Preparation of ketamine tablets for treatment of patients with neuropathicpain

Ketamine is known to have distinguished analgesic effects without anestheti c when administered in a low dose. Since ketamine is not commercially avail able except injection forms, we prepared ketamine tablets for the home-care medication of patients with neuropathic pain. The direct compression or we t granulation method was employed to form 150 mg of tablets containing 50 m g of ketamine. The latter method was superior to the former one in terms of content uniformity, weight variation and disintegration tests of the table ts. Ketamine contents in the tablet prepared by the wet granulation method were unchanged for 12 weeks under the conditions of 25 degrees C and 75% re lative humidity (RH). The C-max and AUC(0-3h) values for ketamine after adm inistration of the tablet were slightly smaller than those of the syrup in a healthy volunteer. However, analgesic effects of the tablet was similar t o that of the syrup in a patient with neuropathic pain. And the tablet was also effective for another four patients with neuropathic pain. These resul ts indicate that ketamine tablets are useful for the home-care medication o f patients with neuropathic pain.