Spectrofluorimetric Approach for Quantification of Cyclizine in the Presence of its Toxic Impurities in Human Plasma; in silico Study and ADMET Calculations.

Cyclizine (CYZ); an antiemetic compound; is widely misused for its euphoric or hallucinatory effects, either by oral or intravenous routes. The concomitant abuse of CYZ among addicted adolescents contributes to neuromuscular disorders that are life-threatening. Consequently, with the company of 1-Methylpiperazine (MPZ) and diphenylmethanol (DPM, Benzhydrol) as pharmacopoeia-reported CYZ impurities, a novel spectrofluorimetric assay for the detection of CYZ, has been established either in human plasma samples or in its parenteral formulation. The native fluorescence of CYZ has been investigated under various conditions. Different parameters affecting relative fluorescence intensity of CYZ including diluting solvent, surfactant, plasma protein solvent, and pH were studied and optimized. The linearity obtained between the fluorescence intensity at emission wavelength 350 nm after excitation at 244 nm and the corresponding CYZ concentrations was in the range 10-1000 ng/mL for measurement of CYZ either in pure form or in human plasma samples, with a appropriate correlation coefficient (r = 0.9999) and 3.10 ng/mL as the limit of detection and 9.41 ng/mL as the limit of quantitation. The suggested procedure was created and validated in accordance with ICH guidelines for quantification of CYZ either in its pure form or its dosage form, and FDA guidelines for the assay of CYZ in human plasma. Finally, in silico study and ADMET predictions were conducted for the studied drug impurities to estimate their pharmacokinetic behaviors. The results showed that both CYZ impurities have higher cellular permeability and maximum tolerated doses, DPM has higher BBB and CNS permeability than MPZ, while MPZ exceeds DPM in total clearance and volume of distribution.

Development and Greenness Assessment of HPLC Method for Studying the Pharmacokinetics of Co-Administered Metformin and Papaya Extract.

Foods with medical value have been proven to be beneficial, and they are extensively employed since they integrate two essential elements: food and medication. Accordingly, diabetic patients can benefit from papaya because the fruit is low in sugar and high in antioxidants. An RP-HPLC method was designed for studying the pharmacokinetics of metformin (MET) when concurrently administered with papaya extract. A mobile phase of 0.5 mM of KH2PO4 solution and methanol (65:35, v/v), pH = 5 ± 0.2 using aqueous phosphoric acid and NaOH, and guaifenesin (GUF) were used as an internal standard. To perform non-compartmental pharmacokinetic analysis, the Pharmacokinetic program (PK Solver) was used. The method's greenness was analyzed using two tools: the Analytical GREEnness calculator and the RGB additive color model. Taking papaya with MET improved the rate of absorption substantially (time for reaching maximum concentration (Tmax) significantly decreased by 75% while maximum plasma concentration (Cmax) increased by 7.33%). The extent of absorption reduced by 22.90%. Furthermore, the amount of medication distributed increased (30.83 L for MET concurrently used with papaya extract versus 24.25 L for MET used alone) and the clearance rate rose by roughly 13.50%. The results of the greenness assessment indicated that the method is environmentally friendly. Taking papaya with MET changed the pharmacokinetics of the drug dramatically. Hence, this combination will be particularly effective in maintaining quick blood glucose control.

Development and validation of stability indicating chromatographic methods for simultaneous determination of citicoline and piracetam.

Citicoline and piracetam were subjected separately to different stress conditions as recommended by the international conference on harmonization. In addition, new stability indicating thin layer chromatographic and ultra high performance liquid chromatographic methods have been developed and validated for simultaneous determination of citicoline and piracetam in presence of their degradation products. Separation on the proposed thin layer chromatographic method was carried out using a developing system containing methanol:chloroform:ammonium chloride buffer (9:1:2, v/v/v) on silica gel plates at 230 nm. On the other hand, the mobile phase in the ultra high performance liquid chromatographic method was composed of water (containing 0.1% triethylamine):ethanol (92:8, v/v). The flow rate was 1 mL/min and ultraviolet detection was at 230 nm. Moreover, results of the developed methods were statistically compared to those obtained by the reported high-performance liquid chromatography method and no significant difference between them was found. The greenness profile of ultra high performance liquid chromatographic method was assessed and compared with those of the previously published high-performance liquid chromatography methods, it was noticed that the proposed ultra high performance liquid chromatographic method more environmentally friendly and greener than other methods.

Stability-indicating chromatographic and chemometric methods for environmentally benign determination of canagliflozin and its major degradation product; A comparative study and greenness assessment.

Recently, concepts of sustainable developments, like considering the environmental effect of chemicals used and the amount of hazardous wastes produced, has gained much interest. In this work, a recently approved treatment for type II diabetes mellitus, canagliflozin, was quantified along with its degradation product by two eco-friendly methods. The first was a specific green HPLC method using a C18 column as a stationary phase and a mobile phase consisting of methanol-water (98:2, v/v) pumped at a flow rate of 1 mL/min with UV detection at 225 nm, and using ibuprofen as an internal standard. The second method was a partial least square chemometric method with the wavelength range 220-320 nm and the data was autoscaled as a preprocessing step for determination of canagliflozin and its degradation product. The greenness profile of the developed methods was studied and compared with the reported methods. The proposed methods were suitable alternatives for the environmentally harmful reported methods for quality control analyses of canagliflozin-containing samples, analysis of pharmaceutical formulations and sensitive tracing of its possible degradation product. The methods were validated as per International Conference on Harmonization guidelines and statistically compared with the reported HPLC method.

Different stability-indicating chromatographic methods for specific determination of paracetamol, dantrolene sodium, their toxic impurities and degradation products.

A well-known analgesic (paracetamol, PAR) and skeletal muscle relaxant [dantrolene sodium (DNS)] have been analyzed without interference from their toxic impurities and degradation products. The studied PAR impurities are the genotoxic and nephrotoxic p-amino phenol (PAP) and the hepatotoxic and nephrotoxic chloroacetanilide, while 5-(4-nitrophenyl)-2-furaldehyde is reported to be a mutagenic and carcinogenic degradation product of DNS. The five studied components were determined and quantified by TLC-densitometric and RP-HPLC methods. TLC-densitometry (method 1) used TLC silica gel and chloroform-ethyl acetate-acetic acid-triethylamine (7:3:0.5:0.05, by volume) as the mobile phase with UV scanning at 230 nm, while RP-HPLC (method 2) was based on separation on a C18 column using methanol-water (55:45, v/v pH 3 with aqueous formic acid) as mobile phase at 1 mL/min and detection at 230 nm. The developed methods were used for determination and quantification of the five studied components in different laboratory-prepared mixtures. The were also applied for analysis of Dantrelax® compound capsules where no interference among the studied components with each other or from excipients was observed. The methods were validated as per International Conference on Harmonization guidelines, and they compared favorably with the reported ones.

Baclofen impurities: Facile synthesis and novel environmentally benign chromatographic method for their simultaneous determination in baclofen.

An efficient, economic and high yielding method was described for the synthesis of baclofen (BAC) pharmacopoeial impurities (impurity A and impurity B) which can be used for gram-scale synthesis. Furthermore, a novel ecofriendly thin-layer chromatographic TLC-densitometric method was established and validated for the determination of BAC and its synthesized impurities. The developed TLC-densitometric method is based on the chromatographic separation using TLC plates (60 F254 ) using a green mobile phase of ethyl acetate-methanol-ammonia solution, 33% (8:2:0.1, by volume) with UV scanning at 220 nm. The proposed method was validated with respect to International Conference on Harmonization guidelines. The validated method was successfully applied for determination of BAC in pure form and in its commercial dosage form. Additionally, the greenness profile of the developed method was evaluated and compared with those of the reported chromatographic methods. The developed method was found to be superior to the published methods, being environmentally benign.

Efficient UPLC and CE methods for the simultaneous determination of azelastine hydrochloride and its genotoxic impurity.

A novel stability-indicating UPLC and CE method was established and validated for the determination of azelastine hydrochloride (AZL) and its genotoxic impurity, benzohydrazide, in the presence of benzalkonium chloride. The developed UPLC method was based on chromatographic separation using a C18 column as a stationary phase and acetonitrile-(0.1% w/v) aqueous sodium lauryl sulfate (55:45, v/v, pH 5 with phosphoric acid) as a mobile phase with a flow rate of 1.2 mL/min and UV detection at 215 nm. The chromatographic run time was ~2 min. The developed CE method depended on using a stationary phase of Standard Bare Fused Silica Capillaries (75 µm i.d. × 59 cm and 50 cm detection length) and the applied voltage was 30 kV using 40 mm phosphate buffer (pH 2 with aqueous H3 PO4 ); the detection wavelength was 225 nm. The analysis time was about 6 min. The suggested methods were successfully applied for the analysis of AZL in a pharmaceutical preparation. The validity of the developed methods was assessed by applying the standard addition technique and no interference from excipients was observed. The results obtained by the proposed methods were statistically analyzed and compared with the manufacturer's method and no significant difference was found between the compared methods.

Green chromatographic method for analysis of some anti-cough drugs and their toxic impurities with comparison to conventional methods.

Toxic solvents are widely used in chemical laboratories, which are dangerous on health, safety of workers, and environment. Green chemistry established different principles to keep safety of environment, one of these goals is to replace toxic solvents by greener alternatives or by minimizing the used volumes. Paracetamol (PAR), Guaifenesin (GUF), Oxomemazine (OX), and Sodium benzoate (SB) combination is a widely used cough preparation. 4- aminophenol (4-AP) is PAR poisonous impurity and related substance. Guiacol (GUC) is GUF impurity and related substance; its presence may lead to rejection of GUF sample. An eco-friendly HPTLC method was developed to quantify the studied drugs and their impurities. Chromatographic separation was achieved on HPTLC 60F254 plates using ethylacetate: methanol: 0.05 M ammonium chloride buffer (100: 2: 5, by volume) as a mobile phase and scanning at 225 nm. The linear ranges were 0.25-3.50, 0.50-8.00, 0.25-4.00, 0.20-8.00, 0.05-4.00, and 0.25-4.00 µg/band for PAR, GUF, OX and SB, 4-AP, and GUC. Method was successfully applied to available syrup and suppositories. It compared well with the reported method. It can be considered as an alternative green method for previously developed TLC method. Greenness profile of the method proved that it is greener than the reported methods being time and solvents saving.

Study of gliquidone degradation behavior by high-performance thin-layer chromatography and ultra-performance liquid chromatography methods.

Gliquidone (GQ) is an oral hypoglycemic agent, belonging to second-generation sulfonylurea derivatives. New high-performance thin-layer chromatography (HPTLC) and ultra-performance liquid chromatography (UPLC) methods have been developed and validated and used for complete stability study of GQ following International Conference on Harmonization guidelines. GQ was subjected to stress and forced degradation under hydrolytic, oxidative and photolytic conditions. The drug was found to be unstable under acidic, alkaline and oxidative conditions with the formation of gliquidone sulfonamide (GQS), while a marked stability was confirmed under thermal and photolytic stress conditions. GQS is the British pharmacopeial impurity A of GQ and also considered as its synthesis intermediate. The developed chromatographic methods have been utilized for anticipating the degradation behavior of GQ under the studied conditions and then used for quantitation of GQ and GQS either in their pure forms or in laboratory prepared mixtures. The methods were successfully applied to GQ in pharmaceutical formulation. The methods have the advantages of being sensitive and less time consuming compared with the reported methods. The obtained results were statistically compared with a reported HPLC method showing no significant difference regarding both accuracy and precision.

Simultaneous determination of methocarbamol and Ibuprofen by first derivative synchronous fluorescence spectroscopic method in their binary mixture and spiked human plasma.

Methocarbamol is formulated with Ibuprofen for treatment of alleviated pain associated with muscle spasm. This manuscript describes a sensitive and selective first derivative synchronous spectrofluorimetric method for simultaneous determination of both drugs. Factors affecting method selectivity were studied where best results were obtained upon using Δ λ = 20 and water as a solvent. Methocartbamol was determined at 283 nm while Ibuprofen at 285.5 nm in the concentration ranges of 0.4-5 and 0.2-4.8 µg/mL, respectively. The applicability of the proposed method was ascertained by application to different laboratory prepared mixtures and marketed formulation. The high sensitivity achieved by the proposed method permitted its application for determination of the drugs in human plasma spiked with pure drugs and their combined tablets. The proposed method showed no significant difference when compared with the reported HPLC method using student's t-test and F-ratio test.

Analysis of binary mixture of oxytetracycline and bromohexine in their combined veterinary formulation by four simple spectrophotometric methods with greenness assessment.

Tetracyclines family is considered as the first-line antibiotic drugs for food animals. Formulating bromhexine (BR) with oxytetracycline (OTC) improved the antibacterial activity of OTC, besides it is considered as a mucolytic agent. Four precise, rapid, and simple spectrophotometric methods were successfully developed for resolution of the overlapped spectra of OTC and BR in their pure form and in their pharmaceutical formulation. The proposed methods are absorption correction (AC), dual wavelength (DW), induced dual wavelength (IDW), and spectrum subtraction (SS) spectrophotometric methods. The developed methods were used for the determination of OTC and BR in the ranges of 2-50 µg/mL and 1-30 µg/mL, respectively for all methods. For (AC) and (SS) methods, OTC and BR were determined at 380 nm and 245.6 nm, respectively after spectral resolution steps. While for (DW) method, the absorbance difference between λ (271.8 -287.6 nm) and λ (245.6 -283.2 nm) were used for the determination of OTC and BR, in order. For IDW, it depended on using the absorbance difference between 271.8 nm and 245.6 nm as well as the equality factor (F) calculated for each drug at the selected wavelengths. In all methods, HCl was used as a solvent and they are validated according to ICH guidelines. Several green metric tools have been developed to evaluate the greenness of the analytical methods like National Environmental Methods Index (NEMI), Modified NEMI, Analytical Eco-scale, Green Analytical Procedure Index (GAPI) and Analytical GREEnness calculator (AGREE), and all ensured the low impact of the suggested approaches on health and environment. The proposed methods are highly selective, robust and precise. Additionally they are time and money effective and can be used in any analytical laboratory.

AQbD TLC-densitometric method approach along with green fingerprint and whiteness assessment for quantifying two combined antihypertensive agents and their impurities.

Preserving the environment, reducing the amount of waste resulting from chemical trials, and reducing the amount of energy consumed have currently become a pivotal global trend. An analytical quality by design (AQbD) based eco-friendly TLC-densitometric method was implemented for quantifying two antihypertensive agents, captopril (CPL) and hydrochlorothiazide (HCZ), along with their impurities; captopril disulphide (CDS), chlorothiazide (CTZ) and salamide (SMD). The analytical target profile (ATP) was first identified, followed by selecting the critical analytical attributes (CAAs), such as retardation factors and resolution between the separated peaks. Critical method parameters (CMPs) that may have a crucial influence on CAAs were identified and emanated through the quality risk assessment phase. A literature survey-based preliminary studies were performed, followed by optimization of the selected CMPs through a custom experimental design to attain the highest resolution with optimum retardation factors. Moreover, method robustness was also tested by testing the design space. Complete separation of the drugs and their impurities was achieved using ethyl acetate: glacial acetic acid (6: 0.6, v/v) as a developing system applied to a 12 cm length TLC plate at room temperature with UV scanning at 215 nm. Calibration graphs were found to be linear in the ranges of (0.70-6.00), (0.10-2.00), (0.20-1.00), (0.07-1.50) and (0.05-1.00) µg/band corresponding to CPL, HCZ, CDS, CTZ, and SMD, respectively. Four different green metric tools were used to evaluate the greenness profile of the proposed method, and results showed that it is greener than the reported HPLC method. Method whiteness assessment was also conducted. Moreover, the method performance was evaluated following the ICH guidelines, and the outcomes fell within the acceptable limits. The developed method could be approved for routine assay of the cited components in their pharmaceutical formulations and bulk powder without interference from the reported impurities. The issue of concern is saving money, especially in developing countries.

Chromatographic analysis of triple cough therapy; bromhexine, guaiafenesin and salbutamol and pharmaceutical impurity: in-silico toxicity profile of drug impurity.

Bromhexine (BR), guaiafenesin (GUF) and salbutamol (SAL) are formulated as Ventocough syrup® (with and without sugar), labeled to contain propyl paraben and sodium benzoate as inactive ingredients. They are used to make coughing more productive and easier. A crucial element and a major issue in the pharmaceutical industry is the control of organic related impurities to obtain safe and effective treatment. Guaiacol (GUL) is reported to be GUF related impurity that was proved to be extremely toxic (toxic rating class 5), and its use should be banned. In this work, In-Silico study and ADMET estimation were conducted to predict GUL pharmacokinetic properties and its toxicity profile. Additionally, two chromatographic methods were conducted to analyze the studied components along with GUF impurity in the presence of the labeled dosage form excipients. The In-Silico study assured that GUL has oral rat acute toxicity and it is considered to be skin sensitizer. On the other hand, the developed TLC- densitometeric method depended on using a mobile phase mixture of hexane: methylene chloride: triethylamine (5.0:6.0:0.3, by volume) as a developing system. UV-Scanning was performed immediately at 275 nm for SAL, GUF and GUL, while scanning at 310 nm was used for scanning BR. Linearity was established in the ranges of 0.25-4.0, 0.25-4.0, 0.5-8.0 and 0.1-1.6 µg/band for BR, SAL, GUF and GUL, respectively. In the developed HPLC method, separation was performed on X-Bridge® C18 column (250 × 4.6 mm, 5 µm) using a solvent mixture of 0.05M disodium hydrogen phosphate pH 3 with aqueous phosphoric acid: methanol (containing 0.3%, v/v triethylamine) (40:60, v/v). Detection was done at 225 nm and separation was achieved within 10 min. Linearity was proved in the range of 2-50 µg/mL for the proposed drugs. Validation of the developed methods was done and all the calculated parameters were within the acceptable limits recommended by ICH guidelines. After that, methods were used to examine the potency of the selected marketed dosage forms and concentrations of all drugs were within the acceptable limits. Additionally, complete separation between the studied drugs and the additives were observed. The developed methods can be used during routine quality control analysis of the proposed drugs when the required issues concern on sensitivity, selectivity and analysis time.

Chromatographic analysis of ciprofloxacin and metronidazole in real human plasma: green analytical chemistry perspective.

Background: Ciprofloxacin and metronidazole are beneficial for treating mixed aerobic/anaerobic infections. Methods: Following the oral administration of ciprofloxacin and metronidazole in healthy volunteers, TLC and HPLC methods were described for their analysis in plasma samples. In the first method, a stationary phase of silica gel TLC F254 plates was used using acetone/water/triethylamine/glacial acetic acid (8:2:0.25:0.1 v/v). The second approach used a C18 column and methanol/aqueous 0.05% triethylamine (25:75 v/v), with a flow rate of 1 ml/min and detection at 325 nm. Four green metrics were used to evaluate the approaches' environmental impact. Conclusion: The study provided the sensitivity required for determination of the two drugs in the collected samples. The findings showed that results were within permitted ranges with minimal environmental impact.

Greenness assessment of UPLC/MS/MS method for determination of two antihypertensive agents and their harmful impurities with ADME/TOX profile study.

Hypertension is described by the world health organization (WHO) as a serious medical problem that significantly affects the heart, brain and kidneys. It is a major cause of premature death worldwide. The present study aims to quantify the combination of captopril (CPL), hydrochlorothiazide (HCZ) and their harmful impurities; captopril disulphide (CDS), chlorothiaizde (CTZ) and salamide (SMD). In-silico study was conducted for estimation of pharmacokinetic parameters (ADMET) as well as toxicity profile of the proposed impurities. The results showed that the three impurities under investigation had poor permeability to CNS and cannot pass the blood-brain barrier (BBB), reducing the likelihood of causing side effects in the brain. On the other hand, all studied impurities were found to be hepatotoxic. In consequence, a highly sensitive and green ultra-performance liquid chromatography- tandem mass spectrometric (UPLC/MS/MS) method was developed and validated for separation of the cited drugs in the presence of their harmful impurities; methanol and 0.1% formic acid (90:10, v/v) mixture was used as a mobile phase, eluted at a constant flow rate of 0.7 mL/min at room temperature. Detection was adopted using a tandem mass spectrometer in a positive mode only for CPL and negative mode for HCZ, CDS, CTZ and SMD. Separation was performed within 1 min. Calibration graphs were found to be linear in the ranges of (50.0-500.0 ng mL-1), (20.0-500.0 ng mL-1), (10.0-250.0 ng mL-1), (5.0-250.0 ng mL-1) and (20.0-400.0 ng mL-1) corresponding to CPL, HCZ, CDS, CTZ and SMD, respectively. Additionally, comparative study of greenness profile was established for the proposed and reported methods using five green metric tools. The proposed method was found to be greener than the reported HPLC method. The developed (UPLC/MS/MS) method was validated according to (ICH) guidelines and it was found to has greater sensitivity, shorter analysis time and lower environmental impact compared to the reported methods.

Determination of ambroxol hydrochloride, guaifenesin, and theophylline in ternary mixtures and in the presence of excipients in different pharmaceutical dosage forms.

Determination of ternary mixtures of ambroxol hydrochloride, guaifenesin, and theophylline with minimum sample pretreatment and without analyte separation has been successfully achieved by using chemometric and RP-HPLC methods. The developed chemometric models are partial least squares (PLS) and genetic algorithm coupled with PLS. Data of the analyses were obtained from UV-Vis spectra of the studied drugs in different concentration ranges. These models have been successfully updated to be applied for determination of the proposed drugs in Farcosolvin syrup and in the presence of a syrup excipient (methyl paraben). In the developed RP-HPLC method, chromatographic runs were performed on an RP-C18 analytical column with the isocratic mobile phase 0.05 M phosphate buffer-methanol-acetonitrile-triethylamine (63.5 + 27.5 + 9 + 0.25, v/v/v/v, pH 5.5 adjusted with orthophosphoric acid) at a flow rate of 1.2 mL/min. The analytes were detected and quantified at 220 nm. The method was optimized in order to obtain good resolution between the studied components and to prevent interference from methyl paraben. Method validation was performed with respect to International Conference on Harmonization guidelines and the validation acceptance criteria were met in all cases. The proposed methods can be considered acceptable for QC of the studied drugs in pharmaceutical capsules and syrup. The results obtained by the suggested chemometric methods for determination of the studied mixture in different pharmaceutical preparations were statistically compared to those obtained by applying the developed RP-HPLC method, and no significant difference was found.

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.

Chromatographic analysis of bromhexine and oxytetracycline residues in milk as a drug analysis medium with greenness profile appraisal.

Tetracyclines are frequently employed in animal husbandry. Bromhexine is a mucolytic drug that improves the efficacy of tetracyclines. It has been reported that residues of tetracyclines in milk may have negative effects on humans. Two versatile and accurate methods were developed for concurrent analysis of oxytetracycline (OTC) and bromhexine (BR) residues in spiked milk samples. Sample preparation was carefully considered for extraction and cleanup using the ecofriendly chemicals acetic acid, 0.1 N EDTA and ethanol or methanol. The first method was a TLC-densitometric method in which TLC plates previously treated with 10% EDTA (pH 9 with 40% sodium hydroxide) were used as a stationary phase. A solvent mixture of methanol : methylene chloride : 2% aqueous acetic acid (8 : 2 : 0.5, by volume) was the developing system, and detection was carried out at 254 nm. Metformin was used as the internal standard, and linearity was achieved in the ranges of 0.2-10 and 0.04-2 µg per band for OTC and BR, respectively. The second method was a RP-HPLC method; separation was performed on a C18 column using an isocratic mixture of ethanol : 7.5% aqueous acetic acid (70 : 30, v/v). Separation was achieved within 10 minutes, and linearity was proven in the ranges of 0.05-50 and 0.05-30 µg mL-1 for OTC and BR, respectively. Diclofenac sodium was used as an internal standard. The proposed methods were validated in accordance with the FDA Center for Veterinary Medicine guidelines. Moreover, the performance and health and environmental impacts of the methods were evaluated using several greenness metrics, namely, the National Environmental Methods Index (NEMI), modified NEMI, Green Analytical Procedure Index (GAPI), Analytical Eco-Scale and Analytical GREEnness (AGREE) metric approaches. All the obtained results proved the validity of the developed methods concerning its performance and ecological effects. The methods can be used to investigate the presence of OTC residues in various marketed milk samples to maintain public health.

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.

Nanoparticle-enhanced in-line potentiometric ion sensor for point-of-care diagnostics for tropicamide abuse in biological fluid.

Point of care (POC), also identified as on-site testing, has evolved as a rapid and accurate technique for drug of abuse screening and analysis. The aim of this work is to detect tropicamide (TPC) abuse in biological fluids; we selected rat plasma as example. We developed a disposal miniaturized, portable, green, and budget-friendly POC solid-state electrochemical sensor based on potentiometric transduction. To attain that, an innovative microfabricated electrode modified with conducting polymer poly(3-octylthiophene) (POT) has been placed on sensitized printed circuit board (PCB). A two-stage optimization process was implemented to develop the fabricated electrode. The first stage of the optimization process depends on screening various ionophores in order to enhance the sensor selectivity towards tropicamide. Copper nanoparticles exhibited the highest selectivity towards TPC. The second stage was utilizing a polymer as an ion-to-electron transducer layer between the copper nanoparticles impregnated ion sensing membrane and the microfabricated solid-contact ion-selective electrode. This polymer was added to boost the stability of the potential drift (1.2 mV/h) due to the hydrophobic behavior of the POT, which precludes the formation of an aqueous layer at the Cu electrode/polymeric membrane interface and improve the limit of detection (1.1 × 10-8 M). Nernstian potentiometric response was accomplished for TPC with a slope of 58.46 ± 0.43 mV/decade and E0 ∼ 189.39 ± 2.12 over the concentration range 1.0 × 10-7 to 1.0 × 10-2 M. The suggested sensor's intrinsic figure of merits include a quick response time (13 ± 2 s) and long life time (45 days). The proposed sensor has been successfully employed in the selective determination of TPC in pharmaceutical formulations, and biological fluids. When the results were compared to those of the official approach, there was no statistically significant difference. The Eco-Scale tool assessed and measured the greenness profile of the established method.