Patent GB-977516-A (GB)
Title: Coating composition
IPC: C08L29/04
Filed: 1962-06-07
Abstract: Compositions for coating tablets comprise (a) a hard wax ingredient selected from water-soluble and water-dispersible waxlike substances with a melting point of at least 45 DEG C., (b) partially hydrolysed polyvinyl acetate and (c) an organic solvent system boiling below 85 DEG C.  Specified waxlike substances are polyethylene glycol, glyceryl monostearate and diglycol stearate. The solvent system may comprise ethyl alcohol, methylene chloride, methyl ethyl ketone, acetone and mixtures thereof.  The compositions may also comprise dyes and pigments, e.g. iron oxide; water-insoluble waxes, e.g. beeswax, lanolin, stearic acid, cocoa butter and cetyl alcohol; plasticizers, e.g. castor oil, mineral oil, corn oil, sesame oil and propylene glycol; soya bean oil; surface active agents, e.g. sorbitan derivatives and sulphated fatty alcohols, and flavouring agents. Examples describe compositions comprising polyethylene glycol, partially hydrolysed polyvinyl acetate, ethanol and acetone, together with (3) castor oil, propylene glycol, sorbitan monooleate, titanium dioxide and dye, and (4) beeswax and dye.ALSO:Medicinal tablets are coated with compositions comprising (a) a hard wax ingredient selected from water-soluble and water-dispersible waxlike substances with a melting point of at least 45  DEG C., (b) partially hydrolysed polyvinyl acetate, and (c) an organic solvent system boiling below 85 DEG C.  Specified waxlike substances are polyethylene glycol, glyceryl monostearate and diglycol stearate.  The solvent system may comprise ethyl alcohol, p  methylene chloride, methyl ethyl ketone, acetone and mixtures thereof.  The compositions may also comprise dyes and pigments, e.g. iron oxide; water-insoluble waxes, e.g. beeswax, lanolin, stearic acid, cocoa butter and cetyl alcohol; plasticizers, e.g. castor oil, mineral oil, corn oil, sesame oil and propylene glycol; soya bean oil; surface active agents, e.g. sorbitan derivatives and sulphated fatty alcohols; and flavouring agents. In examples tablets are coated with compositions comprising poleythylene glycol, partially hydrolysed polyvinyl acetate, ethanol and acetone, together with (3) castor oil, propylene glycol, sorbitan monooleate, titanium dioxide and dye, and (4) beeswax and dye.  In Example (4) a columnar bed of tablets is fluidized by an upflowing stream of air into which the coating composition is atomized.ALSO:Medicinal tablets are coated with compositions comprising (a) a hard wax ingredient selected from water-soluble and water-dispersible waxlike substances with a melting point of at least 45 DEG  C.; (b) partially hydrolysed polyvinyl acetate; and (c) an organic solvent system boiling below 85 DEG  C.  Specified waxlike substances are polyethylene glycol, glyceryl monostearate and diglycol stearate.  The solvent system may comprise ethyl alcohol, methylene chloride, methyl ethyl ketone, acetone and mixtures thereof.  The compositions may also comprise dyes and pigments, e.g. iron oxide; water-insoluble waxes, e.g. beeswax, lanolin, stearic acid, cocoa butter and cetyl alcohol; plasticizers, e.g. castor oil, mineral oil, corn oil, sesame oil and propylene glycol; soya bean oil; surface active agents, e.g. sorbitan derivatives and sulphated fatty alcohols; and flavouring agents. In examples tablets are coated with compositions comprising polyethylene glycol, partially hydrolysed polyvinyl acetate, ethanol and acetone, together with (3) castor oil, propylene glycol, sorbitan mondoleate, titanium dioxide and dye, and (4) beeswax and dye.  In Example (4) a columnar bed of tablets is fluidized by an upflowing stream of air into which the coating composition is atomized.