Effect of sublingual medication of sildenafil citrate/ apomorphine on sexual behaviour of male rats

New tricks for an old dog: A repurposing approach of apomorphine

Apomorphine is a 150-year old nonspecific dopaminergic agonist, currently indicated for treating motor fluctuations in Parkinson's disease. At the era of drug repurposing, its pleiotropic biological functions suggest other possible uses. To further explore new therapeutic and diagnostic applications, the available literature up to July 2018 was reviewed using the PubMed and Google Scholar databases. As many of the retrieved articles consisted of case reports and preclinical studies, we adopted a descriptive approach, tackling each area of research in turn, to give a broad overview of the potential of apomorphine. Apomorphine may play a role in neurological diseases like restless legs syndrome, Huntington's chorea, amyotrophic lateral sclerosis, Alzheimer's disease and disorders of consciousness, but also in sexual disorders, neuroleptic malignant(-like) syndrome and cancer. Further work is needed in both basic and clinical research; current developments in novel delivery strategies and apomorphine derivatives are expected to open the way.

Rapid-Onset Sildenafil Sublingual Drug Delivery Systems: In Vitro Evaluation and In Vivo Pharmacokinetic Studies in Rabbits

The aim of the present study was to prepare sublingual delivery systems for sildenafil and evaluate its relative bioavailability after sublingual administration in rabbits to attain a rapid onset of action with good efficacy at lower doses. For sublingual application, sildenafil and its citrate were formulated in 2 different dosage forms: the first was a sublingual spray consisting of sildenafil in 2 microemulsion systems, oleic acid or propylene glycol (PG), and the second was sublingual tablets prepared with various granulated sublingual sprays adsorbed onto a silicate adsorbant (Florite(®) R), binders (Cyclocel(®) or EMDEX(®)), and disintegrants (Ac-Di-Sol(®) or Kollidon(®) CL). Results showed that sublingual absorption of sildenafil spray prepared with PG was fairly rapid. At a 0.5-mg dose, the mean onset of action was 1.3 ± 0.6 min and lasted for about 1.5 h according to the pharmacokinetic studies. In vivo studies also showed that for sublingual tablets formulated with sildenafil in PG adsorbed onto Florite(®) R at a 1:1 weight ratio then mixed with Cycloel(®) and Ac-Di-Sol(®), the onset action was fast at 1.9 ± 0.4 min and lasted for about 1 h at 0.5 mg. These findings suggest the potential for the sublingual delivery of sildenafil instead of the conventional oral administration.