Oral bioavailability and pharmacokinetics of sildenafil citrate dry foam tablets in rats

Figures & data

Table 1. All ingredients of sildenafil dry foam tablet formulation used in this study

Ingredients	Amount (mg)
Sildenafil citrate	141
Sodium dodecyl sulphate	14
Purified water	1*
Maltodextrin	200
Mannitol	200
Croscarmellose sodium	39
Magnesium stearate	6
Total weight	600

* will be evaporated during manufacturing process

Table 2. Finished product specification and physicochemical properties of sildenafil citrate dry foam tablets

Test	Result
Appearance	Round, flat, white to off-white tablet
Assay of sildenafil	101.2% Labeled amount (100 mg/tab)
Average tablet weight	601 ± 5 mg
Thickness	5.74 ± 0.05 mm
Hardness	5.2 ± 0.3 kg
Disintegration time	< 2 min
Friability	< 1%
Dissolution	Sildenafil was 100% dissolved in 10 min

Table 3. Comparative mean (± SD) of pharmacokinetic parameters of sildenafil and N-desmethyl sildenafil in rats after oral administration

PK parameters	Sildenafil			N-desmethyl sildenafil
	Dry foam tablets	Commercial film coated tablets	Powder	Dry foam tablets	Commercial film coated tablets	Powder
AUC0-6h (μg h/mL)	2.50 ± 0.32	1.95 ± 0.42	1.53 ± 0.61	2.99 ± 0.38	2.67 ± 0.44	2.12 ± 0.71
Cmax (μg/mL)	1.45 ± 0.35	1.19 ± 0.62	0.97 ± 0.27	1.22 ± 0.61	1.18 ± 0.59	0.89 ± 0.42
Tmax (h)	0.5 ± 0.1	0.5 ± 0.2	0.5 ± 0.1	1.0 ± 0.3	1.0 ± 0.2	0.75 ± 0.1
T1/2	0.6 ± 0.2	0.4 ± 0.1	0.5 ± 0.2	1.2 ± 0.3	1.4 ± 0.3	1.6 ± 0.3

Figure 1. Mean plasma concentration—time profiles of sildenafil (A) and N-desmethyl sildenafil (B) after oral administration of sildenafil at a dose of 20 mg/kg in dry foam tablet (solid circles, n = 5), commercial film coated tablets (open circles, n = 5) and sildenafil powder (solid triangles, n = 5) in rats. Data are the mean ± standard deviation (SD).