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.

Stability-indicating liquid chromatography method development for assay and impurity profiling of amitriptyline hydrochloride in tablet dosage form and forced degradation study

Amitriptyline hydrochloride is an antidepressant drug with sedative effects used to treat the symptoms of anxiety, agitation with depression and schizophrenia with depression. A reversed-phase high-performance liquid chromatography method was developed to separate and quantitatively determine the assay and four organic impurities of amitriptyline in tablet dosage form and bulk drugs using a C₁₈ column in an isocratic elution mode with mobile phase consisting of a mixture of pH 7.5 phosphate buffer and methanol. The pH conditions used in the chromatographic separation are discussed. The stability-indicating characteristics of the proposed method were proved using stress testing [5 m HCl at 80°C/1 h, 5 m NaOH at 80°C/1 h, H₂ O (v/w) at 80°C/1 h, 6% H₂ O₂ (v/v) at 25°C/1 h, dry heat at 105°C/24 h and UV-vis light/4 days] and validated for specificity, detection limit, quantitation limit, linearity, precision, accuracy and robustness. For amitriptyline and its four known organic impurities, the quantitation limits, linearity and recoveries were in the ranges 0.25-3.0 μg/ml (r²  > 0.999) and 87.9-107.6%, respectively. The mass (m/z) spectral data of amitriptyline hydrochloride and its impurity are discussed. The proposed LC method is also suitable for impurity profiling and assay determination of amitriptyline in bulk drugs and pharmaceutical formulations.

Development and Validation of HPLC-DAD and UHPLC-DAD Methods for the Simultaneous Determination of Guanylhydrazone Derivatives Employing a Factorial Design

Guanylhydrazones are molecules with great pharmacological potential in various therapeutic areas, including antitumoral activity. Factorial design is an excellent tool in the optimization of a chromatographic method, because it is possible quickly change factors such as temperature, mobile phase composition, mobile phase pH, column length, among others to establish the optimal conditions of analysis. The aim of the present work was to develop and validate a HPLC and UHPLC methods for the simultaneous determination of guanylhydrazones with anticancer activity employing experimental design. Precise, exact, linear and robust HPLC and UHPLC methods were developed and validated for the simultaneous quantification of the guanylhydrazones LQM10, LQM14, and LQM17. The UHPLC method was more economic, with a four times less solvent consumption, and 20 times less injection volume, what allowed better column performance. Comparing the empirical approach employed in the HPLC method development to the DoE approach employed in the UHPLC method development, we can conclude that the factorial design made the method development faster, more practical and rational. This resulted in methods that can be employed in the analysis, evaluation and quality control of these new synthetic guanylhydrazones.