Preparation and evaluation of novel chitosan: gelrite ocular system containing besifloxacin for topical treatment of bacterial conjunctivitis: scintigraphy, ocular irritation and retention assessment

Figures & data

Table 1. Formulation table of besifloxacin sol–gel system with observed gelling capacity.

Formulation code	Chitosan (% w/v)	Gellan gum (% w/v)	PVA (% w/v)	Besifloxacin (% w/v)	Boric acid buffer	Benzalkoniumchloride (ml)	Gelation capacity
CG1	0.25	0.25	2	0.3	100	0.03	+
CG2	0.5	0.25	2	0.3	100	0.03	+++
CG4	0.25	0.5	2	0.3	100	0.03	++++
CG5	0.5	0.5	2	0.3	100	0.03	++
CG6	1	0.5	2	0.3	100	0.03	+++
CG7	0.25	1	2	0.3	100	0.03	+++
CG9	1	1	2	0.3	100	0.03	+++

Table 2. Physicochemical evaluation parameters of besifloxacin sol–gel system.

Formulation code	Appearance	Clarity	pH	Drug content	Osmolarity mOsm/kg
CG1	Light yellow	Clear	4.9	96.3 ± 1.90	334.23 ± 3.21
CG2	Light yellow	Clear	4.7	99.2 ± 1.23	305.43 ± 1.31
CG4	Light yellow	Clear	5.2	98.5 ± 0.89	280.51 ± 2.43
CG5	Light yellow	Clear	5.1	98.23 ± 0.82	286.76 ± 2.54
CG6	Light yellow	Clear	4.8	97.34 ± 1.34	290.65 ± 4.65
CG7	Light yellow	Clear	4.9	98.65 ± 1.12	316.76 ± 3.32
CG9	Light yellow	Clear	5.2	98.87 ± 0.76	302.64 ± 5.76

Table 3. Comparative antimicrobial assessment study of optimized besifloxacin sol–gel system (CG2) and besifloxacin suspension.

	Zone diameter (cm) against P. aeruginosa		Zone diameter against S. aureus
Incubationtime (h)	In situ gel (F2)	BSF suspension	In situ gel (F2)	BSF suspension
1	1.5	1.1	1.4	1.6
6	2.6	1.9	2.5	2.1
12	4.6	2.1	4.4	2.2
24	5.2	1.5	4.8	1.8

Table 4. Comparative pharmacokinetic parameter of optimized besifloxacin sol–gel system (CG2) and besifloxacin suspension.

Pharmacokinetic parameters	In situ gel (CG2)	BSF suspension
Cmax (ng/mL)	471.54 ± 10.23	289.29 ± 14.72
Tmax (h)	2 ± 0.12	1 ± 0.09
AUC0–t (ng/mL. h)	3204.36 ± 14.53	839.25 ± 23.43
AUC0–inf (ng/mL. h)	3853.58 ± 21.54	315.367 ± 24.43
Half-life (h)	6.45 ± 0.14	2.50 ± 0.21
Elimination rate constant (h^−1)	0.162164	0.312536

Figure 1. Rheological study of different batch of BSF sol–gel system.

Figure 2. Ex vivo permeation profile of optimized BSF sol–gel system and BSF suspension across goat cornea.

Figure 3. Histopathology of treated goat cornea (A) optimized BSF sol–gel system (B) BSF suspension.

Figure 4. Het-Cam photograph for ocular irritation study treated with (A) 0.1 N NaOH, (B) Normal saline (C) Optimized BSF sol–gel system.

Figure 5. Comparative in vivo absorption study profile (A) optimized BSF sol–gel system (B) BSF suspension.

Figure 7. Radioactive-loaded gamma scintigraphy image (A) optimized BSF sol–gel system (B) BSF suspension.

Figure 6. Gamma scintigraphy static whole-body images after 6 h of administration (A) optimized BSF sol–gel system (B) BSF suspension.