Stability Indicating RP-HPLC Method for the Simultaneous Determination of Atorvastatin Calcium, Metformin Hydrochloride, and Glimepiride in Bulk and Combined Tablet Dosage Form

Unveiling Impurities: A Comprehensive RP-HPLC Method for Accurate Atorvastatin Impurity Analysis in Pharmaceuticals Using an Accuracy Profile Approach

BACKGROUND

Accurate determination of active pharmaceutical ingredients and impurities is essential for ensuring the safety and effectiveness of medications. This study focuses on the validation of a high-performance liquid chromatography (HPLC) method for quantifying atorvastatin and its impurities, addressing a critical aspect of pharmaceutical analysis.

OBJECTIVE

The primary objective is to conduct a comprehensive validation study for the HPLC method, covering specificity assessment, response function establishment, and a detailed analysis of precision, trueness, and tolerance intervals. The emphasis is on demonstrating the method's precision, accuracy, and stability-indicating capabilities across various concentrations and compounds.

METHODS

The HPLC method is validated through rigorous assessments, including specificity, response function establishment, and analyses of precision, trueness, and tolerance intervals. Induced degradation experiments are conducted to explore atorvastatin's behavior under extreme conditions. Insights into the compound's synthesis and degradation pathways are provided through a proposed mechanism for intramolecular esterification.

RESULTS

The results affirm the precision, accuracy, and stability-indicating capabilities of the validated HPLC method. The method effectively differentiates between atorvastatin and its impurities, showcasing its suitability for pharmaceutical quality control.

CONCLUSIONS

The validated HPLC method emerges as a robust and reliable tool for atorvastatin analysis, contributing significantly to pharmaceutical research and quality control. Its application ensures the safety and efficacy of medications, reinforcing its role in pharmaceutical analysis.

HIGHLIGHTS

This study not only validates a crucial HPLC method for atorvastatin analysis but also provides insights into the compound's behavior under extreme conditions and its synthesis and degradation pathways. The validated method serves as a cornerstone in pharmaceutical research and quality control, ensuring medication safety and efficacy.

Spectrophotometric methods for determination of glimepiride and pioglitazone hydrochloride mixture and application in their pharmaceutical formulation

Simple, accurate, and precise four spectrophotometric methods were developed and validated for simultaneous determination of glimepiride and pioglitazone hydrochloride in their pharmaceutical formulation. The first spectrophotometric method was the dual-wavelength which determined glimepiride at 219.0 and 228.0 nm and pioglitazone hydrochloride at 268.0 nm. The second one is the first derivative of ratio spectra (DD1) spectrophotometry in which the peak amplitudes were used at 238.0 nm and 268.0 nm for glimepiride and pioglitazone hydrochloride, respectively. The third method is ratio subtraction in which glimepiride was determined at 228.0 nm in the presence of pioglitazone hydrochloride which was determined by extended ratio subtraction at 268.0 nm. The fourth method was the ratio difference to determine glimepiride and pioglitazone hydrochloride. Beer's law was confirmed in the concentration range 2.50-15.00 µg mL-1, and 10.00-50.00 µg mL-1 for glimepiride and pioglitazone respectively for the four methods. The proposed methods were used to determine both drugs in their pure powdered form with mean percentage recoveries of 99.91 ± 1.117% for glimepiride and 99.76 ± 0.911% for pioglitazone hydrochloride in method (A). In method (B), the mean percentage recoveries were 100.12 ± 0.89% for glimepiride and 100.02 ± 1.06% for pioglitazone hydrochloride. In method (C) glimepiride was 100.01 ± 0.592% and 99.85 ± 0.845% for pioglitazone hydrochloride by extended ratio subtraction. And finally, in method (D) the mean percentage recoveries were 100.66 ± 0.670% for glimepiride and 99.92 ± 0.988% for pioglitazone hydrochloride. The developed methods were successfully applied for the determination of glimepiride and pioglitazone hydrochloride in pure powder and dosage form. The suggested methods were also used to determine both compounds in laboratory-prepared mixtures. The accuracy, precision, and linearity ranges of the developed methods were determined. The results obtained were compared statistically with the official method, and there was no significant difference between the proposed methods and the official method for accuracy and precision.

Development of a Novel, Fast, Simple HPLC Method for Determination of Atorvastatin and its Impurities in Tablets

Our main target and concept was to develop a method for the determination of the most prescribed antilipemic drug, atorvastatin, together with its related substances, with a single sample preparation and during a single chromatographic run, in the shortest possible period of time, with the lowest possible mobile phase consumption. A new rapid, simple chromatographic method for the determination of atorvastatin and its main specified impurities was developed, using different chromatographic columns. With this new concept of a mobile phase and a powerful core–shell, or a superficially porous silica-based column, satisfactory results for targeted parameters, such as critical peak resolution, run time length, and column backpressure, were achieved. The analysis is performed within a run duration of less than 15 min, which is about six times shorter than the official European Pharmacopoeia method. The chromatogram performances suggests that the method limit of quantification (LOQ) can be about 7 times lower, and the limit of detection (LOD) about 20 times lower, using an injection volume of only 2 µl. This was confirmed by the performed method validation in accordance with the International Conference on Harmonization (ICH) guideline for the validation of analytical procedures Q2(R1), where the selectivity, linearity, accuracy, precision, limit of quantification, and limit of detection were tested and confirmed.

Advanced and multifaceted stability profiling of the first-line antidiabetic drugs metformin, gliclazide and glipizide under various controlled stress conditions

The antidiabetic drugs metformin, gliclazide and glipizide have been widely used and studied in terms of pharmacological and antidiabetic effects, and their individual stability has been studied in the literature. However, the drugs’ combined stability profiling remains poorly understood, and hence the aim of this study was to investigate the collective stability profiling of different combinations at various controlled conditions. Degradation assessments were carried out on metformin, glipizide and gliclazide by applying a stability-indicating HPLC method that was developed and validated in accordance with ICH guidelines. Glipizide, gliclazide, metformin and the binary mixtures (metformin/glipizide and metformin/gliclazide) were subjected to different forced degradation conditions and were detected at 227 nm by an isocratic separation on an Alltima CN column (250 mm × 4.6 mm × 5µ) utilizing a mobile phase that consists of 20 mM ammonium formate buffer (pH 3.5) and acetonitrile at a ratio of (45:55, v/v). The method is linear (R² = 0.9999) at the concentration range 2.5–150 µg/ml for metformin and 1.25–150 µg/ml for sulfonylureas respectively and offers a specific and sensitive tool for their determination in <10 min chromatographic run. All drug peaks were sharp and well separated. Stress degradation revealed that metformin has a remarkable sensitivity to alkaline stress, glipizide was more sensitive to thermal degradation while gliclazide exhibited almost full degradation in acidic, alkaline and oxidative stress conditions.

Development and validation of HPLC and CE methods for simultaneous determination of amlodipine and atorvastatin in the presence of their acidic degradation products in tablets

Two methods were developed for separation and quantitation of amlodipine (AML) and atorvastatin (ATV) in the presence of their acidic degradation products. The first method was a simple isocratic RP-HPLC method while the second was capillary electrophoresis (CE). Degradation products were obtained by acidic hydrolysis of the two drugs and their structures were elucidated for the first time by IR and MS spectra. Degradation products did not interfere with the determination of either drug and the assays were therefore stability-indicating. The linearity of the proposed methods was established over the ranges 1-50 μg mL-1 for AML and ATV in the HPLC method and in the range of 3-50 and 4-50 μg mL-1 for AML and ATV, respectively, in the CE method. The proposed methods were validated according to ICH guidelines. The methods were successfully applied to estimation of AML and ATV in combined tablets.