proposed methods statistically agreed with those obtained by the reported one, with no significant differences in accuracy and precision.

Etodolac Fortified Sodium Deoxycholate Stabilized Zein Nanoplatforms for Augmented Repositioning Profile in Human Hepatocellular Carcinoma: Assessment of Bioaccessibility, Anti-Proliferation, Pro-Apoptosis and Oxidant Potentials in HepG2 Cells

This work aimed to enhance the purposing profile of Etodolac (ETD) in Human Hepatocellular Carcinoma (HCC) HepG2 cells using sodium deoxycholate stabilized zein nanospheres (ETD-SDZN NSs). ETD-SDZN NSs were formulated using the nan-precipitation method and were characterized, in particular, in terms of mean particle size, zeta potential, encapsulation efficiency, colloidal stability and bioaccessibility. Estimations of cytotoxicity, cellular uptake, cell cycle progression, Annexin-V staining, mRNA expression of apoptotic genes and oxidative stress evaluations were conducted. The ETD-SDZN NSs selected formula obtained an average particle size of 113.6 ± 7.4 nm, a zeta potential value of 32.7 ± 2.3 mV, an encapsulation efficiency of 93.3 ± 5.2%, enhanced bioaccessibility and significantly reduced IC50 against HepG2 cells, by approximately 13 times. There was also enhanced cellular uptake, accumulation in G2-M phase and elevated percentage cells in pre-G1 phase, significant elevated mRNA expression of P53, significant reduced expression of Cyclin-dependent kinase 1 (CDK1) and Cyclooxygenase-2 (COX-2) with enhanced oxidative stress by reducing glutathione reductase (GR) level, ameliorated reactive oxygen species (ROS) generation and lipid peroxidation outputs. ETD-SDZN NSs obtained a supreme cell death-inducing profile toward HepG2 cells compared to free ETD. The method of formulation was successful in acquiring the promising profile of ETD in HCC as a therapeutic molecule due to ameliorated cellular uptake, proapoptotic and oxidant potentials.

Quality by design approach for green HPLC method development for simultaneous analysis of two thalassemia drugs in biological fluid with pharmacokinetic study

This work implements a combined experimental approach of analytical quality-by-design (AQbD) and green analytical chemistry (GAC) to develop an HPLC method for simultaneous determination of the two thalassemia drugs, deferasirox (DFX) and deferiprone (DFP), in biological fluid for the first time. This integration was designed to maximize efficiency and minimize environmental impacts, as well as energy and solvent consumption. To accomplish this goal, an analytical quality-by-design approach was performed, beginning with quality risk assessment and scouting analysis, followed by Placket-Burman design screening for five chromatographic parameters. Critical method parameters were thoroughly recognized and then optimized by using a two levels-three factors custom experimental design to evaluate the optimum conditions that achieved the highest resolution with acceptable peak symmetry within the shortest run time. The desirability function was used to define the optimal chromatographic conditions, and the optimal separation was achieved using an XBridge® HPLC RP-C18 (4.6 × 250 mm, 5 μm) column with ethanol : acidic water at pH 3.0 adjusted by phosphoric acid in the ratio of (70 : 30, v/v) as the mobile phase at a flow rate of 1 mL min^-1 with UV detection at 225 nm at a temperature of 25 °C. Linearity was obtained over the concentration range of 0.30-20.00 μg mL^-1 and 0.20-20.00 μg mL^-1 for DFX and DFP, respectively, using 20.00 μg mL^-1 ibuprofen (IBF) as an internal standard. The established method's greenness profile was evaluated and measured using various assessment tools, and the developed method was green. For the validation of the developed method, FDA recommendations were followed, and all the results obtained met the acceptance criteria. The suggested method was successfully used to study the pharmacokinetic parameters of DFX and DFP in rat plasma. Due to the substantial increase in bioavailability of the two iron chelating drugs, the results from this study strongly recommend their co-administration.

Univariate versus multivariate spectrophotometric methods for the simultaneous determination of omarigliptin and two of its degradation products

Six selective spectrophotometric techniques, four univariate and two multivariate ones were developed for the determination of the antidiabetic drug omarigliptin (OMR) along with its hydrolytic and oxidative degradation products. The proposed univariate spectrophotometric methods were ratio subtraction, first derivative, derivative ratio and ratio difference. Linearities were constructed in the range of 10.0-180.0 μg mL^-1 for both OMR & its hydrolytic degradation product and 10.0-110.0 μg mL^-1 for the oxidative degradation one. On the other hand, partial least squares and artificial neural networks were the chosen multivariate approaches. Their linearity ranges were 20.0-60.0 μg mL^-1 for OMR and 10.0-30.0 μg mL^-1 for the two degradation products. All the methods were validated, effectively applied for quantification of the intact drug in its tablet formulation and favorably compared to the reported one.

Spectrophotometric methods for determination of glimepiride and pioglitazone hydrochloride mixture and application in their pharmaceutical formulation

Simple, accurate, and precise four spectrophotometric methods were developed and validated for simultaneous determination of glimepiride and pioglitazone hydrochloride in their pharmaceutical formulation. The first spectrophotometric method was the dual-wavelength which determined glimepiride at 219.0 and 228.0 nm and pioglitazone hydrochloride at 268.0 nm. The second one is the first derivative of ratio spectra (DD1) spectrophotometry in which the peak amplitudes were used at 238.0 nm and 268.0 nm for glimepiride and pioglitazone hydrochloride, respectively. The third method is ratio subtraction in which glimepiride was determined at 228.0 nm in the presence of pioglitazone hydrochloride which was determined by extended ratio subtraction at 268.0 nm. The fourth method was the ratio difference to determine glimepiride and pioglitazone hydrochloride. Beer's law was confirmed in the concentration range 2.50-15.00 µg mL-1, and 10.00-50.00 µg mL-1 for glimepiride and pioglitazone respectively for the four methods. The proposed methods were used to determine both drugs in their pure powdered form with mean percentage recoveries of 99.91 ± 1.117% for glimepiride and 99.76 ± 0.911% for pioglitazone hydrochloride in method (A). In method (B), the mean percentage recoveries were 100.12 ± 0.89% for glimepiride and 100.02 ± 1.06% for pioglitazone hydrochloride. In method (C) glimepiride was 100.01 ± 0.592% and 99.85 ± 0.845% for pioglitazone hydrochloride by extended ratio subtraction. And finally, in method (D) the mean percentage recoveries were 100.66 ± 0.670% for glimepiride and 99.92 ± 0.988% for pioglitazone hydrochloride. The developed methods were successfully applied for the determination of glimepiride and pioglitazone hydrochloride in pure powder and dosage form. The suggested methods were also used to determine both compounds in laboratory-prepared mixtures. The accuracy, precision, and linearity ranges of the developed methods were determined. The results obtained were compared statistically with the official method, and there was no significant difference between the proposed methods and the official method for accuracy and precision.

A green TLC densitometric method for the simultaneous detection and quantification of naphazoline HCl, pheniramine maleate along with three official impurities

Impurity profiling of a pharmaceutical compound is now taking great attention during quality assessment of pharmaceuticals, as presence of small amount of impurities may affect safety and efficacy. In this work, a novel TLC chromatographic method coupled with densitometric detection was established for the simultaneous quantification of naphazoline HCl, pheniramine maleate and three of their official impurities, namely; naphazoline impurity B, pheniramine impurities; A & B. Chromatographic separation was carried out on TLC aluminum silica plates F254, as a stationary phase, using methanol: ethyl acetate: 33.0% ammonia (2.0: 8.0: 1.0, by volume), as a mobile phase. Plates were examined at 260.0 nm and International Council for Harmonisation (ICH) guidelines were followed for method’s validation. Important factors, such as; composition of mobile phase and detection wavelengths were optimized. Linearity was achieved over the ranges of 2.0–50.0 µg band⁻¹ for naphazoline, 10.0–110.0 µg band⁻¹ for pheniramine, 0.1–10.0 µg band⁻¹ for naphazoline impurity B and 2.0–50.0 µg band⁻¹ for both pheniramine impurities. The proposed method was assessed in terms of accuracy, precision and robustness where satisfactory results (recovery % ≈ 100% and RSD < 2) were obtained. The method was also applied for the simultaneous determination of naphazoline HCl and pheniramine maleate, in Naphcon-A^® eye drops, with respective recoveries of 101.36% and 100.94%. Method greenness was evaluated and compared to the reported HPLC one via environmental, health and safety tool. The developed method has much potential over the reported one of being simple, selective, economic and time saving for the analysis of the five cited compounds.

Sustainable Liquid Chromatographic Determination and Purity Assessment of a Possible Add-on Triple-Action Over-the-counter Pharmaceutical Combination in COVID-19

Nowadays, all researchers are focused on combating the pandemic COVID-19. According to recent statistics, most patients are managed at home. An over-the-counter (OTC) triple action formula containing paracetamol (PAR), aspirin (ASP), and diphenhydramine (DIPH) is widely prescribed for pain, fever and as night-time sleep aid. For COVID-19 patients, this combination is now suggested as part of symptomatic therapy and prophylaxis. In this work, two simple liquid chromatographic approaches were designed for simultaneous determination of PAR, ASP, and DIPH in Excedrin® PM caplets, beside three specified official toxic impurities, namely, p-aminophenol, p-nitrophenol, and salicylic acid. The first method comprised high-performance thin-layer chromatographic separation coupled with densitometric quantification, on silica gel HPTLC 60 F₂₅₄ aluminium sheets as the stationary phase, ethyl acetate–methanol-aqueous ammonium hydroxide (10.0: 2.0: 0.1, by volume) as the developing system and scanning was performed at 210.0 nm. The second one is a high-performance liquid chromatography coupled with diode array detector. Successful separation of the six components was performed on XTerra C₁₈ column with isocratic elution of mobile phase 0.1% triethylamine acidified water: methanol (70:30, v/v) adjusted with o-phosphoric acid to pH 3.0 and methanol (90:10, v/v) with flow rate programming and detection at 210.0 nm. Validation of the proposed methods was performed according to ICH guidelines. Both methods were successfully used for quality control of the cited drugs in their marketed formulation. Moreover, the in-vitro release study was monitored using the proposed HPLC-DAD method. The greenness profile of the proposed methods was assessed and comparatively evaluated through various assessment tools, specifically; the analytical eco-scale system, national environmental method index (NEMI), green analytical procedure index (GAPI) and analytical greenness (AGREE) metric.

Swimming exercise versus L-carnosine supplementation for Alzheimer's dementia in rats: implication of circulating and hippocampal FNDC5/irisin

Recent studies have suggested that irisin may act as a potential neurokine. Exercise and L-carnosine supplementation showed neuroprotective effects in Alzheimer's disease (AD)-like conditions. However, the regulation of irisin in the hippocampus of streptozotocin (STZ)-induced memory impairment and its relation to insulin signalling remain to be investigated. This study was designed to compare the effect of swimming exercise and L-carnosine intake on serum, CSF and hippocampal irisin in rats received intracerebroventricular (ICV) injection of STZ. Rats were recruited in swimming paradigm, received oral carnosine (100 mg/kg/day) or vehicle treated. After 5 weeks, rats were sacrificed after neurobehavioural testing. CSF and serum irisin were determined. Hippocampal tissues were used to assess expression of FNDC5/irisin, BDNF and proteins related to insulin signalling, in addition to β-amyloid peptide and phosphorylated tau protein levels. We observed decreased hippocampal, but not CSF or serum, irisin in ICV-STZ-injected rats. Exercise and carnosine intake almost normalized hippocampal FNDC5/irisin expression which was associated with reduced soluble β-amyloid peptide and phosphorylated tau protein, improved BDNF and insulin signalling proteins, with corresponding mitigated cognitive impairments. However, hippocampal FNDC5/irisin was not correlated with serum or CSF irisin levels. Histologically, both interventions ameliorated the hippocampal damage in STZ-injected rats. The current study reveals that carnosine is equivalent to exercise in reversing cognitive decline and Alzheimer's biomarkers. In both interventions, enhancement of hippocampal FNDC5/irisin and insulin signalling may be involved in mediating these neuroprotective effects.

Validated chromatographic methods for the simultaneous determination of a ternary mixture of sulfacetamide sodium and two of its official impurities; sulfanilamide and dapsone

Sulfacetamide sodium is a widely prescribed sulfonamide drug due to its topical antibacterial action on eye and skin. Four impurities are stated in the British Pharmacopoeia among which are sulfanilamide and dapsone. This work presents two specific, accurate and precise chromatographic methods for the simultaneous determination of a mixture of sulfacetamide sodium, sulfanilamide and dapsone. The first method is an isocratic RP-HPLC where the separation of components was achieved on C18 column. A green mobile phase was used consisting of methanol:water (60:40, v/v). The flow rate was 1.0 mL/min and effluent was monitored at 273 nm. The second method is a TLC-spectrodensitometric one where good separation was achieved by using silica plates and a mobile phase consisting of chloroform:dichloromethane:acetic acid (6:2.5:1.5, by volume). Determination was done by densitometry in the absorbance mode at 273 nm. Both methods were validated in compliance with ICH guidelines. They were also successfully applied for the determination of sulfacetamide sodium and its impurities in Ocusol® ophthalmic solutions. The obtained results were statistically compared to the results obtained by applying the official methods of analysis of each component where no significant difference was found with respect to accuracy and precision.

Formulation, optimization, and nephrotoxicity evaluation of an antifungal in situ nasal gel loaded with voriconazole‒clove oil transferosomal nanoparticles

Fungal infections of the paranasal cavity are among the most widely spread illnesses nowadays. The aim of the current study was to estimate the effectiveness of an in situ gel loaded with voriconazole‒clove oil nano-transferosomes (VRC-CO-NT) in enhancing the activity of voriconazole against Aspergillus flavus, which causes rhinosinusitis. The nephrotoxic side effects of voriconazole may be reduced through the incorporation of the clove oil, which has antioxidant activity that protects tissue. The Box‒Behnken design was applied to formulate the VRC-CO-NT. The particle size, entrapment efficiency, antifungal inhibition zone, and serum creatinine concentration were considered dependent variables, and the soybean lecithin, VRC, and CO concentrations were considered independent ones. The final optimized formulation was loaded into a deacetylated gellan gum base and evaluated for its gelation, rheological properties, drug release profile, permeation capabilities, and in vivo nephrotoxicity. The optimum formulation was determined to be composed of 50 mg/mL lecithin, 18 mg/mL VRC, and 75 mg/mL CO, with a minimum particle size of 102.96 nm, an entrapment efficiency of 71.70%, an inhibition zone of 21.76 mm, and a serum creatinine level of 0.119 mmol/L. The optimized loaded in situ gel released 82.5% VRC after 12 hours and resulted in a 5.4-fold increase in drug permeation. The in vivo results obtained using rabbits resulted in a nonsignificant differentiation among the renal function parameters compared with the negative control group. In conclusion, nasal in situ gel loaded with VRC-CO-NT is considered an efficient novel carrier with enhanced antifungal properties with no signs of nephrotoxicity.

Three Smart and Original Spectrophotometric Data Processing Ratio Techniques for Resolving the Partial Overlapped Spectra of the Binary Antiviral Mixture Daclatasvir/Sofosbuvir: Application to Combined Dosage Form Darvoni® Tablets

BACKGROUND

The combination of Daclatasvir (DCV) and sofosbuvir (SFV) is now widely used as an ideal treatment for hepatitis C virus infection. For this purpose, simple, sensitive, rapid and smart spectrophotometric methods were developed and validated for the determination of these drugs in their combined dosage form.

OBJECTIVE

Development οf smart, sensitive, cheap spectrοphοtοmetric methοds fοr determinatiοn (DCV) and (SFV) in their combined dosage.

METHODS

Ratio subtraction (RS) and amplitude modulation (AM) and mean centering spectrophotometric methods were established and validated for the estimation of sofosbuvir (SFV) in existence of daclatasvir without previous separation, utilizing unified regression equation.

RESULTS

A linearity limit of 2.5-25.0 µg/mL was confirmed for the direct measurement of daclatasvir at 316 nm (because there is no interference from sofosbuvir). Linearity was confirmed over a concentration limit of 10.0-80.0 µg/mL for sofosbuvir. The current methods were established as stated by the ICH recommendations and by testing synthetic mixtures of both drugs, the specificity was examined. They were tested on their tablet dosage form and good recovery was obtained.

CONCLUSIONS

The current methods were tested on their tablet dosage form and good recovery was obtained. A statistical study has been established among the current ratio approaches and a published methods and there was no apparent statistical variation was obtained.

HIGHLIGHTS

Both antiviral agents can be quantified in existence of each other by the current methods, which is a great time and cost-saving valor of the developed methods. This valor is even more important in the case of the combined dosage form (Darvoni® tablets) to the pharmaceutical market.

HPLC-UV and TLC-Densitometry Methods for Simultaneous Determination of Sofosbuvir and Daclatasvir: Application to Darvoni® Tablet

Sofosbuvir and daclatasvir are co-formulated as directly acting antiviral agents used for treatment of hepatitis C virus. Two chromatographic methods were developed for their determination; the first one is an Reversed phase-high performance liquid chromatography (RP-HPLC) method, in which the separation was performed on C8 Zorbax® SB column (4.6 × 250 mm, 5 μm) using acetonitrile:water:0.05 M phosphate buffer, pH = 8 (50:45:5, v/v/v) as a mobile phase, and ultraviolet detection was performed at 280 nm. Good resolution was obtained, and linearity was confirmed in the range of 10-100 μg/mL for both drugs. The second method is Thin layer chromatography (TLC)-densitometric one, in which sofosbuvir and daclatasvir were separated on silica gel plates using ethyl acetate:hexane:methanol (9:0.5:0.5, v/v/v) as a developing system and the scanning wavelength was 280 nm. Linearity was confirmed over a concentration range of 0.4-25.4 μg/band for sofosbuvir, whereas for daclatasvir linearity scanning was in the range of 0.4-12.8 μg/band. Both antiviral agents can be quantified simultaneously in one analytical run, which is a great time- and cost-saving valor of the developed methods. This valor is even more important in the case of the combined dosage form (Darvoni® tablets) to the pharmaceutical market.

Smart Mathematical Manipulation of Spectral Signals: Stability Indicating, for the Estimation of Solifenacin Succinate: Anti-Muscarinic Drug, in Existence of its Acid Degradation Product

BACKGROUND

Four rapid, smart, and easy to apply spectrophotometric methods were displayed for the estimation of Solifenacin succinate (SOL) in existence of its acid inspired degradation product.

OBJECTIVE

Development of stability indicating smart, sensitive, cheap spectrophotometric methods for determination of SOL in presence of its acid degradate.

METHODS

(Method A) is dual wavelength (DW) method; where, two wavelengths were selected; 262 and 289 nm were utilized to determine SOL in existence of its acid degradate. (Method B) is developing the first derivative (1D) of the absorption spectra. Peak signal was detected at 276 nm. (Method C) is ratio difference (RD) method where the drug is determined by the difference in signal between two selected wavelengths, at 240 and 259 nm. (Method D) depended on measuring peak signal of the first derivative of the ratio spectra (1DD) at 269 nm.

RESULTS

Calibration curves of the suggested methods exhibited linearity. The selectivity of the suggested methods were ascertained using different laboratory prepared mixtures of SOL with its acid degradate indicating specificity of SOL with accepted recovery values. The suggested methods have been successfully applied to the analysis of SOL in its pharmaceutical dosage form without involvement of additives.

CONCLUSIONS

The presented work applied four resolution techniques, based on absorbance, derivative and/or ratio spectra, for the analysis of SOL in the existence of its acid degradate.

HIGHLIGHTS

Study of degradation pathway of drugs is of great importance nowadays. Hence, acid hydrolysis of SOL was achieved and then SOL determined along with its acid degradate.

Selective Determination of Entecavir in the Presence of its Oxidative Degradate by Spectrophotometric and Chromatographic Methods

BACKGROUND

Entecavir (ENT) is an antiretroviral agent prescribed for the treatment of the hepatitis B virus(HBV) and human immunodeficiency virus(HIV).

OBJECTIVE

Development and validation of three simple, sensitive, selective, and precise methods for determination of ENT in the presence of its oxidative degradation product (ENT deg.).

METHOD

The first method was based on second derivative (D2) spectrophotometry through measuring the peak amplitude of D2 spectra at 293.6 nm. The second one is mean centering of the ratio spectra (MCR), which enabled measurement of the peak amplitude at 280.0 nm. The third method was HPLC, where ENT was separated from ENT deg. using a Zobrax C18 column and methanol:water (30:70, v/v) with pH 3 as a mobile phase. The three developed methods were validated according to the International Conference on Harmonization guidelines.

RESULTS

Linearity range of ENT was 5.00-50.00 μg/mL for both D2 and MCR. However, higher sensitivity was achieved using HPLC (1.00-50.00 μg/mL). Accuracy of ENT were 100.60 ± 0.547%, 101.55 ± 1.2071%, and 100.61 ± 1.207% for D2, MCR, and HPLC methods, respectively, and precision was within 1.280.

CONCLUSIONS

The developed methods were successfully applied for the determination of ENT in Tecavir® tablets without interference from ENT deg. They showed no significant difference in comparison with the official method and they can be applied in the quality analysis of ENT with high selectivity, accuracy, and precision.

HIGHLIGHTS

ENT was quantified using two spectrophotometric (D2 and MCR) methods and an HPLC method in presence of ENT deg. The proposed methods were applied to analysis of ENT tablets with high selectivity, sensitivity, and accuracy.

Implementation of Two Chromatographic Methods for Simultaneous Quantitation of Thioctic Acid, Benfotiamine and Cyanocobalamin

Two accurate and sensitive chromatographic methods have been introduced and validated for the simultaneous determination of thioctic acid, benfotiamine and cyanocobalamin in bulk powders and in their pharmaceutical formulation. Method A is reversed-phase ultra performance liquid chromatographic method with an isocratic elution, where a rapid separation was accomplished on a Zorbax C8 column using a mobile phase of acetonitrile:0.05 M phosphate buffer (pH 6 adjusted by o-phosphoric acid) (23:77, v/v). The retention times (tR) were 0.578, 0.852 and 1.376 for cyanocobalamin, benfotiamine and thioctic acid, respectively. The separated peaks were revealed at 210.0 nm. Method B is a thin-layer densitometric method where the separation of the studied drugs was carried out on silica gel plates using methanol-chloroform-heptane-1-sulphonic acid sodium salt (0.4%) (7:3:0.1, by volume) as a mobile phase, and scanning of the separated bands was done at 240.0 nm. The retardation factor (Rf) values were 0.17, 0.48 and 0.75 for cyanocobalamin, benfotiamine and thioctic acid, respectively. Validation of the methods was achieved following ICH guidelines and the applied methods succeeded to determine the cited drugs in their pure forms and capsules. Results were statistically compared to the manufacturer's method where no significant difference was observed.

Greenness profile assessment of selective liquid chromatographic methods for determination of a quaternary antimigraine combination along with three of their related official impurities

Two selective, sensitive and environmentally safe LC methods were developed and validated for determination of paracetamol, caffeine, ergotamine tartrate and metoclopramide in coformulated antimigraine tablets along with p-aminophenol, p-nitrophenol and theophylline as officially specified impurities. The first is based on high-performance thin-layer chromatography (HPTLC) coupled with densitometric quantitation. Separation was achieved on HPTLC silica gel 60 F₂₅₄ plates as stationary phase using ethyl acetate:aqueous ammonium hydroxide solution:glacial acetic acid (10.0:0.4:0.1, by volume) as a developing system followed by scanning of the separated bands at 210.0 nm. The subsequent method depends on HPLC with diode array detection. The LC separation was accomplished on a Scharlau C₁₈ (250 × 4.6 mm, 5 μm) column using a mixture of 20.0 mm sodium dihydrogen phosphate, pH 3.0, adjusted with o-phosphoric acid and methanol, at a flow rate of 1.3 mL/min in a gradient elution program. The separated peaks were detected at 210.0 nm. The proposed methods have been validated and proven to meet the requirements outlined in the International Council for Harmonisation (ICH) guidelines. The greenness profile evaluation was carried out using three tools, namely, the National Environmental Method Index, the Analytical EcoScale and the Green Analytical Procedure Index tool, and a comparative study was then conducted. Successful application of the developed methods for determination of the cited quaternary mixture in Metograine tablets confirms their suitability regarding the analytical performance and ecological impact in quality control assay and impurity profiling purposes.

Univariate and multivariate assisted spectrophotometric methods for determination of rosuvastatin calcium and fenofibrate in bulk powders and tablets along with their degradation products

Rosuvastatin calcium and fenofibrate are recently co-formulated for treatment of hyperlipidemia. Two selective spectrophotometric approaches were developed, the first is univariate manipulation of spectrophotometric data, where isoabsorptive point and dual wavelength method were applied. The total concentration of rosuvastatin calcium and fenofibrate could be determined at λ = 253.2 nm while rosuvastatin calcium was determined with dual wavelength (λ = 243.5 and 307.9 nm) where linearity was achieved in the range of 2.00-22.00 µg/mL and mean accuracy 100.29 ± 0.568 then, by difference, Fenofibrate was determined in the range of 2.00-22.00 µg/mL and mean accuracy 100.23 ± 0.578. The second approach is a stability indicating multivariate modeling namely principal component regression and partial least squares, where the two drugs were determined in the presence of their degradation products. 17 samples were prepared according to five levels four factors calibration design. The developed models were described by 4 latent variables, and good prediction was evidenced by low root mean square error of prediction. The proposed methods were found to be rapid and simple and required no preliminary separation. Rosuvastatin calcium and fenofibrate were analyzed with mean recoveries 99.54 ± 0.903, 99.88 ± 0.548 and 99.50 ± 0.712, 99.30 ± 0.802, respectively. The two drugs were successfully determined in tablets by the developed methods and the results were compared to HPLC methods, where they were found to be statistically non-significant.

Determination of naphazoline HCl, pheniramine maleate and their official impurities in eye drops and biological fluid rabbit aqueous humor by a validated LC-DAD method

A simple RP-HPLC-DAD method was developed and validated, as per the ICH guidelines, for simultaneous determination of naphazoline HCl (NPZ) & pheniramine maleate (PHN) along with three of their official impurities. Chromatographic separation was performed on a hypersil ODS column (5 mm, 250-4.6 mm i.d.) with isocratic elution using phosphate buffer pH 6.0: acetonitrile (70 : 30, v/v) as mobile phase, at a flow rate of 1.0 mL min-1 and UV detection at 260.0 nm. The developed method was found to be linear over the concentration ranges of 5.00-45.00 μg mL-1 for NPZ and NPZ impurity B and 10.00-110.00 μg mL-1, 10-70 μg mL-1 and 10-120 μg mL-1 for PHN, and PHN impurity A and B, respectively, with correlation coefficient values <0.999 for the five cited compounds. The method was confirmed to be accurate, robust and precise with RSD >2.0%. LOD and LOQ values for the five cited compounds were calculated. Moreover, the method was also validated in rabbit aqueous humor as per the US food and drug administration (FDA) bioanalytical validation guidelines. Finally, the proposed method was applied for the analysis of the two drugs along with their impurities in dosage form and spiked aqueous humor samples.

Quality and Stability Profile Assessment of the Recent Antidiabetic Omarigliptin by Using Different Chromatographic Methods

In a contribution to stability profiling of the recent antidiabetic drug, omarigliptin (OMR), two stability-indicating chromatographic methods were developed and validated. Stability profiling was performed for OMR under different stress conditions as acidic, alkaline, oxidative, photolytic and thermal degradations. Structures elucidation to all formed degradation products were identified using IR and mass spectrometry. Thin Layer Chromatography (TLC) and High-Performance Liquid Chromatography (HPLC) were used. In TLC-densitometric method, aluminum TLC plates precoated with silica gel G.F254 were used as stationary phase along with methanol: ethyl acetate: 33% ammonia (2:8:1,v/v/v) as mobile phase. The obtained chromatograms were scanned at 254 nm over concertation range of 5-70 μg band-1 for OMR. The second chromatographic method was an HPLC one with diode array detection and RP-C18 column with isocratic elution. Mobile phase used was composed of phosphate buffer pH 3.5: acetonitrile (80, 20, v/v), delivered at flow rate of 1.0 mL min-1. Diode array detector was adjusted at 230 nm with linearity range of 15-180 μg mL-1 for OMR. Several factors affecting TLC and HPLC efficiency have been carefully studied. The developed methods were validated according to International Conference on Harmonization guidelines and successfully applied for assessment of OMR in bulk powder and tablets.

Selective spectrofluorimetric determination of two corticosteroids along with their co-formulated drugs and degradation products in ophthalmic solution and aqueous humour

Prednisolone acetate (PNO) and fluorometholone (FRT) are corticosteroids, co-formulated with moxifloxacin HCl (MFX) and cromolyn sodium (CML), respectively. PNO has a negligible quantum yield and its hydrolytic degradation products have enhanced fluorescence, which is 250-fold greater. FRT is a nonfluorescent drug, but its hydrolytic degradation products show reasonable fluorescence; MFX and CML have native fluorescence. Two methods were proposed based on the determination of PNO and FRT via their hydrolytic degradation products in the presence of other degradation products. Method (A) was developed for simultaneous determination of PNO and MFX in the presence of PNO degradation products by measuring peak amplitudes of the first derivative (¹ D) of its enhanced fluorescence; PNO and MFX were measured at 345 and 473 nm, respectively. Method (B) is a synchronous fluorescence spectroscopic method for simultaneous determination of FRT and its co-formulated drug CML in the presence of its degradation products. Fluorescence intensities were measured at λ_em 283 and 347 nm for FRT and CML, respectively, using Δλ = 99.20 nm. Validation of the proposed methods was conducted as per International Council for Harmonisation (ICH) guidelines. The proposed methods were successfully applied for the determination of the proposed drugs in bulk powder, ophthalmic solution, and rabbit's aqueous humour.

Ultra-performance liquid chromatography-tandem mass spectrometric method for quantitation of the recently Food and Drug Administration approved combination of vaborbactam and meropenem in human plasma

A parenteral medical combination containing vaborbactam and meropenem is used mainly to treat complicated urinary tract infections. A novel ultra-performance liquid chromatography tandem mass spectrometric method was developed for the sensitive determination of both compounds in human plasma. Sample preparation was performed by precipitation technique. The chromatographic separation was accomplished using the Acquity C18-BEH column, 0.01 M ammonium formate: acetonitrile (47 : 53, v/v) as a mobile phase with a flow rate of 0.2 ml min-1. Analytes were monitored by applying multiple reaction monitoring. The bioanalytical validation criteria were conducted following the Food and Drug Administration recommendations. The method was linear within range 0.5 to 50 µg ml-1, for both drugs. The intra-day and inter-day precision, as coefficient variation (% CV) and the accuracy, as % bias did not exceed 15% for both drugs. The percentage recovery of targeted analytes was not less than 77%, calculated at three quality control levels. The proposed method showed a suitable lower level of quantification value of 0.50 µg ml-1 for both analytes, which is far lower than the expected C max, which permits the use of this method for pharmacokinetic studies. The proposed method proved to be useful for the evaluation of this combination in both human plasma and pharmaceutical formulation.

Spectral signal processing approaches for selective quantification of the recently FDA approved brand-new combination of Vaborbactam and Meropenem; for conformity assessment of bulk and batch release

Vaborbactam (VBR) and Meropenem (MRP) is a recently approved combination for treatment of complicated urinary tract infection (cUTI). Three different signal processing approaches utilizing UV spectral data has been applied for quality assessment of Vabromere® injection. First, the simplest signal processing method, dual wavelength (DW) was developed, where VBR and MRP were determined at (234.0 & 291.0 nm) and (219.5 & 245.5 nm), respectively. The second one utilized signal processing through derivatization, where, each drug was determined without any interference. This was achieved at 250.0 & 318.0 nm for VBR and MRP, respectively. The third approach is the recently developed algorithm, pure component contribution (PCCA), which efficiently extracts the pure spectrum of each drug and therefore determination is achieved at their λ_max with maximum sensitivity and lowest error. The applied methods were found to be linear in the concentration range of 5.00-100.00 μg/mL and 5.00-150.00 μg/mL, for VBR and MRP, respectively. Minimum solvent consumption and diminished preparation or extraction steps are achieved associated with accurate quantitation of VBR and MRP in bulk powders and injection. The developed methods were successfully compared to a reported HPLC method, where no significant difference was found regarding both accuracy and precision.

4,4'-(((1E,5E)-pentane-1,5-diylidene)bis(azanylylidene))bis(1-dodecylpyridin-1-ium) bromide as a novel corrosion inhibitor in an acidic solution (part I)

The metal corrosion inhibition efficiency of a novel synthesized cationic gemini surfactant (SCGS), namely, 4,4'-(((1E,5E)-pentane-1,5-diylidene)bis(azanylylidene))bis (1-dodecylpyridin-1-ium) bromide, was studied in acidic medium by three techniques. The achieved results displayed the inhibition efficiency of the metal corrosion that was elevated by increasing both the SCGS's concentration and the applied temperature values. Furthermore, it was noticed that the charge transfer resistance value was elevated; however, the constant phase element was decreased with increasing the SCGS concentrations. The SCGS regards an excellent and mixed-type corrosion inhibitor. The adsorption of SCGS has agreed the Langmuir's adsorption isotherm and was related to physisorption and chemisorption.

Green Liquid Chromatographic Methods with Ultraviolet and Tandem Mass Spectrometry Detection: An Application to Ternary Mixture of Paracetamol, Pseudoephedrine, and Cetirizine in Capsules

BACKGROUND

Effective chromatographic methods were developed for the determination of a multicomponent capsule prescribed for treating the common cold. Greening approaches were adopted as opposed to conventional methods.

OBJECTIVES

Two novel, green chromatographic methods were established to quantitatively analyze the combination.

METHODS

First, an HPLC/UV method utilizing green solvents (water and ethanol) and acetic acid to adjust pH at 5 was accomplished. The stationary phase was a ZorbaxSB-C18 column (150 × 4.6 mm, 5 μm), and peaks were detected at 215 nm. The second method is a highly sensitive ultra-performance LC (UPLC)-MS/MS method in which the greening approach was established through the reduction of the analysis time (2 min), decreased solvent consumption (flow rate 300 μL/min), and the utilization of a small volume of samples (injection volume 2 μL). The mixture was separated using a UPLC-BEH C18 column (50 × 2.1 mm, 1.7 μm) with an isocratic elution using methanol-0.1% formic acid aqueous solution (60+40, v/v) as mobile phase and utilizing diphenhydramine as an internal standard. Positive-ion electrospray ionization and multiple reaction monitoring were applied for detection.

RESULTS

Recovery percentages for paracetamol, pseudoephedrine, and cetirizine were 101.70 ± 0.969, 100.18 ± 1.563, and 99.67 ± 1.429 for the HPLC method and 99.18 ± 1.172, 100.03 ± 0.883, and 99.82 ± 0.912 for the UPLC-MS/MS method, respectively.

CONCLUSIONS

The proposed methods efficiently analyzed paracetamol, pseudoephedrine, and cetirizine in Allercet Cold® capsules. Validation of the proposed methods was in accordance with the International Conference on Harmonization recommendations, and statistical comparison with the reported method displayed no significant difference regarding accuracy and precision.

HIGHLIGHTS

Paracetamol, pseudoephedrine, and cetirizine were successfully quantified using two chromatographic methods. The HPLC method developed is considered green, using water and ethanol as a mobile phase. The UPLC-MS/MS method was rapid and determined the three drugs with accuracy at nanogram levels.

Selective and Sensitive Chromatographic Methods for Determination of a Co-Formulated Binary Mixture in Antibacterial Eye Drops and Aqueous Humor in the Presence of Their Degradation Products and Potential Impurities

Prednisolone acetate (PDN) is a corticosteroid anti-inflammatory liable to degradation under different conditions and used with antibiotics in eye drops. Two selective stability-indicating separation techniques were developed for simultaneous determination of PDN and moxifloxacin HCl (MXF) binary mixture in pure forms, ophthalmic formulation, in the presence of PDN impurities and in the presence of their degradation products. The first method was based on HPTLC separation using silica gel 60 F254 HPTLC plates, and a developing system of toluene: ethyl acetate: methanol: ammonia (5.0: 6: 2.0: 0.05, v/v/v/v) is used with detection at 254 nm. The second method was HPLC using a mobile phase of acetonitrile: methanol: deionized water, pH 2.8 (25.0: 35.0: 40.0, v/v/v), at 254 nm. A kinetic study utilizing the developed HPLC method for PDN degradation under different stress conditions was performed. Furthermore, the method was applied for determination in rabbit aqueous humor. Validation was conducted as per ICH guidelines, and system suitability was ascertained. The calibration curves were constructed in the range 0.10-25.00 and 0.20-50.00 μg band-1, for PDN and MXF by HPTLC, while for HPLC, it was 0.02-50.00 and 0.10-50.00 μg mL-1 for both drugs, in order.

Determination of Cimetidine, Famotidine, and Ranitidine Hydrochloride in the Presence of Their Sulfoxide Derivatives in Pure and Dosage Forms by High-Performance Thin-Layer Chromatography and Scanning Densitometry

A selective, precise, and accurate method was developed for the determination of cimetidine (C), famotidine (F), and ranitidine hydrochloride (R·HCI)in the presence of their sulfoxide derivatives. The method involves quantitative densitometric evaluation of mixtures of the drugs and their derivatives after separation by high-performance thin-layer chromatography on silica gel plates (10 × 20 cm) with ethyl acetate–isopropanol–20% ammonia (9 + 5 + 4, v/v) as the mobile phase for both C and F and ethyl acetate–methanol–20% ammonia (10 + 2 + 2, v/v) as the mobile phase for R·HCI; Rf values for C, F, and R·HCI and their corresponding derivatives were 0.85 and 0.59, 0.73 and 0.41, and 0.56 and 0.33, respectively. Developing time was approximately 20 min. For densitometric evaluation, peak areas were recorded at 218, 265, and 313 nm for C, F, and R·HCI, respectively. The relationship between concentration and the corresponding peak area was plotted for the ranges of 5–50 μg/spot for C and 2–20 μg/spot for F and R·HCl. Mean recoveries were 100.39 ± 1.33, 99.77 ± 1.30, and 100.09 ± 0.69% for C, F, and R·HCI, respectively. The proposed method was used successfully for stability testing of the pure drugs in the presence of up to 90% of their degradates, in bulk powder and dosage forms. The results obtained were analyzed statistically and compared with those obtained by the official methods.

Bilinear and trilinear algorithms utilizing full and selected variables for resolution and quantitation of four components with overlapped spectral signals in bulk and syrup dosage form

Spectrophotometric-assisted chemometric techniques are beneficial for resolving spectral overlapping and are considered comparable to traditional chromatographic methods. In this work, different chemometric approaches were applied for simultaneous determination of Bromhexine HCl (BRHX), Guaifenesin (GUA) and Salbutamol sulphate (SALB) in the presence of Guaiacol (GUAIA), without any prior separation. Two-way and three-way techniques were applied. The resolving power of genetic algorithm (GA-PLS), trilinear partial least square (N-PLS) and multivariate curve resolution (MCR-ALS) were investigated. A set of 17 synthetic samples in the concentration range 10.0-30.0 μg/mL of BRHX, GUA and SALB and 6.0-10.0 μg/mL of GUAIA were used in the construction of the calibration models. Commercially available syrup dosage form was successfully analyzed by the developed methods without interference from formulation additives. The developed models were evaluated through calculation of root mean squared error of prediction (RMSEP), the obtained values were 0.263, 0.419 and 0.342 for BRHX, 0.254, 0.318 and 0.503 for GUA and 0.298, 0.268 and 0.302 for SALB using N-PLS, MCR-ALS and GA-PLS, respectively. The resolving power of the developed models was emphasized through comparison with a reported HPLC method, where no significant difference was found regarding both accuracy and precision.