[Effect of auxiliary substances on the bioavailability of tetracycline hydrochloride capsules (an in vitro study)].

The rate of tetracycline hydrochloride transfer into solution from capsules containing different auxiliary substances was studied. It was shown that the dispersity level of tetracycline hydrochloride powder had no significant effect on the capsule disintegration and the rate of the antibiotic transfer into solution. The effect of the auxiliary substance composition on the capsule disintegration and the rate of the antibiotic dissolution was shown. The rate of tetracycline liberation from the capsules containing tetracycline hydrochloride without additives or the antibiotic in combination with 23 per cent of lactose was 4 to 6 times higher than that from the capsules with magnesium carbonate or calcium phosphate as the auxiliary substances.