Regulation of the tetracycline hydrochloride release from polyacrylate microspheres. Part 1
Tsankov, S.; Lambov, N.; Minkov, E.
Die Pharmazie 47(2): 125-128
1992
ISSN/ISBN: 0031-7144 PMID: 1635920 Document Number: 401712
Due to the precipitation of free bases sparingly soluble in water, it is not possible to achieve a uniform release in the gastrointestinal tract of delayed action drugs containing salts of weak bases, e.g. tetracycline hydrochloride, at pH-values surpassing their pKa values. The problem of drug release control can be solved by adding Eudragit L to the polymetacrylate (Eudragit RS) microspheres. It has been established that 30% Eudragit L ensures a gradual uniform release of tetracycline hydrochloride (KOr = 11%/h) irrespective of variations in the pH of the gastrointestinal tract.