title: Effect of particle size on skin permeation and retention of piroxicam in aqueous suspension.
abstract: The effects of particle size on the skin permeation and retention of piroxicam (PXC) in an aqueous suspension were investigated. PXC particles of about 23 nm, 173 nm, and 2.1 microm in size were prepared by the cogrinding of PXC/polyvinylpyrrolidone (PVP) K12/sodium dodecyl sulfate physical mixture (mean particle size, 9.6 microm) using a vibrational rod and ball mills. Particles were stable after storage in 0.1 m acetate buffer (pH 4.5) for 24 h. The amount of PXC that permeated and was retained in hairless mouse skin increased with the reduction of particle size up to 23 nm. Amorphous PXC was formed when PXC was coground with PVP, though the amorphous formation did not affect the amount of PXC permeated. Reduction of particle size to less than 50 nm, and the subsequent increase in surface area of PXC nanocrystals appeared to affect skin permeation and retention behavior.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, Japan. moribe@p.chiba-u.ac.jp
authors.forename: Kunikazu
authors.initials: K
authors.lastname: Moribe
authors.forename: Mizuho
authors.initials: M
authors.lastname: Shibata
authors.forename: Takayuki
authors.initials: T
authors.lastname: Furuishi
authors.forename: Kenjirou
authors.initials: K
authors.lastname: Higashi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Tomono
authors.forename: Keiji
authors.initials: K
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D008297:Male; D051379:Mice; D008812:Mice, Hairless; D010316:Particle Size; D010894:Piroxicam / Q000737:chemistry* / Q000302:isolation & purification / Q000493:pharmacokinetics*; D033362:Powder Diffraction; D012869:Skin Absorption; D013535:Suspensions / Q000737:chemistry* / Q000302:isolation & purification; D014867:Water / Q000737:chemistry
chemical_list: D013535:Suspensions; D014867:Water; D010894:Piroxicam