Karl H. Nollstadt

ANTIFUNGAL LIPOPEPTIDES : STRUCTURE-ACTIVITY RELATIONSHIPS OF 3-HYDROXYGLUTAMINE-MODIFIED PNEUMOCANDIN B0 DERIVATIVES

Abstract Selective methanolysis or dehydration followed by reduction of the 3-hydroxyglutamine residue of pneumocandin B0 (1) or its dideoxy analog 5 (L-692,289) gave the methyl 3-hydroxyglutamate and 3-hydroxyornithine analogs 6 and 9, respectively. Further derivatization of these analogs allowed a study of the SAR at this position. In general, carboxylic acid-containing derivatives were poorer antifungal agents than neutral derivatives while amine-bearing analogs displayed the greatest potency.

Lipopeptide antifungal agents: Amine conjugates of the semi-synthetic pneumocandins L-731,373 and L-733,560

Abstract Amine conjugates of the semi-synthetic 1,3-β-(D)-glucan synthesis inhibitors L-731,373 (3) and L-733,560 (4) were prepared and evaluated for in vitro and in vivo antifungal activity. Tricationic analogs were more potent than the dicationic which were more potent than the monocationic. The L-ornithine conjugate of 4 possessed excellent pharmacokinetic parameters but lacked sufficient antifungal spectrum for development.

Potential of the sulfobetaine detergent zwittergent 3-12 as a desorbing agent in biospecific and bioselective affinity chromatography

The isolation in our laboratories of several antigens of interest from sporulated oocysts of Eimeria species by bioselective adsorption on matrices containing immobilized antigen-specific immunoglobulins IgG was initially unsuccessful. The preparations serving as source materials for these antigens contained low levels of the zwitterionic sulfobetaine detergent, Zwittergent 3-12. Since usually immunoaffinity processes are carried out in the presence of various detergents, we were surprised, subsequently, to find this detergent to be the cause of the problem in that it prevented antigen-antibody binding. These findings led us to study the potential role of Zwittergent 3-12 as an eluting agent from matrices holding bioselectively adsorbed materials. The results of seven case studies are presented in this paper and include experiments with beta-D-galactosidase adsorbed biospecifically and bioselectively on matrices via either specific antibody or inhibitor analogue. In all cases, Zwittergent 3-12 proved to be an effective desorbing agent.