Controlling the melting transition of semi-crystalline self-assembled block copolymer aggregates: controlling release rates of ibuprofen

Abstract

. (2017) Controlling the melting transition of semi-crystalline self-assembled block copolymer aggregates: controlling release rates of ibuprofen. Polymer Chemistry, 8 (35 where PEO is the hydrophilic block (25 wt%) and PODMA/PDSMA is the semi-crystalline hydrophobic block (75 wt%) that gives a thermoresponsive component to the self-assembled aggregates. By varying the relative molar proportion of DSMA to ODMA (from 0:1 to 1:0) in the synthesis of the copolymers by atom transfer radical polymerisation, the melting transition of the hydrophobic block could be varied from 21.5 to 41.1°C in the solid state. When self-assembled in aqueous dispersions the Tm range was 23.4 to 41.3°C, closely matching that of the solid samples. Preliminary analysis of the rate of release of ibuprofen from three of the block copolymer aggregates demonstrated that the rate of release was correlated with the degree of crystallinity of the hydrophobic block and that increasing temperature causes melting and a significantly enhanced release rate.

Sequence of Polyurethane Ionomers Determinative for Core Structure of Surfactant–Copolymer Complexes

“…Interestingly (and presumably the biggest difference between both PUI:PMVP 29 - b -PEO 204 complexes), the periodical arrangement of the polyurethane micelles within the complex core was much more pronounced for the asymmetric PUI-A2 , which gives rise to a 2.7-fold larger correlation length ξ of 6.7 nm ( PUI-A2 ) vs. 2.5 nm ( PUI-S2 ). This distinctly different ordering might have important implications for drug delivery applications, as the packing density and ordering within micellar cores affects both drug loading [ 21 , 22 , 25 , 26 ] and release [ 21 , 22 , 27 , 28 ].…”

“…Drug loading capacity can be increased by tuning the stereostructure [ 21 ] or by stereocomplexation [ 22 ] in the core, by optimizing the solubility parameter of the hydrophobic block towards the drug [ 23 , 24 ], by reducing core crystallinity [ 25 ], or by decreasing the core density (e.g., via a rigid core block) [ 26 ]. Similarly, sustained release can be achieved by tuning the stereostructure of the core-forming block [ 21 ], stereocomplexation in the core [ 27 ], increasing core crystallinity [ 28 ], tuning the core density through variations in the architecture of the hydrophobic block [ 22 ], or increasing the acyl chain length [ 24 ]. Additionally, the architecture of the neutral PEO block can be used to improve both loading and release [ 29 ].…”

Recent Progress in Polymer Cubosomes and Hexosomes

“…Adapted with permission. [ 37 ] Copyright 2017, Royal Society of Chemistry. C) The chemical structure of PEO 39 ‐ b ‐PBMA (c 1 ), Cryo‐EM images of colloids of PEO 45 ‐ b ‐PBMA 110 (c 2 ) and of PEO 45 ‐ b ‐ PBMA 86 (c 3 ).…”

Fluorescent polymer cubosomes and hexosomes with aggregation-induced emission

“…3,7 Nevertheless, this eld is still in its infancy, with many remaining challenges and exciting opportunities. The polymer cubosomes and hexosomes reported in the literature include the following categories according to the architectures of ABCPs: (1) linear diblock copolymers; [13][14][15][16][17][18][19][20][21][22] (2) side-chain diblock copolymers [23][24][25][26][27][28][29][30][31][32][33] with side-chains exhibiting special features (crystalline, [23][24][25][26][27][28] liquid crystalline, 29 nucleobase-pair interaction, 30 halogen bonding interaction, 31 etc. ); (3) diblock copolymers with dendrimer blocks.…”

“… 28 The melting point of the crystalline block was employed to perform the thermally controlled release of ibuprofen previously encapsulated in cubosomes. 28 Driven by the increasing research interest in these polymer colloids with inverted nanostructures, the development of new ABCPs for the controllable preparation of cubosomes and hexosomes with innovative potential applications is highly desirable.…”