Patent ID: 8334284

Claim:
A pharmaceutical composition comprising (a) a compound of the formula (I) in which R 1 is hydrogen or (C 1 -C 4 )-alkyl which may be substituted by hydroxy or (C 1 -C 4 )-alkoxy, R 2 is hydrogen or (C 1 -C 4 )-alkyl, and L is a (C 1 -C 4 )-alkanediyl group in which one CH 2 group may be replaced by an O atom, or is a group of the formula in which * means the point of linkage to the N atom, R 3 is the side group of a natural α-amino acid or its homologues or isomers, or R 3 is linked to R 1 and the two together form a (CH 2 ) 3 or (CH 2 ) 4 group, R 4 is hydrogen or methyl, R 5 is (C 1 -C 4 )-alkyl, and R 6 is hydrogen or (C 1 -C 4 )-alkyl, or a salt thereof, and (b) a pharmaceutically acceptable excipient.