title: Impact of implant composition of twin-screw extruded lipid implants on the release behavior.
abstract: The development of vaccine delivery systems that will remove or reduce the need for repeated dosing has led to the investigation of sustained release systems. In this context, the duration of antigen release is of great importance as is the requirement for concomitant adjuvant release. In this work, lipid implants consisting of cholesterol (CHOL), soybean lecithin, Dynasan 114 (D114), the model antigen ovalbumin (OVA) and the adjuvant Quil-A (QA) were produced by twin-screw extrusion. The release of antigen and adjuvant was investigated in vitro and we observed complete OVA release over a period of 7 days while QA was released in a linear fashion over a period of up to 12 days. In order to extend OVA release, lipid implants were subjected to post-extrusion curing at 45-55°C. The OVA release could be extended to up to 14 days. Furthermore the influence of the implant composition on the release of the model antigen was investigated. It was shown that the percentage of cholesterol in particular plays an important role in modulating release.
authors.affiliation: Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig-Maximilians-Universität München, Butenandtstr. 5, D-81377 Munich, Germany.
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Even
authors.affiliation: School of Pharmacy, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
authors.forename: Sharan
authors.initials: S
authors.lastname: Bobbala
authors.affiliation: School of Pharmacy, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
authors.forename: Kok Liang
authors.initials: KL
authors.lastname: Kooi
authors.affiliation: School of Pharmacy, University of Otago, PO Box 56, Dunedin 9054, New Zealand.
authors.forename: Sarah
authors.initials: S
authors.lastname: Hook
authors.affiliation: Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig-Maximilians-Universität München, Butenandtstr. 5, D-81377 Munich, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Winter
authors.affiliation: Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig-Maximilians-Universität München, Butenandtstr. 5, D-81377 Munich, Germany. Electronic address: julia.engert@cup.uni-muenchen.de.
authors.forename: Julia
authors.initials: J
authors.lastname: Engert
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D002152:Calorimetry, Differential Scanning; D002784:Cholesterol / Q000737:chemistry; D016503:Drug Delivery Systems; D004343:Drug Implants / Q000737:chemistry*; D065546:Drug Liberation; D054709:Lecithins / Q000737:chemistry; D008055:Lipids / Q000737:chemistry*; D010047:Ovalbumin / Q000008:administration & dosage*; D062605:Quillaja Saponins / Q000008:administration & dosage*; D013678:Technology, Pharmaceutical; D014280:Triglycerides / Q000737:chemistry; D014612:Vaccines / Q000008:administration & dosage*
chemical_list: D000276:Adjuvants, Immunologic; D004343:Drug Implants; D054709:Lecithins; D008055:Lipids; D062605:Quillaja Saponins; D014280:Triglycerides; D014612:Vaccines; C036694:trimyristin; C046386:Quil A; D010047:Ovalbumin; D002784:Cholesterol
keywords: Lipid implants; Ovalbumin; Quil-A; Sustained release of antigen; Twin-screw extrusion; Vaccine delivery