## 3 Results and Discussion
Shifts in the melting points were also recorded for BW down to 61.4 \({}^{\circ}\)C, 58.5 \({}^{\circ}\)C and 50.9 \({}^{\circ}\)C, and for CW down to 81.36 \({}^{\circ}\)C, 77.3 \({}^{\circ}\)C and 72.9 \({}^{\circ}\)C, when added with 10%, 25% and 50% carvacrol, respectively. The decrease in the enthalpy, which is the amount of heat involved in thermal events, was compared among the three solid lipids when increasing the concentration of carvacrol (Figure 3). When compared to pure solid lipids, the increase in the carvacrol content (10%, 25% and 50%) induced a decrease in the endothermic events related to melting and therefore the related enthalpy. [PERSON] et al. studied the influence of the loading of capric/capylic triglyceride mixtures (liquid lipid) in stearic acid matrices [37], demonstrating that the increase in melting enthalpy and crystallization was inversely proportional to the amount of oil in the formulation. A decrease in the crystallinity and melting enthalpy was observed, \begin{table}
\begin{tabular}{c c} \hline \hline
**Samples** & **1 st Loss in Mass \(\Delta\)m (\%)** \\ \hline SA 10\% & 10.40\% \\ SA 25\% & 24.44\% \\ SA 50\% & 49.48\% \\ BW 10\% & 9.66\% \\ BW 25\% & 23.74\% \\ BW 50\% & 47.84\% \\ CW 10\% & 7.82\% \\ CW 25\% & 24.20\% \\ CW 50\% & 48.07\% \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Thermogravimetric data recorded for the first mass loss of the solid lipids (SA, BW and CW) containing 10%, 25% and 50% of carvacrol (see Table 1 for composition). which translates a higher disorder of the lipid lattice [37]. Similar results were described when mixing theobroma oil and beeswax, contributing to the nanostructuring of the lipid matrix towards a greater disorder [35]. A less ordered matrix favors a higher loading capacity for active ingredients due to the increased number of voids and vacancies able to accommodate a higher number of molecules in the structure of the lattice. Due to the liquid character of carvacrol, its presence is likely to delay the complete crystalline rearrangement of the solid lipids. A depression in the melting point of the bulk solid lipids was detected upon the increased addition of carvacrol to all three solid lipids. The decrease in the melting peak (T\({}_{\text{peak}}\)), onset temperature,  
Figure 3: Variation of the enthalpy of stearic acid (SA), beeswax (BW) and carnauba wax (CW) with the increased concentration of carvacrol (%, w/w) in each binary mixture. Figure 2: Differential scanning calorimetry curves of the stearic acid (left, SA), beeswax (middle, BW) and carnauba wax (right, CW), in comparison to their binary mixtures containing 10%, 25% and 50% of carvacrol (see Table 1 for composition). enthalpy and the increase in the width of the melting event (WME) of SA, BW and CW when 10%, 25% and 50% of carvacrol was added to the solid lipids demonstrates that monoterne is miscible in the tested concentration range with the three solid lipids (Table 3). [PERSON] et al. [44] has reported similar results for the adding of Transcutot(r) HP up to 20% (w/w) to the solid lipid Precirol(r) ATO 5. The same samples were also analyzed by SAXS, for the recording of the polymorphic changes of the bulk solid lipid with the addition of 10%, 25% and 50% of carvacrol (Figure 4). Bulk SA showed five peaks at \(q\) (nm\({}^{-1}\)) of 1.27, 1.53, 2.25, 3.06 and 3.84, which are typical of highly ordered materials (Figure 4, upper left). Both waves (BW and CW) exhibited peaks with a periodicity, typical of lamellar structures (1:2:3:4...) [49]. With the increasing concentration of carvacrol, some peaks disappeared and/or had lower intensity of some of the solid lipid characteristic peaks, suggesting that monoterne decreased the structure ordering of the bulks, confirming the DSC results [43]. [PERSON] et al. also reported a lamellar crystal arrangement for beeswax [35]. Figure 5 shows the lattice spacing \"\(d\)\" as a function of carvacrol concentration [50]. Lattice spacing \"\(d\)\" was determined using the equation \(d=\leavevmode\
obreak\ 2\pi/q\).