title: Drug delivery from therapeutic self-assembled monolayers (T-SAMs) on 316L stainless steel.
abstract: Delivery of therapeutic agents from self-assembled monolayers (SAMs) on 316L stainless steel (SS) has been demonstrated as a viable method to deliver drugs for localized coronary artery stent application. SAMs are highly-ordered, nano-sized molecular coatings, adding 1-10 nm thickness to a surface. Hydroxyl terminated alkanethiol SAMs of 11-mercapto-1-undecanol (-OH SAM) were formed on 316L SS with 48 hr immersion in ethanolic solutions. Attachment of ibuprofen (a model drug) to the functional SAMs was carried out in toluene for 5 hrs at 60 degrees C using Novozume-435 as a biocatalyst. SAM formation and subsequent attachment of ibuprofen was characterized collectively using X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and contact angle (CA) measure-ments. The quantitative in vitro release of ibuprofen into a "physiological" buffer solution was characterized using reverse phase HPLC. Drug release kinetics showed that 14.1 microg of ibuprofen eluted over a period of 35 days with 2.7microg being eluted in the first day and the remaining being eluted over a period of 35 days. The drug release kinetics showed an increase in ibuprofen elution that occurred during first 14 days (2.7microg in 1 day to 9.5 microg in 14 days), following which there was a decrease in the rate of elution. Thus, functional SAMs on 316L SS could be used as tethers for drug attachment and could serve as a drug delivery mechanism from stainless steel implants such as coronary artery stents.
authors.affiliation: Department of Biomedical Engineering and Department of Chemistry, The University of Texas at San Antonio, 6900 N Loop 1604 W, San Antonio, TX, USA.
authors.forename: Anil
authors.initials: A
authors.lastname: Mahapatro
authors.forename: Dave M
authors.initials: DM
authors.lastname: Johnson
authors.forename: Devang N
authors.initials: DN
authors.lastname: Patel
authors.forename: Marc D
authors.initials: MD
authors.lastname: Feldman
authors.forename: Arturo A
authors.initials: AA
authors.lastname: Ayon
authors.forename: C Mauli
authors.initials: CM
authors.lastname: Agrawal
mesh_terms: D002851:Chromatography, High Pressure Liquid; D016503:Drug Delivery Systems / Q000379:methods*; D054855:Drug-Eluting Stents / Q000592:standards; D007052:Ibuprofen / Q000008:administration & dosage / Q000737:chemistry; D049329:Nanostructures / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000008:administration & dosage* / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D013193:Stainless Steel / Q000737:chemistry*
chemical_list: D004364:Pharmaceutical Preparations; D013193:Stainless Steel; D007052:Ibuprofen