Investigation of Solution-Mediated Phase Transformation of Cefuroxime Acid to Its Acetonitrile Solvate

Solubility determination, dissolution properties and solid transformation of resmetirom (form A) in heptane and seven alcohols

In this work, the solubility of resmetirom (form A) was initially measured in heptane and seven alcohol solvents by gravimetric methods. Then, the transformation temperature between form A and ethanol solvate was determined at 333.76 K. Subsequently, some commonly used models were applied to fit the solubility data, and it was found that the modified Apelblat equation and the Jouyban-Acree-van't Hoff (J-A-V) model achieved the highest correlation accuracy for those in mono-solvents and heptane + propanol, respectively. And the average relative deviation (ARD) values of models were less than 0.5%, indicating a good agreement with the experimental results. Additionally, through density functional theory calculation and the analysis of solvent parameters, it was observed that hydrogen-bonding played primary roles in the dissolution process of resmetirom. The multiple factors such as the polarity of solvent, active site interaction, the molecular size and free volume all affect the solubility of resmetirom. Furthermore, by comparing the experimental and simulated infrared spectra of form A and two alcohol solvates, five characteristic bands were selected for quantification. Partial least squares regression (PLSR), a multivariate statistical analysis method, was used to extract quantitative information. The quantitative analysis model was established based on specific wavelength intervals, which were associated with inter-molecular interactions. Combined with PLSR, a new high-precision quantitative method was established to study the solid transformation process between form A and solvates. From 303.15 to 323.15 K, the rate of transformation from form A to methanol solvate or ethanol solvate was decreased with increasing temperature, revealing that the transformation process was driven by the solubility difference between form A and solvates under the studied conditions. This research will definitely afford necessary solubility data and solvent selection for the design of the crystallization process of resmetirom (form A) in industry, and provide basic data for the production of resmetirom (form A) in the pharmaceutical industry.

Effects of various parameters on solution-mediated phase transformation of calcium d-gluconate: an approach to obtain pure metastable monohydrate

The high risk of solution-mediated phase transformation (SMPT) from the metastable monohydrate to stable Form I makes it difficult to produce pure metastable monohydrate of calcium d-gluconate. In this work, we explored the effect of various operating parameters on the SMPT of calcium d-gluconate in water and proposed an effective approach to obtain the desired monohydrate. First, the two forms of calcium d-gluconate were characterized and compared using powder X-ray diffraction (PXRD), thermal analysis, and Raman spectroscopy. The lower solubility of Form I in water illustrates its higher thermodynamic stability than monohydrate when the temperature is higher than 292 K. Afterward, the SMPT of calcium d-gluconate from monohydrate to Form I was investigated in water using in situ Raman spectroscopy combined with scanning electron microscopy and PXRD. Results showed that the nucleation and growth of Form I was the rate-limiting step in the SMPT from monohydrate to Form I. The phase transformation from monohydrate to Form I was delayed to produce pure monohydrate by decreasing temperature and agitation rate, reducing the amount of solid loading, and increasing the particle size of solid loading. Furthermore, the transformation kinetics were studied by the JMA model to explore how temperature influences the SMPT process. This study enriches the study of the calcium d-gluconate SMPT mechanism, and also provides guidance for obtaining high-quality injection-grade calcium gluconate monohydrate.

Manipulation of Pharmaceutical Polymorphic Transformation Process Using Excipients

BACKGROUND

In the pharmaceutical field, it is vital to ensure a consistent product containing a single solid-state form of the active pharmaceutical ingredient (API) in the drug product. However, some APIs are suffering from the risk of transformation of their target forms during processing, formulation and storage.

METHODS

The purpose of this review is to summarize the relevant category of excipients and demonstrate the availability and importance of using excipients as a key strategy to manipulate pharmaceutical polymorphic transformation.

RESULTS

The excipient effects on solvent-mediated phase transformations, solid-state transitions and amorphous crystallization are significant. Common pharmaceutical excipients including amino acids and derivatives, surfactants, and various polymers and their different manipulation effects were summarized and discussed.

CONCLUSION

Appropriate use of excipients plays a role in manipulating polymorphic transformation process of corresponding APIs, with a promising application of guaranteeing the stability and effectiveness of drug dosage forms.

Crystal structures and phase transformation of two novel solvates of valnemulin hydrochloride

The crystal structures and phase transformation of two novel solvates of valnemulin hydrochloride have been studied.

Preparation, crystal structure and solution-mediated phase transformation of a novel solid-state form of CL-20

The crystal structure, thermodynamic phase diagram, and polymorphic transformation behaviors of CL-20 acetonitrile solvate are systematically investigated.