United States Patent:  6,077,540

Assignee:  Bayer Corporation (Morristown, NJ)

Filed:  August 8, 1997

This invention provides a coating composition in which the principal film former is gelatin for use in coating tablets. The gelatin coating may be used with tablets, with or without any subcoating, and may be applied using conventional equipment. For a subcoated tablet, the coating formulation contains gelatin, a surfactant and a drying agent.

SUMMARY OF THE INVENTION

The invention provides a coating composition, a tablet coated with this composition and methods of preparing the coating composition and of coating the tablet.

The coated tablet is composed of a tablet core containing active ingredients and a continuous gelatin coating contributing from about 0.5% to about 5% by weight of the tablet weight. Preferably, colored coatings, will provide a weight gain of from about 2 to about 3.5% by weight of the tablet weight; a clear coating will be in the lower range, preferably providing about 1% weight gain.

The coating composition contains gelatin, a surfactant, a drying agent and water. A plasticizer may be added to the coating composition. Fish or mammalian gelatin may be used. Preferred surfactants are sodium stearoyl lactylate, calcium stearoyl lactylate and glyceryl monostearate. Preferred drying agents are sodium, magnesium or potassium sulfates. Preferred plasticizers, when used, are propylene glycol monostearate and sodium lactate.

A preferred coating composition contains fish gelatin (from about 5 to 25% by weight), sodium stearoyl lactylate, sodium sulfate, propylene glycol monostearate in water. A particularly preferred composition also includes sodium acetate and sodium lactate.

The coating composition may be prepared generally using low shear mixing. It may be advantageous to adjust the pH of the coating composition into the basic range for some uses.

Claim 1 of 19 Claims

1. A tablet comprising:

a. a subcoated tablet core containing active medicinal or nutritional ingredients; and

b. a continuous gelatin coating on the subcoated tablet core which coating is composed of gelatin, a surfactant; and a drying agent wherein the drying agent is selected from the group consisting of sodium sulfate, magnesium sulfate and potassium sulfate.

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