Selectively water disintegrable materials and catheters made of such materials
Polymeric materials that are blends of polymers having differing water solubility rates are disclosed. The blends may be incorporated into at least a portion of a medical devices such as the shafts of flushable urinary catheters to provide suitable catheter stiffness/flexibility and catheter disintegration in water receptacles such as toilets. The blended material may provide the substrate of the catheter shaft or may provide one or more layers of the catheter.
1. A flushable insertable medical device comprising a shaft at least a portion of which is made of a polymeric material including a blend of polyvinyl alcohol polymers, wherein the blend consists of:
a. approximately 68 wt %-77.5 wt % of a cold-water soluble polyvinyl alcohol;
b. approximately 2.5 wt %-11 wt % of a non-cold water-soluble polyvinyl alcohol;
said polymeric material further including 15 wt %-25 wt % propylene glycol.
2. The medical device of claim 1 wherein the blend is selected to maintain the shape of the catheter while inserted.
3. The medical device of claim 1 wherein said shaft has a bending stiffness of approximately 0.68-46835 MPa mm 4 .
4. The medical device of claim 1 wherein said shaft comprises an inner layer and an outer layer wherein one of said inner and outer layers comprises said polymeric material and the other of said inner and outer layers comprises a water soluble polymer that has a water solubility rate that is different than the water solubility rate of said polymeric material.
5. The medical device of claim 1 wherein said shaft comprises an inner layer, a middle layer and an outer layer wherein at least one of said inner and outer layers comprises said polymeric material and middle said layer comprises a water-soluble polymer that has a water solubility rate that is different than the water solubility rate of said polymeric material.
6. The medical device of claim 4 further comprising an optional primer coating coated onto said outer layer.
7. The medical device of claim 1 , wherein the medical device comprises a urinary catheter.