Optimizing Drug Development: Harnessing the Sustainability of Pharmaceutical Cocrystals

Environmental impacts of the industrial revolution necessitate adoption of sustainable practices in all areas of development. The pharmaceutical industry faces increasing pressure to minimize its ecological footprint due to its significant contribution to environmental pollution. Over the past two decades, pharmaceutical cocrystals have received immense popularity due to their ability to optimize the critical attributes of active pharmaceutical ingredients and presented an avenue to bring improved drug products to the market. This review explores the potential of pharmaceutical cocrystals as an ecofriendly alternative to traditional solid forms, offering a sustainable approach to drug development. From reducing the number of required doses to improving the stability of actives, from eliminating synthetic operations to using pharmaceutically approved chemicals, from the use of continuous and solvent-free manufacturing methods to leveraging published data on the safety and toxicology, the cocrystallization approach contributes to sustainability of drug development. The latest trends suggest a promising role of pharmaceutical cocrystals in bringing novel and improved medicines to the market, which has been further fuelled by the recent guidance from the major regulatory agencies.

Reply to comments by Dr. Ali Shayanfar

Several clarifications are made pertaining to the study on the cocrystallization of 5-fluorouracil (5-FU) and gallic acid (GA). Dr. Shayanfar's perspective in the solubility and biological activity of cocrystals is recognized, and his insightful guidance on solubility determination methodologies is greatly appreciated. A misconception concerning the cytotoxicity assay methodology in the Shayanfar's comments is addressed. Furthermore, the stability of the 5-FU-GA cocrystal during solubility measurement is highlighted, as evidenced by XRD analysis of residual solids. Lastly, the independence of the elevated cytotoxicity of the cocrystal from 5-FU solubility is deliberated, aligning with preceding research outcomes.

Synthesis, Characterization, Theoretical and Experimental Anticancer Evaluation of Novel Cocrystals of 5-Fluorouracil and Schiff Bases against SW480 Colorectal Carcinoma

The chemotherapeutic agent known as 5-fluorouracil (5-FU) is an artificial fluoropyrimidine antimetabolite that has been widely used for its antineoplastic properties. Cocrystals of 5-fluorouracil (5-FU) with five different Schiff bases (benzylidene-urea (BU), benzylidene-aniline (BA), salicylidene-aniline (SA), salicylidene-phenylhydrazine (SPH), and para-hydroxy benzylideneaniline (HBA)) are reported in this study. The newly synthesized cocrystals were analyzed by FTIR and PXRD. In this study, we investigated the antitumor efficacy of 5-FU derivatives in SW480 colon cancer cells via MTT assay at varying dose concentrations. Molecular docking was performed to predict the binding mechanism of TS with various 5-FU complexes. FTIR revealed the presence of respective functional groups in the prepared cocrystals. The frequencies (v) of N-H (3220.24 cm^-1) and carbonyl groups (1662.38 cm^-1) in the spectrum of 5-FU shifted considerably in all derivative cocrystal new interactions. There was a noticeable transformation in the PXRD peak of 5-FU at 2θ = 28.37° in all derivatives. The novelty of the present study lies in the fact that 5-FU-BA showed an anticancer potential IC₅₀ (6.4731) far higher than that of 5-FU (12.116), almost comparable to that of the reference drug doxorubicin (3.3159), against SW480 cancel cell lines, followed by 5-Fu-HBA (10.2174). The inhibition rates of 5-FU-BA and 5-FU-HBA were highest among the derivatives (99.85% and 99.37%, respectively) in comparison with doxorubicin (97.103%). The results revealed that the synthesized 5-FU cocrystals have promising antitumor efficacy compared with previously reported 5-FU and 5-FU. The activities of the cocrystals were rationalized by a molecular modeling approach to envisage binding modes with the target cancer protein.

Cocrystallization of 5-fluorouracil with gallic acid: A novel 5-fluorouracil cocrystal displaying synergistic anti-tumor activity both in oral and intraperitoneal injection administration

Gallic acid (GA) is a naturally occurring polyphenolic compound exhibiting anti-tumor activity. To clarify the capability of GA in optimizing the in vitro/in vivo properties of the first line anti-tumor drug 5-fluorouracil (5-FU) and achieve synergistically enhanced anti-tumor activity, a novel cocrystal hydrate of 5-FU-GA-H₂O was successfully screened and characterized based on various spectroscopic and experimental analysis including Fourier transform infrared spectroscopy (FT-IR), Raman spectra (Raman), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetric (TG) and scanning electric microscope (SEM) techniques. The results suggested the existence of hydrogen bonding interactions between C=O group of 5-FU and O-H group of GA. Although the dissolution rate and solubility of 5-FU-GA-H₂O cocrystal were slowed and lowered compared with that of 5-FU, respectively, the membrane permeability was enhanced for cocrystal compared with that of intact 5-FU and physical mixture (PM) of 5-FU and GA. For the cocrystal, the cumulative amount per unit area of permeated 5-FU in the first 10 h was 2.56 and 9.97 times of that of pure 5-FU and PM, respectively, in the case that transmembrane behavior of 5-FU depended on the type of solution from which the powder was dissolved. Meanwhile, improvement on oral bioavailability by co-crystallization was observed; AUC_0-t of cocrystal was 2.78-fold higher than that of 5-FU. Furthermore, the cocrystal displayed a superior cytotoxic activity on 4T1 mouse breast cancer cells compared with pure 5-FU and even the PM. It was confirmed that the cocrystal solution induced higher autophagic flux than those of 5-FU and PM in 4T1 cell, suggesting that autophagy rather than apoptosis mainly mediated cell death. The obvious difference of tumor inhibition activity between PM and cocrystal in intraperitoneal injection administration indicated that some of the interactions formed in the solid cocrystal could retain in solution in some way. Benefiting from synergistic cytotoxicity, drug efficacy in vivo was enhanced through injection administration of solution from which cocrystal was dissolved.

Solid-state versatility in tranexamic acid drug: structural and thermal behavior of new salts and cocrystals

Tranexamic acid (TNA) is an anti-fibrinolytic hemostatic drug widely used in various medical treatments. Six new salts and five cocrystals of TNA are reported here and the crystal structures of the obtained multicomponent compounds were determined using single-crystal X-ray diffraction (SC-XRD) techniques. TNA formed salts with coformers maleic acid (MEA), nicotinic acid, DL-mandelic acid and saccharin. Salt formation with MEA resulted in three different solid forms, namely TNA-MEA (1:1), TNA-MEA (2:1) and TNA-MEA-H₂O (1:1:1). All synthesized TNA salt structures were crystallized as anhydrous except for TNA-MEA-H₂O (1:1:1). TNA formed cocrystals with phenolic coformers such as catechol (CAT), resorcinol, hydroquinone, pyrogallol (PRG) and phloroglucinol. All cocrystal structures crystallized as hydrates except for TNA-PRG (1:1). The detailed structural investigation using SC-XRD revealed the presence of robust N-H...O and O-H...O hydrogen bonds in TNA salts and cocrystals. In TNA cocrystals, except for TNA-CAT-H₂O (1:1:1), the coformer molecules interact with TNA molecules via bridged water molecules. In all the salt structures, TNA exists as cations, in which both carboxylic and amino groups are protonated (-COOH and -NH₃⁺), while in cocrystals TNA exists as zwitterions with total charge zero. All synthesized multicomponent compounds were further characterized by differential scanning calorimetric, thermogravimetric and Fourier transform infrared analyses, and the formation of new multicomponent compounds were assessed based on the melting temperatures, percentage weight loss and stretching frequencies, respectively, corresponding to TNA/coformer molecules. A powder X-ray diffraction study confirmed the bulk purity of the synthesized crystalline multicomponent compounds.

Co-crystal nanoarchitectonics as an emerging strategy in attenuating cancer: Fundamentals and applications

Cancer ranks as the second foremost cause of death in various corners of the globe. The clinical uses of assorted anticancer therapeutics have been limited owing to the poor physicochemical attributes, pharmacokinetic performance, and lethal toxicities. Various sorts of co-crystals or nano co-crystals or co-crystals-laden nanocarriers have presented great promise in targeting cancer via improved physicochemical attributes, pharmacokinetic performance, and reduced toxicities. These systems have also demonstrated the controlled cargo release and passive targeting via enhanced permeation and retention (EPR) effect. In addition, regional delivery of co-crystals via inhalation and transdermal route displayed remarkable potential in targeting lung and skin cancer effectively. However, more research is required on the use of co-crystals in cancer and their commercialization. The present review mainly emphasizes co-crystals as emerging avenues in the treatment of various cancers by modulating the physicochemical and pharmacokinetic attributes of approved anticancer therapeutics. The worth of co-crystals in cancer treatment, computational paths in the co-crystals screening, diverse experimental techniques of co-crystals fabrication, and sorts of co-crystals and their noteworthy applications in targeting cancer are also discussed. Besides, the game changer approaches like nano co-crystals and co-crystals-laden nanocarriers, and co-crystals in regional delivery in cancer are also explained with reported case studies. Furthermore, regulatory directives for pharmaceutical co-crystals and their scale-up, and challenges are also highlighted with concluding remarks and future initiatives. In essence, co-crystals and nano co-crystals emerge to be a promising strategy in overwhelming cancers through improving anticancer efficacy, safety, patient compliance, and reducing the cost.

Recent Advances in Pharmaceutical Cocrystals: From Bench to Market

The pharmacokinetics profile of active pharmaceutical ingredients (APIs) in the solid pharmaceutical dosage forms is largely dependent on the solid-state characteristics of the chemicals to understand the physicochemical properties by particle size, size distribution, surface area, solubility, stability, porosity, thermal properties, etc. The formation of salts, solvates, and polymorphs are the conventional strategies for altering the solid characteristics of pharmaceutical compounds, but they have their own limitations. Cocrystallization approach was established as an alternative method for tuning the solubility, permeability, and processability of APIs by introducing another compatible molecule/s into the crystal structure without affecting its therapeutic efficacy to successfully develop the formulation with the desired pharmacokinetic profile. In the present review, we have grossly focused on cocrystallization, particularly at different stages of development, from design to production. Furthermore, we have also discussed regulatory guidelines for pharmaceutical industries and challenges associated with the design, development and production of pharmaceutical cocrystals with commercially available cocrystal-based products.

Pharmaceutical cocrystals: A review of preparations, physicochemical properties and applications

Pharmaceutical cocrystals are multicomponent systems in which at least one component is an active pharmaceutical ingredient and the others are pharmaceutically acceptable ingredients. Cocrystallization of a drug substance with a coformer is a promising and emerging approach to improve the performance of pharmaceuticals, such as solubility, dissolution profile, pharmacokinetics and stability. This review article presents a comprehensive overview of pharmaceutical cocrystals, including preparation methods, physicochemical properties, and applications. Furthermore, some examples of drug cocrystals are highlighted to illustrate the effect of crystal structures on the various aspects of active pharmaceutical ingredients, such as physical stability, chemical stability, mechanical properties, optical properties, bioavailability, sustained release and therapeutic effect. This review will provide guidance for more efficient design and manufacture of pharmaceutical cocrystals with desired physicochemical properties and applications.

Supramolecular self-assembly and perfected in vitro/vivo property of 5-fluorouracil and ferulic acid on the strength of double optimized strategy: the first 5-fluorouracial-phenolic acid nutraceutical cocrystal with synergistic antitumor efficacy

For highlighting the predominance of phenolic acid nutraceutical ferulic acid (FR) in regulating the in vivo/vitro performances of anticancer drug 5-fluorouracil (Flu) and strengthening their cooperativity in antitumor effect, thus achieving a major breakthrough in the development of drug-nutraceutical cocrystal with synergistic antitumor action, a cocrystallization strategy of dual optimization is created, in which both the in vivo and vitro natures of Flu are improved by exploiting the FR's excellent physicochemical property. Moreover, Flu's anticancer effects were promoted by exerting the assistant antitumor peculiarity of FR. Such dual optimization of FR for Flu in physicochemical properties and anticancer activities is beneficial for realizing synergistic augmentation effect by taking the benefit of the cooperativeness of Flu and FR in the anticancer ability. Based on this idea, a novel cocrystal of Flu and FR, namely, Flu-FR-H2O, is successfully assembled as the first 5-fluorouracil-nutraceutical cocrystal with synergistic antitumor effect and its explicit structure is resolved. The single-crystal X-ray diffraction demonstrates that Flu and FR have a ratio of 1 : 1 with one equivalent of solvent water in the cocrystal, where one-dimensional hydrogen-bonding helices and FR-Flu hydrogen-bonding pairs, together construct a three-dimensional supramolecular network. By combining experimental evaluation with theoretical analysis, in vitro/vivo pharmaceutical properties are scientifically investigated. Results show that the permeability and aqueous solubility of Flu are respectively elevated by 5.08 and 1.64 folds, which has brought about ameliorated pharmacokinetics, thus providing prolonged retention time and increased oral bioavailability. More interestingly, the cocrystal shows synergistic inhibition ability of Flu and FR against tested tumor cell strains, hence laying the groundwork for reducing the dosage and even the toxic side effects of Flu. As a result of this, the present research not only provides a new strategy for Flu to optimize its physicochemical properties and antitumor activities simultaneously but also offers some opinions for the development of synergistic antitumor pharmaceutical cocrystals.