Triamcinolone acetonide–Eudragit^® RS100 nanofibers and nanobeads: Morphological and physicochemical characterization

Figures & data

Figure 1. SEM images for TA-Eudragit^® RS100 electrosprayed samples (a) and (b): samples with the drug: polymer ratio of 1:5 and solution concentrations of 10% (a) and 20% (b). (c) and (d): samples with the drug: polymer ratio of 1:10 and solution concentrations of 10% (c) and 20% (d).

Figure 2. DSC thermograms of TA; Eudragit^® RS100; PM 1:5 (physical mixture with the drug: polymer ratio of 1:5) and formulations with the drug: polymer ratio of 1:5 prepared using 10% (F1) and 20% (F2) solution concentrations.

Figure 3. X-Ray diffractograms of TA; Eudragit^® RS100; PM 1:5 (physical mixture with the drug: polymer ratio of 1:5); and formulations with the drug: polymer ratio of 1:5 prepared using 10% (F1) and 20% (F2) solution concentrations.

Figure 4. FT-IR spectra of TA; Eudragit^® RS100; PM 1:5 (physical mixture with the drug: polymer ratio of 1:5); and formulations with the drug: polymer ratio of 1:5 prepared using 10% (F1) and 20% (F2) solution concentrations.

Figure 5. Drug release profiles for the pure drug (TA); physical mixtures (PM) and the prepared electrosprayed samples (ES). The values 1:5 and 1:10 indicate drug: polymer ratio. The values of 10%, 15% and 20% represent the total solution concentrations.

Table I. Model-independent parameters of the different samples.

Sample	t50% (min)	Q15min (%)	Q30min (%)
TA	57.3	19.10 ± 0.19	35.57 ± 2.20
PM 1:5	57.5	21.26 ± 0.73	37.00 ± 0.26
PM 1:10	45.2	27.24 ± 0.48	45.28 ± 2.32
ES 1:5 10%	360.0	26.07 ± 2.59	35.50 ± 3.82
ES 1:5 15%	360.0	18.76 ± 0.13	26.67 ± 0.38
ES 1:5 20%	227.0	22.86 ± 2.84	27.36 ± 1.40
ES 1:10 10%	45.0	31.95 ± 0.67	47.45 ± 2.69
ES 1:10 15%	31.0	34.46 ± 1.13	48.46 ± 1.66
ES 1:10 20%	30.0	34.58 ± 2.18	40.98 ± 2.54

PM and ES stand for physical mixture and electrosprayed samples, respectively. 1:5, 1:10 represent TA: Eudragit^® RS100 ratio. 10%, 15% and 20% signify the applied solution concentration. t_50% indicates the time at which 50% of drug was released. Q_15min and Q_30min show the percent of drug dissolved within 15 and 30 min, respectively.

Table II. Parameters of the different kinetic models; squared correlation coefficients (RSQ); and percent error (PE) for the formulations F1–F6.

Model name and equation		F1 ES 1:5 10%	F2 ES 1:5 15%	F3 ES 1:5 20%	F4 ES 1:10 10%	F5 ES 1:10 15%	F6 ES 1:10 20%
Zero order F = k0t	K0	0.03	0.05	0.05	0.05	0.04	0.04
	RSQ	0.695	0.780	0.840	0.636	0.485	0.776
	PE	17.32	28.81	14.45	19.84	22.02	12.32
First order 1 n (1 − F) = − k t	Kf	0.06	0.08	0.08	0.11	0.07	0.09
	RSQ	0.763	0.842	0.888	0.729	0.558	0.856
	E	16.34	27.29	12.85	18.19	21.20	10.98
Higuchi	kH	0.12	0.16	0.15	0.18	0.14	0.15
	RSQ	0.850	0.921	0.953	0.812	0.666	0.911
	PE	12.13	16.39	7.02	14.15	17.46	7.32
Power law ln F = ln kp + plnt	kp	0.36	0.28	0.35	0.49	0.47	0.47
	p	0.23	0.37	0.25	0.24	0.22	0.19
	RSQ	0.931	0.929	0.968	0.919	0.828	0.969
	E	7.39	11.91	5.15	11.03	15.98	4.51
Hixson-Crowell	k1/3	0.02	0.02	0.02	0.03	0.02	0.02
	RSQ	0.740	0.823	0.873	0.699	0.533	0.831
	PE	16.65	27.87	13.37	18.87	21.42	11.35
Square root of mass	k1/2	0.02	0.03	0.03	0.04	0.03	0.03
	RSQ	0.730	0.813	0.865	0.684	0.521	0.818
	PE	16.81	28.03	13.64	18.94	21.55	11.58
Three seconds root of Mass	k2/3	0.03	0.04	0.04	0.04	0.03	0.04
	RSQ	0.718	0.802	0.857	0.668	0.509	0.804
	PE	16.98	28.29	13.90	19.22	21.69	11.82
Weibull ln[-ln(1-F)] = βlntd+βlnt	β	0.28	0.44	0.32	0.35	0.30	0.28
	td	18.81	11.04	12.34	2.66	3.97	4.42
	RSQ	0.949	0.952	0.970	0.944	0.855	0.977
	PE	6.20	9.40	4.96	6.52	10.88	3.36
Linear probability Z = Z0 + qt	Z0	− 0.53	− 0.80	− 0.60	− 0.21	− 0.21	− 0.26
	q	0.09	0.14	0.12	0.13	0.10	0.11
	RSQ	0.653	0.690	0.814	0.641	0.478	0.777
	PE	17.67	28.84	14.75	19.30	21.78	12.01

ES stands for electrosprayed samples. 1:5 and 1:10 represent TA: Eudragit^® RS100 ratio. 10%, 15% and 20% signify the applied solution concentration. F denotes fraction of drug released up to time t. k₀, k_f, k_H, p, k_P, k_1/3, k_1/2, k_2/3, t_d, β, Z₀ and q are parameters of the models. Z is the probit of fraction of drug released at any time. Z₀ is the value of Z when t = 0 and t = 1.