title: Determination of optimal combination of surfactants in creams using rheology measurements.
abstract: The effect of surfactant on the rheological properties of some cream formulations was studied. Two surfactants from two different series were combined to determine the combination which yielded the most viscoelastic structure for creams. The surfactants were the soybean derivatives soya sterol, polyethylene glycol 10 soya sterol and polyethylene glycol 25 soya sterol and the sorbitol derivatives sorbitan monooleate and sorbitan trioleate. The rheological properties of the creams were studied using oscillation stress sweep, oscillation frequency sweep and viscosity tests. Droplet size distribution and conductivity of the creams were also determined. The combination polyethylene glycol 10 soya sterol and sorbitan trioleate yielded the most viscoelastic structure with linearly viscoelastic behaviour.
authors.affiliation: Pharmaceutical Operations, Orion Corporation Orion Pharma, PO Box 425, FIN-20101, Turku, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Korhonen
authors.forename: H
authors.initials: H
authors.lastname: Niskanen
authors.forename: J
authors.initials: J
authors.lastname: Kiesvaara
authors.forename: J
authors.initials: J
authors.lastname: Yliruusi
mesh_terms: D004553:Electric Conductivity; D005079:Excipients; D006860:Hydrogen Bonding; D009824:Ointments / Q000737:chemistry*; D010316:Particle Size; D012212:Rheology / Q000379:methods*; D013501:Surface-Active Agents / Q000737:chemistry*; D014783:Viscosity
chemical_list: D005079:Excipients; D009824:Ointments; D013501:Surface-Active Agents