A green micelle-enhanced first derivative synchronous fluorescence approach for determination of donepezil HCl and trazodone HCl in their pure state, pharmaceutical dosage form and spiked human plasma.

The study's objective is to establish an eco-friendly, sensitive and economical quantitative methodology for the concurrent analysis of donepezil HCl (DPZ) and trazodone HCl (TRZ) in raw materials, tablets and human plasma. The first derivative synchronous fluorescence spectroscopic (FDSFS) technique was applied at constant wavelength difference (∆λ = 120) for assessment of DPZ and TRZ at each other's zero-crossing point at 279 nm and 297 nm, respectively. The submitted technique was validated in accordance with ICH Q2 R1 guidelines and the linearity of the standard calibration curve was observed over the concentration range of 10-500 ng/ml for DPZ and 20-1,000 ng/ml for TRZ. The detection limits (LOD) were found to be 2.65 and 5.4 ng/ml, and the limits of quantitation (LOQ) were 8.05 and 16.3 ng/ml for DPZ and TRZ, respectively. This technique was used further to quantify the studied medications in their laboratory-prepared mixtures, commercial tablets and spiked plasma samples. The results obtained were not significantly different from those acquired from the comparison methods, indicating the high accuracy and precision of the proposed method. Furthermore, the ecological friendliness of the suggested method was evaluated and proven to be excellent using Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE) evaluation tools.

A sustainable sensitive spectrofluorimetric approach for the determination of the multipotent protein lactoferrin in different pharmaceuticals and infant milk formula: Compliance with greenness metrics.

The current study presents the first spectrofluorimetric approach for the estimation of lactoferrin, depending on the measurement of its native fluorescence at 337 nm after excitation at 230 nm, without the need for any hazardous chemicals or reagents. It was found that the fluorescence intensity versus concentration calibration plot was linear over the concentration range of 0.1-10.0 µg/mL with quantitation and detection limits of 0.082 and 0.027 µg/mL, respectively. The method was accordingly validated according to the ICH recommendations. The developed method was applied for the estimation of lactoferrin in different dosage forms, including capsules and sachets with high percent recoveries (97.84-102.53) and low %RSD values (<1.95). Lactoferrin is one of the key nutrients in milk powder and a significant nutritional fortifier. In order to assess the quality of milk powder, it is essential to rapidly and accurately quantify the lactoferrin content of the product. Therefore, the presented study was successfully applied for the selective estimation of lactoferrin in milk powder with acceptable percent recoveries (96.45-104.92) and %RSD values (≤3.607). Finally, the green profile of the method was estimated using two assessment tools: Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE), which demonstrated its excellent greenness.

An eco-friendly and cost-effective HPTLC method for quantification of COVID-19 antiviral drug and co-administered medications in spiked human plasma.

The coronavirus-2 has led to a global pandemic of COVID-19 with an outbreak of severe acute respiratory syndrome leading to worldwide quarantine measures and a rise in death rates. The objective of this study is to propose a green, sensitive, and selective densitometric method to simultaneously quantify remdesivir (REM) in the presence of the co-administered drug linezolid (LNZ) and rivaroxaban (RIV) in spiked human plasma. TLC silica gel aluminum plates 60 F254 were used as the stationary phase, and the mobile phase was composed of dichloromethane (DCM): acetone (8.5:1.5, v/v) with densitometric detection at 254 nm. Well-resolved peaks have been observed with retardation factors (Rf) of 0.23, 0.53, and 0.72 for REM, LNZ, and RIV, respectively. A validation study was conducted according to ICH Q2 (R1) Guidelines. The method was rectilinear over the concentration ranges of 0.2-5.5 µg/band, 0.2-4.5 µg/band and 0.1-3.0 µg/band for REM, LNZ and RIV, respectively. The sensitivities of REM, LIN, and RIV were outstanding, with quantitation limits of 128.8, 50.5, and 55.8 ng/band, respectively. The approach has shown outstanding recoveries ranging from 98.3 to 101.2% when applied to pharmaceutical formulations and spiked human plasma. The method's greenness was assessed using Analytical Eco-scale, GAPI, and AGREE metrics.

Highly fluorescent nitrogen-doped carbon quantum dots prepared using sucrose and urea: Green synthesis, characterization, and use for determination of torsemide in its tablets and plasma samples.

A simple and facile microwave-assisted method was developed for the synthesis of highly fluorescent nitrogen-doped carbon quantum dots (N-CQDs) using sucrose and urea. The produced quantum dots exhibited a strong emission band at 376 nm after excitation at 216 nm with quantum yield of 0.57. The as-prepared N-CQDs were characterized using Fourier-transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) images, and ultraviolet-visible (UV-visible) spectra. The average particle size was 7.7 nm. It was found that torsemide (TRS) caused an obvious quenching of the fluorescent N-CQDs; so, they were used for its spectrofluorometric estimation. An excellent linear correlation was found between the fluorescence quenching of N-CQDs and the concentration of the drug in the range of 0.10 to 1.0 µg/mL with limit of quantitation (LOQ) of 0.08 µg/mL and limit of detection (LOD) of 0.027 µg/mL. The method was successfully applied for the assay of the drug in its commercial tablets and spiked human plasma samples, and the results obtained were satisfactory. Complex GAPI was used for greenness assessment of the analytical procedures and the pre-analysis steps. Interference likely to be introduced from co-administered drugs was also studied.

Spectrofluorometric determination of cinacalcet hydrochloride: greenness assessment and application to biological fluids andin-vitrodissolution testing.

A facile, simple, green and sensitive spectrofluorometric method was developed for determination of the calcimimetic drug cinacalcet hydrochloride. It is used for the treatment of hyperparathyroidism. The drug showed high native fluorescence intensity at 320 nm after excitation at 280 nm. The method was linear over the range of 5.0-400.0 ng ml-1with excellent correlation (R2= 0.9999). Limit of detection (LOD) and limit of quantitation (LOQ) values were 1.19 and 3.62 ng ml-1, respectively. The percentage recovery was found to be 100.42% ± 1.39 (n=8). The proposed method was successfully applied for determination of cinacalcet in spiked human plasma samples with % recoveries of (87.23 to 109.69%). Two recent greenness metrics (GAPI and Analytical Eco-Scale) were chosen to prove the eco-friendly nature of the method. Furthermore, the proposed method was successfully applied to dissolution study of commercial cinacalcet tablets. The interference likely to be introduced by some commonly co-administrated drugs such as metoprolol and itraconazole was studied; the tolerance limits were calculated.

Estimation of Two Diuretics Using Fluorescent Nitrogen Doped Carbon Quantum Dots: Application to Spiked Human Plasma and Tablets.

Highly fluorescent nitrogen doped carbon quantum dots (N-CQDs) were prepared by a single-step method based on microwave heating of cane sugar and urea. The produced N-CQDs were applied as nano-sensors for the spectrofluorimetric determination of eplerenone and spironolactone. A strong emission band at 376 nm was obtained after excitation at 216 nm due to the produced N-CQDs. The native fluorescence of N-CQDs was obviously quenched upon adding increased concentrations of each drug. A strong correlation was found between the fluorescence quenching of N-CQDs and the concentration of each drug. The method was found to be linear over the range of 0.5 to 5.0 µg/mL for eplerenone and 0.5 to 6.0 µg/mL for spironolactone with LOQ of 0.383 µg/mL and 0.262 µg/mL. The developed method was further extended for determination of both drugs in their pharmaceutical tablets and spiked human plasma. The results obtained were statistically compared with those of reported methods. The mechanism of fluorescence quenching of N-CQDs by the two drugs was discussed.

Use of green fluorescent nano-sensors for the determination of furosemide in biological samples and pharmaceutical preparations.

BACKGROUND: Carbon quantum dots (CQDs) are new class of carbon nanoparticles. Recently, they have been widely used as fluorescent probes due to their easy accessibility, optical properties and chemical inertness. Many available precursors are used in the synthesis of carbon quantum dots. The electrical and optical properties of CQDs could be enhanced by doping hetero atoms such as nitrogen or sulfur into their structure. OBJECTIVE: The current work presents the synthesis and characterization of water-soluble nitrogen doped carbon quantum dots (N-CQDs) and their use as fluorescent nano-sensors for the spectrofluorimetric determination of furosemide in its pharmaceutical preparations and spiked human plasma. METHODS: A domestic microwave was used to prepare the N-CQDs by heating a solution of sucrose and urea till complete charring (about ten minutes). The produced N-CQDs exhibit a strong emission band at 376 nm after excitation at 216 nm. Furosemide caused a quantitative quenching in the fluorescence intensity of the produced N-CQDs. RESULTS: The proposed method was validated according to ICH Guidelines. The method was found to be linear over the range of 0.1-1.0 µg/mL with LOQ of 0.087 µg/ml. CONCLUSION: Ecofriendly nano fluorescent sensors (N-CQDs) were successfully synthesized. The size of N-CQDs was distributed in the range of 6.63 nm to 10.23 nm with an average of 8.2 nm. The produced N-CQDs were used as fluorescent probes for the estimation of furosemide in its pharmaceutical preparations as well as spiked human plasma samples.

Green approach for tracking the photofate of ciprofloxacin and levofloxacin in different matrices adopting synchronous fluorescence spectroscopy: a kinetic study.

First derivative synchronous fluorescence spectroscopy (FDSFS) was applied to detect and quantify either ciprofloxacin (CIP) or levofloxacin (LEV) simultaneously with their photodegradation products, where the photolytic pathway for each analyte was found to be pH dependent. Under the guidance of early published articles, the structure of the produced photolytic products could be concluded, and further related to their resultant fluorescence spectra. The proposed method was subjected to full validation procedure which enables its application in investigating the photodegradation kinetics for both drugs. The obtained kinetic parameters were in accordance with previous reports and could be linked to predict the antibacterial activity of the resultant photodegradation products. These facts prove the suitability of the suggested FDSFS to serve as a stability-indicating assay method and to trace the photofate of CIP and LEV in the ecosystem as potential contaminants. Furthermore, the greenness of the suggested analytical methodology was evaluated via 'Green Analytical Procedure Index' (GAPI), which classifies it as an eco-friendly assay. Eventually, no extraction, treatment or preparation steps were needed during all analysis steps, which renders the proposed assay an appealing tool in environmental analysis.

Utility of a xanthene-based dye for determination of nilotinib using two spectroscopic approaches. Applications to bulk powder, capsules, and spiked human plasma.

Novel, selective, facile, and precise spectroscopic approaches were validated to determine nilotinib hydrochloride, a tyrosine kinase inhibitor used to treat patients with chronic myeloid leukemia. These approaches depend on the reaction of the tertiary amine group of nilotinib with erythrosine B in the Britton-Robinson buffer at pH 4. Method I, depends on measuring the absorbance of the formed complex at 551 nm. The absorbance concentration plot showed linearity over the concentration range of 1.0 to 9.0 µg/ml. Method II, involved the measurement of the quenching of the native fluorescence of erythrosine B by adding nilotinib in an acidic medium. The fluorescence quenching of erythrosine B was measured at 549 nm after excitation at 528 nm. This approach showed excellent linearity in the concentration range of 0.04 to 0.7 µg/ml. The limit of detection values for Method I and Method II were 0.225 and 0.008 µg/ml, respectively, while the limit of quantitation values for Method I and Method II were 0.68 and 0.026 µg/ml, respectively. To get the optimal conditions, factors that may affect the formation of the ion-pairing complex were thoroughly examined. The two approaches were carefully validated following the International Conference of Harmonization (ICH Q2R1) guidelines. Statistical assessment of the results achieved using the suggested and previously published comparison approaches showed no significant difference. The approaches were successful in determining nilotinib in a pharmaceutical dosage form as well as spiked human plasma samples. The eco-friendly properties of the methods were evaluated by three different tools.

Investigation of facile spectroscopic approaches for rapid calycosin determination in invitro biological samples and pharmaceuticals; application to the content uniformity of capsules.

Calycosin, the major bioactive isoflavonoid inAstragali Radix and an important anti-viral drug with a variety of pharmacological actions, is being determined by five different spectroscopic methods. Two spectrophotometric methods have been investigated including measuring the absorption spectra at λmax = 270 nm and the first derivative spectra at λ = 288 nm for methods I and II, respectively. For the first time; the native fluorescence of calycosin is measured without adding any reagents. The fluorescence intensity was measured at 340 nm after excitation at 282 nm in method III. The fourth method involves the direct measuring of a first derivative spectrofluorimetric emission peak at 292 nm. In method V synchronous fluorescence spectra were recorded in methanol at Δλ = 70 nm. The linear range for the fluorescence-based methods was 0.05-1.0 µg/mL and for the UV-based methods was 0.5-10.0 µg/mL. The methods were validated per International Council of Harmonization (ICHQ2R1) guidelines. The limits of detection were found to be down to 0.11 and 0.12 µg/mL for the spectrophotometric methods, and 15.0, 18.0,16.0 ng/ mL, for the spectrofluorimetric approaches respectively, representing the high sensitivity. Accordingly, this permitted the quantitation of calycosin in spiked human plasma samples with satisfactory percentage recoveries (94.50.-102.50 %). The methods were utilized for calycosin analysis in different matrices including plasma and capsules with high precision and accuracy.

Utility of a novel turn-off fluorescence probe for the determination of tranilast, an adjunctive drug for patients with severe COVID-19.

Tranilast (TR) could be investigated as a suitable anti-inflammatory and NLRP3 inflammasome inhibitor medication for the treatment of COVID-19 acute patients. Owing to its importance, our study was constructed for the determination of TR using a new, fast, sensitive, and reliable green spectrofluorimetric method. TR was quantified in this study by forming a complex with the acriflavine (AC) reagent. The reaction between TR and AC quenched the fluorescence of AC through the formation of an ion-association complex and the response was measured at 493 nm after excitation at 263 nm. It was observed that the quenching of the fluorescence of AC was linear (r = 0.9998) with the concentration of TR in the range of 1.0-15.0 µg mL-1. The limit of detection was 0.224 µg mL-1, and the limit of quantification was 0.679 µg mL-1. The fluorescence quenching mechanism was carefully studied and was confirmed to be able to analyze TR in its pure form and its prepared pharmaceutical dosage form. To validate the method, the international conference of harmonization (ICH) Q2R1 guidelines were followed. The statistical assessment of the proposed and comparison methods revealed no significant differences between them. Moreover, the green criteria of the method were evaluated and confirmed.

Utility of Kolliphor RH 40 in micellar sensitized fluorescence of the novel tyrosine kinase inhibitor "Erdafitinib": Application to human plasma.

Erdafitinib is the first treatment targeting susceptible fibroblast growth factor receptor (FGFR) genetic alterations in patients with locally advanced or metastatic urothelial carcinoma. A simple and precise spectrofluorimetric method was developed for its determination depending on fluorescence enhancement using Kolliphor RH 40 micellar medium at pH 10. The fluorescence intensity was measured at 495 nm after excitation at 410 nm. Different experimental parameters affecting the fluorescence intensity, including type of organized medium, diluting solvent, buffer type and pH were studied during optimization phase. Validation according to ICH Q2(R1) guidance was fully fulfilled. The method was linear over the range of 50 - 800 ng/mL. The lower limit of detection (LOD) and lower limit of quantitation (LOQ) were 14.36 and 43.50 ng/mL, respectively. The relative standard deviation values of intraday and interday precisions were less than 1.93 %. The proposed method was successfully applied to laboratory-prepared tablets. Furthermore, the high sensitivity of the method allowed its application on spiked human plasma samples with a high percent of recovery. The greenness of the method was investigated as an Eco-friendly alternative for erdafitinib determination with minimal organic solvent consumption.

Two spectroscopic methods for estimation of anti-migraine medications: Sumatriptan and Zolmitriptan based on nucleophilic substitution reaction.

Sensitive and selective spectrophotometric and spectrofluorimetric methods have been developed for the estimation of two anti-migraine drugs, namely sumatriptan succinate (SUM) and zolmitriptan (ZOL). These methods depend on producing a yellow-coloured product after the reaction of the two drugs with 7-chloro-4-nitrobenz-2-oxa-1,3-diazole (NBD-Cl). The reaction products exhibited maximum absorbance at 481 nm in borate buffer of pH 9 and fluorescence emission peak at 540 nm after excitation at 470 nm for the two drugs. The linear ranges were 5-60 µg/ml for SUM and 5-50 µg/ml for ZOL in the spectrophotometric method (Method I), whereas this was 0.4-4 µg/ml for SUM and 0.5-5 µg/ml for ZOL in the spectrofluorimetric method (Method II). The method validity was assessed according to International Council for Harmonisation (ICH) guidelines. Statistical analysis of the results obtained from the proposed and comparison methods confirmed that the proposed methods were highly accurate and precise. The suggested methods could be used for the determination of the mentioned drugs in both pure form and in tablets.

LC-MS/MS monitoring of the colorectal carcinoma cellular uptake and entrapment of sorafenib and its N-oxide active metabolite.

Sorafenib (SOR) is a multikinase inhibitor with a mild activity against colorectal cancer cells due to multi-drug resistance mechanisms. Potentiated SOR activity was expected upon combination with some ginger derived compounds due to their interference with intracellular drug metabolism. Studying such combination necessitates the development of a sensitive validated LC-MS/MS method for the determination of intra and extracellular concentration of SOR and its N-oxide metabolite (SNX) in colorectal cancer cells. SOR, SNX and the internal standard (diclofenac sodium) were efficiently separated on Eclipse plus C18 column (3.0 ×150 mm, 5 µm) using isocratic elution with acetonitrile and 0.01 M ammonium formate aqueous solution containing 0.1% formic acid (69:31, v/v). Sample pretreatment using solid phase extraction was optimized and the mean percent recoveries were more than 97.01% for both analytes. Detection was conducted at positive ion multiple reaction monitoring (MRM) mode and the monitored mass transitions were 465.2 → 252.2 for SOR and 481.1 → 286.0 for SNX. The method was linear over the range 0.25 - 200.00 ng/mL (r2 ≥ 0.9992) for SOR and 0.10 - 125.00 ng/mL (r2 ≥ 0.9990) for SNX in both intra and extracellular matrices. The lower limits of quantification (LLOQ) were 0.25 and 0.10 ng/mL for SOR and SNX, respectively. Accuracies were within 94.25 - 109.45% and precision CV values did not exceed 7.63%. The method was able to monitor the cellular uptake and entrapment of both analytes and to prove the positive effect of the ginger derived compounds on SOR activity.

HPLC-UV determination of erdafitinib in mouse plasma and its application to pharmacokinetic studies.

Erdafitinib is a recently approved fibroblast growth factor receptor (FGFR) inhibitor. It is the first treatment targeting susceptible FGFR genetic alterations for patients with metastatic bladder cancer. A simple validated HPLC-UV method was developed for the determination of erdafitinib in mouse plasma. Erdafitinib and internal standard (rivaroxaban) were efficiently separated on Eclipse plus C18 column (4.6 × 100 mm, 3.5 µm). The mobile phase consisted of acetonitrile and 0.01 M ammonium acetate aqueous solution, adjusted to pH 4.4 with acetic acid (26:74, v/v) and it was eluted isocratically at a flow rate of 1.2 mL/min. The UV detection was at 292 nm and the total run time for each sample was 11 min. The method linearity was validated over the range of 0.05-2.00 µg/mL (r2 ≥ 0.9992) and the lower limit of quantification (LLOQ) was 0.05 µg/mL. The within-run and between-run accuracies were 98.56 and 99.24%, respectively while the CV of the method precision did not exceed 6.52%. Plasma samples were extracted using a solid phase extraction procedure and the extraction recoveries were 97.90 ± 4.58%. The method was optimized for the sensitive determination of the studied drug in mouse plasma and was successfully applied to its pharmacokinetic studies.

Spectrofluorimetric investigation for determination of sumatriptan succinate: application to tablets and spiked human plasma.

A simple and highly sensitive spectrofluorimetric method for the estimation of sumatriptan succinate has been investigated. The suggested method depends on the determination of the intrinsic fluorescence properties of the drug in aqueous systems at λem 350 nm following λex at 225 nm. The linearity range was 10-100 ng/ml, with a detection limit and quantitation limit of 1.2 and 3.6 ng/ml, respectively. The suggested method was sufficiently successful for determination of sumatriptan its pharmaceutical tablets as well as in spiked human plasma. Moreover, the validation parameters were determined following International Council for Harmonisation guidelines. Statistical analysis of the obtained results from the proposed and reference methods showed no significance difference between the two methods regarding accuracy and precision.

Multiobjective optimization of microemulsion- thin layer chromatography with image processing as analytical platform for determination of drugs in plasma using desirability functions.

A new platform was developed for determination of drugs in plasma without extraction or instrumental analysis just using TLC, smart phone digital camera and free image processing software. Lamotrigine, antiepileptic drug was used as model analyte. The proposed platform depends on using oil-in-water (O/W) microemulsion to isolate the drug from plasma proteins and using water-in-oil (W/O) microemulsion as mobile phase for TLC which results in complete separation between lamotrigine and plasma as viewed under UV lamp. The composition of both microemulsions was optimized using Taguchi orthogonal array and Plackett- Burman design. The optimal (O/W) microemulsion predicted composition was 0.01 mL Butyl acetate, 4 mL butanol, 0.925 gm SDS and 8.6 mL water while the (W/O) mobile phase microemulsion was 9 mL Butyl acetate, 1 mL butanol, 0.25 gm SDS, 0.25 mL water. Separation was carried out on a silica gel 60F-254 plate eluted with the (W/O) microemulsion in about 30 min development time. The images of TLC plates were processed using 4 different programs, by comparing their results it was found that "integrated density" measured by Fiji software was the most accurate response that could measure the concentration of lamotrigine in spiked plasma in the range of (20-200) ng/spot. This method was applied also for determination of lamotrigine in lamictal® tablet dosage form using the same mobile phase. The precision of the method was satisfactory; the maximum value of relative standard deviations did not exceed 1.5%. While the accuracy was proved by the low values of % error and high values of recovery.

Digitally enhanced thin layer chromatography for simultaneous determination of norfloxacin and tinidazole with the aid of Taguchi orthogonal array and desirability function approach: Greenness assessment by analytical Eco-Scale.

In this study, an eco-friendly fast simple method was developed for simultaneous determination of norfloxacin and tinidazole based on thin-layer chromatography and image-processing analysis. The binary mixture was separated using reversed phase - thin layer chromatography plates and 30% trifluoroacetic acid only as mobile phase. Mobile phase composition was optimized using Taguchi orthogonal array and Derringer's desirability function. The plates were viewed under UV lamp and photographed by iPhone camera followed by image processing with Fiji software using integrated density as the measured response. As decreasing illumination increases the sensitivity of the method, this method was applied on two different ranges for each drug. The first one was 0.6-6.0 and 0.9-9.0 µg/spot for norfloxacin and tinidazole, respectively measured on the original image with normal illumination. The second one was measured after decreasing the illumination of the captured images at 0.06-0.60 and 0.09-0.90 µg/spot for norfloxacin and tinidazole, respectively. The proposed method was successfully applied for the determination of both drugs in tablets dosage form without interference from the commonly encountered excipients. Analytical Eco-Scale was used to evaluate the greenness profile of the proposed method and it was found to be excellent green analytical method.

Two validated spectrofluorimeteric and high performance liquid chromatography (HPLC) methods with fluorescence detection for the analysis of a new anti-hepatitis C drug, daclatasvir hydrochloride, in raw material or tablet form and in biological fluids.

Two sensitive and accurate methods have been developed for the estimation of daclatasvir (DAC) in its raw material, dosage form and in biological fluids. Method I is based on the measurement of DAC native fluorescence in methanol at 385 nm after excitation at 315 nm. The relationship between fluorescence intensity and concentration was found to be rectilinear over the linearity range (3.0-30.0 ng/ml). There were good per cent recoveries both in the dosage form (99.87 ± 0.84) and in spiked human plasma (99.96 ± 1.54%). Method II utilized reversed-phase high performance liquid chromatography to estimate the antiviral agent daclatasvir hydrochloride against hepatitis C within 4.0 min on a C18 column (Eurosphere. 100-5 C18, 150 × 4.6 mm, Germany) using a mobile phase consisting of acetonitrile and 0.1 M sodium dihydrogen phosphate (30:70, v/v) at pH 3.0 and with a fluorescence detector adjusted to 315 nm and 385 nm for excitation and emission respectively. The calibration curve was linear over the range (20.0-200.0 ng/ml) with SD 1.38%, error 0.56%, recovery 99.99 ± 1.30% in tablets, recovery 100.28 ± 1.73% in spiked urine and recovery 99.63 ± 2.72% in spiked plasma.The new developed methods were successfully applied to the assay of the daclatasvir in tablet form and extended to its determination in real plasma, spiked human plasma and urine. The analytical performance of the proposed method was validated according to International Conference on Harmonization (ICH) guidelines. The proposed methods were compared with the results of a comparison method and it was found that there was no significant difference between the methods, as revealed by Student's t-test and variance ratio F-test.

Simultaneous determination of cetirizine, phenyl propanolamine and nimesulide using third derivative spectrophotometry and high performance liquid chromatography in pharmaceutical preparations.

BACKGROUND: The combination between cetirizine (CET), phenylpropanolamine (PPA) and nimesulide (NMS) under trade name Nemeriv Cp tablet is prescribed for nasal congestion, cold, sneezing, and allergy. Among all published methods for the three drugs; there is no reported method concerning estimation of CTZ, PPA and NMS simultaneously and this motivates us to develop new and simple methods for their assay in pure form and tablet preparations. RESULTS: Two new methodologies were described for the simultaneous quantification of cetirizine (CTZ), PPA and NMS. Spectrophotometric procedures relies on measuring the amplitudes of the third derivative curves at 238 nm for CTZ, 218 nm for PPA and 305 nm for NMS. The calibration graphs were rectilinear over the ranges of 8-90 µg/mL for CTZ, 20-100 µg/mL for PPA and 20-200 µg/mL for NMS respectively. Regarding the HPLC method; monolithic column (100 mm × 4.6 mm i.d) was used for the separation. The used mobile phase composed of 0.1 M phosphate buffer and methanol in the ratio of 40:60, v/v at pH 7.0. The analysis was performed using UV detector at 215 nm. Calibration curves showed the linearity over concentration ranges of 5-40, 10-100 and 10-120 µg/mL for CTZ, PPA and NMS. CONCLUSION: Application of the proposed methods to the laboratory prepared tablets was carried out successfully. The results were compared with those obtained from previously published methods and they were satisfactory. Graphical abstract Graphical abstract represents the chemical structures, representative chromatogram for the HPLC separation of a PPA, b NMS and c CTZ and third derivative absorption spectra of a PPA, b NMS and c CTZ for the spectrophotometric method.