Downstream-Induced Destabilization of Neat Amorphous Drugs: Implications on Solid-State Stability and Performance

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Physical Chemistry

Background:

• Amorphous drug formulations enhance solubility and bioavailability of poorly water-soluble drugs.
• Physical instability, particularly recrystallization, is a major challenge for amorphous drugs during processing.
• Understanding the impact of processing parameters on amorphous solid-state stability is crucial for successful drug product development.

Purpose of the Study:

• To investigate the influence of pharmaceutical compaction parameters (compression pressure and dwell time) on the physical stability and performance of melt-quenched amorphous nifedipine (NIF).
• To characterize the effects of compaction on NIF's amorphous-to-crystalline transformations and dissolution behavior.
• To compare the sensitivity of NIF to compaction-induced destabilization with other amorphous compounds.

Main Methods:

• Preparation of amorphous NIF compacts using varying compression pressures (50-250 MPa) and dwell times (1-60 s).
• Characterization using Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), and Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR).
• Isothermal crystallization studies, full factorial design analysis, intrinsic dissolution rate (IDR) measurements, and porosity analysis.

Main Results:

• Compression accelerated the amorphous-to-β-NIF transformation, with onset times dependent on pressure and dwell time.
• Long-term storage led to NIF β → α polymorphic transformation, accelerated by high humidity.
• Higher compaction generally reduced dissolution, but extreme conditions (250 MPa, 60 s) showed a modest IDR increase; porosity changes partially correlated with stability and dissolution.

Conclusions:

• Pharmaceutical compaction parameters significantly influence the physical stability and dissolution performance of amorphous nifedipine.
• The study highlights the compound-specific nature of compression-induced destabilization in amorphous drug formulations.
• Tailored assessment strategies are essential for downstream processing of amorphous drug formulations to ensure product quality and efficacy.