Analysis of Rifampicin

Significance of the topic

Rifampicin is a cornerstone antibiotic in the treatment of tuberculosis and other bacterial infections. Accurate quantification and impurity profiling of rifampicin are critical for ensuring drug safety, efficacy, and regulatory compliance in pharmaceutical manufacturing and quality control.

Objectives and overview of the study

This application note presents a reversed-phase liquid chromatography method for simultaneous determination of rifampicin and its related compounds. The goal is to achieve baseline separation of the active pharmaceutical ingredient and key impurities for routine quality assurance in analytical laboratories.

Methodology and instrument setup

A Shimadzu LC system equipped with a Shim-pack VP-C8 column (250 mm × 4.6 mm I.D., 5 µm) was used. The mobile phase consisted of methanol, acetonitrile, 0.075 M potassium dihydrogen phosphate, and 1.0 M citric acid in a ratio of 30 : 30 : 36 : 4. Chromatographic conditions were:

• Flow rate: 1.0 mL/min
• Column temperature: 40 °C
• Injection volume: 10 µL
• Detection: UV at 254 nm

Sample pretreatment involved dissolving approximately 10 mg of each standard (rifampicin, quinoid rifampicin, N-oxide rifampicin, rifamycin SV) in acetonitrile, followed by dilution with acetonitrile-water (1 : 1) to obtain a final concentration of ~0.04 mg/mL.

Main results and discussion

The method achieved clear separation of five components:

1. Quinoid rifampicin
2. Impurity A
3. Rifampicin
4. N-oxide rifampicin
5. Rifamycin SV

System suitability criteria such as resolution, tailing factor, and theoretical plate count met compendial requirements, demonstrating robustness and reproducibility.

Benefits and practical applications

• Straightforward sample preparation with common solvents.
• Effective separation of the API and related impurities in under 30 minutes.
• Applicable for routine QC and stability studies in pharmaceutical and contract laboratories.

Future trends and opportunities

Analytical demands continue to evolve toward higher throughput and enhanced sensitivity. Potential developments include:

• Transition to UPLC columns for faster analyses and reduced solvent consumption.
• Coupling with mass spectrometric detection to confirm impurity structures.
• Implementation of green chemistry approaches by substituting less toxic solvents.

Conclusion

The described RP-HPLC method using Shim-pack VP-C8 provides a reliable, reproducible, and accessible approach for the determination of rifampicin and its impurities, supporting stringent quality control requirements in pharmaceutical workflows.

References

No external literature references were provided in the original document.