Patent ID: 8497290

Claim:
A compound according to structure (I) wherein R is b.) an amino acid derivative linked through the carboxylate group selected from the group consisting of alanine and tyrosine; c.) —CH 2 —O(C═O)R 2 where R 2 is methyl, ethyl, n-propyl, isopropyl and * is in the S configuration; d.) —C(═O)R 3 , where R 3 is pyridyl and * is in the S configuration; or f.) —C(═O)(CH 2 ) x SO 3 R 4 where R 4 is hydrogen or C 1 -C 3 alkyl, x is 1 or 2 and * is in the S configuration; or a pharmaceutically acceptable salt, crystalline form, non-crystalline form, or stereoisomer thereof.