Nanogel loaded with surfactant based nanovesicles for enhanced ocular delivery of acetazolamide

Figures & data

Table 1 Composition of acetazolamide nanovesicles

Formulation (F) number	Edge activator (EA)	Ratio of Span 60:EA
F1	Tween 80	90:10
F2		80:20
F3		70:30
F4	Sodium deoxycholate	90:10
F5		80:20
F6		70:30

Abbreviation: Span 60, sorbitan monostearate.

Table 2 The physicochemical characterization of acetazolamide loaded nanovesicles

Formula (F) number	Particle size (nm)	PDI	Zeta potential (mV)	%EE
F1	446.2	0.308	−20.8	58.4
F2	301.1	0.184	−19.3	67.9
F3	218.3	0.142	−18.3	59.2
F4	224.5	0.224	−34.1	76.8
F5	202.9	0.308	−38.1	90.2
F6	194.8	0.438	−41.2	81.3

Abbreviations: %EE, percentage drug entrapment efficiency; PDI, polydispersity index.

Figure 1 Transmission electron microscope (TEM) micrographs of prepared acetazolamide loaded nanovesicles. (A) TEM micrograph of F2 (Span 60:Tween 80 ratio 80:20). (B) TEM micrograph of F5 (Span 60:sodium deoxycholate ratio 80:20).

Abbreviations: F, formulation; Span 60, sorbitan monostearate.

Table 3 Composition and characterization of ACZ-NV nanogels

CS concentration (%w/w)	Viscosity (minimum) (cP)	Farrow’s constant (N)	Surface area of hysteresis loop	Time of adhesion (min)
0.8	89,352	1.4	3198.50	160
1.5	118,246	1.19	3983.95	290
2.5	110,832	1.12	3854.32	282

Note: *All of the gels were loaded with 1% w/w ACZ-NV selected formulation number 5 (F5).

Abbreviations: ACZ-NV, acetazolamide loaded nanovesicle; CS, chitosan.

Figure 2 In vitro release profile of acetazolamide from acetazolamide loaded nanovesicles (ACZ-NVs) and ACZ-NVs loaded in Chitosan nanogel.

Table 4 The entrapment efficiency (EE) measurements (%) and particle size of the prepared nanovesicles during storage at 4°C, 25°C, and 37°C over a period of 3 months

Examined characterization	Initial	4°C	25°C	37°C
Particle size (nm)	202.9	214.3	272.3	523.2
EE (w/w %)	90.2	88.4	80.2	78.2

Table 5 The percent drug content (%) of the prepared nanogel during storage at 4°C, 25°C, and 40°C/75%±5% relative humidity over a period of 1 month

Formulation Days	Drug content %
	4°C	25°C	37°C
0	99.9	99.9	99.9
5	99.6	99.4	98.1
10	98.9	98.7	96.5
15	98.4	97.8	94.3
20	97.9	96.9	91.7
25	97.6	96.1	89.5
30	97.1	95.4	88.9

Figure 3 Effect of different formulations of acetazolamide on lowering intraocular pressure.

Abbreviation: ACZ-NV, acetazolamide loaded nanovesicle.

Figure 4 Histopathological examination; findings were appointed with the arrows shown in each image. (A) Glaucoma retina (retina showing loss of internal nuclear layer and ganglion cells with numerous numbers of vacuoles in the choroid). (B) Glaucomatous optic nerve (optic nerve showing thickening, demyelination, and accumulation of fat vacuoles). (C) Glaucoma retina treated with acetazolamide (ACZ) oral tablet (retina showing some loss of inner plexiform layer and ganglion cells with little vacuoles in choroid). (D) Glaucomatous optic nerve treated with ACZ oral tablet (optic nerve showing Wallerian degeneration and minimal loss of myelin sheath). (E) Glaucoma retina treated with ACZ nanovesicles loaded in Chitosan nanogel (retina showing mild swelling of ganglion cells). (F) Glaucomatous optic nerve treated with ACZ nanovesicles loaded in Chitosan nanogel (optic nerve showing mild edema and thickening with remyelination of nerve fibers). Magnification power was 100×.