Microneedles made from polycarbonate-polycarbonate/polysiloxane copolymer compositions
View Patent ↗A microneedle includes a shaft having a proximal end and a distal end and a capillary space within the shaft, the capillary space (i) connecting the proximal and distal ends or (ii) extending from the distal end of the shaft and connecting with one or more external openings positioned between the proximal end and distal end or (iii) performing the functions of both (i) and (ii). The microneedle includes a polymer mixture which includes (a) optionally polycarbonate, (b) a polycarbonate-polysiloxane copolymer and (c) a mold release agent.
1. A microneedle comprising a shaft having a proximal end and a distal end and a capillary space within said shaft, said capillary space (i) connecting said proximal and distal ends or (ii) extending from the distal end of the shaft and connecting with one or more external openings positioned between the proximal end and distal end or (iii) performing functions both (i) and (ii), said microneedle comprising a polymer mixture which comprises (a) optionally polycarbonate, (b) polycarbonate-polysiloxane copolymer, and (c) mold release agent.
2. The microneedle of claim 1 formed from a polymer mixture comprising:
from greater than 0 wt. % to about 94.9 wt. % polycarbonate;
about 5 wt. % to about 99.9 wt. % polycarbonate-polysiloxane copolymer; and
about 0.1 wt. % to about 1 wt. % mold release agent;
wherein the combined weight percent value of all components does not exceed about 100 wt. %, and wherein all weight percent values are based on the total weight of the polymer mixture.
3. The microneedle of claim 1 , wherein said polymer mixture has a melt volume flow rate (MVR) of greater than 35 cm 3 /min as measured according to ASTM 1133 at 300° C. and 1.2 kg.
4. The microneedle of claim 1 , wherein said polymer mixture has an Izod Notched Impact of at least 35 kJ/m 2 as measured at 3 mm thickness according to ISO 180-1A.
5. The microneedle of claim 1 , wherein the polycarbonate-siloxane copolymer comprises about 4 wt. % to about 97 wt. % siloxane based on the weight of the copolymer.
6. The microneedle of claim 1 , wherein said polymer mixture comprises about 70 wt. % to about 89.5 wt. % polycarbonate and about 10 to about 30 wt. % polycarbonate-siloxane copolymer.
7. The microneedle of claim 1 , wherein said polycarbonate comprises interfacial polycarbonate.
8. The microneedle of claim 1 , wherein said polycarbonate comprises melt polycarbonate.
9. The microneedle of claim 1 , wherein said mold release agent comprises one or more of pentaerythritol stearate, glycerol monostearate, a wax, polyethylene or a poly alpha olefin.
10. The microneedle of claim 1 , wherein said microneedle consists of said polymer mixture.
11. The microneedle of claim 1 , wherein said polymer mixture has a heat deflection temperature (HDT) of at least 120° C. on a 3.2 mm sample at 1.8 MPa as measured according to ISO 75A.
12. A medical device suitable for delivery of a therapeutic agent, said device comprising one or more microneedles of claim 1 .
13. A method of forming a microneedle comprising:
(a) placing a polymer mixture into a mold, said polymer mixture comprising (i) optionally polycarbonate, (ii) polycarbonate-polysiloxane copolymer and (iii) mold release agent, said polymer mixture being at a temperature such that it is flowable;
(b) allowing said polymer to solidify; and
(c) releasing the solidified polymer mixture from said mold.
14. The method of claim 13 , wherein said polymer mixture comprises:
from greater than 0 wt. % to about 94.9 wt. % polycarbonate;
about 5 wt. % to about 99.9 wt. % polycarbonate-polysiloxane copolymer; and
about 0.1 wt. % to about 1 wt. % mold release agent;
wherein the combined weight percent value of all components does not exceed about 100 wt. %, and wherein all weight percent values are based on the total weight of the polymer mixture.
15. The method of claim 13 , wherein said polymer mixture has a melt volume flow rate (MVR) of greater than 35 cm 3 /min as measured according to ASTM 1133 at 300° C. and 1.2 kg.
16. The method of claim 13 , wherein the polycarbonate-siloxane copolymer comprises about 4 wt. % to about 97 wt. % siloxane.
17. The method of claim 13 , wherein said polycarbonate comprises interfacial polycarbonate.
18. The method of claim 13 , wherein said polycarbonate comprises melt polycarbonate.
19. The method of claim 13 , wherein said mold release agent comprises one or more of pentaerythritol stearate, glycerol monostearate, polyethylene, a wax or a poly alpha olefin.
20. The method of claim 13 , wherein said polymer mixture comprises about 70 wt. % to about 89.5 wt. % polycarbonate and about 10 to about 30 wt. % polycarbonate-siloxane copolymer.