Transdermal delivery of tadalafil using a novel formulation

Figures & data

Table 1. Composition of tadalafil gel.

	Formulation code
Composition	F1	F2	F3	F4
Tadalafil (mg)	25	25	25	25
Carbopol 940 (mg)	500	500	500	500
M-T2^a	–	25 mL	25 mL
Oleic acid	–	–	500 µL	500 µL
Triethanolamine (µL)	500	500	500	500
Distilled water	q.s.	q.s.	q.s.	q.s.

^aTadalafil was dissolved in 20% (w/v) HPCD at first and then mixture solutions of PEG and tween 80 were added.

Figure 1. In vitro cumulative amount of tadalafil permeated (µg/cm²) through excised rat skin up to 24 h.

Table 2. The intra-day and inter-day precision and accuracy values for tadalafil in blank plasma.

Intra-day (n = 3)		Inter-day (n = 3)
Accuracy (%)	Precision (RSD %)	Accuracy (%)	Precision (RSD %)
92.8	2.4	92.1	2.4
96.9	3.5	88.6	2.1
93.5	3.9	93.5	1.8

Figure 2. Cytotoxicity of tadalafil solution and gel against. (a) HaCaT cells and (b) Pam212 cells.

Table 3. Permeation parameters of tadalafil from the four different tadalafil gels through the rat skin.

	Flux (µg/cm^2/h)	Accumulative amount^a (µg/cm^2)
F1	0.840 (r^2= 0.961)	20.2 ± 1.8
F2	1.118 (r^2= 0.962)	26.8 ± 0.8
F3	1.506 (r^2= 0.968)	36.2 ± 7.2
F4	1.207 (r^2= 0.948)	28.9 ± 2.4

^aAccumulative amount of tadalafil permeated for 24 h.

Figure 3. Mean plasma concentration–time profiles of tadalafil after transdermal administration of tadalafil gel.

Table 4. Mean pharmacokinetic parameters of tadalafil gels after transdermal delivery.

PK parameters	F1	F2	F3	F4
Cmax (µg/ml)	0.7 ± 0.2	1.1 ± 0.3	1.6 ± 0.4	1.2 ± 0.4
T1/2 (h)	17.0 ± 4.2	17.9 ± 5.3	16.7 ± 0.8	25.2 ± 1.4
Tmax (h)	4.0	4.0	2.0	2.0
AUC0–∞ (µg·h/ml)	17.7 ± 6.0	30.8 ± 13.7	39.6 ± 12.1	35.7 ± 26.5
MRT (h)	25.8 ± 5.8	26.6 ± 9.5	25.2 ± 1.4	19.9 ± 4.8