comprised of a carrier as mentioned above and may also contain a drug substance the carrier of shell 18 may consist of several components including a thermoplastic pharmacologically acceptable solid polymer or blend of polymers that melt or soften upon heating the carrier can also contain other components such as excipients again the melting or softening temperatures must be below the degradation temperature of any of the components of shell 18 therefore the polymer or polymer blend of shell 18 must melt or soften in the range of 50 u00b0 c to 350 u00b0 c preferably in the range of 60 u00b0 c to 250 u00b0 c shell 18 may improve the surface finish of oral dosage form 10 or may delay the drug release from overlay 16 the carrier for all of the layers of oral dosage form 10 can be crystalline amorphous or a mixture of both amorphous and crystalline phases examples of suitable pharmacologically acceptable carriers for core 12 overlay 16 and shell 18 include but are not limited to cellulose ethers such as methylcellulose and ethylcellulose hydroxyalkylcelluloses such as hydroxypropylcellulose and hydroxyalkyl alkylcelluloses such as hydroxyethyl methylcellulose and hydroxypropyl methylcellulose carboxyalkylcelluloses such as carboxymethylcellulose alkali metal salts of carboxyalkylcelluloses such as carboxymethylethylcellulose carboxyalkylcellulose esters cellulose phthalates such as cellulose acetate phthalate and hydroxypropylmethylcellulose phthalate starches thermoplastic starches starch derivatives sugar alcohols such as mannitol pectines such as sodium carboxymethylamylopectine chitin derivatives such as chitosan polysaccharides such as alginic acid alkali metal and ammonium salts thereof carrageenans galactomannans tragacanth agar agar gummi arabicum guar gummi and xanthan gummi polyhydroxyalkylacrylates polyhydroxyalkylmethacrylates polyacrylates polymethacrylates eudragit types polyacrylic acids and salts thereof polymethacrylic acids and salts thereof.