Which formulation strategy is commonly used to improve solubility by converting a drug into an amorphous solid dispersion?

Which formulation strategy is commonly used to improve solubility by converting a drug into an amorphous solid dispersion?

• A. Salt formation
• B. Amorphous solid dispersions
• C. Lipid-coated tablets
• D. Crystal lattice stabilization

Answer: (B)

Turning a poorly soluble drug into an amorphous solid dispersion means dispersing the drug in a polymer matrix so the drug exists in an amorphous, non-crystalline state. This form has higher free energy and weaker lattice energy than a crystal, so it dissolves more readily, increasing apparent solubility and the rate of dissolution. The polymer component helps stabilize the amorphous drug and prevents recrystallization during storage and in the GI tract, which is key for achieving sustained bioavailability improvements. This approach is widely used for BCS class II drugs where solubility limits absorption. Processing methods like spray drying or hot-melt extrusion are commonly employed to create these dispersions, yielding a molecularly dispersed drug within the polymer. Salt formation, by contrast, enhances solubility for ionizable drugs through formation of ionic species, not by creating an amorphous dispersion. Lipid-coated tablets are more about protecting the drug through the GI tract or modifying release, and crystal lattice stabilization aims to keep the drug in a crystalline form, not to improve solubility via an amorphous state.

Turning a poorly soluble drug into an amorphous solid dispersion means dispersing the drug in a polymer matrix so the drug exists in an amorphous, non-crystalline state. This form has higher free energy and weaker lattice energy than a crystal, so it dissolves more readily, increasing apparent solubility and the rate of dissolution. The polymer component helps stabilize the amorphous drug and prevents recrystallization during storage and in the GI tract, which is key for achieving sustained bioavailability improvements.

This approach is widely used for BCS class II drugs where solubility limits absorption. Processing methods like spray drying or hot-melt extrusion are commonly employed to create these dispersions, yielding a molecularly dispersed drug within the polymer.

Salt formation, by contrast, enhances solubility for ionizable drugs through formation of ionic species, not by creating an amorphous dispersion. Lipid-coated tablets are more about protecting the drug through the GI tract or modifying release, and crystal lattice stabilization aims to keep the drug in a crystalline form, not to improve solubility via an amorphous state.