FACTORS INFLUENCING THE INTESTINAL ABSORPTION OF CERTAIN MONOQUATERNARY ANTICHOLINERGIC COMPOUNDS WITH SPECIAL REFERENCE TO BENZOMETHAMINE [N-DIETHYLAMINOETHYL-N'-METHYL-BENZILAMIDE METHOBROMIDE (MC-3199)

¹ Department of Pharmacology, Tufts College Medical School, Boston, Massachusetts

Studies of the absorption of monoquaternary ammonium salts by using in vivo loops in the rat indicate that absorption begins almost at once, reaches a maximum rate very quickly and then rapidly decreases. The total amount absorbed ranged from 10-20 per cent at the end of 3-4 hours, and of this the major portion is absorbed within about one-half hour.

Evidence has been obtained which indicates that this poor absorption of monoquaternary ammonium compounds on oral administration is due to their positive formal charge which promotes the formation of a non-absorbable complex with mucin.