Enhanced dissolution characteristics of piroxicam–Soluplus® nanosuspensions

Figures & data

Table 1. Mathematical models used to predict drug release mechanism.

S. No.	Model	Equation	Plot
1	Zero order	ln(Mo/Mt) = k0t	Cumulative amount of drug released versus time
2	First order	Mo–Mt = k1t	Log of percentage of drug remaining unreleased versus time
3	Higuchi	Mt = K√t	Cumulative percent release versus square root of time
4	Hixson–Crowell	(Mo)^1/3–(Mt)^1/3 = k1/3t	Cube root of drug percentage remaining in the matrix versus time
5	Korsmeyer–Peppas	Mt/M∞ = kt^n	Log of the cumulative percent drug release versus log of time

M_o = the initial amount of drug, M_t = amount of drug dissolved at a particular time, M_∞ = amount of drug released at infinite time. k_o, k₁, K, k_1/3, and k are constants obtained from the linear fit of the respective models.

Figure 1. Phase solubility of piroxicam in different concentrations of the polymer Soluplus®.

Figure 2. Gibbs free energy of transfer values with increasing Soluplus concentrations.

Figure 3. Overlay of the PXRD patterns of piroxicam, Soluplus® and the nanoformulations.

Figure 4. Overlay of the thermal analysis curves of piroxicam, Soluplus® and the nanoformulations.

Figure 5. Overlay of FTIR spectra of piroxicam, Soluplus® and the nanoformulations.

Figure 6. FESEM images of Piroxicam Soluplus Nanoformulations of ratios 2:1 (above) and 1:1 (Below) after 6 hours of milling.

Figure 7. Caco-2 cell viability after exposure to various concentrations of Soluplus® and the nanoformulations (NS PS 1:1 and 1:4 for 12 hours). Significantly different with respect to control: *p < 0.05, ^#p < 0.05.

Figure 8. Dissolution analysis of the nanoformulations in comparison of the pure drug.

Table 2. Dissolution efficiencies achieved with varying polymer content in the formulations.

S. No.	Percentage of polymer	%DE at t = 5	%DE at t = 20	%DE at t = 30	%DE at t = 60	%DE at t = 90	%DE at t = 120
1	0%	4.50	5.99	8.71	14.43	24.01	27.19
2	20%	6.66	8.89	13.88	25.93	32.23	35.49
3	33%	6.91	9.49	16.02	28.79	36.88	40.98
4	50%	12.02	15.08	21.47	35.73	42.92	46.95
5	66%	17.02	22.00	33.52	54.01	65.88	72.31

Table 3. Statistical parameters obtained after fitting the drug release data to various release kinetic models.

	Zero order		First order		Higuchi		Hixson–Crowell		Korsmeyer–Peppas
Polymer%	Slope	R^2	Slope	R^2	Slope	R^2	Slope	R^2	Slope	R^2
0%	−0.15	0.268	−0.005	0.813	4.090	0.942	0.03	0.640	0.721	0.935
20%	−0.15	0.346	−0.002	0.739	4.668	0.782	0.02	0.73	0.748	0.917
33%	−0.16	0.342	−0.002	0.789	6.279	0.886	0.03	0.774	0.775	0.911
50%	−0.12	0.232	−0.003	0.760	6.396	0.856	0.07	0.849	0.632	0.913
66%	−0.14	0.336	−0.02	0.893	9.968	0.873	0.06	0.845	0.640	0.912