[Erythromycin pharmacokinetics in children after rectal and oral administration]. / Farmakokinetika éritromitsina u detei pri rektal'nom vvedenii i prieme vnutr'.

Pharmacokinetics of erythromycin base was studied clinically in children not older than 14 years treated with new children dosage forms of the antibiotic i. e. 0.1 and 0.25 g enteric coated tablets and 0.06 and 0.125 g suppositories. It was noted that the new dosage forms were characterized by higher availability which was 2.5-3 times higher than that after using the erythromycin base tablets without the coating. Systematic increasing of erythromycin availability after the use of the rectal suppositories was observed with increasing of the children age. Absolute absorption in newborns, sucklings and children over 1 year amounted to 28, 36 and 54 per cent respectively.

[Pharmacological availability of erythromycin granules for children's use]. / Farmatsevticheskaia dostupnost' detskoi lekarstvennoi formy éritromitsina v vide granul.

Pharmaceutical availability of erythromycin granules with polymeric coating of different composition+ was studied. With an account of the ++anatomo-physiological features of a child organism and the properties of the antibiotic, acetylphthalyl cellulose in combination with hydroxypropyl methylcellulose or methyl cellulose was used as a film forming agent. The coated granules were estimated by such parameters as the time of disintegration and the rate of dissolution in various media. The results of the study showed that coating of the erythromycin granules with the film composed of acetylphthalyl cellulose and hydroxypropyl methylcellulose in the ratio of 8 to 2 provided the required protection of the antibiotic in acid media and high pharmaceutical availability of the drug.

[Effect of crystallinity on the rate of solution of oxytetracycline hydrochloride]. / Vliianie kristallichnosti na skorost' rastvoreniia oksitetratsiklina gidrokhlorida.

The crystal structure of 2 forms of oxytetracycline hydrochloride prepared with the method of crystallization from various solvents was studied. It was shown that these forms were 2 polymorphic modifications of the antibiotic with different crystal structures. The modification prepared with the method of crystallization from methanol was characterized by better dissolution in water. Its dissolution rate constant was 3 times as higher which makes this crystalline modification of oxytetracycline hydrochloride preferable for preparation of the antibiotic pharmaceutical forms with high bioavailability levels.

[Quality and stability of tetracycline tablets]. / Kachestvo i stabil'nost' tabletok tetratsiklina.

Tetracycline base tablets with dragee (sugar) and gastric soluble film coatings were investigated. Advantages of the tablets with the film coating in the main characteristics, such as bioavailability and levels of tetracycline-like admixtures were shown. The structure of the surface layer of the dragee coating was studied. It was found that the products contained in the coating and magnesium carbonate, in particular, lowered the tablet solubility.

[Comparative evaluation of methacycline hydrochloride capsules and tablets according to their dissolubility and rate of solution]. / Sravnitel'naia otsenka kapsul i tabletok metatsiklina gidrokhlorida po raspadeamosti i skorosti rastvoreniia.

Desintegration and dissolution of capsules and tablets of methacycline hydrochloride were studied. The study on solubility of methacycline hydrochliride capsules filled with methacycline granulate or powder according to the same formula showed that the rate of the antibiotic liberation from the capsules filled with the powder decreased during storage while that from the capsules filled with the granulate did not change. Investigation of the effect of the mass packing value in a drop on the antibiotic liberation from the capsules showed that an increase in the packing coefficient above 1.38 resulted in a marked decrease in the rate of methacycline liberation from the capsules filled with the granulate. No correlation between desintegration and dissolution of methacycline capsules and tablets was found.

[Bioavailability of tetracycline hydrochloride capsules (an in vivo study)]. / Biodostupnost' kapsul tetratsiklina gidrokhlorida (issledovanie in vivo).

Blood absorption of tetracycline hydrochloride of various dispersity levels from capsules containing tetracycline alone or in combination with additives, such as magnesium carbonate and calcium salts was studied on humans. It was found that higher dispersity levels of tetracycline hydrochloride powder in capsules was not accompanied by increased blood absorption of the antibiotic. Addition of magnesium carbonate and calcium salts to the antibiotic in the process of capsulation markedly retarded the blood absorption. Clear correlation between the antibiotic dissolution rate in vitro and intensity of its blood absorption in volunteers was shown.

[Effect of auxiliary substances on the bioavailability of tetracycline hydrochloride capsules (an in vitro study)]. / Vliianie vspomogatel'nykh veshchestv na biodostupnost' kapsul tetratsiklina gidrokhlorida (issledovanie in vitro).

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.

[Properties and stability of tetracycline hydrochloride tablets]. / Nekotorye svoistva i stabil'nost' tabletok tetratsiklina gidrokhlorida.

Three forms of tetracycline hydrochloride tablets were studied, i.e. the uncoated tablets, sugar-coated tablets and the tablets with gastric-soluble film coating. The film-coated tablets had advantages in the main quality characteristics, i.e. the contents of the tetracycline-like admixtures, the active substance and solubility rate. The possibility of the tablet stability investigation by the method of "accelerated aging" was shown.