A Study to Enhance the Oral Bioavailability of S-Adenosyl-L-Methionine (SAME): SLN and SLN Nanocomposite Particles

The endogenous molecule, S-adenosyl-L-methionine (SAMe) is a key factor due to its role in the methylation cycle and modulation of monoaminergic neurotransmission. Since many mental disorders have linked to the monoaminergic system, the level of SAMe in blood and cerebrospinal fluid is important in the treatment of major depression. In this study, solid lipid nanoparticles (SLN) were prepared in order to increase the limited oral bioavailability of SAMe, and SLN based nanocomposite particles (SAMe-SLN-NC) were further developed using an enteric polymer for passive targeting of intestinal lymphatic system. In this manner, it was also aimed to protect SAMe loaded SLN from harsh gastric environment as well as hepatic first-pass metabolism.

Highlights

To increase the oral bioavailability of SAMe, a naturally occurring molecule which has crucial role in many biochemical pathways, for depression treatment.

To obtain SLN nanocomposite particles using enteric polymers to protect SAMe loaded SLN from the gastric environment.

To improve intestinal SAMe permeability via passively targeted lipid-based drug carrier systems.

Dynamic light scattering (DLS) analysis of SLN was performed, drug content was measured, SAMe release patterns were examined and the permeation ability of SAMe was investigated by the Parallel Artificial Membrane Permeability Assay (PAMPA) to characterize SAMe loaded SLN formulation. According to the PAMPA results, SAMe-SLN with the average particle size of 242 nm showed enhanced SAMe permeability in comparison to pure drug. Delayed drug release obtained by SLN nanocomposite particles indicated the protection of drug-loaded SLN in the acidic gastric medium and their intact presence in the intestine. SAMe solution or particle suspensions were prepared using 0.45 (w/v) hydroxypropyl methylcellulose aqueous solution to be applied to groups of animals for pharmacokinetic studies. In vivo pharmacokinetic parameters revealed enhancement in relative bioavailability of SAMe upon oral administration of SLN based formulations. This was attributed to intact absorption of lipid matrix through lymphatic path. A statistically significant increase in SAMe plasma levels was obtained at 15^th and 30^th minutes with SAMe-SLN and at 2^nd and 4^th hours with SAMe-SLN-NC.

Overall results suggest that SLN is a promising carrier to passive lymphatic targeting of SAMe and novel SLN nanocomposite particles which presented efficient oral bioavailability is a potential way for oral delivery of SAMe and treatment of major depression.

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Article information: Gulin Amasya, Ahmet Dogan Ergin, Ozge Erkan, Arif Tanju Ozçelikay, Zerrin Sezgin Bayindir, Nilufer Yuksel. A Study to Enhance the Oral Bioavailability of S-Adenosyl-L-Methionine (SAME): SLN and SLN Nanocomposite Particles, Chemistry and Physics of Lipids, 2021. https://doi.org/10.1016/j.chemphyslip.2021.105086.