Preparation and in vitro evaluation of etoposide-loaded PLGA microspheres for pulmonary drug delivery

Figures & data

Table 1. Factors and levels of the orthogonal design.

	Factors
Levels	X1 (w/w)	X2 (mg/ml)	X3 (mg/ml)	X4 (rpm)
1	1:5	20	0	4000
2	1:10	40	0.05	8000
3	1:15	80	0.1	12 000

X₁, Drug/PLGA ratio (w/w); X₂, PLGA concentration (mg/ml); X₃, etoposide concentration in diluent (mg/ml); X₄, shearing speed (rpm).

Table 2. Results of the orthogonal design.

	Factors
No.	X1 (w/w)	X2 (mg/ml)	X3 (mg/ml)	X4 (rpm)	EE (%)
1	1	1	1	1	21.3
2	1	2	2	2	30.6
3	1	3	3	3	39.7
4	2	1	2	3	24.5
5	2	2	3	1	40.3
6	2	3	1	2	29.4
7	3	1	3	2	30.5
8	3	2	1	3	39.8
9	3	3	2	1	43.5
I^a	30.5	25.4	30.2	35.0
II^a	31.4	36.9	32.9	30.2
III^a	37.9	37.5	36.8	34.7
R	7.4	12.1	6.6	4.8

EE, Encapsulation efficiency of the microspheres; R, range value.

^aAverage EE of each level.

Figure 1. Morphology of etoposide-loaded PLGA microspheres observed under the optical microscope: (A) before freeze-drying and (B) after freeze-drying.

Figure 2. Scanning electron micrograph of etoposide-loaded PLGA microspheres.

Figure 3. Size and size distribution of etoposide-loaded PLGA microspheres: (A) before freeze-drying and (B) after freeze-drying.

Figure 4. DSC analyses of the samples: (A) blank microspheres, (B) etoposide, (C) physical mixture of blank microspheres and etoposide and (D) etoposide-loaded PLGA microspheres.

Figure 5. In vitro release of etoposide from etoposide-loaded PLGA microspheres and etoposide solution (n = 3).