Unique and earth-friendly RP-HPLC approach for quantification and degradation of metoprolol and enalapril maleate: a new approach to combination therapy

Key findings from this study

This research indicates that:

• RP-HPLC successfully quantifies metoprolol and enalapril across the 3–60 µg/mL range with R² ≥ 0.999
• Recovery studies demonstrated 98–102% accuracy for both pharmaceutical agents
• The method maintained analytical specificity in the presence of degradation products while meeting ICH validation requirements

Overview

The study develops a reversed-phase HPLC method to quantify metoprolol and enalapril maleate in pharmaceutical formulations containing both agents. The approach emphasizes sustainable analytical chemistry by replacing toxic reagents and reducing chemical waste while maintaining analytical performance across bulk drugs and finished products.

Methods and approach

Isocratic RP-HPLC configuration employed an InertSustain C8 column (250 × 4.6 mm, 5 µm) with a potassium phosphate buffer (pH 2.5) and ethanol mobile phase in 50:50 ratio. Sample and column temperatures were 5°C and 40°C respectively. The seven-minute method used 20 µL injection volume and 1.0 mL/min flow rate. Validation followed International Council for Harmonization criteria for linearity, accuracy, stability, and limit determination.

Results

The method achieved linear response for both compounds across 3–60 µg/mL range with R² ≥ 0.999. Enalapril demonstrated detection and quantification limits of 0.29 µg/mL and 0.90 µg/mL respectively. Metoprolol exhibited detection and quantification limits of 0.33 µg/mL and 0.98 µg/mL. Recovery studies yielded 98–102% accuracy across both analytes. The method successfully detected and quantified both drugs despite the presence of degradation products, confirming analytical reliability under ICH stability conditions.

Implications

The developed method supports analytical strategies for combination antihypertensive formulations containing metoprolol and enalapril. Integration of both agents in single-dose preparations may improve patient compliance for cardiovascular management while reducing pill burden. The environmentally conscious approach to method development establishes a template for sustainable analytical chemistry in pharmaceutical analysis.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.