A top-down technique to improve the solubility and bioavailability of aceclofenac: in vitro and in vivo studies

Figures & data

Table 1 TPP for the development of nanocrystals of ACF

TPP elements	Target	Product attributes (CQAs)
Dosage form	Nanocrystals filled in the capsule	Identity, assay, uniformity of content
Microbial quality	No contamination	Test for microbial growth
Product performance	Robust manufacturing	Drug content, particle size, PDI, morphology, solid state characteristics, in vitro drug release
PK target efficacy and safety	Bio-performance: better pharmacokinetic profile compared to pure drug	Pharmacokinetic parameters (Cmax, Tmax, AUC, MRT)
Stability	Stable for at least 3 months at accelerated temperature as per ICH guidelines	Assay/drug content, redispersibility (measured by particle size, PDI)

Abbreviations: ACF, aceclofenac; AUC, area under the curve; C_max, maximum plasma concentration; CQAs, critical quality attributes; ICH, International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use; MRT, mean residential time; PDI, polydispersity index; PK, pharmacokinetic; T_max, time for maximum plasma concentration; TPP, target product profile.

Table 2 Risk assessment matrix elucidating the effect of CMAs and CPPs on product attributes

Drug product’s CQAs	Risk assessment matrix
	CMAs			CPPs
	Surfactant type	Conc of surfactant (%)	Amount of drug (mg)	Milling time (h)	Ball mill speed (rpm)	Size of balls (mm)
Particle size	Medium	Medium	Medium	High	High	High
PDI	Medium	High	Medium	High	High	High
Zeta potential	High	High	Medium	Medium	Medium	Medium
Drug content	Low	Low	Low	Low	Low	Low
Rate and extent of release	Medium	Medium	Medium	High	High	High

Abbreviations: CMAs, critical material attributes; CPPs, critical product parameters; CQAs, critical quality attributes; PDI, polydispersity index.

Table 3 Variables in Box-Behnken design to form ACF nano-crystals

Variables	Levels
	−1	0	+1
Independent
A: Size of balls (mm)	5	10	15
B: Conc of stabilizer PVA (%)	0.25	0.5	0.75
C: Amount of drug ACF (mg)	200	300	400
D: Milling time (h)	1	2.5	4
Dependent	Constraints
Y1: Particle size (nm)	Minimize
Y2: PDI	Minimize
Y3: Zeta potential (mV)	Maximize

Abbreviations: ACF, aceclofenac; PVA, polyvinyl alcohol; PDI, polydispersity index.

Table 4 Composition and responses of nanocrystals of ACF

Batches	Independent variables				Dependent variables
	A (mm)	B (%)	C (mg)	D (h)	Y1 (nm)	Y2	Y3 (mV)
1	5	0.5	300	1	1,140±92.85	0.237±0.025	−1.65±0.187
2	5	0.75	300	2.5	874.7±90.30	0.303±0.034	−0.754±0.064
3	10	0.5	200	4	589.9±43.20	0.267±0.023	−1.32±0.143
4	10	0.75	300	1	1,164±82.0	0.596±0.063	−1.4±0.123
5	10	0.25	300	1	615.5±45.10	0.278±0.030	−0.305±0.039
6	10	0.5	300	2.5	689±67.34	0.304±0.035	−0.721±0.087
7	10	0.5	400	4	465.2±27.69	0.358±0.038	−0.314±0.031
8	5	0.5	300	4	849±81.30	0.123±0.013	−1.19±0.092
9	10	0.25	300	4	465.8±20.22	0.298±0.032	−0.656±0.068
10	10	0.5	300	2.5	692.3±35.27	0.209±0.022	−0.955±0.112
11	10	0.75	300	4	917±57.20	0.652±0.079	−0.967±0.097
12	5	0.25	300	2.5	543±49.81	0.318±0.025	−1.43±0.153
13	10	0.25	400	2.5	494.6±50.75	0.348±0.042	−0.0725±0.0085
14	15	0.75	300	2.5	603.8±58.62	0.316±0.026	−1.01±0.120
15	15	0.5	300	1	939.3±103.40	0.568±0.048	−1.3±0.138
16	5	0.5	200	2.5	667±75.48	0.254±0.019	−0.315±0.034
17	10	0.5	300	2.5	712.92±84.74	0.329±0.034	−1.42±0.185
18	15	0.25	300	2.5	596.3±62.30	0.268±0.029	−1.13±0.176
19	15	0.5	400	2.5	1,050.6±87.63	1.000±0.122	−0.789±0.080
20	15	0.5	200	2.5	598±64.37	0.179±0.020	−2.14±0.182
21	10	0.5	300	2.5	651.1±78.32	0.308±0.034	−1.41±0.143
22	10	0.75	200	2.5	520.3±41.64	0.240±0.019	−1.47±0.150
23	10	0.75	400	2.5	552.7±58.32	0.338±0.039	0.255±0.023
24	10	0.5	200	1	737.3±64.11	0.305±0.027	−1.04±0.10
25	5	0.5	400	2.5	1,138±120.05	0.546±0.055	−1.6±0.183
26	10	0.5	400	1	1,121.1±98.93	0.278±0.034	−0.238±0.026
27	10	0.25	200	2.5	810.6±82.09	0.312±0.025	−1.47±0.172
28	10	0.5	300	2.5	667.8±58.32	0.321±0.028	−1.25±0.129
29	10	0.5	300	2.5	642.7±64.80	0.279±0.029	−1.755±0.184
30	15	0.5	300	4	732±70.38	0.515±0.056	−0.395±0.046
31	10	0.5	300	2.5	709.9±89.32	0.459±0.050	−1.99±0.159
32	10	0.5	300	2.5	750.1±60.25	0.323±0.033	−1.415±0.128

Abbreviation: ACF, aceclofenac.

Figure 1 Three-dimensional plots showing the effect of independent variables on particle size.

Notes: (A) Effect of concentration of stabilizer and size of the balls on particle size; (B) Effect of concentration of stabilizer and amount of drug on particle size; (C) Effect of amount of drug and milling time on particle size; (D) Effect of milling time and size of the balls on particle size; (E) Effect of milling time and concentration of stabilizer on particle size; (F) Effect of amount of drug and size of the balls on particle size.

Abbreviation: conc, concentration.

Figure 2 Three-dimensional plots showing the effect of independent variables on PDI.

Notes: (A) Effect of concentration of stabilizer and size of the balls on PDI; (B) Effect of concentration of stabilizer and amount of drug on PDI; (C) Effect of amount of drug and milling time on PDI; (D) Effect of milling time and size of the balls on PDI; (E) Effect of milling time and concentration of stabilizer on PDI; (F) Effect of amount of drug and size of the balls on PDI.

Abbreviations: conc, concentration; PDI, polydispersity index.

Figure 3 Three-dimensional plots showing the effect of independent variables on zeta potential.

Notes: (A) Effect of concentration of stabilizer and size of the balls on zeta potential; (B) Effect of concentration of stabilizer and amount of drug on zeta potential; (C) Effect of amount of drug and milling time on zeta potential; (D) Effect of milling time and size of the balls on zeta potential; (E) Effect of milling time and concentration of stabilizer on zeta potential; (F) Effect of amount of drug and size of the balls on zeta potential.

Abbreviation: conc, concentration.

Table 5 Comparative values for observed and predicted results

Responses	CMAs and CPPs				CQAs
	A (mm)	B (%)	C (mg)	D (h)	Y1 (nm)	Y2	Y3 (mV)
Software-predicted results	5.0	0.25	200	4	489.6	0.103	−0.375
Obtained results	5.0	0.25	200	4	484.7±54.12	0.108±0.009	−0.380±0.045
Error* (%)	–	–	–	–	1.00	−4.85	−1.33

Note:

* Error = (software predicted results − obtained results)/software predicted results ×100.

Abbreviations: CMAs, critical material attributes; CPPs, critical process parameters; CQAs, critical quality attributes.

Figure 4 Design space of ACF nanocrystals comprised of the overlap region of ranges for the different critical quality attributes.

Abbreviations: ACF, aceclofenac; PDI, polydispersity index.

Figure 5 X-ray diffraction patterns for (A) pure unmilled ACF and (B) ACF nanocrystals.

Abbreviation: ACF, aceclofenac.

Figure 6 Differential scanning calorimetric (DSC) thermograms for (A) unmilled ACF (B) physical mixture of unmilled ACF + PVA and (C) ACF nanocrystals.

Abbreviations: ACF, aceclofenac; DSC, differential scanning calorimetric; PVA, polyvinyl alcohol.

Figure 7 Scanning electron microscopy images of (A) unmilled ACF (B) ACF nanocrystals.

Abbreviation: ACF, aceclofenac.

Figure 8 Saturation solubility studies of pure ACF and ACF nanocrystals.

Abbreviation: ACF, aceclofenac.

Figure 9 In vitro release profile of pure ACF and ACF nanocrystals.

Abbreviation: ACF, aceclofenac.

Table 6 Pharmacokinetic parameters for pure ACF and ACF nanocrystals

Parameters	Pure ACF	ACF nanocrystals
Cmax (µg/mL)	1.96±0.17	3.75±0.28a
Tmax (h)	1.00±0.25	1.00±0.25
t1/2 (h)	3.42±0.15	3.27±0.10
AUC0–12 (µg⋅h/mL)	5.8±0.87	9.0±1.00a
MRT (h)	4.30±0.95	4.00±0.69
Ke (h^−1)	0.202±0.001	0.267±0.0005

Notes: All values are expressed as mean ± SD, n=3;

a significantly different at 95% confidence interval.

Abbreviations: ACF, aceclofenac; AUC, area under the curve; C_max, maximum plasma concentration; K_e, elimination rate constant; MRT, mean residential time; T_max, time for maximum plasma concentration; t_1/2, elimination half life.

Figure 10 Plasma concentration-time profile for pure ACF and ACF nanocrystals.

Abbreviation: ACF, aceclofenac.