Simultaneous interactions between a low molecular-weight species and two high molecular-weight species studied by diafiltration

Association Efficiency of Three Ionic Forms of Oxytetracycline to Cationic and Anionic Oil-In-Water Nanoemulsions Analyzed by Diafiltration

“…As expected, the addition 5.0, and 8.0 showed that, at the end of the process, the corresponding size and zeta potential values are conserved with maximum variations in the order of 10% comparing the values before and after diafiltering. The high affinity of the surfactants to the oil droplets may be responsible for that the presence of free surfactants in the filtrate during Blank experiments in which OTC is diafiltered in the absence of the NE O/W show that, according to the literature, 31,33,47,48 the drug does not interact with the DF system at pH 2.8 or 5.0, as the value of k m reaches 0.9 and 0.93, respectively, as can be seen in Table 2. As expected, a good linear behavior is obtained for the corresponding DF profiles, as can be seen in Figure 4.…”

“…The association of drugs to macromolecular formulations in solution may be taken in a wide sense, comprising thermodynamically bound and kinetically bound molecules. 31,48,50,62 The respective molar fractions of molecules bound by each mechanism can be denoted by TB f and KB f , respectively. Thus, the drug AE, denoting the total fraction of drug bound independently of the mechanism of binding, is given by…”

“…[43][44][45] Complex mixtures are filtered through a membrane, which has pores that discriminate between species according to their molecular size. In addition, as a separation technique, DF has emerged as an effective technique to study interactions between LMWS and several macromolecular species including soluble polymers, [25][26][27][28][30][31][32][33][34][46][47][48][49][50] polymeric nanoparticles, 51,52 antibodies, 53 and food matrices, 54 among others. The membrane pore size may be chosen so that only the passage of free LMWS is allowed.…”

“…The membrane pore size may be chosen so that only the passage of free LMWS is allowed. 48 An advantage of the constant volume DF technique is that it allows differentiating kinetically controlled systems, if the release kinetics are much lower than the filtration kinetics, from thermodynamically controlled systems, if the kinetics of equilibrium are much faster than the filtration kinetics. For the latter case, a distribution constant can be calculated from the DF profiles referring the ratio of molecules free in the bulk versus those reversibly bound to the system.…”

Binding of Methylene Blue to Polyelectrolytes Containing Sulfonate Groups

“…[34][35][36][37][38] This is a separation technique that discriminates molecules as a function of their size. The rate of filtration of the LMWS can be related to the strength of its interaction with the PEL, which is unable to pass through the DF membrane.…”