Baughman Jr., "Pharmacokinetic characterization of the novel pulmonary delivery excipient fumaryl diketopiperazine
," Journal of Diabetes Science and Technology, vol.
The compounds were characterized as two diketopiperazines
, cyclo-L-Ala-L-Leu (1)  and cyclo(L-Tyr-L-Pro) (2) ; two nucleosides, cordycepin (3) and Ara-A(4) .
Both natural and synthetic diketopiperazines
have a wide variety of biological activities, including antitumor  (Nicholson et al.
Preliminary synthesis experiments with further MALDITOF MS and HPLC with MS/MS analysis (ESI followed by CIS) showed that all preparations of peptides with GlyGly fragment and some with Gly-X (where X = amino acid residue with Trt side-chain protecting group, mainly N and Q) just following the (Lys-Pro) diketopiperazine
unit prepared by the standard procedure of multiple parallel peptide synthesis on pins (see Section 2 and ) contained a large portion of byproducts lacking Gly residue in this pair.
In one study, for example, an aspartame breakdown chemical called DKP (diketopiperazine
) being tested for safety was not thoroughly mixed into the test animals' food, and the animals reportedly avoided eating it.
Afrezza, MannKind Corp.'s investigational inhaled insulin with fumaryl diketopiperazine
, reaches peak plasma insulin concentrations in just 10 minutes, far faster than currently available rapid-acting insulins.
MannKind was recently faced with the challenge of scaling the manufacture of the small molecule raw material (a diketopiperazine
or DKP) used to prepare Technosphere[R] particles.
Their study reports that any form of heating of aspartame, rapidly causes the formation of diketopiperazine
(DKP) and free phenylalanine.
Kanokmedhakul S, Kanokmedhakul K, Phonkerd N, Soytong K, Kongsaeree P, Suksamrarn A (2002) Antimycobacterial Anthraquinone-Chromanone Compound and Diketopiperazine
Alkaloid from the Fungus Chaetomium globosum KMITL-N0802.
Methyl alcohol breaks down in high temperatures and becomes formaldehyde and diketopiperazine
(DKP) -- both chemicals are known to cause problems in the nervous' system.