Development and validation of a novel RP-HPLC method for simultaneous determination of paracetamol, phenylephrine hydrochloride, caffeine, cetirizine and nimesulide in tablet formulation

Highly electrochemically active Ti3C2Tx MXene/MWCNT nanocomposite for the simultaneous sensing of paracetamol, theophylline, and caffeine in human blood samples

The facile fabrication is reported of highly electrochemically active Ti3C2Tx MXene/MWCNT (3D/1D)-modified screen-printed carbon electrode (SPE) for the efficient simultaneous electrochemical detection of paracetamol, theophylline, and caffeine in human blood samples. 3D/1D Ti3C2Tx MXene/MWCNT nanocomposite was synthesized using microwave irradiation and ultrasonication processes. Then, the Ti3C2Tx/MWCNT-modified SPE electrode was fabricated and thoroughly characterized towards its physicochemical and electrochemical properties using XPS, TEM, FESEM, XRD, electrochemical impedance spectroscopy, cyclic voltammetry, and differential pulse voltammetry techniques. As-constructed Ti3C2Tx-MWCNT/SPE offers excellent electrochemical sensing performance with good detection limits (0.23, 0.57, and 0.43 µM) and wide linear ranges (1.0 ~ 90.1, 2.0 ~ 62.0, and 2.0-90.9 µM) for paracetamol, caffeine, and theophylline, respectively,  in the human samples. Notably, the non-enzymatic electroactive nanocomposite-modified electrode has depicted a semicircle Nyquist plot with low charge transfer resistance (Rct∼95 Ω), leading to high ionic diffusion and facilitating an excellent electron transfer path. All the above results in efficient stability, reproducibility, repeatability, and sensitivity compared with other reported works, and thus, it claims its practical utilization in realistic clinical applications.

Smart green spectrophotometric assay of the ternary mixture of drotaverine, caffeine and paracetamol in their pharmaceutical dosage form

Three green and facile spectrophotometric methods were developed for the assay of Petro® components; drotaverine HCl (DRT), caffeine (CAFF), and paracetamol (PAR). The three methods depend on measuring the absorbance of the studied drugs through their ethanolic solution. The first derivative spectrophotometry (FDS) at (Δλ = 10) were good parameters for DRT and CAFF resolution; DRT and CAFF could be well calibrated using FDS at 320 and 285 nm, respectively. PAR could be estimated at 308 nm utilizing the second derivative spectrophotometry (SDS). Method II relies on the double divisor ratio derivative spectroscopy (DDRDS). The first derivative was applied on each drug where they would be assayed at 309, 288, and 255 nm for DRT, CAFF, and PAR, respectively. Method III depends on the mean centering (MCR) technique. DRT, CAFF, and PAR could be determined at 309, 214, and 248 nm, respectively. The concentrations were rectilinear in the ranges of 2-20 µg/mL for DRT, 1.5-15 µg/mL for CAFF, and 2-40 µg/mL for PAR in double devisor and mean centering but PAR from 5 to 40 µg/mL in derivative method. Method validation was performed according to ICH guidelines assured by the agreement with the comparison method. In addition, greenness assessment of the proposed methods was investigated. The application of the proposed method was extended to analyse tablet dosage form and performing invitro dissolution testing.

Retention behaviour of analytes in reversed phase high performance liquid chromatography - A review

The understanding of principles that drive the separation in reversed phase chromatography plays an important role in the prediction of elution of solutes in RP-HPLC. The separation in RP-HPLC is based on the principle of adsorption and partition. In addition, the log P value, pK_a value of the drug, chromatographic parameters like mobile phase pH, buffer concentration, organic modifier and mobile phase additives also influence the retention and selectivity of the analyte. It is found that hydrophobic, electrostatic, hydrogen bonding and other specific interactions between the stationary phase and the solutes along with the hydrophobicity of an analyte molecule (log P) modify the retention behaviour of the analytes. This article gives special attention to the influence of ionization and ion interaction on the separation of analytes. The drug molecules with different log P value containing protonated and deprotonated acids, bases and zwitterions are selected as examples and this article addresses various issues related to method development, relationships between analyte retention and mobile phase pH and pK_a value of the analyte. The advances in this regard, with highlights on topics such as mechanisms of retention and various factors that influence the retention behaviour of analytes is also updated with suitable examples.

New Electrochemical Sensor Based on Hierarchical Carbon Nanofibers with NiCo Nanoparticles and Its Application for Cetirizine Hydrochloride Determination

A new electrochemical sensor based on hierarchical carbon nanofibers with Ni and Co nanoparticles (eCNF/CNT/NiCo-GCE) was developed. The presented sensor may be characterized by high sensitivity, good electrical conductivity, and electrocatalytic properties. Reproducibility of its preparation expressed as %RSD (relative standard deviation) was equal to 9.7% (n = 5). The repeatability of the signal register on eCNF/CNT/NiCo-GCE was equal to 3.4% (n = 9). The developed sensor was applied in the determination of the antihistamine drug—cetirizine hydrochloride (CTZ). Measurement conditions, such as DPV (differential pulse voltammetry) parameters, supporting electrolyte composition and concentration were optimized. CTZ exhibits a linear response in three concentration ranges: 0.05–6 µM (r = 0.988); 7–32 (r = 0.992); and 42–112 (r = 0.999). Based on the calibration performed, the limit of detection (LOD) and limit of quantification (LOQ) were calculated and were equal to 14 nM and 42 nM, respectively. The applicability of the optimized method for the determination of CTZ was proven by analysis of its concentration in real samples, such as pharmaceutical products and body fluids (urine and plasma). The results were satisfactory and the calculated recoveries (97–115%) suggest that the method may be considered accurate. The obtained results proved that the developed sensor and optimized method may be used in routine laboratory practice.

Rapid and Sensitive Determination of Methylxanthines in Commercial Brands of Tea Using Ultra-High-Performance Liquid Chromatography-Mass Spectrometry

Recently, chromatographic techniques have the potential to be greener in order to reduce the environmental impact. In this work, a new simple, sensitive, efficient, and green analytical method based on UHPLC-MS has been developed for a quick determination of methylxanthines including caffeine, theobromine, and theophylline in tea. Under the optimum conditions, a baseline separation has been achieved within 30 seconds, using isocratic elution consisting of 90% water and only 10% acetonitrile at 0.5 mL/min flow rate (3 mL acetonitrile per hour). The mass spectrometer was operated with the SIR mode in ESI⁺. The developed method was found to be linear in the range of 0.03–5 μg/mL, with correlation coefficients greater than 0.9995 for the three compounds. The respective values of LOD were found to be 0.025, 0.015, and 0.01 μg/mL for caffeine, theobromine, and theophylline, respectively. The proposed assay was applied to 30 commercial tea samples of different brands. Both caffeine and theobromine were found in all tea samples with maximum concentration in sample no. 15, corresponding to 32.6 and 2.72 mg/g of caffeine and theobromine, respectively. On the contrary, theophylline was not detected at all in most samples. When compared with all previous studies that dealt with the same compounds in different matrices, the developed method was found to be the fastest, allowing high-throughput analyses with more than 100 samples/h. The results prove that the method is suitable for routine analysis of methylxanthines and to distinguish the quality of tea samples of various brands.

Robust Chromatographic Methods for the Analysis of Two Quaternary Mixtures Containing Paracetamol, Codeine, Guaifenesin and Pseudoephedrine or Phenylephrine in their Dosage Forms

Two simple validated and highly selective methods for analysis of paracetamol, codeine, guaifenesin and pseudoephedrine or phenylephrine quaternary mixtures were developed. The first method is a high performance liquid chromatography with diode array detection method where separation was successful using Agilent C18 (150 × 4.6 mm) column, gradient elution of phosphate buffer pH 3, methanol and acetonitrile and diode-array detection at 210 nm. The second method is a HPTLC method followed by densitometric measurement of the spots at 257 nm. Separation was carried out on Merck HPTLC aluminum sheets of silica gel using methylene chloride: methanol: glacial acetic acid: ammonia (17.8: 1.68: 0.4: 0.12, v/v) mobile phase. The methods were applied successfully for analysis of both quaternary mixtures in laboratory-prepared tablets and also validated in regards to linearity, precision, accuracy, sensitivity and stability.

Determination of Ibuprofen and Phenylephrine in Tablets by High-Performance Thin Layer Chromatography and in Plasma by High-Performance Liquid Chromatography with Diode Array Detection

Two chromatographic methods (high performance thin layer chromatography (HPTLC) and high performance liquid chromatography-diode array detector (HPLC-DAD)), were addressed for the analysis of a mixture consisted of phenylephrine hydrochloride and ibuprofen in two forms bulk and their combined dosage form. This binary mixture is considered to be a challenging one as the two drugs differ greatly in their chemical and physical properties. Not only this affects their simultaneous analysis, but also hinders their simultaneous extraction from biological fluids as plasma. That is the reason the literature lacks any report for the simultaneous extraction and analysis of these drugs from biological fluids. The concentration ranges of both drugs were 0.1-2.5 μg/spot and 0.1-100 μg/mL by HPTLC and HPLC, respectively. Not only was the HPLC-DAD method applied to the investigated drugs determination in pharmaceutical preparations, but also in spiked human plasma. Extensive study was conducted to optimize their simultaneous extraction from plasma as it was a crucial step for the in vivo analysis. The results obtained by proposed methods and a reference one were statistically comparable by analysis of variance test. No significant difference was recorded between the mean percent levels determined by the proposed methods and the reference one.

Determination of sofosbuvir with two co-administered drugs; paracetamol and DL-methionine by two chromatographic methods. Application to a pharmacokinetic study

AIM

Two rapid and sensitive chromatographic methods have been developed and validated for simultaneous analysis of sofosbuvir (SOF) in rat plasma with two co-administered drugs, paracetamol (PAR) and DL-methionine (MET).

MATERIALS & METHODS

The first method relied on using TLC-densitometry with a developing system consisted of chloroform: methanol: glacial acetic acid: formic acid in the ratio of 9.5: 1: 1.5: 0.5, by volume. The studied analytes and the internal standard naphazoline hydrochloride were scanned at 210 nm. The second method was HPLC method, whereas the analytes and the internal standard cinnarizine were separated on XTerra^® HPLC RP C18 column using gradient elution mode and a mobile phase consisted of methanol: 0.1% aqueous TEA at pH 3 adjusted with orthophosphoric acid at 210 nm.

RESULTS

The TLC-densitometry method showed linearity over concentration ranges of 160-3000 ng/band for SOF and PAR, 300-3000 ng/band for MET, but HPLC method was linear and validated over concentration ranges of 150-5000 ng/ml for SOF, 300-5000 ng/ml for both PAR and MET.

CONCLUSION

All validation parameters met the acceptance criteria according to US FDA guidelines. Pharmacokinetic study was successfully applied and proved the possibility of co-administration of SOF with PAR and MET.

Application of derivative emission fluorescence spectroscopy for determination of ibuprofen and phenylephrine simultaneously in tablets and biological fluids

Two sensitive, rapid, and accurate derivative emission spectrofluorimetric methods applying zero crossing techniques were developed for simultaneous determination of binary mixtures of ibuprofen (IBU) and phenylephrine hydrochloride (PHE) in pure powder, synthetic mixture and combined tablets. The proposed methods were performed via measuring the intersected drug derivative amplitude of one drug at the zero crossing points for the other one and vice versa. The two methods rely on the measurement of the combined drugs native fluorescence after excitation at 270 nm in methanol directly, followed by differentiation using first (D₁) and second derivative (D₂) techniques. Applying the D₁, IBU was measured quantitatively at 293.1 nm at zero crossing of PHE, on the other side; PHE was measured quantitatively at 300.7 nm at zero crossing of IBU. By the same way, applying the D₂, the wavelengths selected were 303.5 nm for IBU and 312.9 nm for PHE. The concentration plots of derivative fluorescence intensity were rectilinear over the range of 0.5-10 μg/mL and 0.025-0.5 μg/mL for IBU and PHE, respectively. The results obtained with average % recoveries ± RSD are 99.73 ± 0.72 (IBU, D₁), 99.49 ± 0.95 (PHE, D₁), 99.79 ± 0.47 (IBU, D₂), and 99.88 ± 0.34 (PHE, D₂) were in good agreement with the comparison method. The proposed methods offer high sensitivity that enable direct analysis of IBU and PHE in spiked human plasma. The proposed methods were entirely validated in terms of ICH guidelines.

Voltammetric determination of phenylephrine hydrochloride using a multi-walled carbon nanotube-modified carbon paste electrode

A chemically modified carbon paste electrode (CPE) was designed by mixing graphite and multi-walled carbon nanotubes (MWCNT). The electrochemical behaviour was studied, and the determination method of phenylephrine hydrochloride (PHE) on this sensor was established. According to the results, the optimal ratio of MWCNTs was approximately 12.5% (w/w). MWCNT-modified carbon paste electrodes (MWCNT-CPEs) showed high electrochemical activity for PHE, producing a sharp oxidation peak current (I _p) at approximately +0.816 V versus a saturated calomel electrode (SCE) reference electrode in phosphate buffer solution (PBS, pH 6.45), and the I _p increased by approximately two times compared to that of the bare CPE. The anodic I _p was linearly related with 5.0 × 10^-6-7.5 × 10^-4 mol l^-1 PHE, with a detection limit of 3.7 × 10^-7 mol l^-1. Furthermore, MWCNT-CPEs were successfully applied to the determination of PHE in injection, eye drop and nasal spray liquid samples as a simple, rapid and low-cost method.

Development and optimization of a generic HPLC method for the simultaneous determination of common ingredients in multi component cough and cold oral drug products using chemometrics

The aim of this work was to develop a single, generally applicable high performance liquid chromatography/diode array detector (HPLC/DAD) method for simultaneous determination of the most frequently used cough and cold active substances and their impurities that would be applicable for a number of possible formulation compositions of cough and cold medicines. The compounds that are separated by the method include eleven active substances: paracetamol, phenylephrine HCl, caffeine, ibuprofen, ascorbic acid, propiphenazone, pheniramine maleate, chlorphenamine maleate, pseudoephedrine HCl, dextromethorphan HBr and cetylpyridinium Cl; five of their impurities: 4-aminophenol, 4-nitrophenol, 4`-chloroacetanilide, chlorphenamine impurity C and ephedrine HCl; and two preservatives: sodium benzoate and propyl parahydroxybenzoate. All 18 compounds were successfully separated on a reversed phase (RP)-HPLC column with superficially porous particles using gradient elution with a very simple mobile phase in 14 minutes with excellent sensitivity and resolution. Method optimization was performed by the design of experiments approach. The proposed method has been validated according to ICH guidelines and proved to be suitable for the simultaneous qualitative and quantitative determination of the selected compounds in different cough and cold dosage forms. Keywords: cough and cold active substances and impurities, HPLC/DAD, superficially porous particles, core-shell particles, chemometrics, design of experiments

New model for prediction binary mixture of antihistamine decongestant using artificial neural networks and least squares support vector machine by spectrophotometry method

In the present study, artificial neural networks (ANNs) and least squares support vector machines (LS-SVM) as intelligent methods based on absorption spectra in the range of 230-300nm have been used for determination of antihistamine decongestant contents. In the first step, one type of network (feed-forward back-propagation) from the artificial neural network with two different training algorithms, Levenberg-Marquardt (LM) and gradient descent with momentum and adaptive learning rate back-propagation (GDX) algorithm, were employed and their performance was evaluated. The performance of the LM algorithm was better than the GDX algorithm. In the second one, the radial basis network was utilized and results compared with the previous network. In the last one, the other intelligent method named least squares support vector machine was proposed to construct the antihistamine decongestant prediction model and the results were compared with two of the aforementioned networks. The values of the statistical parameters mean square error (MSE), Regression coefficient (R²), correlation coefficient (r) and also mean recovery (%), relative standard deviation (RSD) used for selecting the best model between these methods. Moreover, the proposed methods were compared to the high- performance liquid chromatography (HPLC) as a reference method. One way analysis of variance (ANOVA) test at the 95% confidence level applied to the comparison results of suggested and reference methods that there were no significant differences between them.

Rapid High Performance Liquid Chromatography Determination and Optimization of Extraction Parameters of the α-Asarone Isolated from Perilla frutescens L

Response surface methodology (RSM), based on a central composite design, was used to determine the best liquid-to-raw material ratio (10:3–15 mL/g), extraction time (1–3 h), and ethanol concentration (50%–100%) for maximum content of α-asarone from Perilla frutescens (PF) extract. Experimental values of α-asarone were 9.51–46.36 mg/g; the results fitted a second-order quadratic polynomial model and correlated with the proposed model (R² > 0.9354). The best conditions were obtained with extraction time of 1.76 h, liquid-to-raw material ratio of 10:13.5 mL/g, and ethanol concentration of 90.37%. Under these conditions, the model predicted extraction content of 40.56 mg/g, while experimental PF content of α-asarone was 43.84 mg/g dried plant. Optimized conditions determined for maximum content of α-asarone were similar to the experimental range. Experimental values agreed with those predicted, thus validating and indicating suitability of both the model and the RSM approach for optimizing extraction conditions. In addition, a reliable, reproducible and accurate method for the quantitative determination of α-asarone by High Performance Liquid Chromatography (HPLC) analysis was developed with limit of detection (LOD), limit of quantitation (LOQ) values of 0.10 and 0.29 µg/mL and excellent linearity (R² > 0.9999).

Development and validation of multivariate calibration methods for simultaneous estimation of Paracetamol, Enalapril maleate and hydrochlorothiazide in pharmaceutical dosage form

Three multivariate calibration spectrophotometric methods were developed for simultaneous estimation of Paracetamol (PARA), Enalapril maleate (ENM) and Hydrochlorothiazide (HCTZ) in tablet dosage form; namely multi-linear regression calibration (MLRC), trilinear regression calibration method (TLRC) and classical least square (CLS) method. The selectivity of the proposed methods were studied by analyzing the laboratory prepared ternary mixture and successfully applied in their combined dosage form. The proposed methods were validated as per ICH guidelines and good accuracy; precision and specificity were confirmed within the concentration range of 5-35μgmL^-1, 5-40μgmL^-1 and 5-40μgmL^-1of PARA, HCTZ and ENM, respectively. The results were statistically compared with reported HPLC method. Thus, the proposed methods can be effectively useful for the routine quality control analysis of these drugs in commercial tablet dosage form.

Development, Validation and Application of RP-HPLC Method: Simultaneous Determination of Antihistamine and Preservatives with Paracetamol in Liquid Formulations and Human Serum

In this article we describe development and validation of stability indicating, accurate, specific, precise and simple Ion-pairing RP-HPLC method for simultaneous determination of paracetamol and cetirizine HCl along with preservatives i.e. propylparaben, and methylparaben in pharmaceutical dosage forms of oral solution and in serum. Acetonitrile: Buffer: Sulfuric Acid (45:55:0.3 v/v/v) was the mobile phase at flow rate 1.0 mL min^-1 using a Hibar^® Lichrosorb^® C₁₈ column and monitored at wavelength of 230nm. The averages of absolute and relative recoveries were found to be 99.3%, 99.5%, 99.8% and 98.7% with correlation coefficient of 0.9977, 0.9998, 0.9984, and 0.9997 for cetirizine HCl, paracetamol, methylparaben and Propylparaben respectively. The limit of quantification and limit of detection were in range of 0.3 to 2.7 ng mL^-1 and 0.1 to 0.8 ng mL^-1 respectively. Under stress conditions of acidic, basic, oxidative, and thermal degradation, maximum degradation was observed in basic and oxidative stress where a significant impact was observed while all drugs were found almost stable in the other conditions. The developed method was validated in accordance with ICH and AOAC guidelines. The proposed method was successfully applied to quantify amount of paracetamol, cetirizine HCl and two most common microbial preservatives in bulk, dosage form and physiological fluid.

Green approach using monolithic column for simultaneous determination of coformulated drugs

Green chemistry and sustainability is now entirely encompassed across the majority of pharmaceutical companies and research labs. Researchers' attention is careworn toward implementing the green analytical chemistry principles for more eco-friendly analytical methodologies. Solvents play a dominant role in determining the greenness of the analytical procedure. Using safer solvents, the greenness profile of the methodology could be increased remarkably. In this context, a green chromatographic method has been developed and validated for the simultaneous determination of phenylephrine, paracetamol, and guaifenesin in their ternary pharmaceutical mixture. The chromatographic separation was carried out using monolithic column and green solvents as mobile phase. The use of monolithic column allows efficient separation protocols at higher flow rates, which results in short time of analysis. Two-factor three-level experimental design was used to optimize the chromatographic conditions. The greenness profile of the proposed methodology was assessed using eco-scale as a green metrics and was found to be an excellent green method with regard to the usage and production of hazardous chemicals and solvents, energy consumption, and amount of produced waste. The proposed method improved the environmental impact without compromising the analytical performance criteria and could be used as a safer alternate for the routine analysis of the studied drugs.

Development and Validation of a High-Performance Thin-Layer Chromatographic Method for the Simultaneous Determination of Two Binary Mixtures Containing Ketorolac Tromethamine with Phenylephrine Hydrochloride and with Febuxostat

A validated and highly selective high-performance thin-layer chromatography (HPTLC) method was developed for the determination of ketorolac tromethamine (KTC) with phenylephrine hydrochloride (PHE) (Mixture 1) and with febuxostat (FBX) (Mixture 2) in bulk drug and in combined dosage forms. The proposed method was based on HPTLC separation of the drugs followed by densitometric measurements of their spots at 273 and 320 nm for Mixtures 1 and 2, respectively. The separation was carried out on Merck HPTLC aluminum sheets of silica gel 60 F254 using chloroform-methanol-ammonia (7:3:0.1, v/v) and (7.5:2.5:0.1, v/v) as mobile phase for KTC/PHE and KTC/FBX mixtures, respectively. Linear regression lines were obtained over the concentration ranges 0.20-0.60 and 0.60-1.95 µg band(-1)for KTC and PHE (Mixture 1), respectively, and 0.10-1.00 and 0.25-2.50 µg band(-1) for KTC and FBX (Mixture 2), respectively, with correlation coefficients higher than 0.999. The method was successfully applied to the analysis of the two drugs in their synthetic mixtures and in their dosage forms. The mean percentage recoveries were in the range of 98-102%, and the RSD did not exceed 2%. The method was validated according to ICH guidelines and showed good performances in terms of linearity, sensitivity, precision, accuracy and stability.

RETRACTED: Graphene quantum dots decorated CdS doped graphene oxide sheets in dual action mode: As initiator and platform for designing of nimesulide imprinted polymer

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of Editor following concerns raised by a reader. The article uses several electron micrographs which have been used in other publications as well denoting different samples. Fig. 2A was reused from Fig. 3A, Chemical Engineering Journal, Volume 299, 1 September 2016, Pages 244-254, 10.1016/j.cej.2016.04.051. According to the authors this was due to a mistake at the compilation of the manuscript (mixing images from the GO and Cds:GO samples). Fig. 2C was reused (a lower zoom level) from Fig. 1F, Biosensors and Bioelectronics, Volume 89, Part 1, 15 March 2017, Pages 620-626, 10.1016/j.bios.2015.12.085. The inset in Fig. 1F was reused from Fig. 2D, Environ. Sci. Technol., 2015, 49 (10), pp 6117–6126, 10.1021/acs.est.5b00182. These problems with the data presented cast doubt on all the data, and accordingly also the conclusions based on that data, in this publication. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.

Electrochemical sensors based on carbon nanomaterials for acetaminophen detection: A review

This study describes the advancements made over the last five years in the development of electrochemical sensors and biosensors for acetaminophen detection. This study reviews the different configurations based on unmodified and chemically modified carbon nanotubes and graphene. The influence of various modifiers on the two types of materials is presented along with their role on the enhancement of the selectivity and sensitivity of (bio)sensors. The review is focused on a comparative description of the applications of carbon-based nanomaterials towards acetaminophen detection and presents the results in a critical manner.