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 comprising applying an aqueous suspension comprising (i) water; (ii) ethylcellulose; (iii) an ionic surfactant; and (iv) a coalescing agent which is an organic ester having an HLB value of from 3 to 8; to a solid core comprising an active ingredient to form a coating.
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 . The method of claim 1 wherein said coalescing agent comprises a C 5 -C 17 saturated or unsaturated aliphatic hydrocarbon moiety.
5 . The method of claim 4 wherein the coalescing agent is selected from the group consisting of sorbitan esters and propylene glycol monoesters.
6 . The method of claim 5 wherein the coalescing agent is selected from the group consisting of propylene glycol monolaurate and sorbitan monooleate.
7 . The method of claim 1 wherein the coalescing agent is present in an amount between 4% and 30% by weight, based upon the total weight of the ethylcellulose.
8 . The method of claim 1 wherein the surfactant is an anionic surfactant.
9 . The method of claim 8 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 comprising:
a) water;
b) ethylcellulose;
c) an ionic surfactant; and
d) a coalescing agent which is an organic ester an HLB value of from 3 to 8.
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 . The composition of claim 14 wherein said coalescing agent comprises a C 5 -C 17 saturated or unsaturated aliphatic hydrocarbon moiety
18 . The composition of claim 17 wherein the coalescing agent is selected from the group consisting of sorbitan esters and propylene glycol monoesters.
19 . The composition of claim 18 wherein the coalescing agent is selected from the group consisting of propylene glycol monolaurate and sorbitan monooleate.
20 . The composition of claim 14 wherein the coalescing agent is present in an amount between 4% and 30% by weight, based upon the total weight of the ethylcellulose.
21 . The composition of claim 14 wherein the surfactant is an anionic surfactant.
22 . The composition of claim 14 wherein the aqueous suspension further comprises a plasticizer.