Formulation, Characterization and Evaluation against SH-SY5Y Cells of New Tacrine and Tacrine-MAP Loaded with Lipid Nanoparticles

Sara Silva,Nuno Vale,AntóNio J Almeida,Lídia Gonçalves,Joana Marto

doi:10.3390/nano10102089

Abstract

Tacrine (TAC) was the first FDA approved drug for the treatment of Alzheimer’s disease, resulting in increased memory and enhanced cognitive symptoms in patients. However, long-term therapy presents poor patient compliance associated with undesired side effects such as nausea, vomiting and hepatoxicity. To improve its therapeutic efficacy and decrease toxicity, the use of nanoparticles could be applied as a possible solution to delivery TAC. In this context, a project has been designed to develop a new nanostructured lipid carrier (NLC) as a delivery system for TAC and conjugate TAC and model amphipathic peptide (MAP) to decrease TAC limitations. Different formulations loaded with TAC and TAC + MAP were prepared using a combination of Compritol 888 ATO as the solid lipid and Transcutol HP as the liquid lipid component. Physical characterization was evaluated in terms of particle size, surface charge, encapsulation efficiency and in vitro drug release studies. Particle size distributions within the nanometer range were obtained with encapsulation efficiencies of 72.4% for the TAC and 85.6% for the TAC + MAP conjugate. Furthermore, cytotoxicity of all NLC formulations was determined against neuroblastoma cell line SH-SY5Y. The optimized TAC delivery system revealed low toxicity suggesting this could be a potential carrier system to deliver TAC. However, TAC + MAP conjugated even encapsulated in the NLC system demonstrated toxicity against the SH-SY5Y cell line.

Highlights

Tacrine (TAC) is a competitive and reversible inhibitor of both acetylcholinesterase (AChE) and butylcholinesterase [1,2]
We developed a stable and safe dual delivery to improve TAC delivery by combining nanostructured lipid carrier (NLC) with TAC or its conjugate with model amphipathic peptide (MAP) (TAC-MAP) and evaluating their toxicity in vitro, using SH-SY5Y cells to determine its safety for use in future studies of Alzheimer’s disease (AD) models
Three different NLC formulations loaded with TAC or TAC-MAP were prepared using Compritol 888 ATO, different amounts of Transcutol HP as liquid lipid, and Tween 80 as the surfactant

Summary

Introduction

Tacrine (TAC) is a competitive and reversible inhibitor of both acetylcholinesterase (AChE) and butylcholinesterase [1,2]. The mechanism of action of TAC relies on inhibition of AChE, leading to increased availability of acetylcholine associated with an enhancement on the muscarinic effect, improved memory and cognition of AD patients [2]. When compared to the common solid lipid NP, NLCs are characterized by a less ordered structure which reflects on higher drug loading capacity and retention during storage. Another great advantage of this delivery system is the ability to functionalize through conjugation, grafting or coating with polymers and specific ligands (aptamer, peptides, antibodies and others) [19]. Tween 80 was used to stabilize the overall formulation and when used in nanoparticle formulations has demonstrated the ability to enhance blood-brain barrier crossing [24]

Methods

Results

Conclusion