# Role of Phospholipids on Drug Dissolution in Polymer Solid Dispersions Prepared by Hot-Melt Extrusion

## TL;DR

This study explores how phospholipids affect drug dissolution in solid dispersions made using hot-melt extrusion, showing that they can improve process efficiency and drug release.

## Contribution

The novel contribution is demonstrating that phospholipids enhance drug dissolution in SLP-based dispersions without affecting COP-based ones.

## Key findings

- PPC addition improved process yield without requiring a plasticizer.
- SLP-based dispersions showed up to a 5-fold increase in drug dissolution with PPC.
- PPC had no significant effect on COP-based dispersions but enhanced SLP-based ones.

## Abstract

The development of
solid dispersions (SDs) has gained increased
attention in recent decades, leading to successful delivery systems
for various marketed products. In general, combinations of polymers
and lipids in SD formulations have shown promising results in reducing
the disadvantages associated with the isolated use of hydrophilic
excipients such as copovidone (COP) and Soluplus (SLP). This study
investigated the influence of the phospholipid (soy phosphatidylcholine,
PPC, 15 and 30%, w/w) on the dissolution performance of drug-polymer
SDs prepared by hot melt extrusion. A low-solubility model drug (ritonavir,
RTV) was selected for the study. A complete drug amorphization was
observed for all extrudates despite the PPC presence. However, PPC
improved the process yield without requiring a plasticizer. Morphology
and particle size analyses revealed the effects of PPC addition in
the aqueous dispersions prepared from SDs, denoting a higher polymer–lipid
interaction in COP dispersions and the formation of micrometric structures
in both COP and SLP dispersions. COP-based SDs produced almost instantaneous
increases in RTV dissolution of up to 7-fold, while SLP-based SDs
achieved progressive increases over 5-fold. Importantly, PPC incorporation
in COP-based SDs did not have an apparent effect on RTV dissolution
but significantly improved drug dissolution from the SLP-based SDs.
In summary, the role of the lipid mainly depends on the drug-polymer
interactions and lipid concentration. Adding phospholipids enables
the thermal process without needing other adjuvants.