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Received Dec 13, 2017; Revised Apr 16, 2018; Accepted Apr 24, 2018
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1. Introduction
Research hot topics in the drug field are to design drug preparations with high-efficiency delivery [1–3]. Oral solid drugs released from the formulation and dissolved in body fluid is the premise of absorption, so with poor dissolution, drug absorption in vivo is slow and with low bioavailability, therefore not reaching the therapeutic level of plasma concentration and poor clinical treatment [4, 5]. Fat-soluble drugs more easily cross the blood–brain barrier for a pharmacological effect [6]. In preparing conventional formulations for craniocerebral diseases, increasing the drug solubility often requires a number of drug additions, which results in toxicity. Currently, about 40% of clinically used drugs have limited use because of poor dissolution [7, 8].
In recent years, the emergence of nanoformulations for injection has brought hope to solving the problem of drug delivery of fat-soluble drugs. Nanoparticles (NPs) represent a micropectin system composed of nanospheres or nanocapsules with particle size typically <1 μm [9] Because of the small particle size and large specific surface area of NPs, the solubility and dissolution rate of insoluble drugs can be increased after drug loading [10]. Also, with the preparation and surface modification of biomaterials with specific properties, the NPs can feature long circulation and controlled release [11, 12]. Targeted delivery and reduced dose ensure efficacy and reduce side effects.
In this study, we used donepezil, a clinically important drug for treating Alzheimer’s disease, with poor solubility [13] to develop a new type of nanostructured drug. Donepezil is fat-soluble, poorly dissolved in the body, and generally taken orally; with poor drug absorption and low bioavailability, the drug has no tissue-specific, toxic side effects on the peripheral nervous system, and its clinical application is limited. In addition, conventional Aricept should be taken daily to maintain the therapeutic effect. However, in Alzheimer’s patients, with the progression of the disease to a certain stage, the lack of memory of daily medication on a daily basis is an obstacle to the use of donepezil. We need new types of...