Succinic, fumaric, adipic and oxalic acid cocrystals of promethazine hydrochloride

Mechanochemical Synthesis of New Praziquantel Cocrystals: Solid-State Characterization and Solubility

New cocrystals of praziquantel with suberic, 3-hydroxybenzoic, benzene-1,2,4,5-tetracarboxylic, trimesic, and 5-hydroxyisophthalic acids were obtained through ball milling experiments. The optimal conditions for the milling process were chosen by changing the solvent volume and the mechanical action time. Supramolecular interactions in the new cocrystals are detailed based on single-crystal X-ray diffraction analysis, confirming the expected formation of hydrogen bonds between the praziquantel carbonyl group and the carboxyl (or hydroxyl) moieties of the coformers. Different structural characterization techniques were performed for all samples, but the praziquantel:suberic acid cocrystal includes a wider range of investigations such as thermal analysis, infrared and X-ray photoelectron spectroscopies, and SEM microscopy. The stability for up to five months was established by keeping it under extreme conditions of temperature and humidity. Solubility studies were carried out for all the new forms disclosed herein and compared with the promising cocrystals previously reported with salicylic, 4-aminosalicylic, vanillic, and oxalic acids. HPLC analyses revealed a higher solubility for most of the new cocrystal forms, as compared to pure praziquantel.

Cocrystals by Design: A Rational Coformer Selection Approach for Tackling the API Problems

Active pharmaceutical ingredients (API) with unfavorable physicochemical properties and stability present a significant challenge during their processing into final dosage forms. Cocrystallization of such APIs with suitable coformers is an efficient approach to mitigate the solubility and stability concerns. A considerable number of cocrystal-based products are currently being marketed and show an upward trend. However, to improve the API properties by cocrystallization, coformer selection plays a paramount role. Selection of suitable coformers not only improves the drug’s physicochemical properties but also improves the therapeutic effectiveness and reduces side effects. Numerous coformers have been used till date to prepare pharmaceutically acceptable cocrystals. The carboxylic acid-based coformers, such as fumaric acid, oxalic acid, succinic acid, and citric acid, are the most commonly used coformers in the currently marketed cocrystal-based products. Carboxylic acid-based coformers are capable of forming the hydrogen bond and contain smaller carbon chain with the APIs. This review summarizes the role of coformers in improving the physicochemical and pharmaceutical properties of APIs, and deeply explains the utility of afore-mentioned coformers in API cocrystal formation. The review concludes with a brief discussion on the patentability and regulatory issues related to pharmaceutical cocrystals.

The effects of cis and trans butenedioic acid on the physicochemical behavior of lumefantrine

A study of the differences in the effects of cis (maleic acid) and trans (fumaric acid) isomers of butenedioic acid on the crystallinity, amorphous nature, and pharmaceutical behaviour of the antimalarial drug lumefantrine is provided.

Polymer-Assisted Aripiprazole-Adipic Acid Cocrystals Produced by Hot Melt Extrusion Techniques

Pharmaceutical cocrystals are a promising strategy to increase the solubility and dissolution rate of poorly soluble drugs. However, their manufacturing process requires a large quantity of solvents. The present study aimed to produce cocrystals by a solvent-free hot melt extrusion (HME) method to improve their solubility and dissolution rate. Aripiprazole (ARP) and adipic acid (ADP) were used as a weakly basic drug and acidic coformer, respectively. The processability of a plain ARP-ADP physical mixture (PM) compared with a PM with 5% Soluplus® (SOL) was investigated. Incorporating 5% SOL into the ARP-ADP blend reduced the processing torque and improved processability. The effects of temperature and screw speed on the formation of cocrystals were studied, and cocrystals were characterized by differential scanning calorimetry (DSC), fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy, and hot-stage microscopy. FTIR spectra revealed noncovalent interaction between ARP and ADP, which was confirmed by NMR spectra. Similarly, PXRD data exhibited characteristic peaks confirming the formation of new crystalline material. Further, the results indicated that cocrystals demonstrated higher dissolution rates and improved compressibility, as well as enhanced flow characteristics compared with pure ARP, suggesting its suitability in the development of solid dosage forms.