Table 1. Formulation compositions of the swellable/floatable gastroretentive drug delivery system and their swelling ability and floating behavior in deionized water and simulated gastric solution.

Rx	Components (%)				Observation
	HEC 250HHX	PEO 8000K	NaCMC		Swelling index (S w)		Float / Sink
			450cps	2500cps	2 h	6 h
F1–0	100	-	0	-	3.76±0.01	6.99±0.10	Float (>4h)
F1–1	90	-	10	-	4.57±0.07	8.40±0.42	Float (>2h)
F1–2	80	-	20	-	4.90±0.38	10.63±0.33	Float (>4h)
F1–3	70	-	30	-	5.75±0.24	12.61±0.01	Float (>2h)
F1–4	60	-	40	-	5.91±0.32	13.45±0.58	Float (>4h)
F1–5	50	-	50	-	5.80±0.16	13.95±0.34	Sink
F1–6	40	-	60	-	6.20±0.06	13.32±0.14	Sink
F1–7	25	-	75	-	6.19±0.06	9.95±0.29	Float (>4h)
F1–8	10	-	90	-	5.57±0.37	7.19±0.44	Sink
F1–9	0	-	100	-	4.83±0.45	2.28±0.04	Float (>2h)
F1–0*	100	-	0	-	4.05±0.68	7.54±1.17	Float (>8h)
F1–1*	90	-	10	-	3.99±0.25	7.07±0.40	Float (>8h)
F1–2*	80	-	20	-	3.68±0.06	6.61±0.37	Float (>8h)
F1–3*	70	-	30	-	3.60±0.15	6.33±0.02	Float (>8h)
F1–4*	60	-	40	-	3.41±0.07	6.38±0.17	Float (>8h)
F1–5*	50	-	50	-	3.35±0.16	5.81±0.21	Float (<6h)
F1–6*	40	-	60	-	3.22±0.22	4.98±0.15	Float (<4h)
F1–7*	25	-	75	-	2.81±0.11	4.00±0.13	Float (<4h)
F1–8*	10	-	90	-	Erosion	Erosion	Float (<2h)
F1–9*	0	-	100	-	Erosion	Erosion	Float (<1h)
F2–1	90	-	-	10	5.11±0.47	10.40±0.18	Float (>4h)
F2–2	80	-	-	20	6.82±0.25	13.48±0.62	Sink
F2–3	70	-	-	30	8.72±0.11	16.45±1.82	Float
F2–4	60	-	-	40	8.18±0.45	12.66±2.66	Float
F2–5	50	-	-	50	7.86±0.40	13.24±0.40	Sink
F2–6	40	-	-	60	9.79±0.08	10.09±0.02	Sink
F2–7	25	-	-	75	7.32±0.23	7.39±0.03	Float (>4h)
F2–8	10	-	-	90	7.27±0.26	4.71±0.28	Sink
F2–9	0	-	-	100	6.38±1.38	0.68±0.41	Float (>2h)
G-0		100	0	-	4.30±0.50	8.67±0.42	Sink
G-1	-	90	10	-	4.61±0.09	9.96±0.84	Sink
G-2	-	80	20	-	4.83±0.12	11.01±0.06	Sink
G-3	-	70	30	-	5.51±0.14	11.44±0.10	Sink
G-4	-	60	40	-	5.63±0.23	12.30±0.30	Sink

*: Experiments were conducted in simulated gastric solution. For the rest, experiments were conducted in deionized water.