title: Rheological, mechanical and membrane penetration properties of novel dual drug systems for percutaneous delivery.
abstract: In this study it has been demonstrated that mixtures of two solid drugs, ibuprofen and methyl nicotinate, with different but complementary pharmacological activities and which exist as a single liquid phase over a wide composition range at skin temperature, can be formulated as o/w emulsions without the use of an additional hydrophobic carrier. These novel dual drug systems provided significantly enhanced in vitro penetration rates through a model lipophilic barrier membrane compared to conventional individual formulations of each active. Thus, for ibuprofen, drug penetration flux enhancements of three- and 10-fold were observed when compared to an aqueous ibuprofen suspension and a commercial alcohol-based ibuprofen formulation, respectively. Methyl nicotinate penetration rates were shown to be similar for aqueous gels and emulsified systems. Mechanisms explaining these observations are proposed. Novel dual drug formulations of ibuprofen and methyl nicotinate, formulated within the liquid range at skin temperature, were investigated by oscillatory rheology and texture profile analysis, demonstrating the effects of drug and viscosity enhancer concentrations, and disperse phase type upon the rheological, mechanical and drug penetration properties of these systems.
authors.affiliation: School of Pharmacy, The Queen's University of Belfast, Medical Biology Centre, 97 Lisburn Road, BT9 7BL, Belfast, UK. d.woolfson@qub.ac.uk
authors.forename: A D
authors.initials: AD
authors.lastname: Woolfson
authors.forename: R K
authors.initials: RK
authors.lastname: Malcolm
authors.forename: K
authors.initials: K
authors.lastname: Campbell
authors.forename: D S
authors.initials: DS
authors.lastname: Jones
authors.forename: J A
authors.initials: JA
authors.lastname: Russell
mesh_terms: D000287:Administration, Topical; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000737:chemistry; D002482:Cellulose / Q000031:analogs & derivatives; D004655:Emulsions; D007052:Ibuprofen / Q000008:administration & dosage* / Q000737:chemistry; D008567:Membranes, Artificial; D009539:Nicotinic Acids / Q000008:administration & dosage* / Q000737:chemistry; D012212:Rheology; D013535:Suspensions; D014783:Viscosity
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004655:Emulsions; D008567:Membranes, Artificial; D009539:Nicotinic Acids; D013535:Suspensions; C008473:methyl nicotinate; D002482:Cellulose; C002283:hydroxyethylcellulose; D007052:Ibuprofen