Reference

Effect of hydroxyethyltheophylline (HET) on solubility and intrinsic dissolution rate of theophylline

Effect of hydroxyethyltheophylline (HET) on solubility and intrinsic dissolution rate of theophylline. Bhalla, H. L.; Lloyd, Dias (Bombay Coll. Pharm., Bombay 400 098, India). Indian Drugs, 21(8), 345-6 (English) 1984. CODEN: INDRBA. ISSN: 0019-462X. DOCUMENT TYPE: Journal CA Section: 63 (Pharmaceuticals) Hydroxyethyltheophylline (I)(HET) [519-37-9] had a marked effect on the soly. of theophylline (II) [58-55-9]. An increase of 60% in soly. was obsd. in a 2% soln. of HET, while a 4% soln. gave a soly. increase of 100%. Concns. of HET solns. above 4% did not cause such a marked increase in soly., and only a 6% increase in soly. was obsd. when the HET concn. was increased from 4 to 8%. The dissoln. rates of II pellets and their mixt. with various concns. of HET compressed at 2500 kg/cm2 were detd. A marked decrease in T60 (time for 60% dissoln.) values was obsd. up to 40% HET, while beyond this concn., there was no significant change.

Sustained-release tablets

Sustained-release tablets. Korsatko, Werner; Wabnegg, Brigitta (Chemie Linz A.-G.; Lentia G.m.b.H., Austria). Eur. Pat. Appl. EP 108882 A1 23 May 1984, 21 pp. DESIGNATED STATES: R: AT, BE, CH, DE, FR, GB, IT, LI, LU, NL, SE. (German). (European Patent Organization). CODEN: EPXXDW. CLASS: IC: A61K009-22. APPLICATION: EP 83-108864 8 Sep 1983. PRIORITY: AT 82-3791 15 Oct 1982. DOCUMENT TYPE: Patent CA Section: 63 (Pharmaceuticals) Sustained-release tablets are prepd. from at least 20% poly(D-3-hydroxybutyric acid) [29435-48-1] homogeneously mixed with the drug and direct compression. Thus, tablets prepd. from sticks of 7-hydroxyethyltheophylline [519-37-9] 56 mg and poly(D-3-hydroxybutyric acid) 14 mg/stick had a diam. of 6.0 mm and tensile strength of 64 N.