Sublingual testosterone (0.5 mg) produces an increase in sexual motivation and desire in sexually functional women, about 4 hours after its peak RG-7388 in vitro plasma levels (time to maximum concentration [T max] = 15 min) OSI-906 cell line [9]. The testosterone and the PDE-5 inhibitor are released in such a timeframe that the peak plasma concentration of the PDE-5 inhibitor coincides with the 4-hour delay in behavioral effects of the testosterone. In women with low sensitivity to sexual cues,
this combination showed superiority over placebo in increasing sexual satisfaction [7, 10]. For women who have a dysfunctional activation of sexual inhibitory mechanisms during sexual stimulation, Lybridos is developed. Nirogacestat concentration Lybridos is the combination of sublingual testosterone and a 5-HT1A receptor agonist (buspirone), released in such a timeframe that the pharmacological effects of the 5-HT1A receptor agonist coincide with the behavioral window induced by the testosterone administration
[8]. This combination in women with dysfunctional activation of sexual inhibitory mechanisms increased sexual satisfaction compared with placebo [8]. In previous clinical trials, the two components (sublingual testosterone in combination with a PDE-5 inhibitor or 5-HT1A receptor agonist) were administered separately; however, these components have been developed into one single combination tablet in recent phase IIb trials. Both products are intended for use on a ‘per need’ (i.e., not continuous or chronic) basis before anticipated sexual activity. Studies performed by various researchers have clearly indicated a time lag of about 3–4 hours in the pharmacodynamics effect of sublingual testosterone on genital arousal in women and other cognitive and affective functions [9, 11–23]. Therefore, either the PDE5 inhibitor (Lybrido) or (5-HT1a) receptor agonist (Lybridos) component needs to be administered approximately 2–3 hours after administering the
testosterone. In the above-mentioned clinical studies, this was obtained by administering the testosterone sublingually as a solution, followed 2.5 hours later by a PDE-5 inhibitor (sildenafil) or a 5-HT1A receptor agonist (buspirone) Etofibrate as a tablet (to ensure blinding, the tablet was administered in a gelatin capsule), thus creating overlapping peaks in effect of testosterone and sildenafil or buspirone. Because this kind of administration is not suitable and rather cumbersome for daily use in practice, we developed a single oral combination tablet that will deliver testosterone sublingually and, approximately 2.5 hours later in the gastro-intestinal tract, the sildenafil or buspirone component, allowing women with FSIAD to take just one single tablet 3–6 hours before the anticipated sexual activity. The objective of this study was to see if the pharmacokinetic profile of testosterone given sublingually followed 2.