CONTROLLED RELEASE COMPOSITION AND METHOD
In one aspect, the present invention is directed to a method of making a controlled release solid dosage form having an ethylcellulose coating layer, which layer comprises a coalescing agent which is an organic ester having an HLB Value of from 3 to 8. The use of such coalescing agent permits the formation of an effective controlled release coating without the need for a further curing step after the coating process. In other aspects, this invention relates to an aqueous dispersion useful in such method; as well as to the coated dosage form produced.
1 . A method of making a controlled release solid dosage form, wherein:
the process comprises applying an aqueous suspension to a solid core to form a coating; comprising
the aqueous suspension comprises:
(i) water;
(ii) 20-40% by weight ethylcellulose;
(iii) 0.2-2% by weight of an anionic surfactant; and
(iv) a coalescing agent, wherein:
the coalescing agent is an organic ester comprising a C 5 -C 17 saturated or unsaturated aliphatic hydrocarbon moiety,
the coalescing agent has an HLB value of from 3 to 8,
the organic ester is selected from sorbitan esters and propylene glycol monoesters, and
the coalescing agent is present in the aqueous suspension in an amount that is equal to 4-30% by weight of the amount of ethylcellulose present in the aqueous suspension; and
the solid core comprises an active ingredient.
2 . The method of claim 1 wherein the coalescing agent has an HLB Value of from 3.5 to 7.
3 . The method of claim 2 wherein the coalescing agent has an HLB Value of from 4 to 5.
4 - 5 . (canceled)
6 . The method of claim 1 wherein the coalescing agent is selected from the group consisting of propylene glycol monolaurate and sorbitan monooleate.
7 - 8 . (canceled)
9 . The method of claim 1 wherein the surfactant is an alkyl sulfate.
10 . The method of claim 9 wherein the surfactant is sodium lauryl sulfate.
11 . The method of claim 1 wherein the aqueous suspension further comprises a plasticizer.
12 . The method of claim 11 wherein the plasticizer is selected from the group consisting of dibutyl sebacate, diethyl phthalate, triethyl citrate, tributyl citrate, polyethylene glycol, propylene glycol and triacetin.
13 . A solid dosage form produced by the method of claim 1 .
14 . An aqueous suspension composition suitable for producing a controlled release coating, wherein the composition comprises:
a) water;
b) 20-40% by weight ethylcellulose;
c) 0.2-2% by weight of an anionic surfactant; and
d) a coalescing agent, wherein:
the coalescing agent is an organic ester comprising a C 5 -C 17 saturated or unsaturated aliphatic hydrocarbon moiety,
the coalescing agent has an HLB value of from 3 to 8,
the organic ester is selected from sorbitan esters and propylene glycol monoesters, and
the coalescing agent is present in the aqueous suspension in an amount that is equal to 4-30% by weight of the amount of ethylcellulose present in the aqueous suspension.
15 . The composition of claim 14 wherein the coalescing agent has an HLB Value of from 3.5 to 7.
16 . The composition of claim 15 wherein the coalescing agent has an HLB Value of from 4 to 5.
17 - 18 . (canceled)
19 . The composition of claim 14 wherein the coalescing agent is selected from the group consisting of propylene glycol monolaurate and sorbitan monooleate.
20 - 21 . (canceled)
22 . The composition of claim 14 wherein the aqueous suspension further comprises a plasticizer.
23 . The method of claim 1 , wherein no curing step is applied to the coating.
24 . The method of claim 1 , wherein the coalescing agent is present in the aqueous suspension in an amount that is equal to 9-15% by weight of the amount of ethylcellulose present in the aqueous suspension.
25 . The method of claim 1 , wherein the coating has a thickness of 50-250 μm.
26 . The composition of claim 14 , wherein the coalescing agent is present in the aqueous suspension in an amount that is equal to 9-15% by weight of the amount of ethylcellulose present in the aqueous suspension.