Aquacoat ECD - Aqueous Dispersion Coating System

Introduction

Aquacoat ECD is a 30% (w/w) aqueous dispersion of
ethylcellulose (EC) polymer. EC is a hydrophobic coating
material used in a variety of coatings applications to
achieve: sustained release, taste masking and moisture
barrier/sealant.  The major advantage using Aquacoat
ECD over polymer solvent solution is its low viscosity and
non-tacky features. It make you shorten the coating time
and cut the production cost. Besides, It has been certified
as Kosher.Applications

Application of Aquacoat ECD include drug layered
nonpareils, microcrystalline cellulose beads and beads
prepared by extrusion/spheronization for sustained
release applications. Aquacoat ECD has been widely
used in pharmaceutical coating applications, typical
examples include phenylpropanolamine HCL (PPA),
conjugated estrogen, diltiazem, ibuprofen,
chlorpheniramine maleate and theophylline. It also used
as a barrier  to seal out moisture and heat and will
prevent bleed through and assist color adherence for
hard-to-coat compounds like multivitamins. A 50/50 mix of
HPMC and Aquacoat ECD gives a high level of protection
with an immediate release profile. It is also used as a
taste-masking agent for powders, granules and tablets
(including immediate release tablets!).

Specifications

Aquacoat ECD-30 percent by weight dispersion.
Total Solids- 29 - 32 %
Ethylcellulose--. 24.5 - 29.5 %
Sodium lauryl sulfate- 0.9 - 1.7 %
Cetyl alcohol--1.7 - 3.3 %
Hydrogen peroxide-< 50 ppm
Heavy metals-< 10 ppm
Total aerobic microbial count.- < 100 cfu/g
Total yeast and mold count- < 20 cfu/g
PH-. 4.0 - 7.0 pH
Viscosity- < 150 cps


General Coating Conditions

Coating Mixture:
Aquacoat ECD 425.0g (80.6%),
Plasticizer 31.6g (24% DBS NF) 19.4, Water 88 g.

Equipment: Air supension, column 100 mm bottom, Insert
50 mm, Nozzle Orifice1 mm, Partition setting 10 mm

Coating: Product charge 1 kg of 16/20 mesh size
drug-loaded beads, Coating rate 8 - 10 mL/min, Atomizing
air pressure 25 psi, Temperature, inlet 60ºC,
Temperature, outlet 39 - 41ºC, Bed temperature 32 -
35ºC, Relative humidity of inlet air 40%, Coating level
(theoretical) 10%, Drying time post coating15 min, Oven
Curing (needed for sustained release applications) 2
hours at 60ºC.

Comments

Aquacoat ECD is typically coated onto beads for
sustained release applications and the preferred
equipment is a bottom spray fluid bed coater with Wurster
insert. While, conventional coating pans can be used for
tablet coating for taste masking or as a moisture barrier.

And, usually, a 15 weight percent dispersion is
recommended. Stirring Aquacoat ECD before and during
coating is needed, because flocculation may occur.
Plasticizer should be added and allowed to mix (preferred
with a propeller blade) for at least 30 minutes before
adding any other coating ingredients. For sustained
release applications,

Aquacoat ECD is normally applied at 5-15 percent (w/w)
while for taste-masking, 1-2 percent (w/w). After coating,
the coated dosage form is required to place at 60ºC for
two hours for curing (complete the firm formation).

OTHER COATING SYSTEMS:
Enteric Coating System - Eudragit S and L
Aquacoat ECD - Aqueous Dispersion
Coating System
Formula and Process Examples       Zhion@zhion.com