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Background: Cyclizine (CYZ), a commonly used antiemetic drug, has two pharmacopeial toxic impurities, 1-methylpiperazine (MPZ) and diphenylmethanol (DPM). When CYZ parenteral formulations are administered intravenously, both impurities are poisonous, toxic, and harmful to the human body., Objective: Cyclizine was determined along with its hazardous impurities MPZ and DPM by green multivariate calibration using UV-spectroscopic data., Methods: Three multivariate algorithms were used to resolve and quantify overlapped spectral signals: principal component regression (PCR), partial least squares (PLS), and synergistic intervals partial least squares (siPLS). A concentration set containing 16 distinct combinations of CYZ, MPZ, and DPM was randomly prepared, and the absorbance values of the concentration set were determined using the 376 point-wavelength set with an interval of 0.2 nm between 200 and 275 nm., Results: Good linear correlations were established for CYZ, MPZ, and DPM in the concentration ranges of 5.00-25.0, 0.50-2.50, and 0.50-2.50 µg/mL, respectively. The ideal spectral range and associated combinations were chosen based on the lowest root mean error of prediction (RMSEP) and correlation coefficient values (r). The siPLS approach performed better than the PCR and PLS models. The combination of four subintervals, 1, 3, 4, and 7, demonstrated the greatest effect, with RMSEP values of 0.0272, 0.0053, and 0.0315 for CYZ, MPZ, and DPM, respectively, and correlation coefficients of 0.9991, 0.9999, and 0.9997, in order. Various assessment tools were used to evaluate and measure the greenness profile of the established methods. The proposed methods were validated using internal and external validation sets., Conclusions: The three methods were effectively used to determine CYZ in its pure form and parenteral formulations, as well as its toxic impurities. The acquired results were compared statistically to those obtained using the reported HPLC method., Highlights: Cyclizine and its toxic impurities can be determined spectrophotometrically by using the three developed chemometric models., (© The Author(s) 2022. Published by Oxford University Press on behalf of AOAC INTERNATIONAL. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Sulphasalazine (SZ) is a prodrug. Its active metabolite (mesalazine, MZ), which is also available in pharmaceutical formulations, and the major active metabolite of MZ (N-acetyl-5-aminosalicylic acid, AS) are commonly used for the treatment of inflammatory bowel diseases., Objective: Two accurate, precise, sensitive, and specific spectrophotometric methods were developed and validated for determination of the studied components., Methods: The first method is a modified ratio difference spectrophotometric method. In this method, SZ was determined by measuring the peak area from 410-500 nm, while MZ and AS were determined by measuring the difference of the selected amplitude values. The second method is a mean centering of ratio spectra spectrophotometric method., Results: The developed methods were linear over the concentration ranges of 2-35, 2-30 and 1-25 µg/mL for SZ, MZ and AS, respectively., Conclusion: The developed methods were validated according to International Conference on Harmonization guidelines. They were successfully applied for determination of studied analytes. A greenness assessment was undertaken using three different tools., Highlights: Spectrophotometric methods were developed for determination of SZ and its related compounds for the first time. They were designated to be green and eco-friendly and their greenness profiles were evaluated using green solvents to keep the environment clean., (© AOAC INTERNATIONAL 2021. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Two simple, sensitive and validated chromatographic methods were developed for quantitative determination of bromhexine hydrochloride (BHX) in presence of its major impurities, impurity B (IMB) and impurity C (IMC), as specified by British Pharmacopoeia. First method (I) was high-performance thin layer chromatography-densitometry at which the chromatographic separation was performed using silica gel plates and developing system consisted of hexane:acetone:ammonia solution (9:0.5:0.08, by volume) with ultraviolet scanning at 240 nm and linearity was achieved in the ranges of 0.40-10.00, 0.20-2.00 and 0.20-2.00 μg/band of BHX, IMB and IMC, respectively. Also, second chromatographic method (II) was high-performance liquid chromatography (HPLC) where the separation was carried out on C18 column at isocratic mode at flow rate 1.5 mL/min. The mobile phase consisted of methanol:water (90:10, v/v) adjusted to pH 2.5 with O-phosphoric acid and temperature was adjusted to 40°C. The scanning wavelength was 240 nm. The chromatographic run time was 6 min. Linearity of this method was achieved in the ranges of 4.00-40.00, 0.20-10.00 and 0.50-10.00 μg/mL for BHX, IMB and IMC, respectively. The validation of these chromatographic methods was made according to International Conference on Harmonization guidelines. These methods were successfully applied for determination of BHX in its pharmaceutical formulation. Also, statistical comparison was attained between the developed methods and the reported HPLC method using Student's t-test and F-test, and the obtained results showed that there was not any significant difference between them concerning with accuracy and precision., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

This work presents a sensitive, accurate and selective RP-HPLC method for simultaneous determination of cyproheptadine HCl (CPH), its impurity B (dibenzosuberone) and CPH oxidative degradation product (10,11-dihydroxy-dibenzosuberone) in bulk powder and in pharmaceutical formulation. The RP-HPLC method depends on isocratic elution using C8 column and mobile phase consisting of 0.05 M KH2PO4 buffer:methanol (35:65, v/v, pH = 4.5) at a flow rate of 2 mL/min, and the eluant was monitored at 245 nm. Good resolution was obtained with tR values of 3.05, 7.54 and 6.17 min for CPH, impurity and oxidative degradate, respectively. The proposed method has been validated as per ICH guidelines using pure forms of CPH, its impurity and degradation product in pharmaceutical formulation with an accuracy of 100.48, 100.16 and 100.11, respectively. Additional spiking experiments yielded an accuracy of 100 ± 1.6%. Repeatability and intermediate precision results indicated acceptable low <2% RSD values. Moreover, the developed method's statistical results were favorably compared to the previously reported method results regarding both accuracy and precision. The developed method can be applied for analysis of the three components in quality control laboratories., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Ascorbic acid (ASC), paracetamol (PAR) and guaifenesin (GUF) are co-formulated together as analgesic and expectorant effervescent powder. This work describes a selective stability indicating HPTLC-densitometric method which is the first developed stability indicating one for chromatographic separation of the three studied drugs in presence of paracetamol toxic impurity [4-aminophenol (4-AP)] and guaifenesin related substance [impurity, (guaiacol) (GUC)]. The chromatographic separation was carried out on HPTLC 60F254 plates using chloroform-acetone-trifluoroacetic acid (6.5:3.5:0.30, by volume) as a developing system with UV detection at 254 nm. Factors affecting chromatographic separation have been optimized and good separation was obtained between the studied components where (ASC Rf = 0.05, 4-AP Rf = 0.12, GUF Rf = 0.24, PAR Rf = 0.41 and GUC Rf = 0.56). Method validation has been performed according to ICH guidelines and linearity was achieved in the range of 0.4-2.4, 0.4-2.8 and 4-15 μg/band for ASC, PAR and GUF, respectively. In order to evaluate the developed method it was applied for determination of the cited drugs in G.C.Mol® effervescent powder and the obtained results were statistically compared with those obtained by applying the reported HPLC method using Student's t- and F-tests where no significant difference was observed. The developed method has the advantages over the reported HPLC one of being more sensitive and selective which permit its application in quality control analysis of the cited their in presence of drug impurities.

Two accurate, sensitive and highly selective stability-indicating methods are developed and validated for simultaneous determination of Agomelatine (AGM) and its forced degradation products (Deg I and II). The first method is High-Performance Liquid Chromatography for separation and quantitation of AGM, Deg I and II on a C18 column (250 mm × 4.6 mm, 5 μm p.s) in isocratic mode by using a binary mixture of Potassium dihydrogen phosphate (0.05 M, pH adjusted to 2.9 with orthophosphoric acid): acetonitrile (60:40, v/v) at a flow rate of 2 mL/min. The components were detected at 230 nm over a concentration range of 0.5-10 μg/mL for AGM and 0.5-5 μg/mL for both Deg I and II. The second method is High-Performance Thin-Layer Chromatography, where AGM, Deg I and II were separated on silica gel HPTLC F254 plates using chloroform:methanol:ammonia solution (9:1:0.1, by volume) as a developing system. The separated bands were scanned at 230 nm over the concentration range of 0.2-1.2 μg/band for AGM in pure form and human plasma and 0.1-1 μg/band for both Deg I and II. The proposed methods were successfully applied for analysis of AGM in pharmaceutical formulations. The results obtained by the proposed methods were statistically compared to the reported HPLC method revealing high accuracy and good precision.

Two accurate, precise and sensitive high-performance thin layer chromatography (HPTLC) and high-performance liquid chromatography (HPLC) methods were developed for assay of ampicillin (AMP) and dicloxacillin (DX) in the presence of their impurity, 6-aminopenicillanic acid (APA). Method (A) is HPTLC method; using silica gel HPTLC F254 plates as a stationary phase with methanol: chloroform: acetic acid (1:9: 0.2, by volume) as a developing system. All the bands were scanned at 220 nm. Method (B) is reversed phase- HPLC which depended on isocratic elution using C18 column and mobile phase consisting of acetonitrile: water (60:40, v/v), pH adjusted to 4 with orthophosphoric acid, at a flow rate of 1 mL min-1 and ultraviolet detection at 240 nm. The proposed methods were validated as per ICH guidelines and their linearity was evident in the ranges of 0.5-2 μg band-1, 0.4-2 μg band-1 and 0.2-1.2 μg band-1 for method (A) and 5-40 μg mL-1, 5-40 μg mL-1 and 2-16 μg mL-1 for method (B) for AMP, DX and APA, respectively. The proposed methods were successfully used for assay of AMP and DX in pure form and in pharmaceutical formulation where no interference from the excipients was detected.

Two accurate, precise and highly selective stability-indicating methods were adopted for simultaneous determination of benztropine mesylate (BNZ) in presence of its hepatotoxic and carcinogenic degradation product, benzophenone (BPH) either in pure form or in the pharmaceutical formulation without any preliminary separation steps. The first method is a thin layer chromatography (TLC)-densitometric method that depended on separation of BNZ from its degradate on TLC aluminum plates precoated with silica gel 60 F254 as the stationary phase using a developing system consisted of hexane:methylene chloride:triethylamine (5:5:0.6, by volume) and scanning the separated bands at 235 nm. Linear regression analysis data for the calibration plots of BNZ and BPH showed perfect linear relationships over the concentration range of 1.5-10 and 1-10 μg band-1, respectively. The second method is (UPLC) method, at which the mixture was separated on a reversed phase C8 analytical column (1.9 μm ps, 50 mm × 2.1 i.d.) using a mobile phase of acetonitrile: aqueous sodium dodecyl sulfate (50:50, v/v) Adjusted to pH = 3 with phosphoric acid, at a flow rate of 0.5 mL min-1. Quantification was achieved at 210 nm based on peak area and linear calibration curves over the concentration ranges of (20-200 μg mL-1) and (5-50 μg mL-1) for BNZ and BPH, respectively, were obtained. The investigated methods were successfully applied to available dosage form and method validation has been carried out. The results obtained by applying the proposed methods were statistically analyzed and compared with those obtained by reported one and no significant differences were obtained regarding both accuracy and precision., (© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Accurate and precise TLC-densitometric and HPLC-diode-array detector (DAD) methods have been developed and validated to resolve two binary mixtures containing pyridoxine hydrochloride (PYH) with either cyclizine hydrochloride (CYH) or meclizine hydrochloride (MEH). In the developed TLC-densitometric method, chromatographic separation of the three studied drugs was carried out on silica gel 60 F254 plates using a developing system containing methylene chloride + acetone + methanol (7 + 1 + 0.5, v/v/v) scanning separated bands at 220 nm. Beer-Lambert law was obeyed in the ranges of 0.2-5, 0.2-4, and 0.2-4 µg/band for PYH, CYH, and MEH, respectively. On the other hand, the developed HPLC-DAD method depended on chromatographic separation on a Zorbax Eclipse C18 column using methanol-KH2PO4 (0.05 M; 90 + 10, v/v; pH 5, with H3PO4 and KOH) as the mobile phase, a flow rate of 1 mL/min, and UV scanning at 220 nm. A linear relationship was obtained between the integrated peak area and the concentration in the ranges of 10-50, 10-50, and 7-50 µg/mL for PYH, CYH, and MEH, respectively. The proposed methods were successfully applied for the determination of the cited drugs in their pharmaceutical formulations. Statistical comparison with the reported methods using Student's t- and F-tests found there were no significant differences between the proposed and reported methods for accuracy and precision.

Newly established TLC-densitometric and RP-HPLC methods were developed and validated for the simultaneous determination of Piracetam (PIR) and Vincamine (VINC) in their pharmaceutical formulation and in the presence of PIR and VINC degradation products, PD and VD, respectively. The proposed TLC-densitometric method is based on the separation and quantitation of the studied components using a developing system that consists of chloroform-methanol-glacial acetic acid-triethylamine (8 + 2 + 0.1 + 0.1, v/v/v/v) on TLC silica gel 60 F254 plates, followed by densitometric scanning at 230 nm. On the other hand, the developed RP-HPLC method is based on the separation of the studied components using an isocratic elution of 0.05 M KH2PO4 (containing 0.1% triethylamine adjusted to pH 3 with orthophosphoric acid)-methanol (95 + 5, v/v) on a C8 column at a flow rate of 1 mL/min with diode-array detection at 230 nm. The developed methods were validated according to International Conference on Harmonization guidelines and demonstrated good accuracy and precision. Moreover, the developed TLC-densitometric and RP-HPLC methods are suitable as stability-indicating assay methods for the simultaneous determination of PD and VD either in bulk powder or pharmaceutical formulation. The results were statistically compared with those obtained by the reported RP-HPLC method using t- and F-tests.

Two accurate, sensitive, and selective stability-indicating methods are developed and validated for simultaneous quantitative determination of agomelatine (AGM) and its forced degradation products (Deg I and Deg II), whether in pure forms or in pharmaceutical formulations. Partial least-squares regression (PLSR) and spectral residual augmented classical least-squares (SRACLS) are two chemometric models that are being subjected to a comparative study through handling UV spectral data in range (215-350 nm). For proper analysis, a three-factor, four-level experimental design was established, resulting in a training set consisting of 16 mixtures containing different ratios of interfering species. An independent test set consisting of eight mixtures was used to validate the prediction ability of the suggested models. The results presented indicate the ability of mentioned multivariate calibration models to analyze AGM, Deg I, and Deg II with high selectivity and accuracy. The analysis results of the pharmaceutical formulations were statistically compared to the reference HPLC method, with no significant differences observed regarding accuracy and precision. The SRACLS model gives comparable results to the PLSR model; however, it keeps the qualitative spectral information of the classical least-squares algorithm for analyzed components.

This study was designed to establish, optimize and validate a sensitive, selective and accurate high-performance thin layer chromatographic (HPTLC) method for determination of zopiclone (ZPC) and its main impurity, 2-amino-5-chloropyridine, one of its degradation products, in raw material and pharmaceutical formulation. The proposed method was applied for analysis of ZPC and its impurity over the concentration range of 0.3-1.4 and 0.05-0.8 µg/band with accuracy of mean percentage recovery 99.92% ± 1.521 and 99.28% ± 2.296, respectively. The method is based on the separation of two components followed by densitometric measurement of the separated peaks at 305 nm. The separation was carried out on silica gel HPTLC F254 plates, using chloroform-methanol-glacial acetic acid (9:1:0.1, by volume) as a developing system. The suggested method was validated according to International Conference on Harmonization guidelines and can be applied for routine analysis in quality control laboratories. The results obtained by the proposed method were statistically compared with the reported method revealing high accuracy and good precision., (© The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Three methods are presented for the simultaneous determination of diloxanide furoate (DLX) and metronidazole (MTR), used for their antiprotozoal and antiamoebic effect, in the presence of DLX alkaline degradates and in pharmaceutical formulations, without previous separation. The first method is chemometric-assisted spectrophotometry, in which principal component regression and partial least squares were applied. These two approaches were successfully applied to quantify each drug in the mixture using the information included in, the absorption spectra in the range of 225-320 nm. The second method is TLC-densitometry, in which the binary mixture and degradates were separated on silica gel plates using a chloroform-acetone-glacial acetic acid (9.5 + 0.5 + 0.07, v/v/v) mobile phase and the bands were scanned at 254 nm. The last method is HPLC, in which DLX, MTR, and degradates were separated using the mobile phase acetonitrile-0.05 M dibasic potassium phosphate (25 + 75, v/v), adjusted to pH 4 with orthophosphoric acid, at a flow rate of 1 mL/min, on a C18 analytical column. Detection was at 254 nm. The proposed methods were successfully applied for the analysis of DLX and MTR in pharmaceutical formulations, and the results were statistically compared with a reported spectrophotometric method.