Advances in Solid Dispersion Techniques for Enhancing Drug Solubility, Bioavailability and Controlled Release

Solid dispersion (SD) refers to the dispersion of
active ingredients, whether one or more, within inert
carriers in a solid state. This is achieved through methods
like fusion, solvent, or solvent fusion. The solid dispersion
technique is particularly valuable for enhancing the
solubility of inadequately soluble drugs, particularly
those falling under BCS Class II. This technique involves
the utilization of carriers such as polyethylene glycol 4000,
urea, and polyvinylpyrrolidone K 30 to improve the
drug's solubility and dissolution properties. The method
of solid dispersion has been utilized to improve the
solubility, dissolution, and bioavailability of various
natural drug components. Furthermore, solid dispersion
has been investigated as a strategy for developing natural
drug products with controlled or sustained release
characteristics. The mechanism of action of this delivery
system relies on the specific type of solid dispersion, as
well as the interactions among the drugs, carriers, and
other components incorporated into the formulation.
Currently, there are various methods accessible for
characterizing SDs, including X-ray diffraction,
differential scanning calorimetry, FTIR spectroscopy,
and dissolution testing, among others.
The pharmaceutical uses of the Solid Dispersion
technique encompass: augmenting drug absorption,
achieving a uniform distribution of a small drug quantity
in a solid state, and safeguarding unstable drugs by
mitigating processes like hydrolysis, oxidation, and
photooxidation.