Sequential Injection Analysis Method for the Determination of Glutathione in Pharmaceuticals

Area of Science:

• Analytical Chemistry
• Pharmaceutical Analysis

Background:

• Glutathione (GSH) is a critical endogenous antioxidant vital for cellular protection.
• Accurate quantification of GSH in pharmaceutical formulations is essential for quality control and efficacy.

Purpose of the Study:

• To develop and validate a novel sequential injection analysis (SIA) method for determining glutathione (GSH) in pharmaceutical samples.
• To establish a sensitive, rapid, and reliable analytical technique for pharmaceutical quality assessment.

Main Methods:

• Sequential injection analysis (SIA) utilizing the reduction of the Cu(II)-neocuproine complex by GSH.
• Spectrophotometric detection of the resulting orange-yellow Cu(I)-neocuproine complex at 458 nm.
• Optimization of reaction conditions to achieve desired analytical performance.

Main Results:

• The SIA method demonstrated a wide linear calibration range (6.0 × 10^-7–8.0 × 10^-5 mol L^-1) with high linearity (R² = 0.9983).
• Achieved a low limit of detection (2.0 × 10^-7 mol L^-1) and limit of quantification (6.7 × 10^-7 mol L^-1).
• Exhibited good repeatability (3.8% RSD) and a high sampling rate (60 h^-1), with successful application to pharmaceutical samples.

Conclusions:

• The developed SIA method provides a sensitive and efficient means for quantifying glutathione in pharmaceutical products.
• Results obtained using the new method showed no statistically significant difference compared to the standard Pharmacopoeia method.
• This SIA approach offers a viable and robust alternative for routine pharmaceutical analysis of GSH.