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Published on: August 1, 2018
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Amorphous stabilization of BCS II drugs using mesoporous silica
Buu Tu1, Sriramakamal Jonnalagadda1
1Saint Joseph's University, 600 S 43rd Street, Philadelphia, PA 19104, USA.
International Journal of Pharmaceutics
|August 7, 2024
Summary
Mesoporous silica effectively stabilizes amorphous solid dispersions of poorly soluble drugs. Carrier to drug ratio and drug molecular weight are key factors influencing drug crystallinity in these systems.
Area of Science:
- Materials Science
- Pharmaceutical Sciences
- Drug Delivery
Background:
- Many Biopharmaceutics Classification System (BCS) Class II drugs suffer from poor aqueous solubility, limiting their oral bioavailability.
- Amorphous solid dispersions (ASDs) are a promising strategy to enhance the dissolution rate and bioavailability of such drugs.
- Mesoporous silica (MS) offers a high surface area and tunable pore structure suitable for creating ASDs.
Purpose of the Study:
- To investigate the amorphous stabilization of BCS Class II drugs using mesoporous silica as a carrier.
- To evaluate the impact of drug properties (molecular weight, partition coefficient) and formulation parameters (MS grade, carrier to drug ratio) on the solid state of drug-loaded MS.
Main Methods:
- Selected BCS Class II drugs (ibuprofen, fenofibrate, budesonide) were loaded into three grades of mesoporous silica (SY730, SY430, SY350) with varying pore sizes.
- Loading was achieved using solvent immersion and spray drying techniques at different carrier to drug ratios (1:1, 2:1, 3:1) and concentrations.
- Drug-loaded MS particles were characterized using Differential Scanning Calorimetry (DSC) and Powder X-ray Diffraction (PXRD).
Main Results:
- DSC analysis indicated melting point depressions in SY430 and SY350, suggesting drug crystallization confinement within pores.
- PXRD confirmed no polymorphic transitions, and a 3:1 carrier to drug ratio consistently yielded amorphous solid dispersions (indicated by amorphous halo profiles).
- Statistical analyses (Response Surface Regression, CART) identified carrier to drug ratio as the most significant factor, followed by molecular weight, influencing drug crystallinity.
Conclusions:
- Mesoporous silica is an effective carrier for producing amorphous solid dispersions of BCS Class II drugs.
- The carrier to drug ratio and drug molecular weight are critical parameters controlling the amorphous state of the drug within the mesoporous matrix.
- Optimizing these parameters is essential for successful ASD formulation development using mesoporous silica.
