A small library of dendrimers was prepared from a common precursor that is available in 5 g scale in five linear steps at 56% overall yield. The precursor is a generation three dendrimer that displays 48 peripheral sites by incorporating AB4 surface groups. Manipulation of these sites provided six dendrimers that vary in the chemistry of the surface group (amine, guanidine, carboxylate, sulfonate, phosphonate, and PEGylated) that were evaluated for hemolytic potential and cytotoxicity. Cationic dendrimers were found to be more cytotoxic and hemolytic than anionic or PEGylated dendrimers. The PEGylated dendrimer was evaluated for acute toxicity in vivo. No toxicity--neither mortality nor abnormal blood chemistry based on blood urea nitrogen levels or alanine transaminase activity--was observed in doses up to 2.56 g/kg i.p. and 1.28 g/kg i.v.
A 17-year-old white man who showed no obvious signs of trauma was found unresponsive in bed and was pronounced dead at the scene. The decedent had a documented history of heroin abuse and chronic back pain and reportedly self-medicated with Kratom (mitragynine). The autopsy was remarkable only for pulmonary congestion and edema and a distended bladder, both of which are consistent with, though not diagnostic of, opiate use. A laboratory work-up revealed therapeutic levels of over-the-counter cold medications and benzodiazepines. However, of interest was a level of mitragynine at 0.60 mg/L. Given the facts of the case, the Medical Examiner certified the cause of death as "possible Kratom toxicity" and the manner of death was classified as "accident."
Dendrimers based on melamine can reduce the organ toxicity of solubilized cancer drugs administered by intraperitoneal injection. Methotrexate and 6-mercaptopurine, both FDA approved anticancer drugs, are known hepatotoxins. The solubility of these molecules can be increased by mixing them with a dendrimer based on melamine. C3H mice were administered subchronic doses of methotrexate or 6-mercaptopurine with and without a solubilizing dendrimer. Forty-eight hours after dosing, the mice were sacrificed and serum was collected for biochemical analyses. The levels of alanine transaminase, ALT, were used to probe liver damage. When the drugs are encapsulated by the dendrimer, a significant reduction in hepatotoxicity is observed: ALT levels from the rescued groups (drug + dendrimer) were 27% (methotrexate) and 36% (6-mercaptopurine) lower than those of animals treated with the drug alone.
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