Sucrose ester-based biocompatible microemulsions as vehicles for aceclofenac as a model drug: formulation approach using D-optimal mixture design

Alkyl polyglucoside vs. ethoxylated surfactant-based microemulsions as vehicles for two poorly water-soluble drugs: physicochemical characterization and in vivo skin performance

“…Indeed, the isotropic area was wider when a surfactant with shorter chain length was used. This is in accord with the previously reported findings (18,24) where emulsion capacity of the other sugarbased surfactants was decreased as the hydrocarbon chain length increased, i.e., the surfactant with a short chain length was able to bind more water compared to the surfactant with a longer tail. Indeed, with increasing the tail length, the flexibility of the interfacial film becomes limited, making it more rigid (18).…”

“…This is in accord with the previously reported findings (18,24) where emulsion capacity of the other sugarbased surfactants was decreased as the hydrocarbon chain length increased, i.e., the surfactant with a short chain length was able to bind more water compared to the surfactant with a longer tail. Indeed, with increasing the tail length, the flexibility of the interfacial film becomes limited, making it more rigid (18). Therefore, the chemical structure of the APGs and, consequently, chain stiffness had probably some influence on the packaging of surfactant molecules at the interface, causing the differences between the presented phase diagrams.…”

“…Therefore, the chemical structure of the APGs and, consequently, chain stiffness had probably some influence on the packaging of surfactant molecules at the interface, causing the differences between the presented phase diagrams. Although the same phenomenon, i.e., restriction of a total monophasic area by increasing the chain length, was detected for other sugar based surfactants such as sucrose esters (18,24), it should be noted that most of the aforementioned sucrose esters had the same HLB values. Hence, in our case, the observed difference in phase diagrams could not be related only to the surfactant chain length, but also to the HLB values of the selected APGs (P2000 has HLB around 13 and P810 around 15-16) (16,17) due to the different degrees of polymerization and their anomeric purity (7,8,23).…”

“…1a and b), a larger single-phase area could be expected (25). However, these findings are different from those obtained for sugar surfactants (7,18,24), making phase behavior investigation more complex. In addition, in most cases, the investigated sugar surfactants had the same head group as well as HLB values (18,24) and, hence, the phase behavior was dependent on the hydrophobic chain length only.…”

“…Polarization microscopy is a useful technique for distinguishing isotropic microemulsions from liquid-crystalline phases (8), by observing whether the sample rotates the plane of polarized light. Microemulsions, as transparent, monophasic systems, do not interfere with polarized light, so the field of the view remains dark (18).…”