Browsing by Author "Li, Xiaosi"

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    Applications of capillary action in drug delivery
    (Cell Press, 2021) Li, Xiaosi; Zhao, Yue; Zhao, Chao; University of Alabama Tuscaloosa; Northwestern Polytechnical University
    Contrary to the fact that capillary action is ubiquitous in our daily lives, its role in drug delivery has not attracted attention. Therefore, its application in medicine and disease treatment has not been actively developed. This perspective begins by reviewing the principles, advantages, and limitations of the three existing drug delivery strategies: non-covalent interaction, cavity loading, and covalent conjugation. Then, we discussed the principle of capillary action in drug delivery and the influencing factors that determine its performance. To illustrate the advantages of capillary action over existing drug delivery strategies and how the capillary action could potentially address the shortcomings of the existing drug delivery strategies, we described five examples of using capillary action to design drug delivery platforms for disease treatment: marker pen for topical and transdermal drug delivery, microneedle patch with a sponge container for pulsatile drug delivery, core- shell scaffold for sustained release of growth factors, oral bolus for insulin delivery to the esophagus, and semi-hollow floating ball for intravesical and gastroprotective drug delivery. Each of the five drug delivery platforms exhibits certain unique functions that existing drug delivery technologies cannot easily achieve, hence expected to solve specific practical medical problems that are not satisfactorily resolved. As people pay more attention to capillary action and develop more drug delivery platforms, more unique functions and characteristics of capillary action in drug delivery will be explored. Thus, capillary action could become an important choice for drug delivery systems to improve therapeutic drug efficacy, treat diseases, and improve human health.
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    Strategies to Obtain Encapsulation and Controlled Release of Small Hydrophilic Molecules
    (Frontiers, 2020) Li, Qi; Li, Xiaosi; Zhao, Chao; University of Alabama Tuscaloosa
    The therapeutic effect of small hydrophilic molecules is limited by the rapid clearance from the systemic circulation or a local site of administration. The unsuitable pharmacokinetics and biodistribution can be improved by encapsulating them in drug delivery systems. However, the high-water solubility, very hydrophilic nature, and low molecular weight make it difficult to encapsulate small hydrophilic molecules in many drug delivery systems. In this mini-review, we highlight three strategies to efficiently encapsulate small hydrophilic molecules and achieve controlled release: physical encapsulation in micro/nanocapsules, physical adsorption via electronic interactions, and covalent conjugation. The principles, advantages, and disadvantages of each strategy are discussed. This review paper could be a guide for scientists, engineers, and medical doctors who want to improve the therapeutic efficacy of small hydrophilic drugs.
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    Zero-Order Controlled Release of Water-Soluble Drugs Using a Marker Pen Platform
    (American Chemical Society, 2021) Li, Xiaosi; Li, Qi; Zhao, Chao; University of Alabama Tuscaloosa
    Zero-order drug release that releases drugs at a constant rate is beneficial to prolong the therapeutic effect and avoid the side effects of drugs. However, due to the weak interaction between the drug and the carrier, it is particularly challenging to achieve zero-order release of water-soluble drugs. Inspired by the marker pen, which stores the water-based ink in the sponge core and releases a constant amount of ink from the tip for writing, we explore the marker pen as a drug delivery platform to achieve zero-order release of water-soluble drugs. Through the capillary interaction between the material and water, the pen core can absorb the aqueous drug solution to encapsulate and store the water-soluble drug model sodium fluorescein (SF) and can release the encapsulated SF by moving the pen tip across the surface. The results show that the marker pen can release a constant amount of SF at the nanogram level per unit length of the line drawn with the pen, and the cumulative SF release amount has a linear relationship with the length of the line. In addition, the amount of released SF is linear with respect to the SF concentration in the aqueous solution. Moreover, the SF-filled marker pen has excellent long-term stability as evidenced by that the amount of SF released from the pen remains constant within two weeks after filling.