Why does hyaluronidase enhance the diffusion of injected drugs?
Hyaluronidase is an enzyme that breaks down hyaluronic acid, a major component of the extracellular matrix within tissues. When injected locally, hyaluronidase enhances the diffusion and spread of drugs by temporarily degrading the structural barriers formed by hyaluronic acid.
To understand why hyaluronidase enhances drug diffusion, it's important to understand the role of hyaluronic acid in the extracellular matrix. Hyaluronic acid forms a gel-like substance that provides structural support in tissues, including spaces between cells. This gel-like structure acts as a barrier, limiting the movement of molecules, including drugs, through the tissue.
When hyaluronidase is injected, it breaks down the hyaluronic acid into smaller fragments. These fragments reduce the viscosity of the extracellular matrix, effectively "thinning out" the gel-like substance. The degraded matrix with reduced viscosity presents less resistance to the movement of fluids and molecules, thereby enhancing the diffusion of injected drugs throughout the tissue.
In summary, hyaluronidase enhances drug diffusion by breaking down the barrier created by hyaluronic acid, reducing the viscosity of the extracellular matrix and allowing injected drugs to spread more easily through the tissue.