Peptide derivatives as agonists or antagonists of formylpeptide receptors: analysis of their effects on neutrophils

The effects of peptide derivatives as agonists or antagonists of formylpeptide receptors are described, taking into account the related cellular responses by neutrophils. These effects are related to the structure of peptide derivatives, some of which are potent anti HIV-1 agents. Finally, formylpeptide receptor models are depicted

Conformational studies on methionyl-containing diketopiperazines

Circular dichroism measurements on methionyl-containing diketopiperazines have shown that the thioether side chain favours the appearance of fold conformations in the ring. A solvent-dependent conformational distribution has been also found in the case of l-methionylglycine diketopiperazin

Indagini sulla possibilità di ancorare covallentemente peptidi ad un supporto solido

A new synthesis of the oxazolone of benzoil-L-phenylalanine is described. The oxazolones of two peptides, trifluoroacetyl-alanylphenylalanine and henzyloxycarbonyl-prollphenylalanylglycine, sinthesized by this procedure, are used to bond their carboxylic function to an insoluble support obtained from chlorometilated polystyrene-divinylbenzene copolymer and 2,2’,2”-triaminotriethylamine (tren)

Materie Prime: Eccipienti

Le forme farmaceutiche per la somministrazione dei farmaci contengono sostanze ausiliarie note come eccipienti, che svolgono un ruolo importante nei processi di fabbricazione, conservazione e liberazione del principio attivo

Polymeric nanoparticles as drug controlled release systems: a new formulation strategy for drugs with small or large molecular weight

We report a study evaluating the encapsulation and release modalities from poly(D,L lactic acid) (PLA) or poly(D,L-lactide-co-glicolide) (PLGA) micro- and nano-particles of the antiischemic drug N6-cyclopentyladenosine (CPA) and bovine serum albumin (BSA), chosen as protein model. The results obtained by classical preparation methods (nanoprecipitation, single or double emulsion/solvent evaporation) of the particles were compared with those obtained by their formulation with a novel method, employing a thermosensible gel of Pluronic F-127, whose aqueous solutions can be liquid when refrigerated, but gel upon warming. Our results indicate that CPA-loaded nanoparticles, obtained by classical methods, drastically reduce their drug content showing, moreover, any control of the drug release with respect to CPA-loaded microparticles. The novel preparation method allowed us to obtain, instead, CPA encapsulation values in nanoparticles similar to those obtained for microparticles, achieving also a weak control of the drug release. Any drastic reduction of BSA particle content was obtained by decreasing their size from micro- to nano-scales, independently on the employment of classical or novel preparation methods. Moreover, the size reduction induced only a weak increase of the BSA release rate. The patterns of protein released from micro- and nano-particles obtained by the same formulation method were similar. In particular, the micro- and nano-spheres prepared by double emulsion technique showed an incomplete BSA release, characterized by an elevated burst effect followed by a very slow phase. On the other hand, the release from micro- and nano-particles obtained by the novel method was complete and quite regular, being characterized by a little burst release followed by a fast phase. These results have been related to the strong BSA distribution (observed by confocal laser scanning microscope) in the surface or in the core of microparticles obtained by the classical or novel methods, respectively