Premium
An Intelligent Transdermal Formulation of ALA‐Loaded Copolymer Thermogel with Spontaneous Asymmetry by Using Temperature‐Induced Sol–Gel Transition and Gel–Sol (Suspension) Transition on Different Sides
Author(s) -
Cao Dinglingge,
Chen Xi,
Cao Feng,
Guo Wen,
Tang Jingyu,
Cai Caiyun,
Cui Shuquan,
Yang Xiaowei,
Yu Lin,
Su Yong,
Ding Jiandong
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202100349
Subject(s) - materials science , copolymer , suspension (topology) , sol gel , transdermal , chemical engineering , ethylene glycol , polymer chemistry , nanotechnology , composite material , polymer , medicine , mathematics , pharmacology , homotopy , pure mathematics , engineering
Aqueous solutions of some amphiphilic block copolymers undergo a sol–gel transition upon heating and are thus called thermogels. In the thermogel family, some systems also exhibit a gel–sol (suspension) transition at higher temperatures following the sol–gel transition, which is usually ignored in biomedical applications. Herein, for the first time, a case is reported employing both the sol–gel transition and the gel–sol (suspension) transition, which is found in the development of a transdermal hydrogel formulation containing 5‐aminolevulinic acid for photodynamic therapy (PDT) of skin disease. Two poly( d , l ‐lactide‐ co ‐glycolide)‐ b ‐poly(ethylene glycol)‐ b ‐poly( d , l ‐lactide‐ co ‐glycolide) triblock copolymers of different block lengths are synthesized. The transition temperatures of the formulation can be easily adjusted to meet the condition of sol–gel transition temperature ( T gel ) < room temperature ( T air ) < gel–sol (suspension) temperature ( T sol (suspension) ) < body temperature ( T body ) via changing the blending ratio. Therefore, after applying to skin, formulation of spontaneous asymmetry with a hydrogel outside and a sol (suspension) inside can avoid free flowing and achieve rapid release to ensure an efficient PDT. This study demonstrates such a concept via characterizations of the “block blend” biomaterials and drug release profiles, and also via cell experiments, in vitro permeation, and in vivo transdermal delivery studies.