| 摘要 |
<p>1494868 Methyl cellulose ether compositions DOW CHEMICAL CO 2 Dec 1975 [2 Dec 1974 1 Oct 1975] 49494/75 Heading C3F [Also in Division B8] An aqueous cellulose ether composition for preparing pharmaceutical capsules contains from 15 to 30 wt. per cent of a thermally gelling cellulose ether composition having the following characteristics: (1) a methoxy D.S. of 1À5 to 2À0 and a hydroxyalkoxy M.S. of 0À1 to 0À4; (2) a viscosity of 2-10 c.p.s. at 20‹ C. as a 2 wt. per cent aqueous solution, and a thermal gel point of 50-80‹ C.; (3) as a 15-30 wt. per cent aqueous solution at 20‹ C., a viscos.ty of 1000- 10,000 c.p.s. and with Newtonian fluid properties as defined by a power law coefficient n, of 0À9 to 1À0 at shear rates of 0À1 to 10 sec.<SP>-1</SP>; and (4) a 50 sec. gel yield strength at 65‹ C. of at least 150 dynes cm.<SP>-2</SP> as a 15-30 wt. per cent aqueous solution. The cellulose ether composition may be a blend of a methyl cellulose and a hydroxyalkyl cellulose such as hydroxy propyl methyl cellulose. Also used in the examples are ethyl hydroxyethyl cellulose, hydroxyethyl methyl cellulose and hydroxybutyl methyl cellulose. The compositions are manufactured into capsules by dipping heated metal pins into the aqueous composition, removing them and allowing the aqueous layer thereon to gel.</p> |
