A magnetic nanogel based on O-carboxymethylchitosan for antitumor drug delivery: synthesis, characterization and in vitro drug release.

This paper studied the synthesis, characterization and use of the magnetic chitosan nanogel for carrying meleimidic compounds. The hydrogel polymer was prepared using O-carboxymethylchitosan, which was crosslinked with epichlorohydrin for subsequent incorporation of iron oxide magnetic nanoparticles. The characterization revealed that the magnetic material comprises about 10% of the hydrogel. This material is comprised of magnetite and maghemite and exhibits ferro-ferrimagnetic behavior. The average particle size is 4.2 nm. There was high incorporation efficiency of maleimides in the magnetic nanogel. The release was of sustained character and there was a greater release when an external magnetic field was applied. The mathematical model that best explained the process of drug release by the magnetic hydrogel was that of Peppas-Sahlin. The magnetic nanogel proved to be an excellent candidate for use in drug-delivery systems.

New antinociceptive agents related to dihydrosphingosine.

The main objective of this study was to evaluate the antinociceptive activity of three ethylenediamine derivatives and three ß-aminoethanol lipidic derivatives structurally related to dihydrosphingosine. These derivatives were selected on the basis of previous results from in vitro and in vivo anti-inflammatory studies. For all of the assayed compounds, an intraperitoneal dose of 3 mg/kg caused pronounced pain inhibition as measured by the acetic acid-induced writhing model in mice. Compounds 3 and 6 demonstrated strong antinociceptive activity at doses as low as 1 mg/kg and proved to be considerably more potent than the common nonsteroidal anti-inflammatory drugs (NSAIDs), acetylsalicylic acid (ASA) and acetaminophen (ACE). We further analyzed these compounds using the capsaicin- and glutamate-induced pain tests. Compounds 3 and 6 also exhibited considerable antinociceptive effects under these conditions, but their inhibitory effects in the formalin test were less pronounced. The exact mechanism of action for these compounds has yet to be established. However, based the results from a hot-plate test, it can be stated that these new drugs do not interact with the opioid system.

Antinociceptive activity and preliminary structure-activity relationship of chalcone-like compounds.

Chalcones belong to a class of alpha,beta,-unsaturated aromatic ketones which occur abundantly in nature, especially in plants. They are promising and interesting compounds due to their vast applications in pharmaceuticals, agriculture and industry. Several studies have shown that these compounds exert important biological activities in different experimental models. The present work deals with the antinociceptive activity, evaluated against the writhing test, of three series of chalcone-like compounds obtained by the Claisen-Schmidt condensation, using different aldehydes and substituted acetophenones. The results reveal that the compounds synthesized show a significant antinociceptive effect compared with nonsteroidal drugs such as aspirin, paracetamol and diclofenac. They also show that the electronic demand of the substituents is the dominant factor of the biological activity.

Phytochemical and antinociceptive properties of Matayba elaeagnoides Radlk. barks.

A mixture of triterpenes named lupeol (1), alpha-amyrin (2), beta-amyrin (3), and beta-sitosterol (4) has been isolated from the hexane fraction of Matayba elaeagnoides. In addition, scopoletin (5), umbelliferone (6), 3beta-O-D-glycopyranosyl-sitosterol (7) and betulin (8) were isolated from the chloroform fraction. All the structures were identified by spectroscopic techniques in accordance with literature data. The extracts (hydroalcoholic and methanolic) and some fractions (hexane, chloroform, ethyl acetate and butanol) exerted promising antinociceptive effects in mice. In addition, we have tested the pure compound betulin (8). When analyzed against induced pain using the writhing test (3-10 mg kg(-1), i.p.), betulin showed a dose-dependent effect with a calculated ID50 value of 7.74 (6.53-9.17) mg kg(-1) [17.5 (14.7-20.7) micromol kg(-1)] and a maximal inhibition (MI) of 58.3% in relation to the control group. When evaluated in the formalin test (3-10 mg kg(-1), i.p.), this compound inhibited both phases of pain (neurogenic and inflammatory pain), with calculated ID50 values of 18.3 (17.7-18.9) and 8.3 (7.7-8.9) mg kg(-1) [41.5 (38.4-42.7) and 18.8 (17.6-19.9) micromol kg(-1)] and maximal inhibition of 40.8 and 64.39% for the first and second phases, respectively. Using the same models, this compound was several times more active than two clinically used drugs, namely aspirin and paracetamol, suggesting that its main active principle is related to the antinociceptive effect found for the chloroform fraction of M. elaeagnoids barks.