Hybrid CaCO3-mucin crystals: Effective approach for loading and controlled release of cationic drugs

Naturally derived nano- and micro-drug delivery vehicles: halloysite, vaterite and nanocellulose

“…Besides enhancing loading capacity for small drugs, the inclusion of polymers inside crystals may also stabilise them and slow down the VCC recrystallization to calcite that is important for modulating the drug release profile. 91 Loading of molecules into VCC can be performed under mild conditions either during crystal growth (this approach is usually denoted as co-precipitation or co-synthesis 76,92 ) or by means of post-loading into pre-formed VCC crystals (e.g. via adsorption into crystal pores 92 or a recently introduced freezedrying approach 93 ).…”

“…Recrystallization-mediated release occurs due to the phase transition of thermodynamically unstable vaterite to more favorable and non-porous calcite with much lower surface area and therefore much lower drug capacity. 77,91,106 Recrystallization and, as a result, release kinetics can be effectively controlled via the use of additives that fill the pores of the crystals. For instance, hybrids of VCC with ferromagnetic nanoparticles recrystallize to calcite significantly more rapidly than bare vaterite crystals, while multilayer coating or the co-precipitation of the polymers into VCC crystals may decelerate vateritecalcite transformation.…”

“…For instance, hybrids of VCC with ferromagnetic nanoparticles recrystallize to calcite significantly more rapidly than bare vaterite crystals, while multilayer coating or the co-precipitation of the polymers into VCC crystals may decelerate vateritecalcite transformation. 76,91 Notably, plasma proteins like bovine serum albumin (BSA) may also significantly adsorb to the surfaces of VCC crystals, which is of high importance for intravenous administration. Plasma proteins not only suppress the VCC recrystallization and therefore allow prolonged circulation of the crystals but also minimize the neutrophil activation caused by VCC binding to the membranes of the neutrophils.…”

Polyelectrolyte Multilayer Capsule (PEMC)-Based Scaffolds for Tissue Engineering

“…An example includes the loading of doxorubicin into vaterite crystals pre-loaded with mucin ( Figure 8 ). Mucin loading was performed via co-synthesis [ 90 , 182 ]; i.e., when mucin was added during vaterite crystal growth and entrapped within the crystals in a very high amount [ 183 ]. This ensures that a rather large quantity of doxorubicin can be loaded into such composite capsules due to the high electrostatic affinity of doxorubicin to mucin.…”

“… Schematic of the co-synthesis of CaCO 3 -mucin hybrid crystals containing doxorubicin ( I ) and the release of doxorubicin at physiologically relevant conditions ( II ) via diffusion of mucin-doxorubicin complex out due to the re-crystallisation of the CaCO 3 crystals to calcite ( IIa ) and the complex diffusion out of the pores of the vaterite crystals ( IIb ). This schematic is taken with permission from reference [ 183 ], copyright© 2019, Elsevier. …”