Bilayer mucoadhesive microparticles for the delivery of metoprolol succinate: Formulation and evaluation

Figures & data

Table I. Chromatographic conditions used for the estimation of metoprolol succinate.

Stock solution	Methanol
Stationary phase	Agilent Eclipse XDB-C18 column 4.6 mm × 150 mm (5 μm)
Mobile phase	ACN:Methanol:Buffer (20:20:60)
UV detection	222 nm
Flow rate	1.0 ml/min
Dilution	HPLC Grade water

Figure 1. SEM images of metoprolol succinate loaded chitosan microparticles (A) and sodium alginate coated chitosan microparticles (B).

Table II. Effect of drug to polymer ratio on properties of chitosan microparticles.

S. No.	Drug:polymer	Particle size (μm)	Entrapment efficiency (%)	Drug loading (%)
1	1:5	5.56 ± 0.12	64.52 ± 1.01	22.31 ± 0.63
2	2:5	8.68 ± 0.18	72.76 ± 0.85	29.52 ± 0.24
3	3:5	12.63 ± 0.23	57.73 ± 1.56	29.15 ± 0.56
4	4:5	18.43 ± 0.30	27.71 ± 1.37	28.97 ± 0.49

Table III. Effect of alginate coating on microparticles.

S. No.	Core (chitosan):coat (sodium alginate)	Particle size (μm)	Zeta potential (mV)	Particle morphology
1	1:1	10.82 ± 0.67	19.04 ± 0.17	Spherical
2	1:2	12.53 ± 0.42	−12.04 ± 0.09	Spherical
3	1:3	14.79 ± 0.93	−14.06 ± 0.34	Agglomerates
4	1:4	20.98 ± 0.87	−5.67 ± 0.12	Agglomerates

Figure 2. In vitro drug release profile of metoprolol succinate loaded microparticles in 0.1 N HCl (A) and PBS (pH 6.8) (B).

Figure 3. Graph showing plasma profile of various metoprolol succinate formulations.

Table IV. The pharmacokinetic parameters after the administration of metoprolol succinate formulations.

S. No.	Marketed formulation	Chitosan microparticles based formulation	Alginate coated chitosan microparticles based formulation
Cmax (μg/ml)	10.23	22.34	28.10
tmax (h)	2.0	2.0	4.0
t½ (h)	3.04	6.97	7.91
MRT (h)	5.29	9.85	12.15
AUCtotal	71.24	223.07	378.84
Bioavailability increase (fold)	‐	3.13	5.32