*3.11. Stability*

**4. Conclusions**

*3.11. Stability* The optimized clarithromycin SLN (CL10) showed no significant variation in the drug content, particle size, or drug release after 3 months in both storage conditions (4 °C and 25 °C), as noticed in Table 9. Therefore, the stability data indicate good physical The optimized clarithromycin SLN (CL10) showed no significant variation in the drug content, particle size, or drug release after 3 months in both storage conditions (4 ◦C and 25 ◦C), as noticed in Table 9. Therefore, the stability data indicate good physical stability of the prepared SLNs during their storage at 4 ◦C and 25 ◦C for 3 months.

stability of the prepared SLNs during their storage at 4 °C and 25 °C for 3 months.

Drug content (%) 97.6 ± 4.9 95.8 ± 4.6 Particle size (nm) 165 ± 54.6 172 ± 61.5 In vitro drug release (%) 88.8 ± 7.1 86.3 ± 5.0

The solubility of clarithromycin in various lipid and surfactants was studied, and based on solubility criteria, stearic acid (lipid), Tween 80 (nonionic surfactant), and Transcutol P (cosurfactant) were selected for the preparation of SLNs. Initial fractional factorial design suggests that the sonication time and amount of lipid significantly influence the SLN formulation. Further, 32 full factorial design data also confirms that both the factors significantly affect the particle size, drug entrapment efficiency, and drug loading. The drug content and entrapment efficiency of SLNs were enhanced by increasing the concentration of lipid since higher hydrophobicity of the longer chain of stearic acid resulted in a high‐loaded clarithromycin. Ex vivo permeation and in vivo pharmacokinetics data signify greater efficacy by the optimized clarithromycin‐loaded SLN (CL10). Indeed, the clarithromycin observed in the aqueous humor was significantly higher than the minimum effective concentration of clarithromycin in bacterial endophthalmitis. Further, the topical ocular therapy of clarithromycin could be more advantageous than its oral counterpart because topical administration could minimize the side effects as well as diminish the possibility of producing resistant strains of bacteria.

**Table 9.** Stability data of optimized solid lipid nanoparticle batch (CL10) after 3 months.

All values are expressed as mean ± S.D; *n* = 6.


**Table 9.** Stability data of optimized solid lipid nanoparticle batch (CL10) after 3 months.

All values are expressed as mean ± S.D.; *n* = 6.
