Nasal formulations of ketorolac tromethamine: technological evaluation--bioavailability and tolerability in rabbits

This paper describes the development of a novel formulation of the powerful non narcotic analgesic ketorolac tromethamine. This drug is given orally three to four times/day to deliver a total of 30 to 60 mg of drug. Higher doses cannot be given orally because of gastrointestinal side effects and intramuscular injections, three times/day must then be used. The need for injections limits the drug to a clinical setting. Nasal delivery offers a method of achieving the high blood levels of repeated intramuscular injections in a formulation that can be easily applied by the patients. Four formulations were evaluated in "in vitro" and "in vivo" rabbit tests. The best formulation consisted of a 5% solution of ketorolac tromethamine containing 0.3% sodium glycocolate as a known mucosal drug absorption enhancer. Ketorolac applied in this way had a bioavailability greater than 80%. The controlled release nature of nasal delivery also doubled the drug's apparent half life. The drug formulation was stable in three-months stability tests and produced minimal nasal irritation.