Résumé
Nanocapsuling organophosphorus hydrolase (OPH) is a promising strategy, which can improve OPH stability and put it into practical application. Nanocapsule can protect OPH from deactivation, but on the other hand it may block the contact of enzymes and substrates to some extent. Thus, it is worth exploring the influences of nanocapsule density on the enzyme activity and stability. In this study, OPH surface was modified by N-acryloxysuccinimide (NAS), and then the in situ radical polymerization technique was applied to construct a polymer shell around the surface to form the OPH nanocapsule (nOPH). Transmission electron microscope (TEM) and Fourier Transform Infrared (FTIR) was used to characterize the structure of nOPH. The nOPH activity is not influenced by the presence of nanocapsule when the feed ratio of NAS to OPH is below 75. On the contrary, it decreases with the increasing of NAS feed ratio when it is above 75. Furthermore, nOPH activities at high temperatures and in 20% DMSO solutions both first increase and then decrease with the increasing of NAS feed ratio. The results showed that the appropriate density of the nanocapsule could retain the enzyme activity to the maximum extent during the preparation of nOPH nanocapsule, and significantly improve its thermal stability and organic solvent stability. Hence, the results are of great significance to further realize the OPH practical application.
Résumé
Microporous materials can provide interesting tools for different goals from bioimaging to the delivery ofbioactive molecules. In this study, the procedure based on cryo-approaches was designed to formulate thenanoparticles of natural clinoptilolite from the Zeolites mineral family. Applying scanning electron microscopy,clinoptilolite samples were imaged. After aging in the ethanol solution of phosphatidylcholine (lecithin),nanoparticles were encapsulated in the lecithin envelope. The adsorption of lecithin by clinoptilolitenanoparticles was studied by registering the diminution of optical density (OD 235) for ethanol/lecithin solutionat 235 nm with UV spectrometry. The kinetics of lecithin/clinoptilolite complex development was shown toexhibit intricate behavior, when the adsorption of lecithin was followed with its gradual release resulting in theincrease of lecithin content in ethanol solution back toward the original level. The size distribution for thelecithin/clinoptilolite complex was determined with a dynamic light scattering technique. To our knowledge,there are no reports of natural clinoptilolite-based platforms that were used as the for a nanosized capsule withphospholipids shell.
Résumé
Objective To investigate the effect of protamine(PS)coated polylactic acid(PLA)nanocapsule on the immune response of murine bone marrow-derived dendritic cells(BMDCs).Methods PLA nanocapsules were prepared by W1/O/W2 method.Protamine was used to modify the surface of PLA nanocapsule that encapsulated ovalbumin(OVA),a model anti-gen.The prepared OVA/PLA/PS nanocapsules were used to stimulate BMDCs.Flow cytometry was used to analyze the ex-pression of surface molecules CD80,CD83,CD86,MHCⅠ,and MHC Ⅱ,and the uptake of nanocapsule.The levels of IL-12 p70 secreted by BMDCs were detected by ELISA.Results OVA/PLA/PS nanocapsules could significantly up-regulate the expres-sion of CD80,CD83,MHCⅠ,and MHC Ⅱ in BMDCs,and increase the secretion of IL-12 p70 by BMDCs.Furthermore,OVA/PLA/PS nanocapsules could enhance the uptake efficiency of OVA by BMDCs.Conclusion OVA/PLA/PS nanocapsule can en-hance the immune response of BMDCs,and may become a good drug delivery carrier.
Résumé
OBJECTIVE: To investigate the pharmacokinetics and bioequivalence of hyaluronic acid-graft-poly(ethylene glycol)/α-cyclodextrin nanocapsules loaded with asparaginase (AHAPs) in SD rats. METHODS: Rats were randomly divided into two groups. After intravenous injecting AHAPs and free AN, the activity of AN in two groups was assayed at different time points. The pharmacokinetic parameters were calculated by software DAS2.1.1 and the bioequivalence of free AN and AHAPs was judged. RESULTS: AUC0-48 h of AHAPs and free AN were (132.26±1.59) and (46.38±1.98) U·h·mL-1. MRT0-48 h, of AHAPs and free AN were (3.64±0.04) and (1.76±5.99) h. The tmax of AHAPs and free AN were (0.75±0) and (0.08±0) h, respectively. The results showed that AUC0-48 h, MRT0-48 h and tmax of AHAPs increased to 2.85, 2.07 and 9.37 times, respectively, as compared with free AN. The 90% confidential intervals of AUC0-48 h, AUC0-∞ and ρmax of tested formulation were 77.0%-78.5%, 77.0%-78.5%, 94.4%-96.0%, respectively. The tmax checked by nonparametric method has significant difference (P<0.05) between AHAPs and free AN. CONCLUSION: AHAPs can improve the bioavailability and extend the action time of AN in rats. AHAPs and free AN were not bioequivalent. And AHAPs had better pharmacokinetics properties in rats.
Résumé
abstract A simple stability-indicating RP-HPLC/UV method was validated for determination of beclomethasone dipropionate (BD) in nanocapsule suspensions. Chromatographic conditions consisted of a RP C18column (250 mm x 4.60 mm, 5 µm, 110 Å), using methanol and water (85:15 v/v) as mobile phase at 1.0 mL/min with UV detection at 254 nm. The calibration curve was found to be linear in the concentration range of 5.0-25.0 µg/mL with a correlation coefficient > 0.999. Precision was demonstrated by a relative standard deviation lower than 2.0%. Accuracy was assessed by the recovery test of BD from nanocapsules (98.03% to 100.35%). Specificity showed no interference from the components of nanocapsules or from the degradation products derived from acid, basic and photolytic conditions. In conclusion, the method is suitable to be applied to assay BD in bulk drug and in nanocapsules, and it can be employed to study stability and degradation kinetics.
resumo Um método simples de CLAE-FR/UV indicativo de estabilidade foi validado para a determinação do dipropionato de beclometasona (BD) em suspensões de nanocápsulas. As condições cromatográficas foram: coluna C18 fase reversa (250 mm x 4,60 mm, 5 µm, 110 Å), usando como fase móvel metanol e água (85:15 v/v) a 1,0 mL/min, com detecção UV a 254 nm. A curva de calibração foi linear no intervalo de 5,0-25,0 µg/mL com coeficiente de correlação >0,999. A precisão foi demonstrada por um desvio padrão relativo menor que 2,0%. A exatidão foi avaliada pelo teste de recuperação do BD a partir das nanocápsulas (98,03% a 100,35%). O teste de especificidade não mostrou interferência dos componentes das nanocápsulas e nem dos produtos de degradação derivados de condições ácidas, básicas e fotolíticas. Em conclusão, o método é adequado para ser aplicado na avaliação do BD puro e em nanocápsulas e pode ser empregado para o estudo de estabilidade e degradação cinética.