Sigma receptor (σR) ligands have proven to be useful as cancer diagnostics and anticancer therapeutics and their ligands have been developed as molecular probes in oncology. Moreover, various σR ligands generate cancer cell death in vitro and in vivo. These σR ligands have exhibited promising results against numerous human and rodent cancers and are investigated under preclinical and clinical study trials, indicating a new category of drugs in cancer therapy.
2-{2-[3-(1-Adamantyl)-4-fluorophenyl]thiazol-4-yl}ethan-1-amine (1a) and 2-{2-[4-(1-adamantyl)phenyl]thiazol-4-yl}ethan-1-amine (2a) exhibit activity against T. brucei in the range of IC50 = 0.42 μM and IC50 = 0.80 μM, respectively.
The aim of the present investigation was to develop matrix tablet formulations for the in vitro controlled release of two new tuberculocidal adamantane aminoethers (compounds III and IV), congeneric to the adamantane derivative SQ109, which is in final clinical trials, and aminoethers (I) and (II), using carefully selected excipients, such as polyvinylpyrrolidone, sodium alginate and lactose. The tablets were prepared using the direct compression method and dissolution experiments were conducted using the US Pharmacopoeia type II apparatus (paddle method) in gastric and intestinal fluids. The results suggest that both analogues, albeit more lipophilic than SQ109, and aminoethers (I) and (II), have the requisite in vitro release characteristics for oral administration. In conclusion, these formulations merit further assessment by conducting in vivo studies, at a later stage.