Online Classification of Mixed Co-Crystal and Solute Suspensions using Raman Spectroscopy

Oxaliplatin-flavone pharmaceutical co-crystal-CN111205332A: patent spotlight

Co-crystallization is a technique for modifying physicochemical properties of pharmaceutical ingredients with an aim to enhance the therapeutic efficacy and subsequent reduction in toxicity. The patent describes the development of oxaliplatin co-crystals using flavonoids (baicalein and naringenin) via solvent volatilization technique with an objective to improve solubility and stability in GI tract and reduced side/toxic effects. The co-crystals were characterized via differential scanning calorimetry, thermogravimetric analysis, x-ray diffraction analysis. The co-crystals exhibited slow drug release, delayed hydrolysis, low cytotoxicity and enhanced therapeutic activity on human gastric adenocarcinoma cells. However, suitable solvent for co-crystal production, large scale production and regulatory challenges for continuous manufacturing of co-crystals must be addressed.

Determination of co-crystal phase purity by mid infrared spectroscopy and multiple curve resolution

Multivariate Curve Resolution (MCR) was used to determine the phase purity of pharmaceutical co-crystals from mid infrared spectra. An in-silico coformer screening was used to choose one of ten potential coformers. This analysis used quantum chemistry simulation to predict which coformers are thermodynamically inclined to form cocrystals with the model drug, hydrochlorothiazide. The coformer chosen was nicotinamide. An experimental solvent screening by ultrasound assisted slurry co-crystallization was performed to evaluate the capacity of the method to determine phase purity. Afterwards, slurry and slow evaporation co-crystallizations were performed at 10, 25, and 40 °C using 7 solvent systems, and two levels of agitation for the evaporation co-crystallization (on and off). Mid infrared spectroscopy (MIRS) analysis of the products of these co-crystallizations was used to develop an MCR model to determine co-crystal phase purity. The MCR results were compared with a reference co-crystal. Experimental design (DoE) was used to investigate the effect of solvents, temperature, and agitation on the purity of co-crystals produced by slurry and evaporation co-crystallization. DoE revealed that evaporation co-crystallization with agitating at 65 rpm formed co-crystals with greater phase purity. The optimal temperature varied with the solvent used.

Pharmaceutical solvates, hydrates and amorphous forms: A special emphasis on cocrystals

Active pharmaceutical ingredients (APIs) may exist in various solid forms, which can lead to differences in the intermolecular interactions, affecting the internal energy and enthalpy, and the degree of disorder, affecting the entropy. Differences in solid forms often lead to differences in thermodynamic parameters and physicochemical properties for example solubility, dissolution rate, stability and mechanical properties of APIs and excipients. Hence, solid forms of APIs play a vital role in drug discovery and development in the context of optimization of bioavailability, filing intellectual property rights and developing suitable manufacturing methods. In this review, the fundamental characteristics and trends observed for pharmaceutical hydrates, solvates and amorphous forms are presented, with special emphasis, due to their relative abundance, on pharmaceutical hydrates with single and two-component (i.e. cocrystal) host molecules.

Experimental cocrystal screening and solution based scale-up cocrystallization methods

Cocrystals are crystalline single phase materials composed of two or more different molecular and/or ionic compounds generally in a stoichiometric ratio which are neither solvates nor simple salts. If one of the components is an active pharmaceutical ingredient (API), the term pharmaceutical cocrystal is often used. There is a growing interest among drug development scientists in exploring cocrystals, as means to address physicochemical, biopharmaceutical and mechanical properties and expand solid form diversity of the API. Conventionally, coformers are selected based on crystal engineering principles, and the equimolar mixtures of API and coformers are subjected to solution-based crystallization that are commonly employed in polymorph and salt screening. However, the availability of new knowledge on cocrystal phase behaviour in solid state and solutions has spurred the development and implementation of more rational experimental cocrystal screening as well as scale-up methods. This review aims to provide overview of commonly employed solid form screening techniques in drug development with an emphasis on cocrystal screening methodologies. The latest developments in understanding and the use of cocrystal phase diagrams in both screening and solution based scale-up methods are also presented. Final section is devoted to reviewing the state of the art research covering solution based scale-up cocrystallization process for different cocrystals besides more recent continuous crystallization methods.

Real-time HPLC-MS reaction progress monitoring using an automated analytical platform

Automated sampling and in-line dilution allows both homogeneous and heterogeneous reactions to be easily profiled by real-time HPLC-MS.