Characterization of the gels
The TEM micrographs of the SP-NLC gel (Fig. 1) revealed that the SP-NLC particles were spherical in nature. The results obtained from the zetasizer (Table 2S in Supplementary materials) showed smaller particle sizes and higher zeta potential for the SP-NLC gel (239.7 ± 99.48 nm and −21.39 ± 0.051 mV) compared to that of the SP-ALC gel formulation (8093.5 ± 722.83 nm and 5.13 ± 0.05 mV; P < 0.001). SP-NLC particles showed lower polydispersity index of 0.286 ± 0.051 compared to the SP-ALC gel which was 0.951 ± 0.068. The diameters for both gels are an indication of good spreadability (between 5 and 6.5 cm) and also pH was found to be within acceptable limits (pH 4–6). Regarding the rheology, the gels exhibited non-Newtonian independent pseudoplastic and shear thinning behaviour meaning these systems have different viscosities at different shear rates (different rpm; P > 0.05). For more details on these parameters please refer to Supplementary materials in Table 2S.