title: Improved oral bioavailability of human growth hormone by a combination of liposomes containing bio-enhancers and tetraether lipids and omeprazole.
abstract: Liposomes for the oral delivery of human growth hormone (hGH) containing bio-enhancers and tetraether lipids were prepared by dual asymmetric centrifugation. Cetylpyridinium chloride (CpCl), d-α-tocopheryl polyethylene glycol 400 succinate, phenylpiperazine, sodium caprate or octadecanethiol were used as permeation enhancers. In vitro data showed that oligolamellar vesicles with average size in the range of 200-250 nm were formed. Performance of the formulations was investigated both ex vivo by confocal microscopy scans of sections of rat small intestine and in vivo by comparing the area under the plasma curve of hGH after oral or subcutaneous (s.c.) application. The microscopic data reveal an interaction between the liposomal formulation and the intestinal mucus layer. Particularly one formulation, which was designed to be mucus penetrative by addition of a high quantity of TPGS 400 and a ζ-potential close to 0 mV, showed a very strong mucus association in the duodenum and jejunum. Vesicles with CpCl 33% (mol/mol) led to a relative hGH bioavailability of 3.4% compared with s.c. control, whereas free hGH administered orally showed a bioavailability of only 0.01%.
authors.affiliation: Institute of Pharmacy and Molecular Biotechnology, Department of Pharmaceutical Technology and Biopharmacy, University of Heidelberg, Heidelberg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Parmentier
authors.affiliation: Cellnetworks, University of Heidelberg, Heidelberg, Germany.
authors.forename: Götz
authors.initials: G
authors.lastname: Hofhaus
authors.affiliation: Praxis für pädiatrische Endokrinologie and Diabetologie, Frankfurt am Main, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Thomas
authors.affiliation: Institute of Pharmacy and Molecular Biotechnology, Department of Pharmaceutical Technology and Biopharmacy, University of Heidelberg, Heidelberg, Germany.
authors.forename: Laura Clusa
authors.initials: LC
authors.lastname: Cuesta
authors.affiliation: Bernina Plus GmbH, Planegg, Germany.
authors.forename: Felix
authors.initials: F
authors.lastname: Gropp
authors.affiliation: Cellnetworks, University of Heidelberg, Heidelberg, Germany.
authors.forename: Rasmus
authors.initials: R
authors.lastname: Schröder
authors.affiliation: Praxis für pädiatrische Endokrinologie and Diabetologie, Frankfurt am Main, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Hartmann
authors.affiliation: Institute of Pharmacy and Molecular Biotechnology, Department of Pharmaceutical Technology and Biopharmacy, University of Heidelberg, Heidelberg, Germany. Electronic address: gert.fricker@uni-hd.de.
authors.forename: Gert
authors.initials: G
authors.lastname: Fricker
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004386:Duodenum / Q000378:metabolism; D019382:Human Growth Hormone / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007583:Jejunum / Q000378:metabolism; D008055:Lipids / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry* / Q000378:metabolism*; D008297:Male; D009853:Omeprazole / Q000737:chemistry* / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008055:Lipids; D008081:Liposomes; D019382:Human Growth Hormone; D009853:Omeprazole
keywords: archae; dual asymmetric centrifugation; imaging methods; lipogelosomes; liposomes; oral absorption; permeation enhancers; proteins