Helically-Shaped Drug Delivery System
The present invention relates to a helically-shaped medicated veterinary system suitable for delivery of a drug to the vaginal cavity of a female non-human mammal and to a method of manufacture. The drug delivery system is helically-shaped and comprises a three layered polymer fibre. The polymer fibre comprises a polymer core, a polymer intermediate layer comprising a drug, and a polymer skin. The medicated system provides a controlled delivery of drug to the vaginal cavity of the mammal. The present invention also relates to a process of making the springs.
1 - 16 . (canceled)
17 . A helically-shaped medicated veterinary system suitable for delivery of a drug to the vaginal cavity of a female non-human mammal, the system comprising a three layered polymer fibre comprising:
(a) a polymer core comprising a drug;
(b) a polymer intermediate layer comprising a drug covering the core; and
(c) a polymer skin comprising a drug covering the intermediate layer,
wherein the polymeric material in the polymer core, the polymer intermediate layer and the polymer skin comprise ethylene-vinyl acetate copolymer, and
wherein the system comprises a number of loops in the range of more than 1 to 10, and
wherein the outer dimension of the system, when inserted into the vaginal cavity, substantially coincides with the inner dimension at the cervix point of the vaginal cavity.
18 . The drug delivery system according to claim 17 , wherein the system comprises a number of loops in the range of 1.5 to 5.
19 . The drug delivery system according to claim 17 , wherein the helically-shaped system is obtainable by extrusion or by co-extrusion.
20 . The drug delivery system according to claim 17 , wherein the drug has a solubility at 37° C. greater than 0.03% w/w in a polyethylene vinyl acetate matrix containing 28% vinyl acetate by weight.
21 . The drug delivery system according to claim 17 , wherein the drug has a molecular weight of less than 900 Dalton.
22 . The drug delivery system according to claim 17 , wherein the ethylene-vinyl acetate copolymer has a vinyl acetate content of from 6% to 40%.
23 . The drug delivery system according to claim 17 , wherein the system has an efficiency in delivered drug of at least 60%.
24 . The drug delivery system according to claim 17 , wherein the drug is a steroid.
25 . The drug delivery system according to claim 17 , wherein the drug is altrenogest.
26 . A method to control reproductive function in a female non-human mammal which comprises the steps of
(i) positioning the drug delivery system of claim 25 within the vaginal tract; and
(ii) retaining the system within the vaginal tract for at least about 7 days.
27 . The method according to claim 26 to suppress oestrus in a female non-human mammal.
28 . The method according to claim 26 , wherein the mammal is a companion or farm animal.
29 . The method according to claim 28 , wherein the farm animal is a horse, a swine or a head of cattle.
30 . A method to optimize reproductive performance in a female non-human mammal which comprises the steps of
(i) positioning the drug delivery system of claim 25 within the vaginal tract; and
(ii) retaining the system within the vaginal tract for at least about 7 days.
31 . The method according to claim 30 , wherein the mammal is a companion or a farm animal.
32 . The method according to claim 30 , wherein the farm animal is a horse, a swine or a head of cattle.
33 . A method of manufacturing the three-layered drug delivery system of claim 17 comprising:
(i) producing a medicated homogenous polymer core granulate and a medicated homogenous polymer intermediate layer granulate;
(ii) co-extruding the core granulate and the intermediate layer granulate with a polymer skin granulate to form the three-layered drug delivery system.
(iii) collecting the fibre on a reel to form a helically shape and subsequently cutting the fibre to a helically-shaped spring or coiling a spring off-line from a fibre.
34 . The method according to claim 33 , wherein step (i) comprises:
(a) grounding the polymer;
(b) dry powder mixing the grounded polymer with the drug to be loaded in the intermediate layer;
(c) dry powder mixing the grounded polymer with the drug to be loaded in the core;
(d) blend extruding the resulting powder mixtures of steps (b) and (c);
(e) cutting the resulting medicated polymer strands into granules, thereby obtaining a core granulate and an intermediate layer granulate; and
(f) lubricating both core granulate and intermediate granulate with a lubricant; wherein steps (b) and (c) are interchangeable.