as part of the invention the pharmaceutical compositions of h2 derivatives and prodrugs are also presented along with the pharmaceutically acceptable excipients the following excipients can be employed for the compound synthesis low molecular weight carboxymethylcellulose high molecular weight carboxymethylcellulose ethanol tween 20 tween 80 cremophor polyethylene glycol propylene glycol glycerol triethanolamine lactose alpha cyclodextrin beta cyclodextrin hydroxypropyl beta cyclodextrin heptakis methyl beta cyclodextrin and gamma cyclodextrin the administration of h2 derivatives or prodrugs to biological organisms is performed by any pharmaceutical route that is used and accepted for that purpose at greater than 5 u03bcg ml h2 is lethal to leishmania in less than 5 hours the in vitro effect is apparent at 30 minutes after application the parasite structure is modified such that it loses its characteristic form loses refringence becomes spherical and is incapable of multiplying h2 has a cl 50 of 2 6 u03bcm ml for the leishmania mexicana mhom mx 01 tab3 strain the mechanism of cellular damage could not be identified by means of annexin for concentrations greater than 10 u03bcg ml it is thought that a necrosis process rather than apoptosis is likely involved in comparison to other compounds with leishmanicidal activity such as meglumine antimoniate metronidazole or hydroxyurea h2 kills the total amount of parasites more quickly at up to 10 fold faster than any previously described compounds at doses that are ten fold lower or less h2 also presents activity against other protozoa including trypanosoma plasmodium entamoeba and giardia as well as metazoan parasites and microorganisms in general cytotoxicity against murine cells was not found in in vitro studies or in vivo studies using oral parenteral or dermal administration in mice the.