RESUMO
Objective To prepare polymersomes (PSs) by block copolymers，evaluate their membrane structural stability，investigate the H+ transmembrane permeability of PSs and the impact of 1,4-dioxane and establish a foundation for drug encapsulation within polymersomes. Methods PSs were self-assembled by a block copolymer, PEG-PLGA, in a solvent solution. The pH-sensitive fluorescence probe HPTS was employed to examine the H+ transmembrane properties of PSs and compare them with PSs prepared using PBD-b-PEO, PS-b-PEO, and liposomes. The effect of varying concentrations of 1,4-dioxane on PSs’ membrane permeability properties was also investigated. Results The fluorescence excitation spectra of HPTS exhibited pH dependency, which showed a linear correlation between extravesicular H+ concentration and t1/2. Significant differences were observed in the membrane permeability capabilities of PSs with different membrane wall thicknesses. Compared to liposomes, the H+ transmembrane coefficients for the three types of PSs were reduced by 2.39×104, 3.38×104, and 5.48×108 times, respectively. 1,4-dioxane was found to modulate the permeability of PSs’ membranes, which displayed a concentration-dependent relationship. Conclusion PSs exhibited significantly lower membrane permeability compared to liposomes, indicating superior stability. 1,4-dioxane was identified as a modulator of PSs’ permeability, which offered potential for drug loading and release within PSs.
RESUMO
@#For the quality control of cetomacrogol 1000, a gas chromatographic method for the determination of residual impurities in cetomacrogol 1000, such as ethylene oxide, 1, 4-dioxane, ethylene glycol, diethylene glycol and triethylene glycol, was established and validated.The DB-1 column with headspace injection was used to detect ethylene oxide and 1, 4-dioxane with the inlet temperature of 150 °C, the FID temperature of 250 °C, the headspace equilibration temperature of 70 °C and the equilibration time of 45 min.The VF-17MS column with liquid injection was used to detect ethylene glycol, diethylene glycol and triethylene glycol with the inlet temperature of 270 °C, and the FID temperature of 290 °C.The results showed that ethylene oxide and 1,4-dioxane have a good linearity within their specified addition amount ranges (r > 0.999), with the RSD of precision of below 8.0% and the average recovery rates of 90.6% and 101.2%; and that ethylene glycol, diethylene glycol and triethylene glycol also have a good linearity between 3 ? 60 μg/mL (r > 0.999), with the RSD of precision of below 3.0%, and the recovery rates of 96% ~ 103%.The method established in this study has good specificity, linearity, precision and recovery rate, which can effectively detect the multi-component and trace impurities.
RESUMO
In this work the validity of the Jouyban-Acree and Yalkowsky-Roseman models is evaluated to correlate the solubility of indomethacin in 1,4-dioxane + water cosolvent mixtures. The solubility correlation is studied as a function of temperature and cosolvent composition. Both models require only the experimental solubility values in the pure solvents at all the temperatures evaluated. The solubility calculated values by using both models deviate notoriously from experimental values in several cases.
En este trabajo se evaluó la utilidad de los modelos Jouyban-Acree y Yalkowsky-Roseman en la correlación de la solubilidad de la indometacina en mezclas cosolventes 1,4-dioxano + agua. La correlación de la solubilidad se estudió en función de la temperatura y la composición cosolvente. Los dos modelos requieren únicamente los valores de solubilidad en los solventes puros a todas las temperaturas de interés. Los valores calculados se desvían significativamente de los experimentales en muchos casos.