Title:Thermodynamic and Kinetic Aspects Involved in the Development of Nanocarriers and Drug Delivery Systems Based on Cationic Biopolymers
Volume: 22
Issue: 22
Author(s): Ismael D. Bianco, Roxana V. Alasino, Victoria Leonhard and Dante M. Beltramo
Affiliation:
Keywords:
Cationic polymers, drug delivery systems, enthalpy, entropy, nanocarriers.
Abstract: During the last years we have seen an increasing number of reports describing new properties and potential
applications of cationic polymers and derived nanostructures. This review gives a summary of their applications
in drug delivery, the preparation methods for nano and microstructures and will attempt to give a glimpse on
how their structure, chemical composition and properties may be affected or modulated as to make them suitable
for an intended application as drug delivery nanocarriers. The compositional complexity with the existence of several
reacting groups makes cationic nanostructures critically sensitive to the contribution of thermodynamic and kinetic
parameters in the determination of the type and stability of a particular structure and its ability to respond to
changes in environmental conditions in the right time frame. Curiously, and contrarily to what could be expected, despite the fact that
cationic polymers can form strong electrostatic interactions the contribution of the entropic component has been often found to be very
important for their association with negatively charged supramolecular structures. Some general considerations indicate that when considering
a complex multimolecular system like a nanocarrier containing an active ingredient it is frequently possible to find conditions
under which enthalpic and entropic contributions are compensated leading to stable structures with a marginal thermodynamic stability
(free energy change close to zero) which make them able to respond relatively fast to changes in the environmental conditions and therefore
suitable for the design of smart drug delivery systems. Like with other nanocarriers, it should always be kept in mind that the properties
of cationic nanocarriers will depend not only on their chemical composition but also on the properties of the structures formed by
them.
