Quantitative and molecular analysis of buspirone hydrochloride polymorphs

Area of Science:

• Pharmaceutical Sciences
• Solid-State Chemistry

Background:

• Accurate characterization of drug polymorphs is crucial for pharmaceutical safety, efficacy, and process validation.
• Buspirone hydrochloride (BUS-HCl) exists in multiple polymorphic forms, necessitating detailed analysis.

Purpose of the Study:

• To perform quantitative and molecular analysis on two main polymorphs of buspirone hydrochloride (BUS-HCl).
• To investigate the solid-state composition and molecular properties of BUS-HCl polymorphs.

Main Methods:

• Quantitative analysis using X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC).
• Crystal structure determination of Form 1 via single crystal X-ray diffraction.
• Molecular analysis including partial charge distribution using Gaussian simulations.
• Solid-state Nuclear Magnetic Resonance (NMR) spectroscopy (1H and 13C) and predictive modeling using Quantum Mechanics (QM) theory.

Main Results:

• Successful quantitative analysis of two BUS-HCl polymorphs was achieved.
• The crystal structure of Form 1 was elucidated; Form 2 characterization was hindered by production difficulties.
• Molecular electrostatic potential and partial charge analysis provided insights into electronegativity patterns.
• Predictive models for 1H and 13C NMR spectra were developed, correlating well with experimental data.
• Distinct NMR spectral differences between the two polymorphs were identified and explained.

Conclusions:

• The study provides a comprehensive quantitative and molecular characterization of BUS-HCl polymorphs.
• Integrated analytical and computational methods enhance the understanding of solid-state properties.
• The findings support robust quality control and process development in BUS-HCl manufacturing.