Development of a fluorescent nano-sensing probe for atomoxetine analysis: Additional clinical pharmacokinetic study.

Atomoxetine is a psychostimulant drug used for the treatment of attention-deficit/hyperactivity disorder (ADHD) symptoms in people with autism. Herein, eco-friendly fluorescent carbon quantum dots (CQDs) were synthesized using black-eyed pea beans and characterized for the purpose of quantifying atomoxetine in pharmaceutical capsules and human plasma. The selectivity of these CQDs towards atomoxetine was improved by functionalizing their surface with an atomoxetine-tetraphenylborate ion complex. The quantification of atomoxetine is based on measuring the fluorescence quenching of the functionalized CQDs in response to varying concentrations of atomoxetine. The Stern-Volmer plot was employed to investigate the mechanism through which atomoxetine quenches the fluorescence intensity of the CQDs. The outcomes indicated a dynamic quenching mechanism. The applied method was optimized and validated in compliance with ICH requirements, resulting in excellent linearity across the concentration range of 50-800 ng/mL. The developed method was successfully used to quantify atomoxetine in pharmaceutical dosage form and human plasma with acceptable accuracy and precision outcomes. In addition, the method was applied for clinical pharmacokinetic study of atomoxetine in the plasma of children diagnosed with both autism and ADHD. Atomoxetine was rapidly absorbed after a single oral dose of 10 mg, reaching maximum concentration within two hours and having a half-life (t1/2) of 3.11 h. Moreover, the method demonstrates a notable degree of eco-friendliness, as evidenced by two greenness evaluation metrics; Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE).

Spectrophotometric determination of celecoxib and tramadol in the new approved formulated dosage form using principle component regression assistive model.

Celecoxib and tramadol have been combined in a novel FDA-approved medication to address acute pain disorders requiring opioid treatment when other analgesics proved either intolerable or ineffective. The absorbance spectra of celecoxib and tramadol exhibit significant overlap, posing challenges for their individual quantification. This study introduces a spectrophotometric quantification approach for celecoxib and tramadol using a principle component regression assistive model to assist resolving the overlapped spectra and quantifying both drugs in their binary mixture. The model was constructed by establishing calibration and validation sets for the celecoxib and tramadol mixture, employing a five-level, two-factor experimental design, resulting in 25 samples. Spectral data from these mixtures were measured and preprocessed to eliminate noise in the 200-210 nm range and zero absorbance values in the 290-400 nm range. Consequently, the dataset was streamlined to 81 variables. The predicted concentrations were compared with the known concentrations of celecoxib and tramadol, and the errors in the predictions were evidenced calculating root mean square error of cross-validation and root mean square error of prediction. Validation results demonstrate the efficacy of the models in predicting outcomes; recovery rates approaching 100 % are demonstrated with relative root mean square error of prediction (RRMSEP) values of 0.052 and 0.164 for tramadol and celecoxib, respectively. The selectivity was further evaluated by quantifying celecoxib and tramadol in the presence of potentially interfering drugs. The model demonstrated success in quantifying celecoxib and tramadol in laboratory-prepared tablets, producing metrics consistent with those reported in previously established spectrophotometric methods.

Utilization of absorbance subtraction and ratio difference green spectrophotometric methods for the quantification of alfuzosin hydrochloride and tadalafil in their binary mixture.

Alfuzosin hydrochloride and tadalafil fixed-dose combination tablets were recently formulated for the treatment of individuals with lower urinary tract symptoms caused by benign prostatic hyperplasia. Herein, the first spectrophotometric methods for quantitative analysis of alfuzosin hydrochloride and tadalafil in their binary mixture were established. The spectral overlapping of alfuzosin hydrochloride and tadalafil made direct simultaneous analysis unfeasible. Therefore, two mathematical methods were used to solve these overlapping spectra: absorbance subtraction and ratio difference. The absorbance subtraction method manipulates the zero absorption spectra of the studied drugs at the isoabsorptive point (272 nm) and uses the absorbance factor of pure ALF to calculate the absorbance of the studied drugs in the mixture at the isoabsorptive point. The ratio spectra method, on the other hand, manipulates the ratio spectra of the studied drugs, which are obtained by dividing each drug's zero absorption spectra by a divisor spectrum from the second drug. The ratio amplitude difference between 251 nm and 211 nm was directly proportional to alfuzosin hydrochloride, whereas between 292 nm and 222 nm it was directly proportional to tadalafil. The methods used were verified in accordance with the recommendations of the ICH and demonstrated adequate linear regression in working ranges of 1-15 µg/mL for alfuzosin hydrochloride and 3-40 µg/mL for tadalafil. The methods were accurate, precise, and selectively employed to quantify alfuzosin hydrochloride and tadalafil in their combined tablets.

Development of a highly sensitive and green first-derivative synchronous fluorescence spectroscopic method for the simultaneous quantification of telmisartan and rosuvastatin: Greenness metric assessment and application to a pharmacokinetic study in rats.

Hypertension and hyperlipidemia frequently coexist and are correlated with elevated cardiovascular adverse outcomes. Fixed dose combination tablets containing antihypertensive and antihyperlipidemic drugs have the potential to improve patient compliance. Telmisartan and rosuvastatin fixed dose combination tablet has been recently formulated. This study provided the first fluorescence spectroscopic method for simultaneously quantifying telmisartan and rosuvastatin in tablet dosage form and plasma. The native fluorescence spectra of telmisartan and rosuvastatin completely overlapped, making direct measurement unachievable. However, through the implementation of synchronous fluorescence measurements of telmisartan and rosuvastatin at a Δλ = 60, distinct narrow bands were observed at 358 nm and 375 nm, respectively. Regrettably, the challenge of overlapping remained unresolved. Nevertheless, by converting these synchronous spectra into first-order spectra, the problem of overlapping was completely resolved. This conversion also allowed for the selective quantification of telmisartan and rosuvastatin at 374 nm and 358 nm, respectively. The validity of this method was confirmed in accordance with ICH guidelines, yielding satisfactory results in terms of the validation characteristics. The method demonstrated linear relationships between the response and the studied drugs concentrations in working range of 50-1000 ng/mL for telmisartan and 100-2000 ng/mL for rosuvastatin. The described methodology was applied for the pharmacokinetic study of telmisartan and rosuvastatin in rat plasma after a single oral dose of 4 mg/kg telmisartan and 50 mg/kg rosuvastatin. Pharmacokinetic analyses revealed a moderate drug-drug interaction between the two drugs, which was not considered to be clinically significant. Moreover, the described method was assessed in terms of sensitivity and environmental sustainability against three previously documented methods. The comparison effectively underscores the supremacy of the proposed technique over the documented techniques.

Spectrofluorimetric determination of vitamin D in the serum of autistic and healthy children using functionalized graphene quantum dots.

Vitamin D is one of the most essential nutrients for brain development, and deficiencies during pregnancy and early childhood development might be associated with autism. Regular monitoring of serum 25-hydroxyvitamin D3 level could help in early diagnosis and therapy. Analytical measurement of serum 25-hydroxyvitamin D3 level using the traditional matrix-matched calibration technique yields inaccurate results due to absence of serum matrix free from 25-hydroxyvitamin D3. The aim of this work was to develop a validated spectrofluorimetric methodology based on the standard addition approach for quantifying 25-hydroxyvitamin D3 levels in real serum samples of autistic children. The spectrofluorimetric methodology utilizes functionalized graphene quantum dots as a fluorescent probe for selective quantification of 25-hydroxyvitamin D3 level, which is based on measuring the quenching properties of 25-hydroxyvitamin D3 on a fluorescent probe. The standard addition approach exhibits a minimal matrix interference since it identically utilizes the same matrix of each study sample for creating its own calibration curve. The method was validated using the guidelines outlined in ICH M10 draft for endogenous compounds quantification. The method was successfully applied for quantifying the serum 25-hydroxyvitamin D3 levels in autistic and healthy children, and autistic children had significantly lower serum 25-hydroxyvitamin D3 levels (with a mean ± SD of 23.80 ± 17.19) when compared to healthy children (with a mean ± SD of 50.13 ± 18.74, P < 0.001). These results suggested an association between vitamin D deficiency and autism.

Derivative spectroscopy and wavelet transform as green spectrophotometric methods for abacavir and lamivudine measurement.

Herein, two different sustainable and green signal processing spectrophotometric approaches, namely, derivative spectroscopy and wavelet transform, have been utilized for effective measurement of the antiretroviral therapy abacavir and lamivudine in their pharmaceutical formulations. These methods were used to enhance the spectral data and differentiate between the absorption bands of abacavir and lamivudine in order to accurately measure their concentrations. For determining abacavir and lamivudine, the first derivative spectrophotometric method has been applied to the zero-order and ratio spectra of both drugs. The same approach has been tested using the continuous wavelet transform method where a second order 2.4 of rbio and bior wavelet families were found to be optimum for measuring both drugs. Validation of the proposed methods affirmed their reliability in terms of linearity over the concentration range 1.5-30 µg/mL and 1.5-36 µg/mL for abacavir and lamivudine, respectively, precision (RSD < 2 %), and accuracy with mean recoveries ranging between 98 % and 102 %. Additionally, these spectrophotometric methodologies were applied to real pharmaceutical preparations and yielded results congruent with a prior chromatographic method. Most prominently, the proposed methods stood out for their greenness and sustainability with 97 points as evaluated by the analytical eco-scale method and a score value of 0.79 as analyzed by AGREE method, thereby making them suitable for resource-limited settings and highlighting the potential for broader application of green analytical methods in pharmaceutical analysis.

Green spectrofluorimetric quantification of aspirin, olmesartan, and metoprolol in spiked human plasma.

Low dose aspirin is routinely taken with antihypertensive drugs such as olmesartan and metoprolol to avoid the cardiovascular and renal outcomes associated with high blood pressure. The first spectrofluorimetric method for quantifying aspirin, olmesartan, and metoprolol in spiked human plasma is described here. The emission/excitation wavelengths of Aspirin, olmesartan, and metoprolol were 404 nm/290 nm, 372 nm/250 nm, and 302 nm/230 nm, respectively. The native fluorescence spectra of metoprolol do not overlap with those of aspirin or olmesartan, although the spectra of aspirin and olmesartan overlap. As a result, metoprolol could be measured directly in a mixture at 302 nm following excitation at 230 nm. Using synchronous fluorescence spectrometry at Δλ = 110 allowed for the determination of olmesartan at 364 nm with no interference from aspirin and metoprolol. Coupling the synchronous fluorescence spectrometry with second-order derivative allowed for the determination of aspirin at 426 nm with no interference from olmesartan and metoprolol. The suggested approach has been validated using ICH M10 criteria for bioanalytical method validation and was effectively utilized for quantification of tested medications in human plasma with reasonable accuracy and precision findings. Furthermore, using two greenness metrics, the Green Analytical Procedure Index and the Analytical GREEnness, the suggested method obtained a high greenness score.

Development and validation of analytical methods for selective determination of albuterol and budesonide in Airsupra inhalation aerosol using spectrophotometry.

Airsupra inhalation aerosol is a recently approved FDA medication that combines albuterol and budesonide for treating or preventing bronchoconstriction and lowering the risk of relapses in asthma patients who are 18 years of age and older. To selectively determine albuterol and budesonide in both pure and pharmaceutical dosage forms, two analytical methods were developed: the zero-order absorption method and the dual-wavelength method. Even though the two drugs absorption spectra overlapped, the distinctive peak of budesonide at the zero absorbance point of albuterol, 245 nm, allowed for direct detection of budesonide in the combination using the zero-order absorption method. The mathematical dual-wavelength method, on the other hand, allowed for the measurement of both albuterol and budesonide by choosing two wavelengths for each drug in such a way that the absorbance difference for the second drug was zero. Budesonide exhibited comparable absorbance values at wavelengths 227 and 261.40 nm; hence, these two wavelengths were utilized to identify albuterol; similarly, 221.40 and 231.20 nm were chosen to determine budesonide in their binary mixes. The methods were validated according to the ICH guideline for validation of analytical procedures Q2(R1) and demonstrated excellent linearity, sensitivity, accuracy, precision, and selectivity for determining both drugs in synthetic mixed solutions and pharmaceutical formulations. The availability of these analytical methods would be valuable for the pharmaceutical industry and regulatory authorities for quality control and assessment of pharmaceutical formulations containing albuterol and budesonide.

Higher sensitive selective spectrofluorometric determination of ritonavir in the presence of nirmatrelvir: application to new FDA approved co-packaged COVID-19 pharmaceutical dosage and spiked human plasma.

BACKGROUND: Ritonavir was recently combined with nirmatrelvir in a new approved co-packaged medication form for the treatment of COVID-19. Quantitative analysis based on fluorescence spectroscopy measurement was extensively used for sensitive determination of compounds exhibited unique fluorescence features. OBJECTIVE: The main objective of this work was to develop higher sensitive cost effective spectrofluorometric method for selective determination of ritonavir in the presence of nirmatrelvir in pure form, pharmaceutical tablet as well as in spiked human plasma. METHODS: Ritonavir was found to exhibit unique native emission fluorescence at 404 nm when excited at 326 nm. On the other hand, nirmatrelvir had no emission bands when excited at 326 nm. This feature allowed selective determination of ritonavir without any interference from nirmatrelvir. The variables affecting fluorescence intensity of ritonavir were optimized in terms of sensitivity parameters and principles of green analytical chemistry. Ethanol was used a green solvent which provided efficient fluorescence intensity of the cited drug. RESULTS: The method was validated in accordance with the ICH Q2 (R1) standards in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy, precision and specificity. The described method was successfully applied for ritonavir assay over the concentration range of 2.0-20.0 ng/mL. CONCLUSION: Ritonavir determination in the spiked human plasma was successfully done with satisfactory accepted results.

Application of a nucleophilic substitution reaction for spectrofluorimetric determination of aripiprazole in pharmaceutical dosage form and plasma matrix; greenness assessment.

Aripiprazole is an antipsychotic medicine used to treat a variety of mental disorders, including irritability linked with autism disorder in children. Herein, a green and highly sensitive spectrofluorimetric method was developed for the determination of aripiprazole in pharmaceutical dosage form and plasma matrix. The method based on the formation of a fluorescent adduct from the nucleophilic substitution reaction of 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-chloride) with aripiprazole, which can be detected at 542 nm following excitation at 481 nm. Factors that affect the development and fluorescence sensitivity of the reaction product were investigated and optimized. The reaction yielded the most optimal fluorescence responses when it was performed using 1.5 mL of 0.2 % w/v NBD-chloride, 1.5 mL of borate buffer pH 9, heating at 80 °C for 20 min, and ethanol as a diluting solvent. The method was validated as per ICH guidelines for analytical and bioanalytical procedures. Good linearity was established between the fluorescence responses of the reaction product and aripiprazole concentrations in the range of 100-1200 ng/mL with adequate accuracy and precision results. The applied method was very sensitive and selectively determined aripiprazole in pharmaceutical and plasma matrices with no interferences. Furthermore, the compliance of the proposed method with the principles of green analytical chemistry was evaluated in comparison with the reported method using analytical eco-scale and AGREE metrics. The outputs proved that the proposed method complied more with the principles of green analytical chemistry than the reported method.

Adjusted green spectrophotometric determination of favipiravir and remdesivir in pharmaceutical form and spiked human plasma sample using different chemometric supported models.

The environmentally friendly design of analytical methods is gaining interest in pharmaceutical analysis to reduce hazardous environmental impacts and improve safety and health conditions for analysts. The adaptation and integration of chemometrics in the development of environmentally friendly analytical methods is strongly recommended in the hope of promising benefits. Favipiravir and remdesivir have been included in the COVID-19 treatment guidelines panel of several countries. The main objective of this work is to develop green, tuned spectrophotometric methods based on chemometric based models for the determination of favipiravir and remdesivir in spiked human plasma. The UV absorption spectra of favipiravir and remdesivir has shown overlap to some extent, making simultaneous determination difficult. Three advanced chemometric models, classical least squares, principal component regression, and partial least squares, have been developed to provide resolution and spectrophotometric determination of the drugs under study. A five-level, two-factor experimental design has been used to create the described models. The spectrally recorded data of favipiravir and remdesivir has been reviewed. The noise region has been neglected as it has a negative impact on the significant data. On the other hand, the other spectral data provided relevant information about the investigated drugs. A comprehensive evaluation and interpretation of the results of the described models and a statistical comparison with accepted values have been considered. The proposed models have been successfully applied to the spectrophotometric determination of favipiravir and remdesivir in pharmaceutical form spiked human plasma. In addition, the environmental friendliness of the described models was evaluated using the analytical eco-scale, the green analytical procedure index and the AGREE evaluation method. The results showed the compliance of the described models with the environmental characteristics.

Guava-fruit based synthesis of carbon quantum dots for spectrofluorometric quantitative analysis of risperidone in spiked human plasma and pharmaceutical dosage forms.

Autism is one of the most pressing issues facing the international community in recent years, particularly in Middle Eastern countries. Risperidone is a selective serotonin type 2 and dopamine type 2 receptor antagonist. It is the most administered antipsychotic medication in children with autism-related behavioral disorders. Therapeutic monitoring of risperidone may improve safety and efficacy in autistic individuals. The main objective of this work was to develop a highly sensitive green fitted method for the determination of risperidone in the plasma matrix and pharmaceutical dosage forms. Novel water-soluble N-carbon quantum dots were synthesized from guava fruit, a natural green precursor, and used for determination of risperidone based on quenching fluorescence spectroscopy phenomena. The synthesized dots were characterized by transmission electron microscopy and Fourier transform infrared spectroscopy. The synthesized N-carbon quantum dots exhibited aquantum yield of 26.12% and showed a strong emission fluorescence peak at 475 nm when excited at 380 nm. The fluorescence intensity of the N-carbon quantum dots decreased with increasing risperidone concentration, indicating that the fluorescence quenching was concentration dependent. The presented method was carefully optimized and validated according to the guidelines of ICH, and it demonstrated good linearity in a concentration range of 5-150 ng mL-1. With a LOD of 1.379 ng mL-1 and a LOQ of 4.108 ng mL-1, the technique was extremely sensitive. Due to the high sensitivity of the proposed method, it could be effectively used for the determination of risperidone in the plasma matrix. The proposed method was compared with the previously reported HPLC method in terms of sensitivity and green chemistry metrics. The proposed method proved to be more sensitive and compatible with the principles of green analytical chemistry.

Quantitative analysis of two COVID-19 antiviral agents, favipiravir and remdesivir, in spiked human plasma using spectrophotometric methods; greenness evaluation.

Favipiravir and remdesivir have been included in the COVID-19 treatment guidelines panel of several countries. The main objective of the current work is to develop the first validated green spectrophotometric methods for the determination of favipiravir and remdesivir in spiked human plasma. The UV absorption spectra of favipiravir and remdesivir have shown some overlap, making simultaneous determination difficult. Due to the considerable overlap, two ratio spectra manipulating spectrophotometric methods, namely, ratio difference and the first derivative of ratio spectra, enabled the determination of favipiravir and remdesivir in their pure forms and spiked plasma. The ratio spectra of favipiravir and remdesivir were derived by dividing the spectra of each drug by the suitable spectrum of another drug as a divisor to get the ratio spectra. Favipiravir was determined by calculating the difference between 222 and 256 nm of the derived ratio spectra, while calculating the difference between 247 and 271 nm of the derived ratio spectra enabled the determination of remdesivir. Moreover, the ratio spectra of every drug were transformed to the first order derivative using ∆λ = 4 and a scaling factor of 100. The first-order derivative amplitude values at 228 and 251.20 nm enabled the determination of favipiravir and remdesivir, respectively. Regarding the pharmacokinetic profile of favipiravir (Cmax 4.43 µg/mL) and remdesivir (Cmax 3027 ng/mL), the proposed methods have been successfully applied to the spectrophotometric determination of favipiravir and remdesivir in plasma matrix. Additionally, the greenness of the described methods was evaluated using three metrics systems: the national environmental method index, the analytical eco-scale, and the analytical greenness metric. The results demonstrated that the described models were in accordance with the environmental characteristics.

Green-adapted spectrophotometric determination of fostemsavir based on selective bromophenol blue extraction; reduction of hazardous consumption using computational calculations.

A computationally-assisted and green spectrophotometric method has been developed for the determination of fostemsavir, a recently FDA-approved drug used in combination with antiretroviral drugs to treat multidrug-resistant HIV-1 infection. The method was developed using computational studies and solvent selection based on green chemistry principles. The density functional theory method was employed to identify bromophenol blue as the preferred acid dye for efficient extraction of fostemsavir. The solvent selection process involved a careful evaluation of the green ranking of solvents, which led to the use of water as the solvent. The method involved the extraction of fostemsavir with bromophenol blue to form a yellow ion-pair complex, which exhibited maximally sharp peaks at 418 nm, enabling sensitive visible spectrophotometric determination of fostemsavir in bulk and pharmaceutical preparations. The extraction procedures were optimized, and the method was demonstrated to be sensitive over the concentration range of 2-12 µg/mL fostemsavir. Furthermore, the method was evaluated with respect to green chemistry principles using the analytical eco-scale, the green analytical method index, and analytical greenness metric approach, all of which confirmed that the data obtained by the proposed method were environmentally acceptable.

Synchronous spectrofluorimetric determination of favipiravir and aspirin at the nano-gram scale in spiked human plasma; greenness evaluation.

Favipiravir and aspirin are co-administered during COVID-19 treatment to prevent venous thromboembolism. For the first time, a spectrofluorometric method has been developed for the simultaneous analysis of favipiravir and aspirin in plasma matrix at nano-gram detection limits. The native fluorescence spectra of favipiravir and aspirin in ethanol showed overlapping emission spectra at 423 nm and 403 nm, respectively, after excitation at 368 nm and 298 nm, respectively. Direct simultaneous determination with normal fluorescence spectroscopy was difficult. The use of synchronous fluorescence spectroscopy for analyzing the studied drugs in ethanol at Δλ = 80 nm improved spectral resolution and enabled the determination of favipiravir and aspirin in the plasma matrix at 437 nm and 384 nm, respectively. The method described allowed sensitive determination of favipiravir and aspirin over a concentration range of 10-500 ng/mL and 35-1600 ng/mL, respectively. The described method was validated with respect to the ICH M10 guidelines and successfully applied for the simultaneous determination of the mentioned drugs in pure form and in the spiked plasma matrix. Moreover, the compliance of the method with the concepts of environmentally friendly analytical chemistry was evaluated using two metrics, the Green Analytical Procedure Index and the AGREE tool. The results showed that the described method was consistent with the accepted metrics for green analytical chemistry.

Simultaneous green TLC determination of nirmatrelvir and ritonavir in the pharmaceutical dosage form and spiked human plasma.

Quantitative analysis of pharmaceutical compounds up to Nano gram levels is highly recommended to introduce feasible and sensitive tool for determination of the compounds in the pharmaceutical and biological samples. Nirmatrelvir plus ritonavir was recently approved in the US, the UK and Europe as a new co-packaged dosage form for the treatment of COVID-19. The objective of this work was to develop a more sensitive TLC method based on using ß-cyclodextrin as a chiral selector additive in the mobile phase for simultaneous determination of nirmatrelvir and ritonavir in pure form, pharmaceutical formulation and spiked human plasma. The analysis procedures were developed using TLC aluminum silica gel plates and methanol-water- 2% urea solution of ß-cyclodextrin (40:10:.5, by volume) as a mobile phase with UV detection at 215 nm. The developed method was successfully applied over a linearity range of 10-50 ng/band for both nirmatrelvir and ritonavir. The method was validated for limits of detection and quantitation, accuracy, precision, specificity, system suitability, and robustness. Furthermore, the eco-friendliness of the proposed method was assessed using the analytical eco-scale and the green analytical procedure index. The described method exhibited compliance with green analytical chemistry principles based on common green metric values.

Adjusted green HPLC determination of nirmatrelvir and ritonavir in the new FDA approved co-packaged pharmaceutical dosage using supported computational calculations.

The greening of analytical methods has gained interest in the quantitative analysis field to reduce environmental impact and improve safety health conditions for analysts. Nirmatrelvir plus ritonavir is a new FDA approved co-packaged medication developed for the treatment of COVID-19. The aim of this research was to develop green fitted HPLC method using pre experimental computational testing of different stationary phases as well as selecting mobile phase regarding to green analytical chemistry principles. Computational study was designed to test the physical interaction between nirmatrelvir and ritonavir and different columns (C8, C18, Cyano column). The study showed that the C18 column was better for simultaneous HPLC analysis of the cited drugs. Regarding to green point of view, mobile phase consisted of ethanol: water (80:20, v/v) provided an efficient chromatographic separation of nirmatrelvir and ritonavir within a short analytical run time, reasonable resolution and excellent sensitivity. Isocratic elution was performed on a selected C18 column and a green adjusted mobile phase at flow rate of 1 mL/min and UV detection at 215 nm. The chromatographic system allowed complete baseline separation with retention times of 4.9 min for nirmatrelvir and 6.8 min for ritonavir. The method succeeded to determine nirmatrelvir and ritonavir over the concentration range of 1.0-20.0 µg/mL in the pure form and in pharmaceutical dosage form. Greenness profiles of the applied HPLC method was assessed using analytical eco-scale, the green analytical procedure index and the AGREE evaluation method. The results revealed adherence of the described method to the green analytical chemistry principles. The authors hope to provide a promising challenge for achieving green goals through integrating computational tools and applying them with green assessment metrics.

Green fitted second derivative synchronous spectrofluorometric method for simultaneous determination of remdesivir and apixaban at Nano gram scale in the spiked human plasma.

Remdesivir and apixaban have been included in the treatment guidelines of several countries for severe COVID-19 infections. To date, no analytical method has been developed for the determination of remdesivir and apixaban in plasma matrix. The main objective of this work was to develop a highly sensitive, green-adapted spectrofluorometric method for the determination of remdesivir and apixaban at the Nanoscale. Remdesivir and apixaban showed overlapping fluorescence emission spectra at 403 nm and 456 nm when excited at 246 nm and 285 nm, respectively. This overlap was resolved in two steps. The first step was synchronous fluorescence scanning of remdesivir and apixaban, and the second step was manipulation of the second-order derivative for the obtained spectra. These steps allowed complete resolution of the overlapping fluorescence spectra and selective determination of remdesivir and apixaban at 410 and 469 nm, respectively. The variables affecting the synchronous scanning of the aforementioned drugs were optimized in terms of sensitivity parameters and principles of green analytical chemistry. The described method allowed sensitive determination of remdesivir and apixaban over the concentration range of 5-200 ng/mL and 50-3000 ng/mL, respectively. The described method was validated and successfully applied for the simultaneous determination of the mentioned drugs in pure form and in spiked human plasma.

Spectrophotometric Quantitative Analysis of Aspirin and Vonoprazan Fumarate in Recently Approved Fixed-Dose Combination Tablets Using Ratio Spectra Manipulating Tools.

BACKGROUND: Low-dose aspirin (ASP) is prescribed to millions of people around the world as a secondary preventative strategy for the majority of significant cardiovascular events; however, it carries a substantial risk of gastric ulcer and bleeding. Cabpirin® tablets, which include low-dose ASP and vonoprazan fumarate (VON), are approved in Japan for the treatment of acid-related diseases in patients who require a low dose of ASP but are at risk of ASP-associated gastric ulcers. OBJECTIVE: This paper describes the first published quantitative analytical approaches for the determination of ASP and VON. METHOD: The normal ultraviolet absorption spectra of ASP and vonoprazan overlap significantly. The ratio spectra of the studied drugs were created and manipulated by ratio difference (RD) and first derivative of ratio spectra approaches. In the RD approach, the differences in the amplitude values between 229 and 283 nm enabled the quantitative analysis of ASP, and the differences in the amplitude values between 255 and 212 nm enabled the quantitative analysis of vonoprazan. In the first derivative of the ratio spectra approach, the created ratio spectra of each drug were transformed to the first-order derivative. ASP could be determined selectively at 237.40 nm without interference from vonoprazan. Moreover, vonoprazan could be determined selectively at 244 nm without interference from ASP. RESULTS: The applied approaches were validated according to the ICH guideline, with good results. Linear correlations were obtained for ASP and vonoprazan over concentration ranges of 2-25 and 1-10 µg/mL, respectively. CONCLUSIONS: The described methods were optimized, validated, and applied for determination of the studied drugs in the synthetic mixtures and in pharmaceutical tablets without interferences. HIGHLIGHTS: Two spectrophotometric ratio spectra manipulating approaches were developed for the determination of the ASP and vonoprazan in their pharmaceutical combination tablets.

Different spectrophotometric methods for simultaneous determination of lesinurad and allopurinol in the new FDA approved pharmaceutical preparation; additional greenness evaluation.

Lesinurad and allopurinol have been formulated in a combined dosage form providing a new challenge for the treatment of gout attacks. Two mathematical based spectrophotometric methods, area under the curve, and artificial neural networks have been developed for simultaneous determination of lesinurad and allopurinol in pure form and in combined pharmaceutical dosage form. Area under the curve has been utilized to resolve the spectral overlap between lesinurad and allopurinol. Values of area under the curve and area absorptivity were measured at two selected wavelength ranges of 242-250 nm and 255-265 nm. Two mathematically constructed equations have been used to determine the concentrations of the drugs under the study. Advanced chemometry based model, artificial neural network, has been developed utilizing the UV spectral data of lesinurad and allopurinol through various defined steps. A five-level, two-factor experimental design was used to construct 25 mixtures. Thirteen mixtures were used to set up the calibration model and 12 mixtures were used to construct a validation set. The artificial neural network model was optimized to enable precise spectrophotometric determination of the drugs under the study. The described mathematically bases spectrophotometric methods have been successfully applied to the determination of lesinurad and allopurinol in the new combined, Duzallo® tablets. Furthermore, the greenness of the described methods was assessed using four different tools namely, the national environmental method index, the analytical eco-scale, the green analytical procedure index and the AGREE evaluation method. The proposed methods showed more adherence to the greenness characters in comparison to the previously reported HPLC method.