Routes of administration, pharmacokinetics, dosage
The parenteral route of administration (subcutaneous, intramuscular, and intravenous) is used in malignancies and other systemic diseases, such as, for example, rheumatoid arthritis, chronic granulomatous disease, and systemic sclerosis. Intermittent injections as well as continuous infusion for several hours have been used. Taking into account the dynamics of the ligand-receptor complex, continuous and high-frequency infusions do not seem justified. The IFN
-receptor complex is internalized (see Chapter 2, Section 2.4; and Chapter 4) and new functional receptors appear on the cell membrane after 4 to 12 hours. Therefore, administration of interferon before the appearance of new receptors would be useless. In clinical trials the intermittent administration has given better results than the continuous infusion (e.g., Rinehart et al. 1986; Machida et al. 1987; Quesada et al. 1987; Takaku et al. 1987; Kobayashi and Urabe 1988; Satake et al. 1993).