Niosomal encapsulation of ethambutol hydrochloride for increasing its efficacy and safety

Figures & data

Table 1. Types of prepared ethambutol hydrochloride niosomal formulations with mean percent entrapment.

Formulation	Non-ionic surfactant (NIS)	Charge inducing agent (CIA)	NIS: CHOL:CIA molar ratio	Mean drug entrapped (%) ± SD (SE)^a
F1	Span 60	Neutral	1:1	12.20 ± 3.11 (1.27)
F2	Span 60	Negative (DCP)	1:1:0.1	19.62 ± 3.21 (1.21)
F3	Span 60	Positive (SA)	1:1:0.1	18.89 ± 1.82 (0.74)
F4	Span 60	Neutral	4:2	23.17 ± 3.55 (1.25)
F5	Span 60	Negative (DCP)	4:2:1	23.11 ± 1.80 (0.73)
F6	Span 60	Positive (SA)	4:2:1	22.43 ± 3.31 (1.17)
F7	Span 85	Neutral	1:1	17.90 ± 1.12 (0.45)
F8	Span 85	Negative (DCP)	1:1:0.1	24.60 ± 2.57 (1.05)
F9	Span 85	Positive (SA)	1:1:0.1	18.40 ± 1.73 (0.71)
F10	Span 85	Neutral	4:2	21.87 ± 1.82 (0.74)
F11	Span 85	Negative (DCP)	4:2:1	25.49 ± 1.37 (0.56)
F12	Span 85	Positive (SA)	4:2:1	25.81 ± 1.73 (0.70)

^aMean of six experiments.

Table 2. ZP, mean particle diameters and PI of investigated niosomes.

Formula	ZP^c	Mean particle diameter (nm)	PI^b
F1^a	35.88	775.55	0.774
F1	43.82	570.75	0.601
F2^a	63.58	397.30	0.521
F2	70.50	812.85	1.061
F3^a	23.23	1084.45	0.824
F3	19.81	530.25	0.667
F4^a	51.74	320.25	0.448
F4	51.89	324.65	0.692
F5^a	99.36	137.40	0.468
F5	76.30	521.10	0.778
F6^a	17.06	2847.20	1.313
F6	0.00	1163.40	0.869
F7^a	62.76	61.51	0.466
F7	76.02	58.35	0.540
F8^a	91.45	92.35	1.055
F8	82.73	145.65	0.872
F9^a	27.62	223.70	0.707
F9	24.15	165.80	1.395
F10^a	76.10	58.05	0.645
F10	56.91	46.75	0.475
F11^a	72.23	119.45	1.847
F11	69.21	63.85	0.974
F12^a	26.30	360.00	1.656
F12	13.93	180.70	0.498

^aDrug-free niosomes.

^bPolydispersity index.

^cZeta potential.

Figure 3. Mean percent ethambutol hydrochloride released from F2 and F4 in phosphate buffer saline (pH 7.4).

Figure 4. Mean amount of ethambutol hydrochloride deposited in mice lungs (ng/mg lung) after single s.c. injection of free drug compared with F2 and F4.

Figure 5. AUC of ethambutol HCl deposited in mice lungs (ng/mg lung) after single s.c. injection of the three treatment groups.

Table 3. Mean RSLW values for lungs and bacterial counts of guinea pig lung homogenates receiving different treatments.

Group no.	Treatment received	Mean RSLW ± SD (SE)^a	Mean CFU/gm lung^a	Mean log CFU/gm lung ± SD (SE)
1	Control (Saline) 6 days weekly	18.55 ± 0.97 (0.56)	2.41 × 10^9	9.38 ± 0.38 (0.22)
2	Control drug-free niosomes (4:2 neutral) twice weekly	17.06 ± 0.63 (0.36)	2.08 × 10^9	9.32 ± 0.62 (0.36)
3	Free ethambutol hydrochloride 6 days weekly	11.94 ± 0.44 (0.26)	2.09 × 10^6	6.32 ± 0.13 (0.075)
4	Free ethambutol hydrochloride twice weekly	13.15 ± 0.90 (0.52)	1.38 × 10^7	7.14 ± 0.34 (0.20)
5	Negatively charged ethambutol hydrochloride niosomes (1:1:0.1) (F2) twice weekly	9.71 ± 0.66 (0.38)	2.60 × 10^5	5.41 ± 0.32 (0.18)
6	Neutral ethambutol hydrochloride niosomes (4:2) (F4) twice weekly	11.06 ± 0.32 (0.18)	12.24 × 10^5	6.09 ± 0.44 (0.25)

^aEach value is a mean of three animals.

Figure 6. Histopathological examination of guinea pigs organs infected and differently treated (H&E, ×40), (a) Lung infected and treated with free ethambutol hydrochloride 6 days weekly for 6 weeks, show focal lymphoid cells aggregation (arrow) and diffuse lymphoid cells infiltration in between the air alveoli, (b) Livers show wide circumscribed area of necrosis replacing the hepatic parenchyma (n), (c) Spleens show mild depletion in central portion of the white pulp (f), (d) Lungs infected and treated with free ethambutol hydrochloride twice weekly for 6 weeks, show granuloma formation mainly cellular (g) with central necrosis, (e) Livers show granuloma formation (g) with haemorrhages (h) and hyperplasia in bile duct (arrow), (f) Spleens show the necrosis in the lymphoid cells in the center of the white pulps (g), (g) Lungs infected and treated with ethambutol hydrochloride niosomes (1:1:0.1 negative) (F2) twice weekly for 6 weeks, show collapse (arrow) and emphysema (e) in air alveoli, (h) Livers show hyperplasia in bile duct (arrow) in the portal area, (i) Spleens show intact white pulp (w) with hemosiderosis in red pulp, (j) Lungs infected and treated with ethambutol hydrochloride niosomes (4:2 neutral) (F4) twice weekly for 6 weeks, show cellular granuloma with central necrosis (g) replacing the lung parenchyma, (k) Livers show granuloma formation mainly from lymphoid cells (g) with hyperplasia in bile duct (arrow) and degeneration in other hepatocytes (d), (l) Spleens show lymphoid cellular necrosis in the white pulp (d), (m) Lungs of the control group infected and receiving saline, show granuloma with central necrosis replacing the lung parenchyma (g, n), (n) Livers show necrosis in the central zone of the granuloma (n) surrounded by other leucocytes (m), (o) Spleens show diffuse proliferation of epitheloid cells (m) with necrobiosis in the lymphoid cells and diffuse hemosiderosis (h), (p) Lungs of the control group infected and receiving neutral drug-free niosomes of the molar ratio Span 60: cholesterol (4:2), show cellular granuloma formation without central necrosis (g), (q) Livers show granuloma formation with central necrosis without fibrous connective tissue capsule formation (g) and (r) Spleens show cellular granuloma formation with central necrosis (N).