Pharm Res DOI 10.1007/s11095-014-1318-2
RESEARCH PAPER
Investigations on the Viscoelastic Performance of Pressure Sensitive Adhesives in Drug-in-Adhesive Type Transdermal Films Hans-Michael Wolff & Irsan & Kalliopi Dodou
Received: 30 August 2013 / Accepted: 28 January 2014 # The Author(s) 2014. This article is published with open access at SpringerLink.com
ABSTRACT Purpose We aimed to investigate the effect of solubility parameter and drug concentration on the rheological behaviour of drugin-adhesive films intended for transdermal application. Methods Films were prepared over a range of drug concentrations (5%, 10% and 20% w/w) using ibuprofen, benzoic acid, nicotinic acid and lidocaine as model drugs in acrylic (Duro-Tak 874287 and Duro-Tak 87900A) or silicone (Bio-PSA 7-4301 and Bio-PSA 7-4302) pressure sensitive adhesives (PSAs). Saturation status of films was determined using light microscopy. Viscoelastic parameters were measured in rheology tests at 32°C. Results Subsaturated films had lower viscoelastic moduli whereas saturated films had higher moduli than the placebo films and/or a concentration-dependent increase in their modulus. Saturation concentration of each drug in the films was reflected by decreasing/ increasing viscoelastic patterns. The viscoelastic windows (VWs) of the adhesive and drug-in-adhesive films clearly depicted the effect of solubility parameter differences, molar concentration of drug in the adhesive film and differences in PSA chemistry. Conclusions Drug solubility parameters and molar drug concentrations have an impact on rheological patterns and thus on the adhesive performance of tested pressure sensitive adhesives intended for use in transdermal drug delivery systems. Use of the Flory equation in its limiting form was appropriate to predict drug solubility in the tested formulations. KEY WORDS acrylic adhesive . rheology . silicone adhesive . solubility parameter . transdermal patch H.
RESEARCH PAPER
Investigations on the Viscoelastic Performance of Pressure Sensitive Adhesives in Drug-in-Adhesive Type Transdermal Films Hans-Michael Wolff & Irsan & Kalliopi Dodou
Received: 30 August 2013 / Accepted: 28 January 2014 # The Author(s) 2014. This article is published with open access at SpringerLink.com
ABSTRACT Purpose We aimed to investigate the effect of solubility parameter and drug concentration on the rheological behaviour of drugin-adhesive films intended for transdermal application. Methods Films were prepared over a range of drug concentrations (5%, 10% and 20% w/w) using ibuprofen, benzoic acid, nicotinic acid and lidocaine as model drugs in acrylic (Duro-Tak 874287 and Duro-Tak 87900A) or silicone (Bio-PSA 7-4301 and Bio-PSA 7-4302) pressure sensitive adhesives (PSAs). Saturation status of films was determined using light microscopy. Viscoelastic parameters were measured in rheology tests at 32°C. Results Subsaturated films had lower viscoelastic moduli whereas saturated films had higher moduli than the placebo films and/or a concentration-dependent increase in their modulus. Saturation concentration of each drug in the films was reflected by decreasing/ increasing viscoelastic patterns. The viscoelastic windows (VWs) of the adhesive and drug-in-adhesive films clearly depicted the effect of solubility parameter differences, molar concentration of drug in the adhesive film and differences in PSA chemistry. Conclusions Drug solubility parameters and molar drug concentrations have an impact on rheological patterns and thus on the adhesive performance of tested pressure sensitive adhesives intended for use in transdermal drug delivery systems. Use of the Flory equation in its limiting form was appropriate to predict drug solubility in the tested formulations. KEY WORDS acrylic adhesive . rheology . silicone adhesive . solubility parameter . transdermal patch H.
