AYERST's FULL NDA FOR INDERAL ORAL SOLUTION WILL INCLUDE CLINICAL STUDY

AYERST's FULL NDA FOR INDERAL ORAL SOLUTION WILL INCLUDE CLINICAL STUDY results from tests the firm is now conducting, Ayerst said in a July 23 petition to FDA regarding approval requirements for propranolol oral solutions. Ayerst "has conducted and is currently conducting clinical studies to evaluate the safety and efficacy of an oral liquid formulation of Inderal. This data is being compiled for the filing of an original new drug application for an oral liquid Inderal formulation. It is out intention to submit this application within the immediate future. Ayerst maintained that FDA should require clinical studies demonstrating safety and efficacy as a condition of approval of any oral liquid formulation of propranolol. Clinical studies are necessary, Ayerst asserted, because the pharmacodynamic and pharmacokinetic characteristics of oral liquid propranolol differ from the solid dosage form enough to affect the safety and efficacy of the product. Because clinical studies of safety and effectiveness should be conducted, Ayerst maintained, FDA should not approve oral liquid propranolol formulations under its ANDA procedures. However, the agency has already said in response to a petition from Roxane Labs that oral liquid forms of the drug are suitable for ANDA submissions. Oral liquid forms of propranolol, Ayerst said, should be studied for safety because "it is well known that propranolol is a membrane-stabilizing agent with strong local anesthetic properties. Although residence time in the mouth, pharynx and esophagus may be short, it may be prolonged in some pediatric and geriatric patients. The solution will make contact with an extensive mucosal area and may, therefore, have significant effects on swallowing and mouth feel resulting from these properties. The incidence of nausea and/or vomiting in response to a sudden load of propranolol in solution on the stomach should also be determined," the firm maintained. Ayerst also said that "it is obvious" that a liquid propranolol product "will have substantial use in the pediatric population, particularly between the ages of newborn to six years, when tablet swallowing is problematic. Therefore, any sponsor seeking to market such an oral solution should be required to submit adequate data on the safety of propranolol in the pediatric population." Efficacy studies should be done because a liquid form of the drug "can have significantly different pharmacokinetic behavior relative to the standard Inderal tablets. More rapid absorption, beginning in the buccal mucosa, which bypasses the liver, as well as more rapid saturation of liver extracting capacity, may be expected. These differences have implications in terms of dose equivalence with Inderal tablets in the various therapeutic uses of propranolol," Ayerst declared.