title: Model study of the pressure build-up during subcutaneous injection.
abstract: In this study we estimate the subcutaneous tissue counter pressure during drug infusion from a series of injections of insulin in type 2 diabetic patients using a non-invasive method. We construct a model for the pressure evolution in subcutaneous tissue based on mass continuity and the flow laws of a porous medium. For equivalent injection forces we measure the change in the infusion rate between injections in air at atmospheric pressure and in tissue. From a best fit with our model, we then determine the flow permeability as well as the bulk modulus of the tissue, estimated to be of the order 10-11-10-10 m2 and 105 Pa, respectively. The permeability is in good agreement with reported values for adipose porcine tissue. We suggest our model as a general way to estimate the pressure build-up in tissue during subcutaneous injection.
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk A/S, Hillerød, Denmark.
authors.forename: Maria
authors.initials: M
authors.lastname: Thomsen
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anier
authors.initials: A
authors.lastname: Hernandez-Garcia
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Joachim
authors.initials: J
authors.lastname: Mathiesen
authors.affiliation: Novo Nordisk A/S, Hillerød, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Poulsen
authors.affiliation: Novo Nordisk A/S, Hillerød, Denmark.
authors.forename: Dan N
authors.initials: DN
authors.lastname: Sørensen
authors.affiliation: Nordsjæ llands Hospital, Hillerød, Denmark; Klinisk Epidemiologisk Afdeling, Aarhus Universitetshospital, Aarhus, Denmark; Steno Diabetes Center A/S, Gentofte, Denmark.
authors.forename: Lise
authors.initials: L
authors.lastname: Tarnow
authors.affiliation: Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Robert
authors.initials: R
authors.lastname: Feidenhans'l
mesh_terms: D000273:Adipose Tissue / Q000503:physiopathology; D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000503:physiopathology; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D007279:Injections, Subcutaneous / Q000009:adverse effects*; D007328:Insulin / Q000008:administration & dosage; D008297:Male; D010539:Permeability; D011312:Pressure; D050151:Subcutaneous Fat / Q000503:physiopathology; D040521:Subcutaneous Tissue / Q000503:physiopathology; D013552:Swine
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin