title: Penetration of crystalline powder particles into excised human skin membranes and model gels from a supersonic powder injector.
abstract: The penetration of crystalline ibuprofen particles into excised human skin membranes and model target gels on actuation with the PowderJect ND1 ballistic needle-free injector has been examined. The deliverable dose of powder exiting the device is approximately 50% of the total cassette loading; the rest is lost via a gap forced open between the injector base and the surface of the target gel. It could be shown that substantial comminution of two different ibuprofen particle size fraction (38-53 microm, 53-75 microm) occurs within the injector on actuation. This resulted in an equiparation of the two initially different size fractions. Reduced comminution occurs with an ibuprofen/PVP (95:5) particulate formed by spray-drying/compaction/milling. On actuation into excised human skin membranes approximately 37% of cassette dose is recovered from the stratum corneum by stripping, and only 3% from the epidermis. It is concluded that powder delivery is mainly intra-epidermal with few particles fully breaching the stratum corneum. This is a consequence of the relative magnitude of the particle diameter (approximately 48 microm) and the stratum corneum thickness (approximately 10 microm). A 'soft' polyethylene glycol monolayer target gel gives the closest total percentage recovery of powder to that seen with the excised human skin membranes. Bilayer gels differentiated between surface impact/retention and penetration, but were difficult to handle. Powder penetration studies should therefore preferentially to be performed with human skin-membranes.
authors.affiliation: Department of Pharmaceutics, Friedrich-Alexander University, Erlangen, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Lahm
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Lee
mesh_terms: D000279:Administration, Cutaneous; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005780:Gelatin; D005782:Gels; D006801:Humans; D007052:Ibuprofen / Q000008:administration & dosage*; D066298:In Vitro Techniques; D007267:Injections / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D011092:Polyethylene Glycols; D011208:Powders; D012869:Skin Absorption
chemical_list: D005782:Gels; D011208:Powders; D011092:Polyethylene Glycols; D005780:Gelatin; D007052:Ibuprofen