Ophthalmic controlled release in situ gelling systems for ciprofloxacin based on polymeric carriers

Figures & data

Table 1.  Composition of prolonged-action in situ ciprofloxacin eye gels.

Formulation code	Concentration (%W/W)
	Drug	HPMC	CP934	CP971	MC	Tween	alginate
F1	0.3	1.5	0.5	—	—	1
F2	0.3	1.5		0.5	—	1	—
F3	0.3	—	0.5	—	1.5	1	—
F4	0.3	—	—	—	—	1	2
F5	0.3	1	0.4	—	—	1	—
F6	0.3	1	0.5	—	—	1	—

Table 2.  Physical properties of prolonged action in in situ ciprofloxacin eye gels.

Formulation code	Gelling capacity (min ± SD)	Viscosity (CPs) (10 rpm)	Adhesiveness (N mm)
F1	11.66 ± 0.58	4296.3	0.0903
F2	3.67 ± 0.58	2870.97	0.0717
F3	> 37 ± 0.00	1600	0.2761
F4	2.33 ± 1.16	262	0.0643
F5	2.68 ± 0.58	1797	0.0863
F6	7.67 ± 1.15	2176	0.0893

Scheme 1.  Chemical structure of ciprofloxacin.

Figure 1.  In vitro diffusion of ciprofloxacin from controlled release gel formulations.

Figure 2.  (a) General structure of Carbopol polymers. (b) schematic diagram of the structure of alginate showing (a) the constituent sugars, (b) their relevant linkages, and (c) possible intramolecular patterns of the different sugars.

Table 3.  The time required for the release of 20% of the original mass of ciprofloxacin from gel formulation.

Formulation code	T20% (min)
F1	135
F2	108
F3	113
F4	110
F5	105
F6	123

Table 4.  Kinetic parameters obtained from the release equation.

Formulation code	k	N
F1	0.1215	1.022
F2	0.1383	1.051
F3	0.1246	1.029
F4	0.1425	1.032
F5	0.2111	0.975
F6	0.1698	0.973

Figure 3.  Evaluation of the antimicrobial efficiency of ciprofloxacin gel on (a) E. coli, (b) S. aureus, and (c) P. aeruginosa as a function of time.

Figure 4.  Comparison of the diameters of the inhibition zones of E. coli, S. aureus, and P. aeruginosa.