Preparation, optimization, and in vitro simulated inhalation delivery of carvedilol nanoparticles loaded on a coarse carrier intended for pulmonary administration

Figures & data

Table 1 Sample of training data records indicating the composition and properties of CAR nanosuspensions

Record	Drug load (mg)	Stabilizer typea	Stabilizer HLB	Stabilizer molecular weight	PEOb	PPOc	PEO/PPO ratio	Weight of stabilizer (mg)	Drug/stabilizer ratiod	Phase volume ratio	Water volume (mL)	Average PS ± SD (nm)	Average PDI ± SD	Average ZP ± SD (mV)
1	25.00	1.00	22.00	12,600.00	198.00	65.00	3.05	50.00	0.50	10.00	50.00	270.75±10.11	0.15±0.07	−5.88±0.25
2	25.00	1.00	22.00	12,600.00	198.00	65.00	3.05	50.00	0.50	4.00	20.00	1,192.00±26.87	1.00±0.00	−15.25±1.63
3	25.00	1.00	22.00	12,600.00	198.00	65.00	3.05	100.00	0.25	10.00	50.00	495.45±31.60	0.46±0.01	−14.90±1.44
4	25.00	1.00	22.00	12,600.00	198.00	65.00	3.05	100.00	0.25	4.00	20.00	1,542.50±38.89	0.39±0.04	−14.80±2.03
5	25.00	1.00	22.00	12,600.00	198.00	65.00	3.05	75.00	0.33	10.00	50.00	395.60±6.08	0.18±0.03	−8.93±0.89
6	25.00	1.00	22.00	12,600.00	198.00	65.00	3.05	75.00	0.33	4.00	20.00	918.75±3.18	0.29±0.00	−15.10±1.15
7	25.00	2.00	24.00	8,400.00	152.00	30.00	5.07	50.00	0.50	10.00	50.00	850.00±22.54	0.74±0.17	−18.70±0.14
8	25.00	2.00	24.00	8,400.00	152.00	30.00	5.07	50.00	0.50	4.00	20.00	3,200.00±75.12	1.00±0.00	−19.20±1.56
9	25.00	2.00	24.00	8,400.00	152.00	30.00	5.07	100.00	0.25	10.00	50.00	399.75±14.29	0.44±0.03	−19.00±0.73
10	25.00	2.00	24.00	8,400.00	152.00	30.00	5.07	100.00	0.25	4.00	20.00	798.00±62.23	0.49±0.09	−26.70±1.26
11	25.00	2.00	24.00	8,400.00	152.00	30.00	5.07	75.00	0.33	10.00	50.00	339.35±17.89	0.25±0.10	−19.80±1.89
12	12.50	3.00	12.00	5,750.00	38.00	69.00	0.55	37.50	0.33	4.00	20.00	361.75±21.25	0.40±0.02	−10.10±0.94

Notes:

a Pluronic surfactant type (1 denotes F127, 2 denotes F68, and 3 denotes P123);

b polyethylene oxide units;

c polypropylene oxide units; and

d drug:stabilizer ratio (1:2, 1:3, and1:4).

Abbreviations: CAR, carvedilol; HLB, hydrophilic–lipophilic balance; PS, particle size; PDI, polydispersity index; SD, standard deviation; ZP, zeta potential.

Table 2 ANOVA statistics obtained from model training and testing data sets

Property	Source of variation	Sum of squares	DFa	MSEb	RMSEc	CF ratiod
Average PS (nm)	Model	41,682,100	25	1,667,284.00	1,291.23	3.28
	Error	2,543,100	5	508,620.00	713.18
	Total	44,225,200	30
	Covariance term	Sum of errors
	526,462	13.7687
	Train set R^2	94.02%
	Test set R^2	93.40%
Average PDI	Model	913.71	25	36.54	6.04	2.63
	Error	69.5449	5	13.91	3.73
	Total	962.321	30
	Covariance term	Sum of errors
	−20.9333	−7.04133
	Train set R^2	92.77%
	Test set R^2	90.44%
Average ZP (mV)	Model	968.07	25	38.72	6.22	12.89
	Error	15.02	5	3.00	1.73
	Total	996.29	30
	Covariance term	Sum of errors
	13.198	−0.181534
	Train set R^2	98.49%
	Test set R^2	82.28%

Notes:

a Degrees of freedom;

b mean sum of squared errors;

c root mean-squared error;

d computed F ratio.

Abbreviations: ANOVA, analysis of variance; PDI, polydispersity index; PS, particle size; ZP, zeta potential.

Table 3 ANOVA statistics obtained from model validation data sets

Property	Source of variation	Sum of squares	DFa	MSEb	RMSEc	CF ratiod
Average PS (nm)	Model	10,736,667	25	429,467	655.33	4.83
	Error	1,867,767	−21	88,941	298.23
	Total	12,604,433	4
	Covariance term	Sum of errors
	−898,333.3	−370.45
	Validation set R^2	85.18%
Average PDI	Model	0.33797833	25	0.0135	0.12	6.18
	Error	0.04594167	−21	0.0022	0.05
	Total	0.38392	4
	Covariance term	Sum of errors
	−0.0495858	−0.344973
	Validation set R^2	88.03%
Average ZP (mV)	Model	152.285	25	6.0914	2.47	11.04
	Error	11.591	−21	0.5519	0.74
	Total	163.876	4
	Covariance term	Sum of errors
	−3.49	−42.25
	Validation set R^2	92.93%

Notes:

a Degrees of freedom;

b mean sum of squared errors;

c root mean-squared error;

d computed F ratio.

Abbreviations: ANOVA, analysis of variance; PDI, polydispersity index; PS, particle size; ZP, zeta potential.

Figure 1 Response surface plots showing influence of some formulation variables on nanosuspension average particle size: (A) stabilizer type and wt of stabilizer; (B) ratio of hydrophilic to hydrophobic units and wt of stabilizer; (C) number of PPO units and wt of stabilizer; (D) drug/stab ratio and phase volume ratio.

Abbreviations: PS, particle size; PPO, polypropylene oxide; stab, stabilizer; Wt, weight.

Figure 2 Response surface plots showing influence of some formulation variables on nanosuspension average polydispersity index: (A) number of PEO units and ratio of hydrophilic to hydrophobic units; (B) drug load and stabilizer type; (C) m.wt and stabilizer HLB; (D) phase volume ratio and water volume.

Abbreviations: PDI, polydispersity index; PEO, polyethylene oxide; m.wt, molecular weight; HLB, hydrophilic–lipophilic balance.

Figure 3 Response surface plots showing influence of some formulation variables on nanosuspension average zeta potential: (A) drug/stab ratio and ratio of hydrophilic to hydrophobic units; (B) drug load and stabilizer type; (C) number of PEO units and wt of stabilizer; (D) number of PPO units and wt of stabilizer.

Abbreviations: ZP, zeta potential; PPO, polypropylene oxide; PEO, polyethylene oxide; stab, stabilizer; Wt, weight.

Table 4 Model-generated optimized solution and its analogous fresh and lyophilized experimental nanosuspensions

Solution	Desirability	Nanosuspension independent variables (inputs)						Dependent variables (output properties)
		X1	X2	X8	X9	X10	X11	Y1	Y2	Y3
		Drug load (mg)	Stabilizer type	Weight of stabilizer (mg)	Drug/stabilizer ratio	Phase volume ratio	Water volume (mL)	PS (nm)	PDI	ZP (mV)
Population 1	1.00	23	1	48.80	0.47	9	45	280.52	0.25	−9.50
Fresh NS	NA	23	1	48.80	0.47	9	45	277.90	0.19	−10.38
Lyophilized NS	NA	23	1	48.80	0.47	9	45	316.40	0.20	−8.94

Abbreviations: NS, nanosuspension; PS, particle size; PDI, polydispersity index; ZP, zeta potential; NA, not applicable.

Figure 4 Transmission electron micrograph for the optimized carvedilol nanosuspension.

Figure 5 Scanning electron micrograph of freeze-dried nanosuspension showing dispersed spherical nanoparticles inside a crystalline matrix of cryoprotectant (red circle).

Figure 6 Differential scanning calorimetry (DSC) curves of carvedilol (CAR), Pluronic F127 (PL), sodium deoxycholate (SDC), mannitol (MN), physical mixture (PM), and lyophilized nanosuspension (NS).

Figure 7 Powder X-ray diffraction patterns of carvedilol (CAR), Pluronic F127 (PL), sodium deoxycholate (SDC), mannitol (MN), physical mixture (PM), and lyophilized nanosuspension (NS).

Figure 8 Percentage of CAR dissolved from optimized nanosuspension formula compared to the coarse drug.

Abbreviation: CAR, carvedilol.

Table 5 The aerodynamic characteristics of coarse CAR powder and CAR nanoparticles

Parameter	Coarse drug (mean ± SD)	Nanoparticles (mean ± SD)
Total emitted dose (µg; TED)	1,472.00±312.00	1,794.00±178.00
Total emitted dose% (% of nominal dose; TED%)	73.60±15.60	89.70±8.90
Fine particle dose (µg; FPD)	818.40±94.20	1,469.30±77.10
Fine particle fraction (% of emitted dose; FPF)	55.60±6.40	81.90±4.30
Mass median aerodynamic diameter (µm; MMAD)	4.20±1.50	2.80±1.20
Geometric standard deviation (GSD)	2.10±0.40	1.70±0.50

Abbreviations: CAR, carvedilol; SD, standard deviation.