RT Journal Article
SR Electronic
T1 Nonlinear Tissue Permeability Drives Tissue Pressure and Injection Distribution: A Computational Investigation of Subcutaneous Injections
JF PDA Journal of Pharmaceutical Science and Technology
JO PDA J Pharm Sci Technol
FD Parenteral Drug Association (PDA)
SP 516
OP 517
DO 10.5731/pdajpst.2024.012969
VO 78
IS 4
A1 Lovald, Scott
A1 Agarwal, Shashank
A1 Radhakrishnan, Anuradha
A1 Casey, Vincent
A1 Rau, Andrew
YR 2024
UL http://journal.pda.org/content/78/4/516.abstract
AB There is a significant opportunity to expand the understanding of subcutaneous injection mechanics with an aim to increase injectable volume while controlling tissue strain and associated subject pain. Computational modeling can evaluate the mechanics of subcutaneous injections as a supplement to experimental, animal and clinical studies. The objectives of this study are to (1) develop a computational model for subcutaneous injection in tissue, (2) investigate the influence anisotropic tissue permeability has on bolus formation, and (3) explore the effects that injection flow rate and viscosity have on injection flow and tissue strain. Poroelastic models with subsurface flow were implemented in finite element software (COMSOL, ABAQUS). Pore pressure and injectate distribution showed excellent agreement with experimental results when evaluated at multiple injection rates (20 ml/hr, 120 ml/hr and 360 ml/hr). Including the anisotropy of tissue permeability causes the injectate to preferentially spread horizontally, similar to experimentally observed bolus distributions. Cases are presented to provide additional insight into injection mechanics, including variations on the delivery rate, the injection volume, viscosity and the thickness of the subcutaneous layer. The results support the use of computational modeling as a valid tool for understanding tissue strains and injectate distributions for large volume injections.