Eudragit-coated aceclofenac-loaded pectin microspheres in chronopharmacological treatment of rheumatoid arthritis

Figures & data

Table 1.  Effect of different variables on particle size, swelling index and entrapment efficiency.

Formulation code	Variables	Production yield (%)	Entrapment efficiency (%)	Mean particle size (µm)	Swelling index	In vitro drug release within 8 h (%)
APM1	Drug to polymer ratio 1:3 ratio 1:3	97.60 ± 1.03	79.10 ± 0.39	29.05 ± 0.72	0.35 ± 1.34	83.12 ± 1.12
APM2	1:4	98.11 ± 0.56	80.00 ± 1.66	32.80 ± 0.31	0.51 ± 1.03	71.14 ± 0.97
APM3	1:5	95.00 ± 1.35	81.93 ± 1.23	37.90 ± 0.29	0.63 ± 0.32	66.23 ± 1.72
APM4	1:6	91.00 ± 0.26	84.58 ± 1.56	38.85 ± 0.36	0.75 ± 0.54	61.12 ± 2.14
APM5	Emulsifier concentration 0.5%	94.01 ± 2.13	70.68 ± 0.49	57.48 ± 0.35	0.67 ± 0.18	64.83 ± 2.61
APM6	1.0%	95.12 ± 0.98	76.19 ± 0.87	55.00 ± 0.68	0.56 ± 1.02	70.41 ± 1.44
APM7	1.5%	95.60 ± 0.33	80.02 ± 0.79	43.16 ± 1.23	0.48 ± 1.23	76.56 ± 0.78
APM8	2.0%	97.62 ± 1.96	84.58 ± 1.49	31.32 ± 0.21	0.39 ± 1.11	83.17 ± 0.92
APM9	Stirring speed 500 rpm	99.12 ± 1.88	87.00 ± 1.86	38.15 ± 0.36	0.43 ± 0.45	61.19 ± 1.16
APM10	1000 rpm	95.61 ± 1.77	90.01 ± 1.46	33.16 ± 0.49	0.54 ± 0.65	72.47 ± 1.62
APM11	1500 rpm	92.62 ± 1.52	96.08 ± 1.09	31.30 ± 0.25	0.65 ± 0.12	76.34 ± 1.25
APM12	2000 rpm	90.61 ± 0.77	97.01 ± 0.23	29.05 ± 0.58	0.78 ± 0.66	86.42 ± 2.17
APM13	Stirring time 15 min	90.83 ± 1.48	69.64 ± 0.39	55.00 ± 0.64	0.60 ± 0.44	66.45 ± 2.41
APM14	30 min	90.10 ± 1.95	80.00 ± 0.13	42.56 ± 1.22	0.50 ± 0.71	75.99 ± 0.94
APM15	45 min	93.26 ± 2.26	86.28 ± 1.42	37.89 ± 0.28	0.41 ± 0.23	82.13 ± 0.89
APM16	60 min	93.93 ± 0.53	90.60 ± 1.13	31.34 ± 0.20	0.34 ± 0.13	99.18 ± 2.12

Average ± SD (n = 3).

The underlined values are optimal parameters and are used in other variables, e.g. Formulation APM₁ prepared with drug to polymer ratio of 1:3, emulsifier concentration of 2.0%, stirring speed of 2000 rpm and stirring time of 60 min.

Figure 1.  DSC of: (a) aceclofenac; (b) pectin; and (c) aceclofenac-loaded pectin microspheres.

Figure 2.  FT-IR of: (a) aceclofenac; (b) pectin; and (c) aceclofenac-loaded pectin microspheres.

Figure 3.  The cumulative percentage drug release in SCF enzyme induced medium (a) APM 1--APM 4, (b) APM 5--APM 8, (c) APM 9--APM 12, (d) APM 13--APM 16.

Figure 4.  SEM photograph: (a) uncoated and (b) coated microspheres.

Figure 5.  The %CDR of Eudragit-coated pectin microspheres and Eudragit microspheres alone in SCF.

Table 2.  Effect of test formulation (E-APM₁₆) on CFA-induced paw edema in rats.

		Paw volume (ml)
Treatment	Dose (mg/kg)	5th Day	10th Day	15th Day
Normal (normal saline)	2 ml/kg	0.21 ± 0.01	0.20 ± 0.01	0.24 ± 0.03
CFA	0.1 ml	0.56 ± 0.02^a	0.64 ± 0.01^a	0.72 ± 0.02^a
Standard	10	0.23 ± 0.01^b	0.26 ± 0.01^b	0.28 ± 0.01^b
Pectin microspheres	10	0.26 ± 0.03^c	0.28 ± 0.02^c	0.30 ± 0.02^c

N = 6 rats in each group; p < 0.05.

Significant differences from CFA, standard and pectin microspheres treated groups, respectively, using student’s t-test at are as follows: ^ap < 0.05 versus normal; ^bp < 0.05 versus CFA; and ^cp < 0.05 versus CFA.

Table 3.  Effect of test formulation (E-APM₁₆) on antioxidant status in liver of control and experimental animals.

Treatment	Dose (mg/kg)	LPO	SOD	CAT	GPx
Normal (Group I)	–	176.5 ± 4.48	4.54 ± 0.05	52.36 ± 2.17	8.75 ± 1.45
CFA (Group II)	0.1 ml	292.4 ± 8.67^a	1.82 ± 0.02^a	31.92 ± 2.36^a	4.65 ± 1.20^a
Pectin microspheres (Group III)	10	201.48 ± 3.24^b	2.39 ± 0.21 ^b	47.40 ± 1.98^b	8.24 ± 1.19^b
Standard (Group IV)	10	198.45 ± 3.18^c	2.61 ± 0.02^c	43.12 ± 1.12^c	7.12 ± 0.80^c

Values are mean ± SEM (n = 6).

^aSignificance at the level of p < 0.05 Group I versus Group II, ^bsignificance at the level of p < 0.05 Group II versus Group III and ^csignificance at the level of p < 0.05 Group I versus Group IV.

Data were analyzed by one-way analysis of variance followed by Tukey multiple comparison test.

LPO = µ moles of MDA/min/mg protein; GPx = µ moles of GSH oxidized/min/mg protein; SOD = units/min/mg protein; CAT = µ mole of H₂O₂ consumed/min/mg protein.

Figure 6.  Plasma drug concentration–time curve.

Table 4.  Comparison of pharmacokinetic parameters of optimized batch microsphere (E-APM₁₆) and standard.

Parameters	Standard	Pectin microsphere
Cmax (ng/ml)	260.12 ± 2.22	281.29 ± 3.56*
Tmax (h)	0.48 ± 3.2	8.27 ± 4.26**
AUC0-n	705.13 ± 18.20	1645.12 ± 20.45**
AUCtotal	1288.82 ± 20.21	2620.95 ± 24.85**
AUMC0-n	1311.23 ± 15.26	12651.4 ± 18.29**
AUMCtotal	6283.19 ± 16.21	37174.7 ± 20.12**
T1/2	3.82 ± 2.17	6.01 ± 3.39**
Kel	0.181 ± 2.28	0.124 ± 4.21**

All values are expressed as mean ± SEM, n = 6; C_max, peak plasma concentration; T_max, time of peak plasma concentration; T_1/2, elimination half-life; AUC, area under the curve; and K_el, elimination rate constant.

*Significant compared to pure drug (p < 0.05) and **significant compared to microspheres in rats (p < 0.05).