rapid aqueous ethyl cellulose pseudo latex wurster fluid ... … · rapid aqueous ethyl cellulose...
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600 Markley StreetNorristown, PA 19401thinkoutsidethebeaker.com
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To achieve faster spray rates with aqueous ethyl cellulose (EC) pseudo latex coating systems while reducing particle to particle and equipment adhesion in a Wurster column by formulating with glyceryl mono-stearate (GMS) as a talc alternative.
Aqueous pseudo-latex coating systems coating comprising ammoniated EC dispersion applied to a multi-particulate dosage form (1mm microcrystalline cellulose placebo spheres). In addition to EC, coating systems contain plasticizer and an anti- adherent excipient (varying type and amount). The anti-adherent effectiveness of GMS was compared with an equal amount of talc (10% of the polymer solids); both formulations with triethyl citrate at 10% of polymer. GMS effectiveness was also evaluated at 2% of polymer solids. GMS was incorporated into EC formulations as a component of Plasacryl. For all experiments an initial spray rate of 15g/min to 1kg of spheres was applied to 10% weight gain. Coated spheres were evaluated by analytical sieving to quantify particle to particle adhesion. Coating was then resumed at 20g/min. Spheres were coated using a Vector fluid bed FLM1; constant equipment settings included column height and width, column gap, gun extension, air and liquid caps, degree of liquid cap protrusion, volume and temperature of process air, and atomizing air.
Ethyl cellulose being used in sustained release coatings is commonly applied at high weight gains resulting in lengthy coating runs. Multi-particulate EC coating times are typically further lengthened by slow spray rates necessary to prevent the problem of particle adhesion. This study has demonstrated that aqueous EC coating of multi-particulates may be accomplished with higher spray rates and improved quality, and while using less anti-adherent excipient, when the excipient choice is GMS over traditional
% A
gg
lom
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tion
80%
60%
40%
20%
Rapid Aqueous Ethyl Cellulose Pseudo Latex Wurster Fluid Bed Coating Using Glyceryl Mono-Stearate as a Talc-Alternative Anti-Adherent
PURPOSE
METHODS
CONCLUSIONS
RESULTS
S. P. [email protected]
N. Kirkland
C. A. Signorino, Ph.D.
Aquacoat ECD
Talc Slurry
Triethyl Citrate
Deionized Water
55.6
1.7
37.2
FormulationComponent
% ofFormula
SolidsContent
TOTAL
% TotalSolids
5.6
0%
20%100.0
30%
20%
83.3
8.3
100% 8.3
0.0
100.0
Aquacoat ECD
GMS
Triethyl Citrate
Deionized Water
59.5
1.8
38.3
FormulationComponent
% ofFormula
SolidsContent
TOTAL
% TotalSolids
0.4
0%
20%100.0
30%
100%
89.3
1.8
100% 8.9
0.0
100.0
Aquacoat ECD
GMS
Triethyl Citrate
Deionized Water
55.6
1.7
41.0
FormulationComponent
% ofFormula
SolidsContent
TOTAL
% TotalSolids
1.7
0%
20%100.0
30%
100%
83.3
8.3
100% 8.3
0.0
100.0
At 15g/min 10% talc was not effective with 15.1% particle to particle adhesion. At 20g/min talc yielded 75.1% batch agglomeration. At 15g/min 10% GMS resulted in only 1.07% adhesion. The batch with GMS at 2% of polymer solids gave the best results with 0.19% agglomeration at 15g/min and 5.7% agglomeration at 20g/min.
1.07% 0.19%
5.7%
10%20 g/min.
10%15 g/min.
10%15 g/min.
2%15 g/min.
2%20 g/min.
Talc
GMS15.1%
75.1%