Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
276 words
A sustained release diltiazem formulation for oral administration comprising a pellet substantially free of an organic acid which may have an irritating effect, the said pellet having: (a) a central inactive sphere; (b) a plurality of alternating first and second layers surrounding the sphere to form a core, the first layer comprising a water soluble pharmaceutically acceptable polymeric material and the second layer comprising diltiazem or a pharmaceutically acceptable salt thereof; and (c) an outer coating comprising first inner membrane layers applied to said core, said first inner membrane layers comprising a first water insoluble pharmaceutically acceptable polymer, and a single outer membrane forming a relatively thick and homogeneous layer surrounding said first inner membrane layers and comprising a second water insoluble pharmaceutically acceptable polymeric material different from said first water insoluble pharmaceutically acceptable polymer; the number of the first inner membrane layers and the single outer membrane being selected to be effective to permit the release of the diltiazem from the pellet at a rate allowing controlled absorption thereof over a twelve hour period following oral administration, the rate being measured in vitro as a dissolution rate of the pellet which when measured in a type 2 dissolution apparatus according to U.S. Pharmacopeia XXII substantially corresponds to the following dissolution pattern: (a) from 15 to 40% of the total diltiazem is released after 4 hours of measurement; (b) from 40 to 70% of the total diltiazem is released after 8 hours of measurement; (c) from 50 to 85% of the total diltiazem is released after 12 hours of measurement; (d) from 70 to 100% of the total diltiazem is released after 24 hours of measurement.
Claim 2
Dependent Claim
276 words
A sustained release diltiazem formulation for oral administration comprising a pellet substantially free of an organic acid which may have an irritating effect, the said pellet having: (a) a central inactive sphere; (b) a plurality of alternating first and second layers surrounding the sphere to form a core, the first layer comprising a water soluble pharmaceutically acceptable polymeric material and the second layer comprising diltiazem or a pharmaceutically acceptable salt thereof; and (c) an outer coating comprising first inner membrane layers applied to said core, said first inner membrane layers comprising a first water insoluble pharmaceutically acceptable polymer, and a single outer membrane forming a relatively thick and homogeneous layer surrounding said first inner membrane layers and comprising a second water insoluble pharmaceutically acceptable polymeric material different from said first water insoluble pharmaceutically acceptable polymer; the number of the first inner membrane layers and the single outer membrane being selected to be effective to permit the release of the diltiazem from the pellet at a rate allowing controlled absorption thereof over a twelve hour period following oral administration, the rate being measured in vitro as a dissolution rate of the pellet which when measured in a type 2 dissolution apparatus according to U.S. Pharmacopeia XXII substantially corresponds to the following dissolution pattern: (a) from 15 to 40% of the total diltiazem is released after 4 hours of measurement; (b) from 40 to 70% of the total diltiazem is released after 8 hours of measurement; (c) from 50 to 85% of the total diltiazem is released after 12 hours of measurement; (d) from 70 to 100% of the total diltiazem is released after 24 hours of measurement.
Claim 3
Dependent Claim
27 words
The formulation of claim 1 wherein the water soluble pharmaceutically acceptable polymeric material is selected from the group consisting of polyvinylpyrrolidone, polyethyleneglycol, polyvinyl alcohol and their mixtures.
Claim 4
Dependent Claim
46 words
The formulation of claim 1 wherein the first water in soluble pharmaceutically acceptable polymeric material is ethylcellulose and wherein the second water insoluble pharmaceutically acceptable polymeric material is selected from the group consisting of a copolymer of acrylic and methacrylic acid esters and cellulose acetate phthalate.
Claim 5
Dependent Claim
36 words
The formulation of claim 1 including a lubricant in said first membrane layers and in said single outer membrane, said lubricant being selected from the group consisting of talc, calcium stearate, zinc stearate and magnesium stearate.
Claim 6
Dependent Claim
13 words
The formulation of claim 1 including a plasticizer in said single outer membrane.
Claim 7
Dependent Claim
21 words
The formulation of claim 5 wherein said plasticizer is selected from the group consisting of diethylphthalate, polyethyleneglycols, dibutyl phthalate and triacetin.