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Non-contact, Label-free Monitoring of Cells and Extracellular Matrix using Raman Spectroscopy
Published on: May 29, 2012
Quantitative spatial distribution of sirolimus and polymers in drug-eluting stents using confocal Raman microscopy
K M Balss1, G Llanos, G Papandreou
1Cordis Corporation, a Johnson & Johnson Company, Welsh and McKean Roads, Spring House, Pennsylvania 19477, USA. kbalss@crdus.jnj.com
Journal of Biomedical Materials Research. Part A
|September 19, 2007
Summary
Raman spectroscopy accurately quantifies sirolimus and polymer distribution on drug-eluting stents. This method provides precise measurements for sirolimus-eluting coronary stent components, crucial for quality control.
Area of Science:
- Analytical Chemistry
- Materials Science
- Biomedical Engineering
Background:
- Drug-eluting stents (DES) are critical in treating coronary artery disease.
- Accurate quantification of drug distribution on DES is essential for efficacy and safety.
- Characterizing the solid-phase distribution of drugs and polymers on stents presents analytical challenges.
Purpose of the Study:
- To develop and validate Raman spectroscopy methods for quantifying sirolimus and polymer distribution on CYPHER Sirolimus-eluting Coronary Stents.
- To establish calibration curves for sirolimus, poly(ethylene-co-vinyl acetate) [PEVA], and poly(n-butyl methacrylate) [PBMA].
- To assess the accuracy of Raman spectroscopy in predicting drug and polymer content on coated stents.
Main Methods:
- Confocal Raman spectral depth profiling was employed on 16 unique drug-polymer formulations.
- Calibration curves were generated for sirolimus, PEVA, and PBMA based on spectral data.
- The developed calibration models were validated on three independent drug-polymer coated stents.
- Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy was used for comparative analysis.
Main Results:
- Linear calibration models were established for sirolimus (0-100 wt%), PEVA (0-100 wt%), and PBMA (0-100 wt%).
- Raman spectroscopy predicted sirolimus content with high accuracy (within 1 wt% of laboratory assay).
- Polymer content was predicted within 7 wt% of the formulation solution content.
- ATR-FTIR confirmed linear responses for sirolimus and polymer content.
Conclusions:
- Raman spectroscopy is a reliable and accurate technique for quantitative analysis of drug and polymer distribution on DES.
- The developed spectral methods enable precise quality control of sirolimus-eluting stent coatings.
- This approach facilitates a deeper understanding of drug-polymer interactions and distribution within stent coatings.
