## 3 Results and Discussion
### Yield  
The product yield of the encapsulation process is a parameter that describes the amount of powder recovered in the collection vessel of the spray dryer. Encapsulation efficiency (EE%) and loading capacity (LC) depend on the amount of inhibitor in the particles. EE% is the amount of inhibitor successfully encapsulated in the polymeric matrix whereas LC (%) determines the percentage of microspheres that corresponds to the encapsulated material. Product yield (PY%), encapsulation efficiency (EE%) and loading capacity (LC) for the different spray-dried CMC.BTA microspheres are displayed in Table 4.  
The inlet temperatures determine the volatilization (evaporation) rate of the solvent. In addition, inlet temperatures should be selected according to the boiling point of the solvent as well as the glass-transition temperature of the polymeric materials to be used. To ensure timely volatilization, inlet temperatures used in spray drying are generally higher than the boiling point of the solvent [15]. Product yields, presented in Table 4, show values between 43 and 63%. These results are in accordance with results previously reported in the literature for carboxymethylcellulose microspheres and spray drying at a laboratory-scale, and therefore, are considered acceptable values [40; 41; 42]. Overall, low product yields may be a consequence of different factors, such as small volumes of liquid feed (50 mL), and the aspiration of smaller and lighter particles by the spray dryer's exhaustion system directly to the outlet filter, failing \begin{table}
\begin{tabular}{c c c c c} \hline \hline \begin{tabular}{c} **Condition** \\ **Number** \\ \end{tabular} & \begin{tabular}{c} **Outlet** \\ **Temperature (\({}^{\circ}\)C)** \\ \end{tabular} & \
\begin{tabular}{c} **Product Yield (\%)** \\ **Efficiency (\%) \({}^{\circ}\) \\ \end{tabular} &
\begin{tabular}{c} **Encapsulation** \\ **(gstra/gnicaparticle)\({}^{\circ}\)** \\ \end{tabular} \\ \hline
1 & \(86\pm 2\) & \(63.4\pm 1.4\) & \(39.0\) & \(15.6\) \\ \hline
2 & \(82\pm 2\) & \(60.3\pm 1.2\) & \(35.9\) & \(14.3\) \\ \hline
3 & \(82\pm 2\) & \(45.2\pm 1.2\) & \(36.9\) & \(14.8\) \\ \hline
4 & \(80\pm 2\) & \(60.2\pm 1.2\) & \(34.4\) & \(13.7\) \\ \hline
5 & \(106\pm 2\) & \(43.5\pm 1.5\) & \(37.6\) & \(15.0\) \\ \hline
6 & \(106\pm 2\) & \(48.5\pm 1.5\) & \(36.1\pm 0.4\) & \(14.4\pm 0.2\) \\ \hline \hline \end{tabular} \({}^{\star}\)–standard deviations obtained were very small and, therefore, do not significantly influence the values of EE% and LC%, with the exception of condition 6.  
\end{table} 
Table 4: Effect of the different spray drying conditions on the product yield and loading capacity of the CMC.BTA-MS. \begin{table}
\begin{tabular}{c c} \hline \hline \
\begin{tabular}{c} **Condition Number** \\ \end{tabular} &
\begin{tabular}{c} **Moisture Content (\%)** \\ \end{tabular} \\ \hline
1 & \(2.0\pm 0.23\) \\ \hline
2 & \(2.3\pm 0.12\) \\ \hline
3 & \(1.9\pm 0.32\) \\ \hline
4 & \(2.0\pm 0.48\) \\ \hline
5 & \(1.9\pm 0.02\) \\ \hline
6 & \(1.8\pm 0.07\) \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Moisture content of CMC.BTA-MS obtained by different spray drying conditions. to be separated in the cyclone and collected in the collection vessel [42; 43; 44]. Nevertheless, reports in the literature have shown that product yields may be influenced, among other spray drying parameters, by inlet air temperatures and compressed air-flow rates (spray flow rate) [14; 45], two parameters studied in the present work, and thus, subject to deeper assessment. According to the literature, high inlet temperatures increase the drying rate, leading to enhanced powder productivity and high yields [14]. However, an overall analysis of the obtained results suggests that an increase in inlet temperature had a detrimental effect on the product yield. An evaluation of the outlet temperatures for the different experimental conditions, may provide some insight on whether an increase in inlet temperatures negatively affects the process yield.