Friction

Jones DS, Garvin CP, Gorman SP (2001)
Design of a simulated urethra model for the quantitative assessment of urinary catheter lubricity
Evidence of lower insertion/withdrawal friction of hydrophilic coated catheters.
In vitro study on LoFric and other hydrophilic catheters.

Lundgren J, Bengtsson O, Israelsson A, Jonsson AC, Lindh AS, Utas J (2000)
The importance of osmolality for intermittent catheterisation of the urethra
Evidence of lower friction and less epithelial cell damage with high osmolality associated with the LoFric catheter.
Histology study in rabbit.

Waller L, Telander M, Sullivan L (1997)
The importance of osmolality in hydrophilic urethral catheters: a crossover study
Provides evidence that physiological osmolality of the hydrophilic catheter coating results in less sticking and lower withdrawal friction. For example, 3 incidents of sticking were observed in 2 patients among LoFric users while 42 incidents of sticking were observed in 9 patients among users of other hydrophilic catheter.
Cross-over study on LoFric and other hydrophilic catheter in 14 users.