title: Coated minispheres of salmon calcitonin target rat intestinal regions to achieve systemic bioavailability: Comparison between intestinal instillation and oral gavage.
abstract: Achieving oral peptide delivery is an elusive challenge. Emulsion-based minispheres of salmon calcitonin (sCT) were synthesized using single multiple pill (SmPill®) technology incorporating the permeation enhancers (PEs): sodium taurodeoxycholate (NaTDC), sodium caprate (C10), or coco-glucoside (CG), or the pH acidifier, citric acid (CA). Minispheres were coated with an outer layer of Eudragit® L30 D-55 (designed for jejunal release) or Surelease®/Pectin (designed for colonic release). The process was mild and in vitro biological activity of sCT was retained upon release from minispheres stored up to 4months. In vitro release profiles suggested that sCT was released from minispheres by diffusion through coatings due to swelling of gelatin and the polymeric matrix upon contact with PBS at pH6.8. X-ray analysis confirmed that coated minispheres dissolved at the intended intestinal region of rats following oral gavage. Uncoated minispheres at a dose of ~2000I.U.sCT/kg were administered to rats by intra-jejunal (i.j.) or intra-colonic (i.c.) instillation and caused hypocalcaemia. Notable sCT absolute bioavailability (F) values were: 5.5% from minispheres containing NaTDC (i.j), 17.3% with CG (i.c.) and 18.2% with C10 (i.c.). Coated minispheres administered by oral gavage at threefold higher doses also induced hypocalcaemia. A highly competitive F value of 2.7% was obtained for orally-administered sCT-minispheres containing CG (45μmol/kg) and coated with Eudragit®. In conclusion, the SmPill® technology is a potential dosage form for several peptides when formulated with PEs and coated for regional delivery. PK data from instillations over-estimates oral bioavailability and poorly predicts rank ordering of formulations.
authors.affiliation: UCD School of Veterinary Science and UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland; Sigmoid Pharma, Dublin City University, Invent Centre, Dublin 9, Ireland.
authors.forename: Tanira A S
authors.initials: TAS
authors.lastname: Aguirre
authors.affiliation: Sigmoid Pharma, Dublin City University, Invent Centre, Dublin 9, Ireland.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Aversa
authors.affiliation: Sigmoid Pharma, Dublin City University, Invent Centre, Dublin 9, Ireland.
authors.forename: Mónica
authors.initials: M
authors.lastname: Rosa
authors.affiliation: Programa de pós Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Sílvia S
authors.initials: SS
authors.lastname: Guterres
authors.affiliation: Programa de pós Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Departamento de Química Orgânica, Instituto de Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
authors.forename: Adriana R
authors.initials: AR
authors.lastname: Pohlmann
authors.affiliation: Sigmoid Pharma, Dublin City University, Invent Centre, Dublin 9, Ireland.
authors.forename: Ivan
authors.initials: I
authors.lastname: Coulter
authors.affiliation: UCD School of Veterinary Science and UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland. Electronic address: david.brayden@ucd.ie.
authors.forename: David J
authors.initials: DJ
authors.lastname: Brayden
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D050071:Bone Density Conservation Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D002116:Calcitonin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D045744:Cell Line, Tumor; D019343:Citric Acid / Q000737:chemistry; D003652:Decanoic Acids / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry; D005960:Glucosides / Q000737:chemistry; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D014677:Pharmaceutical Vehicles / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D013657:Taurodeoxycholic Acid / Q000737:chemistry
chemical_list: D050071:Bone Density Conservation Agents; D003652:Decanoic Acids; D004655:Emulsions; D005960:Glucosides; D014677:Pharmaceutical Vehicles; D011109:Polymethacrylic Acids; C038300:methylmethacrylate-methacrylic acid copolymer; D019343:Citric Acid; C031071:decanoic acid; D013657:Taurodeoxycholic Acid; C028815:salmon calcitonin; D002116:Calcitonin
keywords: Intestinal permeation enhancers; Oil and water emulsions; Oral bioavailability; Oral peptide and protein delivery; Salmon calcitonin