Hydroxypropyl methylcellulose acetate succinate-based spray-dried dispersions: an overview

Area of Science:

• Pharmaceutical Sciences
• Materials Science

Background:

• Low-solubility drugs present significant formulation challenges, limiting their bioavailability and therapeutic efficacy.
• Amorphous solid dispersions (ASDs) are a key strategy to improve the dissolution and absorption of poorly soluble compounds.
• Hydroxypropyl methylcellulose acetate succinate (HPMCAS) has emerged as a promising polymer for creating stable ASDs.

Purpose of the Study:

• To evaluate the efficacy of HPMCAS-based spray-dried dispersions (SDDs) for enhancing the performance of low-solubility drugs.
• To investigate the physical stability and in vitro/in vivo characteristics of these SDDs.
• To develop a predictive framework for selecting appropriate formulation strategies based on drug properties.

Main Methods:

• Preparation of SDDs using HPMCAS and various low-solubility model drugs.
• In vitro dissolution testing in biorelevant media (bile-salt/lecithin solutions).
• Solid-state characterization (e.g., amorphous phase assessment, stability studies).
• In vivo pharmacokinetic studies to determine bioavailability.
• Construction of a Tm/Tg versus log P map for formulation guidance.

Main Results:

• HPMCAS-SDDs successfully generated supersaturation in vitro and significantly increased oral bioavailability in vivo across diverse drug structures.
• The SDDs formed amorphous drug/polymer colloids in dissolution media, increasing free drug concentration and micellar drug.
• The dry powders were single-phase amorphous systems, with drugs remaining amorphous and stable during storage.
• A Tm/Tg versus log P map was established, correlating drug properties with formulation success.

Conclusions:

• HPMCAS-based SDDs are effective in achieving supersaturation and enhancing the bioavailability of low-solubility drugs.
• These formulations provide a stable amorphous drug delivery system suitable for pharmaceutical development.
• The developed map serves as a valuable tool for guiding the formulation strategy of poorly soluble drugs based on their physicochemical properties.