Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1231254 | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy | 2013 | 8 Pages |
In-situ ATR–FTIR spectroscopy and line shape analysis of the diagnostic spectral region was used to quantify the bound amount and release of the antibiotic streptomycin (STRP) at polyelectrolyte (PEL) multilayers (PEM) of poly(ethyleneimine) (PEI) and poly(acrylic acid) (PAA) or PEI and sodium alginate (ALG). Unlike common concepts based on the drug enrichment of the release medium, this analytical concept allowed to measure quantitatively the drug depletion in the delivery matrix. The measured kinetic in situ ATR–FTIR data were analysed by a modified Korsmeyer–Peppas equation based on two characteristic release parameters k and n.As main experimental parameters the number of PEL layers (adsorption steps) z and the STRP/PEL ratio were varied. For z = 8 the STRP/PEL ratio showed the most significant influence on release kinetics, whereby for STRP/PEL = 1:25 slowest (n = 0.77) and lowest (k = 21.4%) and for STRP/PEL = 1:5 most rapid (n = 0.30) and highest (k = 58.6%) drug releases were found. PEM-PEI/ALG-8 (STRP/PEL = 1:5) revealed slower release rates (n = 0.58) and lower released STRP amounts (k = 17.1%) compared to PEI/PAA. UV–VIS data on time dependent STRP enrichment of the release medium showed a similar trend compared to respective ATR–FTIR data on STRP depletion in PEM. Released amounts of around 1–2 mg from the herein introduced PEM films could be determined. The introduced analytical concept will be used as screening tool for other drugs, drug eluting films and bone substituting materials.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► In situ ATR–FTIR spectroscopy was used as an interfacial drug delivery screening method. ► Streptomycin (STRP) depletion kinetics at polyelectrolyte (PEL) multilayers was quantified. ► Kinetic UV–VIS data on STRP enrichment in the release medium supported respective ATR–FTIR data. ► Kinetic release data on various samples could be analysed by modified Korsmeyer–Peppas equation. ► Number of PEL layers and STRP/PEL ratio were crucial parameters for sustained STRP release.