Simultaneous determination of 2-furfuraldehyde, 5-hydroxymethylfurfuraldehyde and malonaldehyde in mixtures by derivative spectrophotometry and partial least-squares analysis

Advanced chemometric methods for simultaneous quantitation of caffeine, codeine, paracetamol, and p-aminophenol in their quaternary mixture

Two different multivariate techniques have been applied for the quantitative analysis of caffeine, codeine, paracetamol and p-aminophenol (PAP) in quaternary mixture, namely, Partial Least Squares (PLS-1) and Artificial Neural Networks (ANN). For suitable analysis, a calibration set of 25 mixtures with various ratios of the drugs and PAP impurity were established using a 4-factor 5-level experimental design. The most meaningful wavelengths for the chemometric models were chosen using Genetic Algorithm (GA) as a variable selection technique. By using an independent validation set, the validity of the proposed methods was evaluated. A comparative study was established between the three multivariate models (PLS-1, GA-PLS and GA-ANN). The comparison between the various models revealed that the GA-ANN model was superior at resolving the highly overlapped spectra of this quaternary combination. The drugs were successfully quantified in their pharmaceutical dosage form utilizing the GA-ANN models.

A quick and simple paper-based method for detection of furfural and 5-hydroxymethylfurfural in beverages and fruit juices

Improper storage and transportation of non-alcoholic beverages can, over longer periods, induce Maillard reaction, degrading nutritional components and generating genotoxic and carcinogenic by-products such as furfural and 5-hydroxymethylfurfural (HMF), rendering products unsafe for human consumption. Here, we describe a rapid quantitative solution-based method and test-strips for detection of furfural and HMF. The standard spectroscopic method indicated an LOD of 0.006 ± 0.003% (v/v) and 0.005 ± 0.002% (v/v) for furfural and HMF, respectively in fruit juice samples. The novel chromogenic test-strip has sensitivity of 0.008% (v/v) and 0.004% (v/v) for furfural and HMF, respectively in the same samples of fruit juice. Thus, the developed method and test-strips were specific for furfural and HMF and can be used to help ensure food safety and quality in various industrial applications.

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.

Full spectrum and genetic algorithm-selected spectrum-based chemometric methods for simultaneous determination of azilsartan medoxomil, chlorthalidone, and azilsartan: Development, validation, and application on commercial dosage form

Five various chemometric methods were established for the simultaneous determination of azilsartan medoxomil (AZM) and chlorthalidone in the presence of azilsartan which is the core impurity of AZM. The full spectrum-based chemometric techniques, namely partial least squares (PLS), principal component regression, and artificial neural networks (ANN), were among the applied methods. Besides, the ANN and PLS were the other two methods that were extended by genetic algorithm procedure (GA-PLS and GA-ANN) as a wavelength selection procedure. The models were developed by applying a multilevel multifactor experimental design. The predictive power of the suggested models was evaluated through a validation set containing nine mixtures with different ratios of the three analytes. For the analysis of Edarbyclor® tablets, all the proposed procedures were applied and the best results were achieved in the case of ANN, GA-ANN, and GA-PLS methods. The findings of the three methods were revealed as the quantitative tool for the analysis of the three components without any intrusion from the co-formulated excipient and without prior separation procedures. Moreover, the GA impact on strengthening the predictive power of ANN- and PLS-based models was also highlighted.

A comparative study of two analytical techniques for the simultaneous determination of amprolium HCl and ethopabate from combined dosage form and in presence of their alkaline degradation

Chemometric and separation-based techniques (HPLC) are the most applicable and versatile analytical techniques for the analysis of multicomponent mixtures, in the present contribution, a comparison was highlighted between the two analytical techniques of utmost importance as stability indicating assays: UV-spectrophotometry and HPLC-UV focusing on the greenness of each for the simultaneous determination of amprolium HCl (AMP) and ethopabate (ETHOP) in the presence of their alkaline degradation products. The first method was chemometric methods applied were PLS-1, GA-PLS and GA-ANN. To compare the prediction ability of the models, a 4-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. The validity of the proposed methods was assessed using an independent validation set of 5 mixtures. The comparison between the different models showed the superiority of ANN model in solving the highly overlapped spectra of the quaternary mixture, yet using inexpensive and easy to handle instruments like the UV-VIS spectrophotometer. The ANN method was used for the quantitative analysis of the drugs in pharmaceutical dosage form via handling the UV spectral data. The second method was based on liquid chromatographic HPLC determination of AMP and ETHOP using C18 column (250 × 4.6 mm²)-PRONTOSIL 5 μm, a mobile phase consisting of methanol: Hexane sulphonic acid sodium salt at (pH = 3.4 ± 0.2) adjusted by orthophosphoric acid (55: 45 v/v). Quantitation was achieved with UV detection at 270 nm at temperature 24 °C. Linearity, accuracy and precision were found to be acceptable over the concentration range of 10.0-70.0 and 1.0-25.0 μg·mL^-1 for AMP and ETHOP, respectively. The proposed methods could be successfully applied for the routine analysis of the studied drugs either in their pure bulk powders or in their pharmaceutical preparations without any preliminary separation step. The results obtained were statistically compared with those obtained by applying the reported method.

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.

Full spectrum and selected spectrum based multivariate calibration methods for simultaneous determination of betamethasone dipropionate, clotrimazole and benzyl alcohol: Development, validation and application on commercial dosage form

Five different chemometric methods were developed for the simultaneous determination of betamethasone dipropionate (BMD), clotrimazole (CT) and benzyl alcohol (BA) in their combined dosage form (Lotriderm® cream). The applied methods included three full spectrum based chemometric techniques; namely principal component regression (PCR), Partial Least Squares (PLS) and Artificial Neural Networks (ANN), while the other two methods were PLS and ANN preceded by genetic algorithm procedure (GA-PLS and GA-ANN) as a wavelength selection procedure. A multilevel multifactor experimental design was adopted for proper construction of the models. A validation set composed of 12 mixtures containing different ratios of the three analytes was used to evaluate the predictive power of the suggested models. All the proposed methods except ANN, were successfully applied for the analysis of their pharmaceutical formulation (Lotriderm® cream). Results demonstrated the efficiency of the four methods as quantitative tool for analysis of the three analytes without prior separation procedures and without any interference from the co-formulated excipient. Additionally, the work highlighted the effect of GA on increasing the predictive power of PLS and ANN models.

Intranasal haloperidol-loaded miniemulsions for brain targeting: Evaluation of locomotor suppression and in-vivo biodistribution

Haloperidol is a commonly prescribed antipsychotic drug currently administered as oral and injectable preparations. This study aimed to prepare haloperidol intranasal miniemulsion helpful for psychiatric emergencies and exhibiting lower systemic exposure and side effects associated with non-target site delivery. Haloperidol miniemulsions were successfully prepared by spontaneous emulsification adopting 2(3) factorial design. The effect of three independent variables at two levels each namely; oil type (Capmul®-Capryol™90), lipophilic emulsifier type (Span 20-Span 80) and HLB value (12-14) on globule size, PDI and percent locomotor activity inhibition in mice was evaluated. The optimized formula (F4, Capmul®, Tween 80/Span 20, HLB 14) showed globule size of 209.5±0.98nm, PDI of 0.402±0.03 and locomotor inhibition of 83.89±9.15% with desirability of 0.907. Biodistribution study following intranasal and intravenous administration of the radiolabeled (99m)Tc mucoadhesive F4 revealed that intranasal administration achieved 1.72-fold higher and 6 times faster peak brain levels compared with intravenous administration. Drug targeting efficiency percent and brain/blood exposure ratios remained above 100% and 1 respectively after intranasal instillation compared to a maximum brain/blood exposure ratio of 0.8 post intravenous route. Results suggested the CNS delivery of major fraction of haloperidol via direct transnasal to brain pathway that can be a promising alternative to oral and parenteral routes in chronic and acute situations. Haloperidol concentration of 275.6ng/g brain 8h post intranasal instillation, higher than therapeutic concentration range of haloperidol (0.8 to 5.15ng/ml), suggests possible sustained delivery of the drug through nasal route.

Advanced stability indicating chemometric methods for quantitation of amlodipine and atorvastatin in their quinary mixture with acidic degradation products

Two advanced, accurate and precise chemometric methods are developed for the simultaneous determination of amlodipine besylate (AML) and atorvastatin calcium (ATV) in the presence of their acidic degradation products in tablet dosage forms. The first method was Partial Least Squares (PLS-1) and the second was Artificial Neural Networks (ANN). PLS was compared to ANN models with and without variable selection procedure (genetic algorithm (GA)). For proper analysis, a 5-factor 5-level experimental design was established resulting in 25 mixtures containing different ratios of the interfering species. Fifteen mixtures were used as calibration set and the other ten mixtures were used as validation set to validate the prediction ability of the suggested models. The proposed methods were successfully applied to the analysis of pharmaceutical tablets containing AML and ATV. The methods indicated the ability of the mentioned models to solve the highly overlapped spectra of the quinary mixture, yet using inexpensive and easy to handle instruments like the UV-VIS spectrophotometer.

Waterpipe smoke: a considerable source of human exposure against furanic compounds

Smoking of waterpipes became increasingly popular in the Western hemisphere in recent years. Yet, up to now only little is known about the health hazards and on the composition of waterpipe smoke. To obtain more information on the ingredients present in waterpipe smoke we utilized two different approaches. Based on headspace-solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) instrumentation we identified new compounds present in the waterpipe smoke. Additional reversed-phase-high performance liquid chromatography-diode array detection (RP-HPLC-DAD) then led us to perform reliable quantification of the newly detected chemical species. Upon identification of a range of different furanic compounds such as 5-(hydroxymethyl)-2-furaldehyde (HMF), 2-furaldehyde, and others, we developed an easy-to-perform and fast RP-HPLC-DAD method to quantify these compounds in the complex matrix of waterpipe smoke. The detection limits range from 0.04 μg for HMF to 7.1 μg for 3-furan methanol per smoking session. Linearity, intra- and inter-day precision and recovery were determined and proved excellent. We analyzed 5 waterpipe tobacco brands and found up to 62.3±11 mg of HMF generated during one waterpipe smoking session. The applied smoking protocol comprised 171 puffs of 530 mL each and 2.6s duration every 20s. Our results reveal that waterpipe smoking constitutes a major source of HMF exposure. Furthermore, we found a distinct filter effect of the bowl water for all furanic compounds investigated except HMF.

Validated stability indicating methods for determination of nitazoxanide in presence of its degradation products

Three sensitive, selective and reproducible stability-indicating methods are presented for determination of nitazoxanide (NTZ), a new anti-protozoal drug, in presence of its degradation products. Method A utilizes the first derivative of ratio spectra spectrophotometry by measurement of the amplitude at 364.4 nm using one of the degradation products as a divisor. Method B is a chemometric-assisted spectrophotometry, where principal component regression (PCR) and partial least squares (PLS) were applied. These two approaches were successfully applied to quantify NTZ in presence of degradation products using the information included in the absorption spectra in the range 260–360 nm. Method C is based on the separation of NTZ from its degradation products followed by densitometric measurement of the bands at 254 nm. The separation was carried out on silica gel 60F₂₅₄, using chloroform–methanol–ammonia solution–glacial acetic acid (95:5:1:1 by volume, pH=5.80) as a developing system. These methods are suitable as stability-indicating methods for the determination of NTZ in presence of its degradation products either in bulk powder or in pharmaceutical formulations. Statistical analysis of the results has been carried out revealing high accuracy and good precision.

Spectrophotometric and spectrodensitometric determination of triamterene and xipamide in pure form and in pharmaceutical formulation

Sensitive and validated UV-spectrophotometric, chemometric and TLC-densitometric methods were developed for determination of triamterene (TRM) and xipamide (XIP) in their binary mixture, formulated for use as a diuretic, without previous separation. Method A is the isoabsorptive point spectrophotometry, in which TRM concentration alone can be determined at its λ(max) while XIP concentration can be determined by measuring total concentration of TRM and XIP at their isoabsorptive point followed by subtraction. Method B is the ratio subtraction spectrophotometry, where XIP can be determined by dividing the spectrum of the mixture by the spectrum of TRM (as a divisor) followed by subtracting the constant absorbance value of the plateau region, then finally multiplying the produced spectrum by the spectrum of the divisor, while TRM concentration can be determined at its λ(max). Method C is a chemometric-assisted spectrophotometry where classical least squares, principal component regression, and partial least squares were applied. Method D is a TLC-densitometry; this method depends on quantitative densitometric separation of thin layer chromatogram of TRM and XIP using silica gel plates at 254 nm. The proposed methods were successfully applied for the analysis of TRM and XIP in their pharmaceutical formulation and the results were statistically compared with the established HPLC method.

Simultaneous determination of nifuroxazide and drotaverine hydrochloride in pharmaceutical preparations by bivariate and multivariate spectral analysis

The quantitative predictive abilities of the new and simple bivariate spectrophotometric method are compared with the results obtained by the use of multivariate calibration methods [the classical least squares (CLS), principle component regression (PCR) and partial least squares (PLS)], using the information contained in the absorption spectra of the appropriate solutions. Mixtures of the two drugs Nifuroxazide (NIF) and Drotaverine hydrochloride (DRO) were resolved by application of the bivariate method. The different chemometric approaches were applied also with previous optimization of the calibration matrix, as they are useful in simultaneous inclusion of many spectral wavelengths. The results found by application of the bivariate, CLS, PCR and PLS methods for the simultaneous determinations of mixtures of both components containing 2-12microgml(-1) of NIF and 2-8microgml(-1) of DRO are reported. Both approaches were satisfactorily applied to the simultaneous determination of NIF and DRO in pure form and in pharmaceutical formulation. The results were in accordance with those given by the EVA Pharma reference spectrophotometric method.

Determination of the minor component bromhexine in cotrimoxazole-containing tablets by absorption spectrophotometry and partial least-squares (PLS-1) multivariate calibration

The mucolitic bromhexine [N-(2-amino-3,5-dibromobenzyl)-N-methylcyclohexylamine] has been determined in cotrimoxazole-containing tablets by partial least-squares (PLS-1) multivariate of spectrophotometric calibration data in the spectral range 310-350 nm. In the studied commercial tablets, cotrimoxazole is present in large excess (ca. 100:1 in weight) with respect to bromhexine, and a high degree of spectral overlapping exists among bromhexine and cotrimoxazole components. However, the obtained recoveries are reasonably good with the presently discussed technique.

Simultaneous determination of rifampicin, isoniazid and pyrazinamide in tablet preparations by multivariate spectrophotometric calibration

The use of multivariate spectrophotometric calibration is presented for the simultaneous determination of the active components of tablets used in the treatment of pulmonary tuberculosis. The resolution of ternary mixtures of rifampicin, isoniazid and pyrazinamide has been accomplished by using partial least squares (PLS-1) regression analysis. Although the components show an important degree of spectral overlap, they have been simultaneously determined with high accuracy and precision, rapidly and with no need of nonaqueous solvents for dissolving the samples. No interference has been observed from the tablet excipients. A comparison is presented with the related multivariate method of classical least squares (CLS) analysis, which is shown to yield less reliable results due to the severe spectral overlap among the studied compounds. This is highlighted in the case of isoniazid, due to the small absorbances measured for this component.

Simultaneous multivariate spectrophotometric analysis of paracetamol and minor components (diphenhydramine or phenylpropanolamine) in tablet preparations

The use of multivariate spectrophotometric calibration is reported for the analysis of two decongestant tablets, where paracetamol is the principal component and diphenhydramine or phenylpropanolamine are the minor components. The resolution of these mixtures has been accomplished without prior separation or derivatisation, by using partial least-squares (PLS-1) regression analysis of electronic absorption spectral data. Although the molar ratios of paracetamol to the minor components were 38:1 and 25:1 respectively, the latter have been determined with high accuracy and precision, and with no interference from tablet excipients. PLS is able to take into account small deviations of paracetamol from linearity in the studied concentration range. The application of classical least-squares (CLS) analysis yields unsatisfactory results, due to the low absorbances of the minor components within the range where all components obey Beer's law.

Multicomponent determination of flavour enhancers in food preparations by partial least squares and principal component regression modelling of spectrophotometric data

Three multivariate calibration methods, partial least squares (PLS-1 and PLS-2) and principal component regression (PCR), were applied to the simultaneous determination of three flavour enhancers (inosine 5'-monophosphate, guanosine 5'-monophosphate and monosodium glutamate), in mixtures by ultraviolet/visible absorption spectrophotometry. The absorption and first- and second-derivative absorption spectra of the ternary mixtures were used to perform the optimization of the calibration matrices by the PLS and PCR methods. The results obtained by the application of the different chemometric approaches are discussed and compared. No significant advantages were found for the prior differentiation step. The proposed method was applied satisfactorily to the determination of inosine 5'-monophosphate and guanosine 5'-monophosphate in several food preparations, in the presence of monosodium glutamate.