Analysis of MDP

Nuclear magnetic resonance spectroscopy and mass spectrometry have been used for the analysis of MDP and its analogues, as previously discussed, and, sometimes also infra-red spectroscopy (20, 73). In this section, other analytical procedures useful in analysis and determination of physico-chemical specification of commercially available MDP will be reviewed briefly. 

The homogeneity of MDP can be checked by descending paper chromatography using w-butanol-acetic acid-water (5 1 2). ethyl acetate- 

as all the N-acetyl-muramyl-peptides, can be precipitated by addition of ether from its ethanol or methanol solution, but it occludes a considerable amount of solvent judging from elemental analysis. Repeated lyophilization allows the elimination of all traces of solvent 33). 

This review was submitted for publication in 1979. Since then a great number of new derivatives of MDP have been synthesized, proving the continuous and ever increasing interest in this field. This addendum contains bibliography published until August 1980 only the most interesting new compounds are mentioned, without details of their synthesis. 

Among many L-amino acids tested, only L-valine and L-a-amino-butyric acid can replace L-alanine in MDP to give enhanced adjuvant active analogues (76). 

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