Doxorubicin chemomyectomy: injection of monkey orbicularis oculi results in selective muscle injury.

Doxorubicin was injected into the preseptal portion of the orbicularis oculi of one lower eyelid in each of two cynomolgus monkeys at a dose of 2 mg. One monkey was observed for 4 days and the other for 68 days after doxorubicin injection. Although some skin ulceration was seen, it was completely healed by 3 weeks postinjection. The preseptal portion of the orbicularis oculi in both monkeys showed extensive signs of injury. At 4 days after doxorubicin injection many necrotic muscle fibers could be seen. Very few muscle fibers in the preseptal portion of the muscle remained by 68 days after injection. The pretarsal portion of the injected orbicularis oculi was relatively normal, with little evidence of injury. It appears that doxorubicin injection into the lower lid resulted in a gradient of muscle injury, with increasing severity at decreasing distances from the injection site. The extent of muscle injured is related to the dose and injection site and indicates the ability to selectively control the injury within a muscle. The ramifications of this effect on the use of doxorubicin for permanent treatment of blepharospasm and other related diseases are discussed in this first report of the injection of this drug into the eyelids of nonhuman primates.