Computational analysis and physico-chemical characterization of an inclusion compound between praziquantel and methyl-beta-cyclodextrin for use as an alternative in the treatment of schistosomiasis

Schistosomiasis is still an endemic disease in many regions, with 250 million people infected with Schistosoma and about 500,000 deaths per year. Praziquantel (PZQ) is the drug of choice for schistosomiasis treatment, however it is classified as Class II in the Biopharmaceutics Classification System, as its low solubility hinders its performance in biological systems. The use of cyclodextrins is a useful tool to increase the solubility and bioavailability of drugs. The aim of this work was to prepare an inclusion compound of PZQ and methyl-beta-cyclodextrin (MeCD), perform its physico-chemical characterization, and explore its in vitro cytotoxicity. SEM showed a change of the morphological characteristics of PZQ:MeCD crystals, and IR data supported this finding, with changes after interaction with MeCD including effects on the C-H of the aromatic ring, observed at 758 cm(-1). Differential scanning calorimetry measurements revealed that complexation occurred in a 1:1 molar ratio, as evidenced by the lack of a PZQ transition temperature after inclusion into the MeCD cavity. In solution, the PZQ UV spectrum profile in the presence of MeCD was comparable to the PZQ spectrum in a hydrophobic solvent. Phase solubility diagrams showed that there was a 5.5-fold increase in PZQ solubility, and were indicative of a type A(L) isotherm, that was used to determine an association constant (K(a)) of 140.8 M(-1). No cytotoxicity of the PZQ:MeCD inclusion compound was observed in tests using 3T3 cells. The results suggest that the association of PZQ with MeCD could be a good alternative for the treatment of schistosomiasis.

Eugenol em juvenis de tilápia do nilo: concentrações e administrações sucessivas

Several anesthetics are used in aquaculture to reduce the stress caused by management. In the field, the most common anesthetic is benzocaine, but several authors are researching about eugenol. The objective of this study were to compare the action of these drugs on the anesthetics stages and measure the effects of successive administration of eugenol on the anesthetics stages in Oreochromis niloticus. In the first test, fish (47.73 +/- 8.73 g and 14.23 +/- 0.81 cm) were subjected to five concentrations of eugenol (40, 60, 80, 100 and 120 mg L-1) and one of benzocaine (100 mg L-1). All the anesthetic concentrations tested were able to induce fish to all stages of anesthesia, and revealed an inverse relationship between the induction times and increased concentrations. The minimum concentration of eugenol to induce anesthesia was 100 mg L-1. In the second test, the juveniles (38.07 +/- 5.00 g and 12.70 +/- 0.54 cm) were exposed to concentrations of 60, 80, 100 mg L-1 of eugenol, as determined in the first test. Evaluating the differences between successive days, there was no significant difference (P > 0.05) between anesthetics stages in the concentrations of eugenol tested, suggesting that the residue of eugenol was removed from the fish in less than 24 hours.

Benzocaine and eugenol as anesthetics for Brycon hilarii

A utilização de produtos anestésicos durante práticas de manejo é frequentemente empregada, porém doses corretas de diferentes fármacos e para espécies distintas ainda estão em fases de pesquisa. O objetivo do estudo foi determinar a melhor concentração de benzocaína e eugenol para juvenis de piraputanga (B. hilarii). Foram utilizados 104 juvenis de piraputanga com peso médio de 50,04 ± 20,80 g e comprimento total médio de 16,30 ± 12,32 cm adquiridos em uma piscicultura comercial localizada na região Oeste do Estado do Paraná. O trabalho foi conduzido no Laboratório de Aquicultura do Grupo de Estudos de Manejo na Aquicultura - GEMAq da Universidade Estadual do Oeste do Paraná (UNIOESTE). Os animais foram submetidos a cinco concentrações de benzocaína (50,0; 100,0; 150,0; 200,0 e 250,0 mg L-1) e sete concentrações de eugenol (50,0; 100,0; 150,0; 200,0; 250,0; 300,0 e 350 mg L-1), para a aferição dos tempos referentes à letargia. Para a recuperação, os animais foram mantidos em aquários livre do anestésico e observado o tempo em que retornaram às atividades normais. A melhor dose de benzocaína verificada foi de 100 mg L-1, enquanto a melhor dose de eugenol foi entre 100 e 150 mg L-1.

Eugenol como anestésico para jundiá (Rhamdia voulezi) em diferentes pesos

The study aimed to find the better concentration of eugenol for anesthesia of silver catfish (Rhamdia voulezi) with different weights. Were used 240 catfish distributed in randomized blocks in factorial scheme (5x4) total 20 treatments, in others words, five different weights: 32,5; 75; 150; 300 e 450g and four eugenol concentrations: 50, 75, 100 e 125 mg.l(-1). For each treatment were used 12 fish randomly chosen and exposed individually for each concentration. After of anesthesia the fish were transferred for net-cage with 0,7m(3), being fed and observed by 96 hours for monitoring of mortality. The eugenol was efficient for anesthesia in silver catfish all concentrations and weights and after of 96 hours no mortality have been verified. At these experimental conditions the best concentration of eugenol for anesthetic inducing and recuperation of silver catfish with weight varying from 32,5 and 450 g is 50 mg.l(-1).