Transdermal delivery of venlafaxine hydrochloride: the effects of enhancers on permeation across pig ear skin

Spray-Dried Cytisine-Loaded Matrices: Development of Transbuccal Sustained-Release Tablets as a Promising Tool in Smoking Cessation Therapy

Cytisine (CYT) has emerged as a promising molecule to treat nicotine addiction, since it acts as a partial agonist of nicotinic acetylcholine receptors. However, its unfavorable pharmacokinetic properties lead to multiple administrations per day, reducing the patient’s compliance and increasing the side effects. To overcome these drawbacks, CYT buccal administration is here proposed. Firstly, CYT stability in the buccal environment was assessed and its intrinsic ability to permeate/penetrate the tissue was determined by applying CYT solutions at increasing concentrations. Furthermore, a spray-drying method was selected and optimized as it is an eco-friendly, easily scalable and effective technique to obtain uniform and reproducible CYT-loaded (5% w/w) pharmaceutical powders, which were directly compressed, thus obtaining different buccal delivery systems (BDSs). The obtained BDSs were homogeneous and reproducible and embedded CYT in its amorphous form. The mechanism of CYT release was evaluated in vitro and found to be mainly driven by a Fickian diffusion phenomenon. Predominantly, the ex vivo permeation assays highlighted the ability of the BDSs to enhance CYT permeation, also producing high drug fluxes through the mucosa. Speculative mathematical evaluations based on the already-known CYT pharmacokinetic parameters showed that CYT-loaded BDSs could potentially be sufficient to obtain a therapeutic effect, thus making the reported formulations suitable candidates for further in vivo trials.

Enhancement strategies for transdermal drug delivery systems: current trends and applications

Transdermal drug delivery systems have become an intriguing research topic in pharmaceutical technology area and one of the most frequently developed pharmaceutical products in global market. The use of these systems can overcome associated drawbacks of other delivery routes, such as oral and parenteral. The authors will review current trends, and future applications of transdermal technologies, with specific focus on providing a comprehensive understanding of transdermal drug delivery systems and enhancement strategies. This article will initially discuss each transdermal enhancement method used in the development of first-generation transdermal products. These methods include drug/vehicle interactions, vesicles and particles, stratum corneum modification, energy-driven methods and stratum corneum bypassing techniques. Through suitable design and implementation of active stratum corneum bypassing methods, notably microneedle technology, transdermal delivery systems have been shown to deliver both low and high molecular weight drugs. Microneedle technology platforms have proven themselves to be more versatile than other transdermal systems with opportunities for intradermal delivery of drugs/biotherapeutics and therapeutic drug monitoring. These have shown that microneedles have been a prospective strategy for improving transdermal delivery systems.