Development and Evaluation of Chemometric Models for the Estimation of Sumatriptan in the Presence of Naproxen and a Degradation Product Using UV Spectrophotometry.

BACKGROUND: Chemometrics is a discipline that allows the spectral resolution of drugs in a pharmaceutical formulation along with degradation product and it is as an alternative to chromatographic methods. OBJECTIVE: Sumatriptan (SUM) is co-formulated with naproxen (NAP) and used in acute migraine attacks. SUM which has physiological importance has not been subjected to any stability-indicating chemometric approaches yet so there is a need for accurate and safe method for the assay of the cited drug in their preparation. SUM was determined in pharmaceutical formulation along with NAP and in presence of alkali-induced degradation product with simple and cost-effective multivariate approaches using spectrophotometric data. The greenness and blueness assessment was applied using different ecological metrics, including green analytical procedure index (GAPI), analytical greenness metric (AGREE), analytical eco-scale (AES) & new "blueness" evaluation using BAGI tool, respectively. METHODS: Three chemometric approaches were applied for the stability-indicating determination of SUM in presence of NAP. Classical least squares (CLS), Partial least squares (PLS) and Principal components regression (PCR), three multivariate calibration numerical models that were performed on the UV- spectra of the mixtures, were used to achieve the best resolution. RESULTS: Sumatriptan was analyzed with mean accuracies for PLS (100.29 ± 1.318) and for PCR (100.60 ± 1.564). The presented methods were compared and validated for their quantitative analyses. Moreover, statistical comparison between the results obtained by the proposed models and the official methods showed no significant differences. CONCLUSION: The proposed multivariate calibrations were accurate and specific for quantitative analysis of the studied component. PLS is the best method that has the capacity for qualitative analysis of SUM and it is suitable for routine analysis and stability studies of it in quality control laboratories. Various ecological assessment metrics confirmed the long-standing eco-friendliness of the suggested models.

A novel green spectrofluorimetric method for simultaneous determination of antazoline and tetryzoline in their ophthalmic formulation.

A novel spectrofluorimetric method has been developed for determination of antazoline (ANT) and tetryzoline (TET) in their pharmaceutical formulation. A combined application of synchronous spectrofluorimetry and second derivative mathematical treatment was developed. The proposed method depends on reacting the cited drugs with dansyl chloride (DNS-Cl) being a suitable derivatizing agent generating highly fluorescent derivatives measured at emission wavelengths of 703.0 and 642.0 nm after excitation wavelengths of 350.0 and 320.0 nm for ANT and TET, respectively. The joint use of synchronous spectrofluorimetry with second derivative mathematical treatment is for the first time to be developed and optimized in aid of using fluorescence data manager software generating second derivative peak amplitudes at 556.5 nm for ANT and 516.7 nm for TET. Linear responses have been represented over a wide range of concentration (0.5-12.0 µg/mL for ANT and 0.5-10.0 µg/mL for TET). Additionally, statistical comparison of the developed method with the official ones has been carried out where no significant difference was found. Additionally, greenness profile assessment was accomplished by means of four metric tools. Indeed, the method developed is found to be precise, sensitive, and discriminating to assess the cited drugs for regular analysis.

A Novel Spectrofluorimetric Determination of Antazoline and Xylometazoline in their Ophthalmic Formulation; Green Approach and Evaluation.

A green developed spectrofluorimetric method has been applied for Antazoline (ANT) and Xylometazoline (XLO) determination in both pharmaceutical formulation and pure form. The developed method is synchronous spectrofluorimetry coupled with the second derivative mathematical tool for the determination of antazoline and xylometazoline in their dosage form. The developed method depends on reacting the cited drugs with dansyl chloride, a suitable derivatizing agent, to generate highly fluorescent derivatives. The products formed were measured at emission wavelengths; 703.0 and 712.0 nm after being excited at wavelengths; 350.0 and 355.0 nm for antazoline and xylometazoline, respectively. Synchronous spectrofluorimetry coupled with second derivative mathematical tool was developed and optimized using fluorescence data manager software generating second derivative peak amplitudes at 556.5 nm for antazoline and 598.0 nm for xylometazoline. Linear responses have been represented over a wide range of concentration 0.5-12.0 µg/mL for antazoline and 0.1-10.0 µg/mL for xylometazoline, correspondingly. Method validation was successfully applied. Additionally, statistical comparison of developed method with official ones has been carried out where no significant difference was found. Evaluation of the method's greenness was proven using several assessment tools. Indeed, the method developed is found to be precise, sensitive, and discriminating to assess the cited drugs for regular analysis.

Exquisite integration of quality-by-design and green analytical approaches for simultaneous determination of xylometazoline and antazoline in eye drops and rabbit aqueous humor, application to stability study.

This work implements a stability indicating HPLC method developed to simultaneously determine xylometazoline (XYLO) and antazoline (ANT) in their binary mixture, rabbit aqueous humor and cited drug's degradates by applying analytical quality-by-design (AQbD) combined with green analytical chemistry (GAC) experiment for the first time. This integration was designed to maximize efficiency and minimize environmental impacts, as well as energy and solvent consumption. Analytical quality-by-design was applied to achieve our aim starting with evaluation of quality risk and scouting analysis, tracked via five parameters chromatographic screening using Placket-Burman design namely: pH, temperature, organic solvent percentage, flow rate, and wavelength detection. Recognizing the critical method parameters was done followed by optimization employing central composite design and Derringer's desirability toward assess optimum conditions that attained best resolution with satisfactory peak symmetry with short run time. Optimal chromatographic separation was attained by means of an XBridge® C18 (4.6 × 250 mm, 5 µm) column through isocratic elution using a mobile phase consists of phosphate buffer (pH 3.0): ethanol (60:40, by volume) at a 1.6 mL/min flow rate and 230.0 nm UV detection. Linearity acquired over a concentration range of 1.0-100.0 µg/mL and 0.5-100.0 µg/mL for XYLO and ANT, respectively. Furthermore, imperiling cited drugs' stock solutions to stress various conditions and satisfactory peaks of degradation products were obtained indicating that cited drugs are vulnerable to oxidative degradation and basic hydrolysis. Degradates' structures were elucidated using mass spectrometry. Applying various assessment tools; namely: analytical greenness (AGREE), green analytical procedure index (GAPI), analytical eco-scale, and national environmental method index (NEMI), Greenness method's evaluation was applied and proved to be green. In fact, the developed method is established to be perceptive, accurate, and selective to assess cited drugs for routine analysis.

Green TLC-Densitometric Method for Simultaneous Determination of Antazoline and Tetryzoline: Application to Pharmaceutical Formulation and Rabbit Aqueous Humor.

Ophthalmic pharmaceutical preparation containing antazoline (ANT) and tetryzoline (TET) is prescribed widely as an over the counter medication for allergic conjunctivitis treatment. Development of a selective, simple and environmentally friendly thin-layer chromatographic method established to determine both ANT and TET in their pure forms, pharmaceutical formulation and spiked aqueous humor samples. By using silica gel plates and means of a developing system consists of ethyl acetate:ethanol (5:5, by volume), the studied drugs separation was achieved, and scanning was carried out at 220.0 nm for the separated bands with a 0.2-18.0 µg/band concentration range for each of ANT and TET. Standard addition technique application was carried out to determine the proposed method validity. Statistical comparison was made between the proposed method and the official methods ANT and TET showing no significant difference concerning accuracy and precision. Furthermore, greenness profile assessment was accomplished by means of four metric tools, namely, analytical greenness, green analytical procedure index, analytical eco-scale and national environmental method index.Highlights.

A novel smartphone HPTLC assaying platform versus traditional densitometric method for simultaneous quantification of alfuzosin and solifenacin in their dosage forms as well as monitoring content uniformity and drug residues on the manufacturing equipment.

The large popularity and rapid technology of smartphones have opened new avenues for their integration into different analytical methodologies and drug quality monitoring as a portable, easily accessible, and user-friendly detector. Herein, a novel and portable smartphone-based high-performance thin layer chromatographic (HPTLC) approach is proposed for the simultaneous analysis of two urological drugs, alfuzosin and solifenacin, which treat benign prostatic hyperplasia accompanied by overactive bladder syndrome. First, chromatographic separation was accomplished using an ecofriendly mobile phase, then the developed plates were visualized using Dragendorff's reagent and photographed via a smartphone's rear-facing camera fixed on a fabricated two-illumination-source chamber. The intensities of the drug spots were quantified using open-source image analysis software ImageJ over the concentration ranges of 2.0 to 30.0 µg per band for both drugs with acceptable results in ICH validation parameters. To improve the method's accuracy and reproducibility, various construction and shooting key parameters were investigated and optimized. Moreover, the study was extended to compare the obtained results with those of a benchtop densitometric method using a Camag TLC Scanner 3 at 215.0 nm; the densitometric method provided an additional assessment tool for peak purity and was capable of assaying lower drug concentrations over a linearity range of 0.2-8.0 µg per band for alfuzosin and 0.1-6.0 µg per band for solifenacin. The fast, simple, reliable, green merits of the proposed HPTLC/smartphone method suggest that it is an excellent platform for assaying marketed combined capsules and assuring their content uniformity. Moreover, the high sensitivity of the densitometric method was used, for the first time, to determine the residual content of the cited drugs on manufacturing equipment surfaces for cleaning validation. Finally, the environmental impact of the developed methods was evaluated based on green analytical chemistry principles.

Spectrophotometric platform windows' exploitation for the green determination of Alcaftadine in presence of its oxidative degradation product.

This study presents the determination of Alcaftadine (ALF) in its oxidative degradation product presence by applying comprehensive study comparative of four different green stability indicating spectrophotometric approaches through successful exploitation of different spectrophotometric platform windows. Window I; based on absorption spectrum zero order data manipulation using the newly developed extended absorbance difference (EAD). Window II; based on derivative spectra by second order derivative (D2) data manipulation. Window III; based on ratio spectra applying constant multiplication (CM) and absorptivity centering via factorized ratio difference spectrum (ACT-FSRΔP) methods data manipulation. Finally, window IV; based on derivative of ratio spectrum by virtue of first derivative of ratio spectral (DD1) method data manipulation. Calibration curves construction were over linearity range; 1.0-14.0 µg/mL for ALF. The proposed methods accuracy, precision, and linearity range were determined and validated as per ICH guidelines. Moreover, they were able to analyze ALF in raw form, dosage form and in existence of its oxidative degradation product. Statistical comparisons were done between the proposed methods and the reported one showing no significant difference concerning accuracy and precision. Furthermore, greenness profile assessment was accomplished by means of four metric tools; namely: analytical greenness (AGREE), green analytical procedure index (GAPI), analytical eco-scale, and national environmental method index (NEMI).

Does the Ethnic Difference Affect the Pharmacokinetics of Favipiravir? A Pharmacokinetic Study in Healthy Egyptian Volunteers and Development of Level C In-vitro In-vivo Correlation.

Favipiravir is an antiviral drug used to treat influenza and is also being investigated for the treatment of SARS-CoV-2. Its pharmacokinetic profile varies depending on ethnic group. The present research examines the pharmacokinetic features of favipiravir in healthy male Egyptian volunteers. Another goal of this research is to determine the optimum dissolution testing conditions for immediate release tablets. In vitro dissolution testing was investigated for favipiravir tablets in three different pH media. The pharmacokinetic features of favipiravir were examined in 27 healthy male Egyptian volunteers. The parameter "AUC0-t" vs. percent dissolved was used to develop level C in vitro in vivo correlation (IVIVC) to set the optimum dissolution medium to achieve accurate dissolution profile for favipiravir (IR) tablets. The in vitro release results revealed significant difference among the three different dissolution media. The Pk parameters of twenty-seven human subjects showed mean value of Cpmax of 5966.45 ng/mL at median tmax of 0.75 h with AUC0-∞ equals 13325.54 ng.h/mL, showing half-life of 1.25 h. Level C IVIVC was developed successfully. It was concluded that Egyptian volunteers had comparable Pk values to American and Caucasian volunteers, however they were considerably different from Japanese subjects. AUC0-t vs. % dissolved was used to develop level C IVIVC to set the optimum dissolution medium. Phosphate buffer medium (pH 6.8) was found to be the optimum dissolution medium for in vitro dissolution testing for Favipiravir IR tablets.

Novel solid-contact ion-selective electrode based on a polyaniline transducer layer for determination of alcaftadine in biological fluid.

Fabrication of a novel ion selective electrode for determining alcaftadine was achieved. The glassy carbon electrode (GCE) was utilized as a substrate in fabrication of an electrochemical sensor containing polyaniline (PANI) as an ion-to-electron transducer layer. A PVC polymeric matrix and nitrophenyl-octyl-ether were employed in designing the ion-sensing membrane (ISM). Potential stability was improved and minimization of electrical signal drift was achieved for inhibition of water layer formation at the electrode interface. Potential stability was achieved by inclusion of PANI between the electronic substrate and the ion-sensing membrane. The sensor's performance was evaluated following IUPAC recommendations. The sensor dynamic linear range was from 1.0 × 10-2 to 1.0 × 10-6 mol L-1 and it had a 6.3 × 10-7 mol L-1 detection limit. The selectivity and capabilities of the formed alcaftadine sensor were tested in the presence of its pharmaceutical formulation excipients as well as its degradation products. Additionally, the sensor was capable of quantifying the studied drug in a rabbit aqueous humor. Method's greenness profile was evaluated by the means of Analytical Greenness (AGREE) metric assessment tool.

LC-MS/MS-based metabolite quantitation of the antiviral prodrug baloxavir marboxil, a new therapy for acute uncomplicated influenza, in human plasma: Application to a human pharmacokinetic study.

Baloxavir marboxil (BXM) is a novel orally administrated prodrug for the treatment of acute uncomplicated influenza. In the present study, a bioanalytical LC-MS/MS method was developed and validated for the quantification of baloxavir acid (BXA), the active form of baloxavir marboxil in plasma of healthy volunteers using dolutegravir as an internal standard (IS) following plasma protein precipitation with acetonitrile. BXA and the internal standard were chromatographically separated using Waters Xterra® MS C8 column (5 µm, 4.6 × 50 mm) and a mobile phase comprised of 10.0 mM ammonium formate pH 3.5 and acetonitrile (80:20, v/v) delivered at a flow rate of 0.6 mL/min. The transitions of m/z 484.00 → 247.0 and 420.30 → 277.1 for BXA and IS, respectively in multiple reaction monitoring (MRM) mode in a positive ESI interface were used for quantitation through triple-quad mass spectrometry, API 4000. The method linearity was proven across the concentration range of 0.5-200.0 ng/mL, adjusted, and validated completely in accordance with the bioanalytical guidelines of the United States-FDA. Finally, the present method was effectively applied for the pharmacokinetic study of BXA in healthy human volunteers with accepted reproducibility and ruggedness.

High performance anion exchange chromatographic and colorimetric methods for quality assessment of total and free polysaccharide content in Haemophilus influenzae type b conjugate vaccine containing lactose.

The presence of lactose as a stabilizer in Haemophilus influenzae type b (Hib) conjugate vaccine is a challenge for chromatographic resolution of its total and free poly ribosyl ribitol phosphate (PRP) content. Sample pretreatment using ultrafiltration was performed and had removed ≥95% of lactose in shorter time compared to the conventional dialysis process. Separation of free unconjugated PRP was performed using solid-phase extraction C4 cartridges. Hib conjugate vaccine was then analyzed for determination of total and free PRP, using two validated techniques: high performance anion exchange chromatography with pulsed amperometry (HPAEC-PAD) for ribitol determination and a colorimetric assay for phosphorus determination. Lactose removal had enabled a rapid chromatographic assay via fast depolymerization of PRP using high temperature treatment. Modifying the burning process in the colorimetric assay reduced the analysis time significantly compared to the pharmacopoeial method. Linearity was obtained over the range of 0.10-10.0 µg mL-1 for the HPAEC method and in the range of 1.0-8.0 µg mL-1 for the colorimetric one. Stability of Hib conjugate vaccine was investigated. The HPAEC results revealed about a 35% increase in free PRP content after storage under stressed conditions (moisture and temperature). The proposed methods offered a reliable and economic platform for assessing the immunogenicity, efficacy and stability of Hib conjugate vaccine containing lactose for the biopharmaceutical industry.

A validated LC-MS/MS method for determination of antiviral prodrug molnupiravir in human plasma and its application for a pharmacokinetic modeling study in healthy Egyptian volunteers.

A fully validated, simple, rapid and reproducible liquid chromatography-tandem mass spectrometry method was developed to determine NHC (N-hydroxycytidine), the active metabolite of Molnupiravir (MOL) in human plasma; one of the limited treatment options for SARS-CoV-2 in plasma of healthy volunteers. The internal standard (IS) used was ribavirin. The extraction of analyte and IS from plasma was performed using acetonitrile as a solvent for protein precipitation. Agilent Zorbax Eclipse plus C18, 4.6 × 150 mm, (5 µm) was used for chromatographic separation using a mixture of methanol0.2 % acetic acid (5:95, v/v) as a mobile phase that was pumped at a flow rate of 0.9 mL/min. Detection was performed on a triple quadrupole mass spectrometer operating in multiple reaction monitoring (MRM) employing positive ESI interface using API4500 triple quadrupole tandem mass spectrometer system, with the transitions set at m/z 260.10 â†’ 128.10 and 245.10 â†’ 113.20 for NHC and IS respectively. Method validation was performed in accordance with United States FDA bioanalytical guidance. The concentration range of 20.0-10000.0 ng/mL was used to establish linearity via weighted linear regression approach (1/x2). Moreover, the analyzed pharmacokinetic data from twelve Egyptian healthy volunteers were used to develop a population pharmacokinetic model for NHC. The developed model was used to perform simulations and evaluate the current MOL dosing recommendations through calculating the maximum concentration (Cmax) "the safety metric" and area under the curve (AUC0-12 h) "the efficacy metric" for 1000 virtual subjects. Geometric mean ratios (GMR) with their associated 90% confidence intervals (CI) compared to literature values were computed. Geometric means of simulation-based Cmax and AUC0-12 were 3827 ng/mL (GMR = 1.05; 90% CI = 0.96-1.15) and 9320 ng.h/mL (GMR = 1.04; 90% CI = 0.97-1.11), respectively indicating that current MOL dosage can achieve the therapeutic targets and dose adjustment may not be required for the Egyptian population. The developed model could be used in the future to refine MOL dosage once further therapeutic targets are identified.

Molecular size distribution assessment of Haemophilus influenzae vaccine containing lactose by HPAEC-PAD and colorimetric assays.

Molecular size distribution of Haemophilus influenzae type b (Hib) conjugate vaccine is an important indicator for its immunogenicity and stability. Molecular size distribution was evaluated by High-Performance Protein Chromatography on Sepharose CL-4B column, and fractions were pooled. The use of high flow rate, incorporation of a calibration standard with the injected buffer and pooling method yielded a superior assay compared to conventional pharmacopeial method. The pools were analyzed for determination of distribution coefficient (KD) of 0.2 and 0.5 using two validated techniques: High Performance Anion Exchange Chromatography with pulsed amperometric detection (HPAEC-PAD) for ribitol determination and an optimized colorimetric assay for phosphorus determination. Linearity was achieved over range of 0.10-10.0 µg/mL and 1.0-8.0 µg/mL with LOD of 0.03 and 0.28 µg/mL for HPAEC and colorimetric assays, respectively. The developed assays were successfully applied in quality control monitoring of Hib conjugate vaccine. The optimized colorimetric method had shortened the analysis time to 25 min compared to 3.5 h for the European pharmacopeial assay by modifying the burning process. HPAEC stability results revealed 40% decrease in MSD after stressed storage conditions. The proposed assays offer a reliable and economic platform for monitoring the quality attributes of Hib for biopharma industry.

A sensing platform of molecular imprinted polymer-based polyaniline/carbon paste electrodes for simultaneous potentiometric determination of alfuzosin and solifenacin in binary co-formulation and spiked plasma.

Solid contact ion-selective electrodes (ISEs) have witnessed versatile applications in pharmaceutical and biological analysis however they suffer from some limitations. Besides formation of water layer, the doped ion exchanger in sensing membrane fails to distinguish between two ionic species having relatively similar lipophilicity and carrying same charges. Those shortcomings practically hampered the simultaneous determination of alfuzosin and solifenacin in their combined pharmaceutical combination. Hence, this paper was directed to develop two carbon paste electrodes allowing their simultaneous determination based on molecular imprinted polymers (MIPs). Efforts were firstly directed to stabilize the potential signals through synthesis of polyaniline (PANI) nanoparticles with 26 nm particle size as confirmed by means of UV-spectrophotometry, Zeta-sizer and transmission electron microscope. This was followed by its doping at electrode/ion selective membrane interface leading to diminished potential drift, better Nernstian slopes and lower limit of detections. Secondly, MIPs for each drug were prepared by precipitation polymerization technique and fully characterized by Fourier-transform infrared spectroscopy, field-emission scanning electron microscope, differential scanning calorimetry, surface area analysis and rebinding studies. The prepared MIPs were then incorporated in membrane cocktail and doped over PANI layer. The graved cavities inside MIPs act as synthetic host-tailored receptors that could recognize and bind specifically to each drug. The obtained Nernstian slopes were 57.16 mV/decade for alfuzosin MIP-based sensor and 58.17 mV/decade for solifenacin MIP-based one with respective LOD values of 7.9 × 10-7 M and 8.9 × 10-8 M. Moreover, no interference was ostensibly detected from dosage form excipients, plasma constituents or degradation products/official impurities allowing quantification of alfuzosin and solifenacin in their combined capsule, spiked human plasma and in presence of their degradation products.

Fingerprinting and iso-absorptive resolution techniques for the spectrally overlapping Dutasteride and Silodosin mixture: Content uniformity testing along with greenness profile assessment.

The realm of spectrophotometric analysis has witnessed a remarkable progress in inventing faster and simpler resolution techniques for spectrally overlapping drug mixtures. Eco-friendly and progressive spectrophotometric methods were firstly developed in this work, for the simultaneous determination of Dutasteride (DUT) and Silodosin (SLD) in their newly-marketed dosage form. The proposed methods focused on the unique spectral features of this mixture including spectral extension of SLD over DUT spectrum as well as existence of iso-absorptive points. By such way, the methods were classified into two categories; the first one was "fingerprint resolution techniques" including constant extraction coupled with spectrum subtraction and ratio subtraction coupled with constant multiplication methods. The former represented a new modification to the classical constant extraction method where one divisor and lower steps were manipulated instead. The second category was "iso-absorptive resolution techniques", such as absorptivity centering, absorbance subtraction and amplitude modulation methods. Different solvents were investigated where ethanol was found to be the optimum one regarding drugs solubility, signal sensitivity and environmental, health & safety (EHS) score. Validity of the suggested methods was assessed as per ICH-guidelines and found to be linear over concentration ranges of 5.0-90.0 µg/mL for DUT and 5.0-120.0 µg/mL for SLD. The methods were successfully applied for quantifying the cited drugs in their combined dosage form and evaluating their content uniformity. Moreover, the insignificant statistical difference between the proposed methods and official HPLC ones encourages the utilization of such spectrophotometric methods as greener and faster candidates, especially in modest quality control laboratories. Methods' greenness profile was finally guaranteed through several assessment tools, namely; national environmental methods index (NEMI), analytical eco-scale, green analytical procedure index (GAPI) and analytical greenness (AGREE) metric.

A novel stability-indicating HPLC-DAD method for determination of favipiravir, a potential antiviral drug for COVID-19 treatment; application to degradation kinetic studies and in-vitro dissolution profiling.

Modern pharmaceutical analysis is paying a lot of attention to the stability of novel drug formulations as well as establishment of suitable stability-indicating approaches. In the current work, a comprehensive stability-indicating HPLC-DAD method has been developed and validated for determination of favipiravir (FAV) which is a novel and emerging antiviral option in COVID-19 treatment. The stability of FAV was examined under different stress conditions. FAV was found to be susceptible to acid, base hydrolysis and oxidative degradation. Structure elucidation of the forced degradation products was carried out using mass spectrometry (MS) operated in electrospray ionization mode. Effective separation of FAV and its induced degradation products was achieved using isocratic elution mode on Zorbax C18 column maintained at 30 °C. The mobile phase used was comprised of 25.0 mM phosphate buffer (pH 3.5 ± 0.05) containing 0.1% (w/v) heptane sulphonic acid sodium salt-methanol-acetonitrile (62:28:10, by volume), delivered at flow rate of 1.0 mL/min. The diode array detector signal for FAV was monitored at 321.0 nm over a concentration range of 6.25-250.00 µg/mL. The potential mechanisms for generation of degradation products were postulated through comparison of MS1 fragmentation pattern of FAV and its degradation products. Moreover, the proposed method was also extended to study the degradation kinetics. Additionally, dissolution profiling of FAV in different media was monitored. Clearly, the suggested approach is accurate, reliable, time-saving, and cost-effective. As a result, it may be utilized for regular quality control and stability assessment of FAV in its tablet dosage form.

Stability-Indicating Determination of Tedizolid Phosphate in the Presence of its Active Form and Possible Degradants.

Tedizolid phosphate is an antibiotic prodrug that is metabolized into tedizolid which is used against various resistant bacterial strains. In this study, tedizolid phosphate was subjected to stress degradation conditions, namely, hydrolysis (neutral, acidic and alkaline), thermal, oxidative and photolytic ones. The prodrug was stable toward thermal and photolytic stress conditions, while it showed significant degradation upon applying oxidative and hydrolytic conditions. Two suggested chromatographic methods are described for separation and determination of tedizolid phosphate from the resulted degradation products. The first method is HPLC using Waters Xselect HSS C18 (250 × 4.6 mm, 5 µm) analytical column and mobile phase composed of phosphate buffer (50 mM, pH 6.5):acetonitrile (70:30, %v/v) pumped at flow rate of 1.0 mL/min with UV-detection at 300 nm. The second method is a TLC coupled with densitometric quantitation, precoated silica TLC-plates as a stationary phase and a mobile phase of methanol:butanol:ethyl acetate:ammonia (33%, w/v) (60:20:20:10,%v/v) were used. The chromatographed plates were scanned at 300 nm. The linearity was confirmed over concentration range of 1-100 µg/mL and 1-12 µg/band for HPLC and TLC-densitometric methods, respectively. Both methods were found to be suitable for determination of tedizolid phosphate in pure form and in its pharmaceutical formulations.

Eco-Friendly Chromatographic Methods for Determination of Acemetacin and Indomethacin; Greenness Profile Assessment.

BACKGROUND: The green chemistry approach was developed for the purpose of saving the environment by using green solvents. Applying green analytical chemistry principles to traditional methods is considered a challenge. Acemetacin is a commonly used analgesic prodrug that bioactivates to indomethacin. OBJECTIVE: Developing two simple, eco-friendly chromatographic methods for simultaneous determination of acemetacin and indomethacin. METHOD: The first method is HPLC-DAD. Separation was performed on a Waters XBridge® Shield RP18 (250 × 4.6 mm, 5 µm) analytical column with ethanol-ammonium acetate buffer (50 mM, pH 3.5 ± 0.1; 60:40, v/v) as a mobile phase at a flow rate of 1 mL/min at 25 ± 0.5°C and UV detection at 254 nm. The other method is TLC coupled with densitometric quantification using pre-coated silica TLC plates and butanol-ethyl acetate (70:30, v/v) elution system. The plates were scanned at 254 nm. RESULTS: Both methods were validated according to International Conference on Harmonization guidelines. Linearity was confirmed for both over a concentration range of 1-100 µg/mL for the HPLC method and 0.2-7 µg/band for TLC-densitometric method. The methods' greenness was evaluated by the National Environmental Methods Index, Eco-Scale, Green Analytical Procedure Index metrics and Analytical GREEnness Metric Approach. CONCLUSIONS: The proposed methods were found to be suitable for determination of studied drugs in their marketed formulations and is suggested for routine analysis in quality control laboratories. HIGHLIGHTS: The developed HPLC method shortened the elution time of the analyzed drugs saving more time and money and the TLC method lowered the drugs' detection limit. HPLC and TLC methods were validated for the assay of acemetacin and indomethacin. The methods' greenness was evaluated and compared to published methods. The developed HPLC method shortened the elution time of the analyzed drugs, saving time and money and the TLC method lowered the drugs' detection limit.

Chaotropic salts impact in HPLC approaches for simultaneous analysis of hydrophilic and lipophilic drugs.

Simultaneous determination of drugs with different physicochemical properties necessitates thorough research and careful selection of high-performance liquid chromatography conditions. In the present study, various concepts of high-performance liquid chromatography method development for this aim have been discussed. Moreover, the work was motivated by the advantages of utilizing different chaotropic anions as a new promising approach to overcome the limitations of ion-pairing agents commonly used for this purpose. Based on log P values, atorvastatin (log P = 6.36) and lisinopril (log P = -1.22) were chosen as representative examples for lipophilic and hydrophilic drugs, respectively. Several simple, economic, fast, and reliable high-performance liquid chromatography methods were developed for their simultaneous analysis and are presented in a comparative manner, highlighting their advantages and limitations. Peak elution profile showed satisfying retentions and resolution about 3. Photo-diode array calculations were exploited for identifying the molecules by their ultra-violet spectra and peak purity, calculated and presented as rectangular-shaped ratio grams. The linearity check showed excellent results and satisfactory system suitability parameters of both peaks. This confirms the investigation results and conclusions for the influence of the chaotropic salts on N-containing molecules, by increasing their retentivities, and improving peak shapes, even on different quality columns without end-capping and base-deactivating of separation matrixes.

A novel LC-MS/MS method for determination of the potential antiviral candidate favipiravir for the emergency treatment of SARS-CoV-2 virus in human plasma: Application to a bioequivalence study in Egyptian human volunteers.

A novel, fast and sensitive LC-MS/MS method was developed and validated for the bioanalysis of the antiviral agent favipiravir (FAV); a promising candidate for treatment of SARS-CoV-2 (COVID-19) in human plasma using pyrazinamide as an internal standard (IS). Simple protein precipitation was adopted for plasma sample preparation using methanol. Chromatographic separation was accomplished on Eclipse plus C18 column (50 × 4.6 mm, 3.5 µm) using a mobile phase composed of methanol-0.2 % acetic acid (20:80, v/v) pumped at a flow rate 0.6 mL/min in an isocratic elution mode. The API4500 triple quadrupole tandem mass spectrometer was operated with multiple-reaction monitoring (MRM) in negative electrospray ionization interface for FAV and positive for IS. The MRM function was used for quantification, with the transitions set at m/z 156.00→ 113.00 and m/z 124.80→ 81.00 for FAV and IS. The method was optimized and fully validated in accordance to US-FDA guidelines. Linearity was acquired over a concentration range of 100.0-20000.0 ng/mL by computing using weighted linear regression strategy (1/x2). The proposed method was effectively applied for the pharmacokinetic evaluation of FAV and to demonstrate the bioequivalence of a new FAV formulation (test) and reference product in healthy Egyptian human volunteers.