In a series of hydrocortisone 17-esters, hydrocortisone 17-butyrate (HC-17B) has almost optimal lipophilicity resulting in a topical effect comparable to that of the fluorinated corticosteroids as measured in the McKenzie test on the human skin. In rats its systemic effects are weak, being in the order of those of hydrocortisone. In man systemic effects have been demonstrated, but no exact comparative data are available. Important factors controlling the intensity of systemic effects are: rate of liberation into plasma from the depot in the horny layer, rate of metabolic degradation, and rate of plasma clearance. In rats the main factor seems to be rapid clearance from plasma (t1/2 = 0.5 h) by selective concentration in the liver and, to a lesser extent, in the kidneys. Rapid hydrolysis by esterases in plasma and liver plays an additional role. In man hydrolysis by esterases appears to be rather slow; the rate of clearance from plasma is still unknown, whereas the absorption from the intact skin into the blood seems to be very slow (t1/2 = 25 h).
In a series of experiments a new 5% solution of oxytetracycline (Vendarcin®) was compared with Rolitetracycline 5% and/or 2.5% without a local anesthetic when injected in animals by several topical and systemic routes of administration. These routes were: subcutaneous, intramuscular, intravenous, intra-arterial, intra-articular, intraperitoneal, intrapleural, intrathecal and subconjunctival. The primary aim of the investigation was to find out how the Vendarcin solution compared with Rolitetracycline solution in producing irritant effects at the site of injection. To try to provoke local effects in some cases rather high doses were used. This occasionally resulted in severe systemic effects. If indicated, liver and kidneys were macroscopically and microscopically examined. The findings will be discussed immediately following the description of the results of each route of administration employed. Our experiments lead to the conclusion that, in general, animal tissues tolerate 5% Vendarcin at the site of injection much better than they do 5% and/or 2.5% Rolitetracycline. Moreover, there are clear indications that the systemic toxicity of Vendarcin is also less.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.