Second-derivative synchronous fluorescence spectroscopy for the simultaneous determination of fluphenazine hydrochloride and nortriptyline hydrochloride in pharmaceutical preparations

Simultaneous spectrophotometric determination of fluphenazine HCl and nortriptyline HCl in presence of their potential impurities perphenazine and dibenzosuberone in bulk and pharmaceutical formulation

Fluphenazine HCl (FLU) is an anxiolytic, while Nortriptyline HCl (NOR) is an anti-depressant. They are co-formulated together to treat depression and schizophrenia. Perphenazine (PER) and dibenzosuberone (DBZ) are the pharmacopeial impurities of FLU and NOR, respectively. Four spectrophotometric and multivariate chemometric methods were developed to determine the two drugs together or in presence of their two impurities in their bulk and pharmaceutical formulation. Method (A) is the triple divisor-ratio derivative (TDR) method, where the zero order spectrum of each component was divided by a mixture of the other 3 components, then the peak amplitudes of the first derivative spectra of FLU, NOR and DBZ were measured at 265, 245.4 and 283.2 nm, respectively. Method (B) is the double divisor-ratio difference-dual wavelength (DD-RD-DW) method, in which each component spectrum mixture was divided by a binary mixture of 2 of the interfering components. In the resulting ratio spectra, the amplitude difference is calculated between 2 wavelengths at which the third interfering component has zero difference. Methods (C and D) are the principle component analysis (PCA) and partial least squares (PLS) models. Methods (A and B) failed to quantify PER (FLU impurity), while (C and D) succeeded to quantify all components. The four methods have been applied for the prediction of the FLU and NOR in their pharmaceutical formulation with good accuracy and precision. The proposed methods have been validated according to the ICH guidelines and the results were within the acceptable limits.

Four Greenness Evaluations of Two Chromatographic Methods: Application to Fluphenazine HCl and Nortriptyline HCl Pharmaceutical Combination in Presence of Their Potential Impurities Perphenazine and Dibenzosuberone

Nowadays, when analysts develop a new method, they are taking into consideration the green aspects of the developed method. Two chromatographic methods were developed for the determination of antidepressant pharmaceutical combination nortriptyline hydrochloride and fluphenazine hydrochloride in presence of their potential impurities and the methods were assessed using four tools; eco-scale, analytical greenness profile (AGP), analytical greenness metric approach (AGREE), and green analytical procedure index (GAPI). Method (A) was RP-HPLC, in which the separation was carried out on C18 column (250 × 4.5 mm, 5 µm) by gradient elution using mobile phase consisting of a mixture of water containing 0.1% H3PO4 (pH 2.25) and methanol, at a flow rate of 2 mL/min with DAD detection at 254 nm. Method (B) was TLC, in which the separation was carried out on silica gel TLC F254 plates. The mobile phase used was a mixture of methanol and acetone (9:1, v/v) with UV detection at 245 nm. The proposed methods agreed with ICH guidelines of method validation and were successfully applied for determination of the proposed components in their dosage form and the results were compared statistically to those obtained by the reported RP-HPLC method with no significant difference; which suggests the application of the developed methods for routine quality control analysis of these drugs.

A Characteristic Interval Modeling Method for Simultaneous Detection of Multiple Metal Ions

Aiming at the problems of low accuracy and large prediction errors caused by the serious overlap of multi-metal spectral signals in zinc smelting industrial wastewater, a characteristic interval modeling method is proposed. First, according to the absorption spectra of mixed solution, the characteristic intervals of copper and nickel are preliminarily screened by using different partition lengths. Second, take the smallest root mean squares error of cross validation and the largest correlation coefficient as the evaluation indicators, compare the full-spectral model and each local model, and select the optimal feature sub-intervals of copper and nickel. Last, the partial least squares method is used to model the combined wavelengths of the optimal sub-intervals to realize the simultaneous detection of copper and nickel. The linear determination ranges are 0.3-3.0 mg/L for copper and nickel. the correlation coefficients of copper and nickel are 0.9974 and 0.9966, respectively. The results show that the method reduces the complexity of the wavelength variable screening process, improves the accuracy of the model, and lays the foundation for the accurate analysis of polymetallic ions in zinc smelting industrial wastewater.

A Nonlinear Integrated Modeling Method of Extended Kalman Filter Based on Adaboost Algorithm

In the zinc hydrometallurgical purification process, the concentration ratio of zinc ion to trace nickel ion is as high as 105, so that the nickel spectral signal is completely covered by high concentration zinc signal, resulting in low sensitivity and nonlinear characteristics of nickel spectral signal. Aiming at the problem that it is difficult to detect nickel in zinc sulfate solution, this paper proposes a nonlinear integrated modeling method of extended Kalman filter based on Adaboost algorithm. First, a non-linear nickel model is established based on nickel standard solution. Second, an extended Kalman filter wavelength optimization method based on correlation coefficient is proposed to select wavelength variables with high signal sensitivity, large amount of information and strong nonlinear correlation. Finally, a nonlinear integrated modeling method based on Adaboost algorithm is proposed, which uses extended Kalman filter as a basic submodel, and realizes the stable detection of trace nickel through the weighted combination of multiple basic models. The results show that the average relative error of this method for detecting nickel is 4.56%, which achieves accurate detection of trace nickel in zinc sulfate solution.

Difference spectrophotometric method for the determination of Fluphenazine hydrochloride in tablets using peroxomonosulfate

The oxidative derivatization method using potassium hydrogenperoxomonosulfate for the indirect spectrophotometric determination of Fluphenazine hydrochloride is presented. Potassium hydrogenperoxomonosulfate is introduced as a derivatizing agent for Fluphenazine hydrochloride, yielding the sulfoxide. This reaction product was successfully used for the spectrophotometric determination of the Fluphenazine hydrochloride. The UV spectroscopic detection of the sulfoxide proved to be a more robust and sensitive method. The elaborated method allowed the determination of Fluphenazine hydrochloride in the concentration range of 0.2-30 µg mL-1. The molar absorptivity at 349 nm is 5.6×103 (dm3cm-1mol-1). The limit of quantification, LOQ (10S) is 0.24 µg/mL. A new spectrophotometric technique was developed and the possibility of quantitative determination of Fluphenazine hydrochloride in tablets 5.0 mg was demonstrated. The present method is precise, accurate and excipients did not interfere. RSD for Fluphenazine Hydrochloride 5.0 mg tablets was 1.37 %.

Spectrofluorometric method for the determination of ascorbic acid in pharmaceutical preparation using l-tyrosine as fluorescence probe

Ascorbic acid is a vital nutrient and antioxidant that is commonly used as an additive in commercial products. Quantitation of ascorbic acid is highly desired in the medical, food, and cosmetic industries. A spectrofluorometric assay for sensitive determination of ascorbic acid was developed using l-tyrosine as a fluorescent probe. The native fluorescence intensity of tyrosine was quenched using ascorbic acid. The linear range was 0.03-30.00 μM, and the limit of detection was 0.01 μM. The method exhibited excellent precision, accuracy, specificity, and robustness. Components of pharmaceutical preparations that are commonly found with ascorbic acid did not interfere with detection. The procedure was successfully employed for determination of ascorbic acid content in pharmaceutical tablets, injections, and nutrient supplements with satisfactory results. A Stern-Volmer plot and fluorescence lifetime revealed that quenching was attributed to the inner filter effect and static quenching. Isothermal titration calorimetry confirmed the formation of a complex between tyrosine and ascorbic acid, with a binding constant of 1.68 × 10³ M^-1 and reaction stoichiometry of 0.94. Thermodynamic parameters suggested spontaneous complexation via hydrophobic interactions as the dominant binding force. This method is promising for the simple and rapid determination of ascorbic in the pharmaceutical industry.

Simultaneous determination of nortriptyline hydrochloride and fluphenazine hydrochloride in microgram quantities from low dosage forms by liquid chromatography-UV detection

A novel method for the simultaneous high-performance liquid chromatographic determination of nortriptyline hydrochloride and fluphenazine hydrochloride was developed and validated. Fluvastatin sodium was used as internal standard. The determination was performed on a Hypersil Gold C₈ column (250 mm × 4.6 mm i.d., 5 μm particle size) at 25 °C; the mobile phase, consisting of a mixture of formic acid (0.1 M, pH 2.16)-methanol (33:67, v/v), was delivered at a flow rate of 1.1 mL/min and detector wavelength at 251 nm. The retention time of nortriptyline, fluphenazine and fluvastatin was found to be 5.11, 8.05 and 11.38 min, respectively. Linearity ranges were 5.0–1350.0 and 10.0–1350.0 μg/mL with limit of detection values of 0.72 and 0.31 μg/mL, for nortriptyline and fluphenazine, respectively. Results of assay and recovery studies were statistically evaluated for its accuracy and precision. Correlation coefficients (r²) of the regression equations were greater than 0.999 in all cases. According to the validation results, the proposed method was found to be specific, accurate, precise and could be applied to the simultaneous quantitative analysis of nortriptyline and fluphenazine.