Novel analytical method based on chemometric models applied to UV-Vis spectrophotometric data for simultaneous determination of Etoricoxib and Paracetamol in presence of Paracetamol impurities.

The multivariate models that are used for spectral data analysis have many beneficial applications, and one of the important applications is the analysis of drugs and their impurities. Three Chemometrically-assisted spectrophotometric models have been proposed and validated. The proposed models are Partial Least Squares (PLS), Artificial Neural Networks (ANN), and Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS). The advanced chemometric models were applied to resolve the significantly overlapping spectra of Etoricoxib (ETO) and Paracetamol (PCM), along with impurities of PCM namely; P-aminophenol (PAP) and P-hydroxy acetophenone (PHA). The proposed models succeeded in simultaneously analyzing the mixture of ETO and PCM along with the impurities of PCM. So, the proposed techniques can be used without requiring a separation step in the analysis of pharmaceutical formulation. Moreover, no significant differences were found when the results of the suggested and published chemometric models were compared statistically with the reported HPLC method.

Point-of-care electrochemical sensor for selective determination of date rape drug "ketamine" based on core-shell molecularly imprinted polymer.

Misuse of illicit drugs is a serious problem that became the primary concern for many authorities worldwide. Point-of-care (POC) diagnostic tools can provide accurate and fast screening information that helps to detect illicit drugs in a short time. A portable, disposable and reproducible core-shell molecularly imprinted polymer (MIP) screen-printed sensor was synthesized as a POC analyzer for the assay of the date rape drug "ketamine hydrochloride" in different matrices. Firstly, the screen-printed electrode substrate was modified electrochemically with polyaniline (PANI) as an ion-to-electron transducer interlayer to improve the potential signal stability. Secondly, core-shell MIP was prepared, the core consisting of silica nanoparticles prepared by Stober's method, while the MIP shell was synthesized onto silica nanoparticles surface by copolymerizing methacrylic acid functional monomer and the crossing agent; ethylene glycol dimethacrylate in the presence of ketamine as a template molecule. Finally, the core-shell MIP was incorporated into the PVC membrane as an ionophore and drop-casted over PANI modified screen-printed carbon electrode. The imprinting process and the morphology of MIP were examined using scanning electron microscopy, Fourier-transform infrared and X-ray photoelectron spectroscopic methods. The sensor exhibited a short response time within 3-5 s in a pH range (2.0-5.0). The potential profile indicated a linear relationship in a dynamic concentration range of 1.0 × 10-6 M to 1.0 × 10-2 M with a slope of 54.7 mV/decade. The sensor was employed to determine ketamine in biological matrices and beverages.

Validated HPLC-PDA methodology utilized for simultaneous determination of Etoricoxib and Paracetamol in the presence of Paracetamol toxic impurities.

Etoricoxib (ETO), Paracetamol (PCM), and two toxic impurities for Paracetamol impurity K (4-aminophenol (PAP)) and impurity E (para-hydroxy acetophenone (PHA)) were separated using a simple and selective HPLC method that was tested for the first time. PCM is a commonly used analgesic and antipyretic medication that has recently been incorporated into COVID-19 supportive treatment. Pharmaceuticals containing PCM in combination with other analgesic-antipyretic drugs like ETO help to improve patient compliance. The studied drugs and impurities were separated on a GL Sciences Inertsil ODS-3 (250 × 4.6) mm, 5.0 µm column, and linear gradient elution was performed using 50 mM potassium dihydrogen phosphate adjusted to pH 4.0 with ortho-phosphoric acid and acetonitrile as mobile phase at 2.0 mL/min flow rate at 25 °C and UV detection at 220 nm. The linearity range was 1.5-30.0 µg/mL for ETO and PCM while 0.5-10.0 µg/mL for PAP and PHA, with correlation coefficients (r) for ETO, PCM, PAP, and PHA of 0.9999, 0.9993, 0.9996, and 0.9998, respectively. The proposed method could be used well for routine analysis in quality control laboratory.

Experimentally designed electrochemical sensor for therapeutic drug monitoring of Ondansetron co-administered with chemotherapeutic drugs.

The experimental design extracts valuable information about the main effects and interactions from the least number of experiments. The current work constructs a solid-state sensor for selective assay of Ondansetron (OND) in pharmaceutical dosage form and plasma samples. During optimization, the Design Expert® statistical package constructed a custom design of 15 sensors with different recipes. We fed the software with the experimentally observed performance parameters for each sensor (slope, LOQ, correlation coefficient, and selectivity coefficient for sodium ions). The computer software analyzed the results to construct a prediction model for each response. The desirability function was adjusted to optimize the Nernstian slope, minimize the LOQ and selectivity coefficients, and maximize the correlation coefficient (r). The practical responses of the optimized sensor were close to those predicted by the model (slope = 60.23 mV/decade slope, LOQ = 9.09 × 10-6 M, r = 0.999, sodium selectivity coefficient = 1.09 × 10-3). The sensor successfully recovered OND spiked to tablets and human plasma samples with mean percentage recoveries of 100.01 ± 1.082 and 98.26 ± 2.227, respectively. Results were statistically comparable to those obtained by the reference chromatographic method. The validated potentiometric method can be used for fast and direct therapeutic drug monitoring of OND co-administered with chemotherapeutic drugs in plasma samples.

Experimentally designed chemometric models for the assay of toxic adulterants in turmeric powder.

Turmeric is an indispensable culinary spice in different cultures and a principal component in traditional remedies. Toxic metanil yellow (MY), acid orange 7 (AO) and lead chromate (LCM) are deliberately added to adulterate turmeric powder. This work compares the ability of multivariate chemometric models with those of artificial intelligent networks to enhance the selectivity of spectral data for the rapid assay of these three adulterants in turmeric powder. Using a custom experimental design, we provide a data-driven optimization for the sensitive parameters of the partial least squares model (PLS), artificial neural network (ANN) and genetic algorithm (GA). The optimized models are validated using sets of genuine turmeric samples from five different geographical regions spiked with standard adulterant concentrations. The optimized GA-PLS and GA-ANN models reduce the root mean square error of prediction by 18.4%, 31.1% and 55.3% and 25.0%, 69.9% and 88.4% for MY, AO and LCM, respectively.

Advanced chemometric methods as powerful tools for impurity profiling of drug substances and drug products: Application on bisoprolol and perindopril binary mixture.

Impurity profiling has a rising importance nowadays due to the increased health problems associated with impurities and degradation products found in several drug substances and formulations. Three advanced, accurate and precise chemometric methods were developed as impurity profiling methods for a mixture of bisoprolol fumarate (BIS) and perindopril arginine (PER) with their degradation products which represent drug impurity or a precursor to such impurity. The methods applied were Partial Least Squares (PLS-1), Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) and Artificial Neural Networks (ANN). Genetic Algorithm (GA) was used as a variable selection tool to select the most significant wavelengths for the three chemometric models. For proper analysis, a 5-factor 5-level experimental design was used to establish a calibration set of 25 mixtures containing different ratios of the drugs and their degradation products (impurities). The validity of the proposed methods was assessed using an independent validation set. The designed models were able to predict the concentrations of the drugs and the degradation products/impurities in the validation set and pharmaceutical formulation. The proposed methods presented a powerful alternative to traditional and expensive chromatographic methods as impurity profiling tools.

Optimization of localized surface plasmon resonance hot spots in surface-enhanced infrared absorption spectroscopy aluminum substrate as an optical sensor coupled to chemometric tools for the purity assay of quinary mixtures.

Surface-enhanced infrared absorption spectroscopy offers an alternative to conventional IR spectroscopy and utilizes the signal enhancement exerted by the plasmon resonance of nanostructured metal thin films. Citrate-capped silver nanoparticles were prepared in a single-step method, and their morphology was identified using transmission electron microscopy, scanning electron microscopy, ultraviolet/visible spectrophotometry, and Zetasizer. The nanoparticles generated were deposited on the surface of cheap aluminum slides for different durations aiming for the selection of the best time producing a thin film, suitable to act as a lab-on-a-chip SEIRA substrate. These substrates were coupled to partial least squares regression tools for simultaneous resolving of the quinary mixture in commercial dosage forms of bisoprolol, perindopril, bisoprolol acid degradation product, bisoprolol alkali degradation product, and perindoprilat in concentration ranges of 15-75, 60-300, 15-55, 12-60, and 20-80 µg/mL with limits of detection values of 0.69, 3.43, 0.97, 1.25, and 1.09 µg/mL, respectively. Overall, we could demostrate that the localized surface plasmon resonance sensor coupled to chemometrics provides cheap, simple, selective, multiplex, rapid, and molecular specific procedures for impurity detection, which would be beneficial in many applications for quality control and quality accuracy of active pharmaceutical ingredients.

Green HPLC-DAD and HPTLC Methods for Quantitative Determination of Binary Mixture of Pregabalin and Amitriptyline Used for Neuropathic Pain Management.

First analytical methods were herein developed for determination of pregabalin (PGB) and amitriptyline (AMT) as an active binary mixture used for management of neuropathic pain whether in pure forms or in human biological fluids (plasma/urine). First method is green high-performance liquid chromatography-diode array detector (HPLC-DAD) after derivatization of PGB with ninhydrin (NIN) on a reversed-phase C18 column using a mobile phase consisting of ethanol:water (97:3%, v/v) pumped isocratically at 0.8 mL/min; AMT were scanned at 215 nm, whereas PGB-NIN was scanned at 580 nm. Second method is High-performance thin-layer chromatography (HPTLC), where PGB and AMT were separated on silica gel HPTLC F254 plates, using ethanol:ethyl acetate:acetone:ammonia solution (8:2:1:0.05, by volume) as a developing system. AMT peaks were scanned at 220 nm, whereas PGB peaks were visualized by spraying 3% (w/v) ethanolic NIN solution and scanning at 550 nm. Linear calibration curves were obtained for human plasma and urine spiked with PGB and AMT over the ranges of 5-100 µg/mL and 0.2-2.5 µg/band for PGB, and 1-100 µg/mL and 0.1-2.0 µg/band for AMT for HPLC-DAD and HPTLC methods, respectively. The suggested methods were validated according to Food and Drug Administration guidelines for bioanalytical methods validation and they can be applied for routine therapeutic drug monitoring for the concerned drugs.

Widening the applications of the Just-Dip-It approach: a solid contact screen-printed ion-selective electrode for the real-time assessment of pharmaceutical dissolution testing in comparison to off-line HPLC analysis.

Over past years, the field of pharmaceutical dissolution testing has significantly expanded to cover not only the quality control of dosage forms, but also to play an important role in the bioavailability testing paradigm and screening of most formulations. These tests usually need a very long time sampling and monitoring, so that the automation of sampling is laborsaving. Problems often occur with these automatic devices due to sampling lines that may disconnect, crimp, carry over, become mixed up, or are inadequately cleaned. Potentiometric sensors, such as liquid contact (LC-ISE) or solid contact ion-selective electrodes (SC-SP-ISE), can provide timely data to be used for the real-time tracking of the amount of active pharmaceutical ingredients (APIs) released in the dissolution medium without these problems. In this work, we adopted the Just-Dip-It approach as a process analytical technology solution with the ultimate goal of advancing the ion selective sensors to their most effective use in pharmaceutical analysis. Two sensors were fabricated, the traditional LC-ISE and SC-SP-ISE. The sensing poly-vinyl chloride membranes of two electrodes were prepared using 2-nitrophenyl octyl ether as a plasticizer to soften the membrane, and the reduction in resistance to pioglitazone ions (PIO) permeability was achieved through the incorporation of sodium tetraphenylborate and calix[8]arene as a cationic exchanger salt and inclusion complexing ligand, respectively. Finally, prepared membranes were turned into the flexible perm-selective slices of hydrophobic plastic, which work as a barrier to other compounds, except for the PIO cation in the concentration range of 1 × 10-6 to 1 × 10-2 M and 1 × 10-5 to 1 × 10-2 M for SC-SP-ISE and LC-ISE, respectively. The challenges and opportunities of both sensors in comparison to a developed HPLC method were discussed for the dissolution testing of the combination dosage forms of pioglitazone. Potentiometric methods were validated according to IUPAC guidelines, while HPLC was validated according to ICH guidelines to ensure accuracy and precision.

Stability-Indicating RP-HPLC and CE Methods for Simultaneous Determination of Bisoprolol and Perindopril in Pharmaceutical Formulation: A Comparative Study.

Two fast, accurate and selective stability-indicating methods were developed and validated for the simultaneous determination of bisoprolol, perindopril and three of their possible degradation products. The first proposed method was a gradient reversed phase-high-performance liquid chromatography (HPLC) method, whereas the second was a capillary electrophoresis method. The structures of the obtained degradation products were elucidated using infrared and mass spectrometry. They were also confirmed to be either a drug impurity in the British Pharmacopoeia or a precursor to such impurity. The linearity for bisoprolol and perindopril was achieved in the range of 1-20 µg mL-1 and 5-30 µg mL-1 for HPLC and capillary electrophoresis methods, respectively. The proposed methods were validated according to the International Conference on Harmonisation guidelines. The HPLC method proved to be more sensitive and succeeded in the quantitative determination of the obtained degradation products. Also, it was able to quantify perindopril impurity up to three times lower than the desired limit set by the British Pharmacopoeia. They were successfully employed in the determination of bisoprolol and perindopril in their combined pharmaceutical formulation.

Surface enhanced infrared absorption spectroscopy (SEIRA) as a green analytical chemistry approach: Coating of recycled aluminum TLC sheets with citrate capped silver nanoparticles for chemometric quantitative analysis of ternary mixtures as a green alternative to the traditional methods.

The past two decades have seen the full expansion of all fields of Nanotechnology, Chemometrics, Recycling, and Vibration spectroscopy into most of the research areas. The proposed method involves the harmonization of the previously mentioned fields as a vital tool to fulfill the concepts of sustainability and green analytical chemistry. This may reduce the negative impact of analytical laboratory activities on the surrounding environment and enables the implementation of sustainable development principles to analytical laboratories. This work compares the performance of surface enhanced infrared spectroscopy (SEIRA) with traditional chromatographic techniques for quantification of active pharmaceutical ingredients concerning the twelve principles of green analytical chemistry. The used aluminum TLC slides were recycled to be used as a SEIRA substrate. Citrate capped silver nanoparticles were synthesized via one step chemical reduction method, characterized, and deposited on the surface of the recycled aluminum TLC slides to be used as an active mid-infrared surface for quantification of the active pharmaceutical ingredient's combinations. SEIRA coupled with PLSR chemometric tool was developed, validated and successfully applied to mixtures having diverged concentration ranges (5, 30 and 500 µg ml-1) of Pholcodine, Pseudoephedrine and Paracetamol, respectively. Pholcodine is a synthetic or semi-synthetic opium alkaloid that derived from morphine. Pseudoephedrine is a sympathomimetic agent that is prohibited in sports competitions by the world antidoping agency at certain concentration levels. Paracetamol has analgesic and antipyretic actions. After optimization of the method parameters and number of latent factors, a good linear calibration model of the PLSR strategy was obtained as indicated by the lowest root mean square error of calibration and prediction obtained and the regression coefficients R2 of 0.9912, 0.9888, and 0.9992, respectively. The calibration ranges for the three drugs in their pharmaceutical combinations was 2.5-12.5, 15-75 and 200-600 µg ml-1, respectively. The method showed high resolving power for the three drugs in presence of excipients and good recoveries were obtained in a range of 97-102% with relative standard deviation < 2. The developed lab on a chip SEIRA analyzer in comparison to the traditional chromatographic techniques does not only fulfill the twelve principles of GAC but also it combines the merits of high throughput straightforward fingerprint analyzers, portable to measure samples on its place, cost effective, reduced sample volume and solvent consumption, coupled with intelligent chemometric tools to analyze multiple samples, reduced trials and time to get results.

Chemical fingerprinting and quantitative monitoring of the doping drugs bambuterol and terbutaline in human urine samples using ATR-FTIR coupled with a PLSR chemometric tool.

The use of performance-enhancing drugs is prohibited in sports competitions according to the World Anti-Doping Agency (WADA) regulations. Here, ATR-FTIR spectroscopy coupled with a partial least squares regression (PLSR) chemometric tool was used for the detection of the misuse of such substances. Bambuterol and its metabolite terbutaline have been included in the list of prohibited doping agents. Therefore, we used bambuterol and terbutaline as models for the accurate and simultaneous qualitative and quantitative analysis of bambuterol and terbutaline in human urine samples. The method was straightforward and once the urine samples were collected, they could be directly applied to the surface of the ZnSe prism (ATR unit) to get the results within one minute. A calibration set with a partial factorial design was used to develop the PLSR model that could be used to predict the concentration of unknown samples containing the two drugs. The developed method was carefully validated and successfully applied to the urine sample analysis of human volunteers. The drugs were quantified at nanogram level concentrations. A side-by-side comparison of the proposed method with the routine GC-MS method was performed to demonstrate the challenges and opportunities of each method.

Correction: Chemical fingerprinting and quantitative monitoring of the doping drugs bambuterol and terbutaline in human urine samples using ATR-FTIR coupled with a PLSR chemometric tool.

[This corrects the article DOI: 10.1039/C9RA10033D.].

Determination of pioglitazone, its metabolite and alogliptin in human plasma by a novel LC-MS/MS method; application to a pharmacokinetic study.

A novel, high throughput and sensitive LC-MS/MS assay method was developed and fully validated for quantitative determination of pioglitazone, its hydroxyl metabolite and alogliptin in human plasma. A simple and rapid sample preparation procedure based on protein precipitation technique with acetonitrile was utilized. Chromatographic separation was achieved on C8 (50 × 4.6 mm, 5 µm) Kinetex® analytical column using methanol and 0.1% formic acid in a gradient elution mode at a flow rate of 0.7 mL/min with injection volume of 8 µL. Detection was performed on a triple quadrupole mass spectrometer accompanied with electrospray ionization (ESI) technique in positive mode, operating in multiple reaction monitoring, with the transitions of 357.2 → 119.1, 373.1 → 150.1, 340.3 → 116.1, 361.1 → 138.1 and 343.2 → 116.1 m/z for pioglitazone, its hydroxyl metabolite, alogliptin, pioglitazone-d4 (IS-1) and alogliptin-d3 (IS-2), in order. Analysis was achieved within 4 min over a linear concentration range of 10-3000 ng/mL, 5-2000 ng/mL and 3-300 ng/mL, for pioglitazone, hydroxyl pioglitazone and alogliptin, in order. The method was fully validated according to FDA guidelines. The developed method was used for estimation of the three studied analytes in human plasma and pharmacokinetic parameters were demonstrated after oral dose administration of Oseni® tablets to Egyptian healthy volunteers.

Attenuated Total Reflectance Fourier Transformation Infrared spectroscopy fingerprinted online monitoring of the kinetics of circulating Butyrylcholinesterase enzyme during metabolism of bambuterol.

We have described a continuous flow ATR-FTIR method for measuring some of the Butyrylcholinesterase enzyme kinetics (Km and Vmax). This is done by developing a circulating system to be close as much as possible to the human circulation using human serum as a source of the enzyme with adjusted pH, isotonicity and temperature to give the maximum affinity of the enzyme towards its substrate (bambuterol). The experiment was running continuously for 90 min to monitor the production of terbutaline from the zero time of its appearance with a measured spectrum in each minute using ZnSe prism. The method was selective and successful for determination of Vmax to be 8.16 × 10-8 mol/min/ml and Km to be 2.28 × 10-5 mol, showing high affinity of the enzyme towards its prodrug substrate Bambuterol. This study critically probes the quantitative ability of the ATR-FTIR method for terbutaline, which was validated according to ICH guidelines showing high accuracy 100.39% and high selectivity towards the produced terbutaline, as the produced spectrums considered as fingerprint of each compound.

Comparative stability-indicating chromatographic methods for determination of 4-hexylresorcinol in pharmaceutical formulation and shrimps.

Three chromatographic stability-indicating methods were developed for determination of 4-hexylresorcinol in pure form and in a pharmaceutical formulation. Method A was based on a gradient elution liquid chromatographic HPLC determination of 4-hexylresorcinol, its related impurities and in presence of its degradation products. UPLC-MS/MS (Method B) was described for determination of the cited drug in presence of its degradation products. Method C was a thin- layer chromatography (TLC)-densitometry method for the separation and determination of the active ingredient, one of its related impurities and in presence of its degradation products. The mechanism of alkali, oxidative and photodegradation of 4-hexylresorcinol was studied according to ICH guidelines. The degradation products were characterized by the LC-MS/MS method. Methods A and B were applicable for determination of 4-hexylresorcinol residues in shrimp meat. The studied drug was easily degraded in alkali medium giving toxic compounds. The results obtained by the proposed methods were statistically analyzed and compared with those obtained by applying a reported method.

Successive ratio subtraction coupled with constant multiplication spectrophotometric method for determination of hydroquinone in complex mixture with its degradation products, tretinoin and methyl paraben.

A sensitive and selective stability-indicating successive ratio subtraction coupled with constant multiplication (SRS-CM) spectrophotometric method was studied and developed for the spectrum resolution of five component mixture without prior separation. The components were hydroquinone in combination with tretinoin, the polymer formed from hydroquinone alkali degradation, 1,4 benzoquinone and the preservative methyl paraben. The proposed method was used for their determination in their pure form and in pharmaceutical formulation. The zero order absorption spectra of hydroquinone, tretinoin, 1,4 benzoquinone and methyl paraben were determined at 293, 357.5, 245 and 255.2 nm, respectively. The calibration curves were linear over the concentration ranges of 4.00-46.00, 1.00-7.00, 0.60-5.20, and 1.00-7.00 µg mL(-1) for hydroquinone, tretinoin, 1,4 benzoquinone and methyl paraben, respectively. The pharmaceutical formulation was subjected to mild alkali condition and measured by this method resulting in the polymerization of hydroquinone and the formation of toxic 1,4 benzoquinone. The proposed method was validated according to ICH guidelines. The results obtained were statistically analyzed and compared with those obtained by applying the reported method.

Chromatographic Determination of Aminoacridine Hydrochloride, Lidocaine Hydrochloride and Lidocaine Toxic Impurity in Oral Gel.

Two sensitive and selective analytical methods were developed for simultaneous determination of aminoacridine hydrochloride and lidocaine hydrochloride in bulk powder and pharmaceutical formulation. Method A was based on HPLC separation of the cited drugs with determination of the toxic lidocaine-related impurity 2,6-dimethylaniline. The separation was achieved using reversed-phase column C18, 250 × 4.6 mm, 5 µm particle size and mobile phase consisting of 0.05 M disodium hydrogen phosphate dihydrate (pH 6.0 ± 0.2 adjusted with phosphoric acid) and acetonitrile (55 : 45, v/v). Quantitation was achieved with UV detection at 240 nm. Linear calibration curve was in the range of 1.00-10.00, 13.20-132.00 and 1.32-13.20 µg mL(-1) for aminoacridine hydrochloride, lidocaine hydrochloride and 2,6-dimethylaniline, respectively. Method B was based on TLC separation of the cited drugs followed by densitometric measurement at 365 nm on the fluorescent mode for aminoacridine hydrochloride and 220 nm on the absorption mode for lidocaine hydrochloride. The separation was carried out using ethyl acetate-methanol-acetic acid (65 : 30 : 5 by volume) as a developing system. The calibration curve was in the range of 25.00-250.00 ng spot(-1) and 0.99-9.90 µg spot(-1) for aminoacridine hydrochloride and lidocaine hydrochloride, respectively. The results obtained were statistically analyzed and compared with those obtained by applying the manufacturer's method.