In vivo coefficient of kinetic friction: study of urinary catheter biocompatibility.

An animal model was developed to measure objectively the in vivo intrinsic coefficient of kinetic friction (COFk) of various catheter materials. Uncoated red rubber catheters had the highest COFk of the three materials tested. The Biocath catheter exhibited less COFk when compared with the standard silicone catheter. Although the etiology of urethral strictures is multifactorial, better biocompatibility as measured by in vivo COFk may be an important factor in the inevitable urethral trauma and irritation associated with indwelling catheterization and possibly with postcatheterization urethral stricture formation.