Analysis of Penicillin Sodium related substances

Importance of the Topic

Ensuring the purity of β-lactam antibiotics is essential to maintain efficacy and patient safety. Monitoring trace impurities in penicillin sodium helps regulatory compliance and quality assurance in pharmaceutical production.

Objectives and Study Overview

This work presents a reversed-phase high-performance liquid chromatography method for the separation and quantification of penicillin sodium and its related impurities. Key goals include achieving baseline resolution of listed degradation products within a single run suitable for routine quality control.

Methodology

The study employs a Shim-pack GIS C18 column with a gradient elution of phosphoric buffer–methanol and acetonitrile. Critical parameters such as mobile phase composition, flow rate, column temperature, and detection wavelength are optimized to resolve multiple impurities alongside the principal drug.

Used Instrumentation

• Column: Shim-pack GIS C18 (250×4.6 mm I.D., 5 μm; P/N 227-30106-08)
• Mobile Phases: A) Phosphoric buffer (KH2PO4 with KOH, pH 3.4) : methanol = 72:14, B) acetonitrile
• Gradient Program: 13.5% B (0–14.5 min) to 36% B (38.5–50.5 min), returning to 13.5% B (51.5–62.5 min)
• Flow Rate: 1.0 mL/min
• Column Temperature: 34 °C
• Injection Volume: 20 µL
• Vials: LabTotal Vial for LC/LCMS (P/N 227-34001-01)
• Detection: UV at 225 nm

Main Results and Discussion

System suitability tests demonstrated clear resolution of eleven impurities (E, I, F variants, J, H, D, G) and the penicillin peak with sharp, symmetric shapes. The gradient method achieved complete separation within 62.5 minutes, ensuring reproducible retention times and peak areas suitable for quantitative analysis.

Benefits and Practical Applications

• Robust separation of multiple β-lactam impurities in a single analysis
• High sensitivity and reproducibility for routine quality control
• Adaptable to pharmaceutical production settings for batch release testing

Future Trends and Possibilities

Advances may include ultra-high-performance LC to reduce run times, coupling with mass spectrometry for enhanced impurity identification, and automation to increase throughput. Development of greener mobile phases and microscale columns could further improve sustainability and efficiency.

Conclusion

The described HPLC method using Shim-pack GIS C18 effectively separates penicillin sodium and its related substances, offering a reliable tool for pharmaceutical quality control. Its robust performance and adaptability make it valuable for regulatory compliance and process monitoring.