title: Rheological studies on pressure-sensitive silicone adhesives and drug-in-adhesive layers as a means to characterise adhesive performance.
abstract: Pressure-sensitive adhesives are viscoelastic polymers used in the formulation of transdermal patches that allow attachment of a patch onto the skin. Established criteria exist that correlate viscoelastic parameters with adhesive performance. In this study, fulfillment of the adhesive performance criteria was examined using two silicone adhesives with different tack properties. The viscoelastic parameters of high and low tack silicone adhesives (BIO-PSA High Tack 7-4302 and BIO-PSA Low Tack 7-4102) were determined and compared with the criteria described by Chu and Dahlquist. Drug-in-adhesive layers were prepared using the high tack adhesive combined with nortriptyline HCl or paracetamol. The effect of drug addition on the viscoelastic properties of the adhesive was examined. The high tack adhesive showed congruence with the established criteria although with a modified range of viscoelastic moduli to that described by Chu. Examination of the low tack adhesive showed that it did not possess the appropriate viscoelastic properties for bonding onto the skin. The addition of the drugs into the high tack adhesive caused a concentration-dependent increase in its cohesive strength. This effect was independent of the physicochemical properties of the drugs tested.
authors.affiliation: Sunderland Pharmacy School, School of Health, Natural and Social Sciences, University of Sunderland, Wharncliffe Street, Sunderland SR1 3SD, UK.
authors.forename: Kwong Yat
authors.initials: KY
authors.lastname: Ho
authors.forename: Kalliopi
authors.initials: K
authors.lastname: Dodou
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage / Q000737:chemistry; D000279:Administration, Cutaneous; D004337:Drug Carriers; D004548:Elasticity; D016014:Linear Models; D008956:Models, Chemical; D009661:Nortriptyline / Q000008:administration & dosage / Q000737:chemistry; D009991:Oscillometry; D010316:Particle Size; D011312:Pressure; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods; D033081:Shear Strength; D012828:Silicones / Q000737:chemistry*; D012995:Solubility; D014014:Tissue Adhesives / Q000737:chemistry*; D014783:Viscosity
chemical_list: D004337:Drug Carriers; D012828:Silicones; D014014:Tissue Adhesives; D000082:Acetaminophen; D009661:Nortriptyline