title: The effect of self-assembled layers on the release behavior of rifampicin-loaded silicone.
abstract: Providing a long period of sustained antibiotic release is one of the important challenges in the development of clinical shunts for long-term implantation. A cast-molding approach was used to load rifampicin into the silicone precursor before curing. Sustained in vitro release from rifampicin-loaded silicone for upwards of 110 days at a level of approximately 2-4 microg/cm2 per day was achieved. Quantitative comparisons of Staphylococcus epidermidis adhesion on untreated and rifampicin-loaded silicone surfaces were carried out to demonstrate the effect of rifampicin to discourage the bacterial adhesion. It was shown that the fresh 8.3% rifampicin-loaded silicone decreased bacterial adherence by 99.8%. Bacterial adherence on rifampicin-loaded silicone surfaces after 90 days release (eluted silicone) was decreased by 94.8%. A new approach was used to tune the initial burst effect and prolong long lasting release by introducing self-assembled perfluorodecyltrichlorosilane (FAS) and octadecyltrichlorosilane (OTS) layers. FAS layered structures can tune the burst effect and prolong the subsequent continuous release to achieve the long-term delivery. Significant decreases in initial burst effect (70.3% for multi-FAS layers and 39.7% for FAS monolayer) and enhanced long-term release (approx. 10 microg/cm2 per day for FAS monolayer for 110 days and approx. 15 microg/cm2 per day for multi-FAS layers for 60 days) were observed.
authors.affiliation: Department of Chemical Engineering and Materials Science, Wayne State University, 5050 Anthony Wayne Drive, Detroit, MI 48202, USA.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Liang
authors.forename: Anfeng
authors.initials: A
authors.lastname: Wang
authors.forename: Haiying
authors.initials: H
authors.lastname: Tang
authors.forename: Ting
authors.initials: T
authors.lastname: Cao
authors.forename: James P
authors.initials: JP
authors.lastname: McAllister
authors.forename: Steven O
authors.initials: SO
authors.lastname: Salley
authors.forename: K Y Simon
authors.initials: KY
authors.lastname: Ng
mesh_terms: D000904:Antibiotics, Antitubercular / Q000737:chemistry*; D001422:Bacterial Adhesion; D002408:Catheters, Indwelling / Q000382:microbiology; D020099:Coated Materials, Biocompatible; D003692:Delayed-Action Preparations / Q000494:pharmacology; D006849:Hydrocephalus / Q000628:therapy; D016459:Prosthesis-Related Infections / Q000517:prevention & control*; D012293:Rifampin / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012828:Silicones / Q000737:chemistry* / Q000494:pharmacology; D013212:Staphylococcus epidermidis / Q000187:drug effects; D013997:Time Factors
chemical_list: D000904:Antibiotics, Antitubercular; D020099:Coated Materials, Biocompatible; D003692:Delayed-Action Preparations; D012821:Silanes; D012828:Silicones; C065893:trichlorosilane; D012293:Rifampin