Research and Development in Preventive Dentistry.
Final technical rept. 1 Jan-31 Dec 79,
ABCOR INC WILMINGTON MA BIOMEDICAL DIV
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Lidocaine hydrochloride was microencapsulated in a biodegradable polymer, polyL- lactide, using an air suspension coating technique. Eight coating runs produced microcapsules of various sizes and polymerdrug ratios. The final run L-8 produced 50 drug microcapsules. These microcapsules of 125-149 micrometers size range, released about 50 of their drug in 2.5 hours into an agitated aqueous solution at 37deg C. Anesthesia was demonstrated using the sciatic nerve block test in the rat. Microcapsules were injected in aqueous suspensions and compared to injection of lidocaine solution. Because of problems of injecting large quantities of 125-149 micrometers suspensions, 4 lidocaine in a faster-releasing microcapsule suspension 74-105 micrometers fraction was compared to a 4 lidocaine solution. A delayed block was evident, but an increased duration was not achieved with these microcapsules at this lidocaine concentration.