Irritancy after Intradermal Injection

Intradermal tolerance of local anesthetics can be used as a screening selection criterion for finding an optimal local anesthetic. Luduena Hoppe (1952), Luduena et al. (1960) determined intradermal irritancy by the trypan blue method according to Hoppe et al. (1950). 

Albino rabbits of either sex weighing 2 to 3 kg are fastened securely in a supine position and the hair carefully clipped from the abdominal area with a fine-bladed clipper. The bare abdominal surface is marked 

The threshold concentration is taken as that concentration expressed in %, which produces no more than a mild irritation. 

Henn Brattsand (1966), using the trypan-blue test, reported that intradermal irritancy of mepivacaine in rabbits was less than with tetracaine, whether the solution contained adrenaline or not. 

Using the trypan-blue test, Luduena et al. (1972) found that racemic, (+)- and (-)-mepivacaine had the same intradermal irritancy. 

---

Briefly, the GPMT uses intradermal injection with and without FCA for induction, followed on days 5-8 by topical irritation/induction, followed by topical challenge for 24 h on days 20-22. Readings are made 24 h after removal of the challenge dose, and again after another 24 h. If the results are equivocal, the animals may be rechallenged 1 week later. 

The toxicity of palytoxin via several other routes of administration has been investigated (Table 32.7). This substance is highly toxic after intramuscular or subcutaneous injection, or following intratracheal instillation [90,96]. No toxicity was recorded after intrarectal administration of palytoxin at 10 [tg/kg [90]. Renal necrosis and pulmonary damage were recorded in animals given palytoxin intradermally [96], and local irritation and swelling, associated with edema and necrosis, were observed after both intradermal injection and percutaneous application. Severe irritation, involving ulceration and conjunctivitis, was induced by application of palytoxin to the eye [96]. 

---