Thermodynamic and kinetic aspects involved in the development of nanocarriers and drug delivery systems based on cationic biopolymers (Review)

BIANCO I.D.; ALASINO R.V.; LEONHARD V.; BELTRAMO D.M.

CURRENT PHARMACEUTICAL DESIGN.

BENTHAM SCIENCE PUBL LTD

Lugar: Oak Park; Año: 2016 vol. 22 p. 1 - 16

1381-6128

p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 10); line-height: 120%; text-align: left; }p.western { font-family: "Liberation Serif",serif; font-size: 12pt; }p.cjk { font-family: "Droid Sans Fallback"; font-size: 12pt; }p.ctl { font-family: "FreeSans"; font-size: 12pt; }a:link { color: rgb(0, 0, 255); }During thelast years we have seen an increasing number of reports describingnew properties and potential applications of cationic polymers andderived nanostructures. This review gives a summary of theirapplications in drug delivery, the preparation methods for nano andmicrostructures and will attempt to give a glimpse on how theirstructure, chemical composition and properties may be affected ormodulated as to make them suitable for an intended application asdrug delivery nanocarriers. The compositional complexity with theexistence of several reacting groups makes cationic nanostructurescritically sensitive to the contribution of thermodynamic and kineticparameters in the determination of the type and stability of aparticular structure and its abilityto respond to changes in environmental conditions in the right timeframe.Curiously, and contrarily to what could be expected, despite the factthat cationic polymers can form strong electrostatic interactions thecontribution of the entropic component has been often found to bevery important for their association with negatively chargedsupramolecular structures. Some general considerations indicate thatwhen considering a complex multimolecular system like a nanocarriercontaining an active ingredient it is frequently possible to findconditions under which enthalpic and entropic contributions arecompensated leading to stable structures with a marginalthermodynamic stability (free energy change close to zero) which makethem able to respond relatively fast to changes in the environmentalconditions and therefore suitable for the design of smart drugdelivery systems. Like with other nanocarriers, it should always bekept in mind that the properties of cationic nanocarriers will dependnot only on their chemical composition but also on the properties ofthe structures formed by them.