3.7. Preparation of OCM-CS and CS NPs The weight ratios between OCM-CS:CaCl2 and CS:TPP are critical and controls the particle size and size distribution of the nanoparticles [19, 20]. The size characteristics

have been found to affect the biological performance of NPs [34]. The changes in the PS and PI for series of OCM-CS:CaCl2 and CS:TPP weight ratios revealed that as the concentration of crosslinkers was increased, PS and PI of NPs were increased to NPs in micron range. The increase in CaCl2 and TPP concentration in the mixing ratio leads to agglomeration of OCM-CS and CS in NPs. The optimum OCM-CS:CaCl2 and CS:TPP weight ratios that resulted in particles of submicron range were found to be 4:1, Inhibitors,research,lifescience,medical 5:1, and 6:1. These ratios were loaded with 50% DRZ and NPs were studied for PS,

PI, zeta potential, and entrapment efficiency. 3.8. Particle Size and PI of NPs Particle size distribution of DRZ loaded OCM-CSNPs varied from 212.4 ± 0.79nm to 500.4 ± 11.88nm with PI varying from 0.244 ± 0.016 to 0.444 ± 0.028 as the weight ratio of OCM-CS:CaCl2 changed from 6:1 Inhibitors,research,lifescience,medical to 4:1. It was clear that Inhibitors,research,lifescience,medical by incrementing OCM-CS in the weight ratio, blank OCM-CSNPs of smaller sizes were produced (Table 4). Incorporation of the DRZ into OCM-CSNPs led to increase of their size compared with blank NPs. This could be attributed to reduction in ionic interactions between OCM-CS and CaCl2 during formation of NPs due to the positive charge induced on DRZ molecules by ionization Inhibitors,research,lifescience,medical in distilled water (pH 7) [20]. A similar trend was observed

for CSNPs (Table 5). Particle size and PI varied from 250.3 ± 2.63 to 490.9 ± 4.80 and 0.442 ± 0.030 to 0.313 ± 0.009, respectively, as the CS:TPP weight ratio of Inhibitors,research,lifescience,medical DRZ loaded CSNPs was changed from 6:1 to 4:1. Table 4 Effect of drug loading on PS and PI of OCM-CSNs. Table 5 Effect of drug loading on PS and PI of CSNs. 3.9. Zeta Potential of NPs Zeta potential values varied from −18.03 ± 0.404 to −28.57 ± 0.513 as the OCM-CS:CaCl2 weight ratio changed from 4:1 to 6:1. The negative zeta potential values for OCM-CSNPs were attributed to the presence of negatively charged carboxyl groups (COO−) [35]. When the proportion of OCM-CS in polymer: cross linker, weight ratio was high the zeta potential value was also high (Table 6). The high zeta potential value demonstrated the availability of excessive anionic charged on OCM-CSNPs. The zeta potential values in Drug_discovery all ratios indicated the moderate stability of OCM-CSNPs. In the case of CSNPs, zeta potential values were positive, indicative of protonated amino group (NH3+) of CS. CSNPs followed the similar trend that with the increase of CS in CS:TPP weight ratio the positive zeta potential also increased indicating excess of NH3+ (Table 7). Table 6 Effect of drug loading on zeta potential and EE of OCM-CSNs. Table 7 Effect of drug loading on zeta potential and EE of CSNs. 3.10.