New conformational polymorph of hydrochlorothiazide with improved solubility

Pharmaceutical approaches for enhancing solubility and oral bioavailability of poorly soluble drugs

High solubility in water and physiological fluids is an indispensable requirement for the pharmacological efficacy of an active pharmaceutical ingredient. Indeed, it is well established that pharmaceutical substances exhibiting limited solubility in water are inclined towards diminished and inconsistent absorption following oral administration, consequently resulting in variability in therapeutic outcomes. The current advancements in combinatorial chemistry and pharmaceutical design have facilitated the creation of drug candidates characterized by increased lipophilicity, elevated molecular size, and reduced aqueous solubility. Undoubtedly, the issue of poorly water-soluble medications has been progressively escalating over recent years. Indeed, 40% of the top 200 oral medications marketed in the United States, 33% of drugs listed in the US pharmacopoeia, 75% of compounds under development and 90% of new chemical entities are insufficiently water-soluble compounds. In order to address this obstacle, formulation scientists employ a variety of approaches, encompassing both physical and chemical methods such as prodrug synthesis, salt formation, solid dispersions formation, hydrotropic substances utilization, solubilizing agents incorporation, cosolvent addition, polymorphism exploration, cocrystal creation, cyclodextrins complexation, lipid formulations, particle size reduction and nanoformulation techniques. Despite the utilization of these diverse approaches, the primary reason for the failure in new drug development persists as the poor aqueous solubility of pharmaceutical compounds. This paper, therefore, delves into the foundational principles that underpin the implementation of various formulation strategies, along with a discussion on the respective advantages and drawbacks associated with each approach. Additionally, a discourse is provided regarding methodological frameworks for making informed decisions on selecting an appropriate formulation strategy to effectively tackle the key challenges posed during the development of a poorly water-soluble drug candidate.

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.

Interaction and Compatibility Studies in the Development of Olmesartan Medoxomil and Hydrochlorothiazide Formulations under a Real Manufacturing Process

A drug–drug and drug–excipient interactions and compatibilities study was conducted for two fixed-dose combination (FDC) products containing olmesartan medoxomil (OLM)/hydrochlorothiazide (HCT) 20/12.5 mg and OLM/HCT 40/12.5 mg during their development including storage. The study consisted of the evaluation of samples retrieved during all stages of a real manufacturing process. Powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), thermogravimetry (TGA), Fourier transform infrared spectroscopy (FT-IR), and contact angle techniques were applied to the samples to determine interactions and incompatibilities. Dissolution tests and long-term stability studies were conducted to evaluate dosage form performance. Results showed weak solid–state interactions able to obtain a eutectic mixture of OLM and HCT while microcrystalline cellulose (MC) impacted the thermal stability of both drugs. Reliable dissolution and long-term stability tests confirmed that the interactions observed were not considered incompatibilities because they were not influenced by the performance of the final products.

Creation of Hydrochlorothiazide Pharmaceutical Cocrystals Via Hot-Melt Extrusion for Enhanced Solubility and Permeability

Crystal engineering is an emerging tool for altering the physicochemical properties of drug candidates. The objective of the current investigation was to develop cocrystals of hydrochlorothiazide (HCT) with coformers such as nicotinamide (NIC), resorcinol (RSL), and catechol (CAT) using hot-melt extrusion (HME) technology. The liquid-assisted grinding (LAG) method was used to prepare cocrystals by grinding the drug and coformer in a definite molar ratio as a reference and to check the feasibility of cocrystal formation. Cocrystals were prepared using HME and evaluated with differential scanning calorimetry, Fourier transform infrared spectroscopy, X-ray diffractometry, and scanning electron microscopy and compared with LAG cocrystals. Barrel temperature was the critical process parameter for producing high-quality cocrystals in HME. All cocrystals exhibited improved solubility compared to the native drug, and HCT-NIC cocrystals showed a two-fold increase in solubility. Similarly, HCT-RSL and HCT-CAT showed higher solubility profiles and improved diffusion/permeability characteristics compared to that of the pure HCT due to the drug-coformer interactions in the cocrystals. In this study, the solubility of the coformer was the key factor determining cocrystal solubilization. However, hot-melt extrusion is an alternative technology for creating pharmaceutical cocrystals and has potential for industrial scale-up.

Recent advances in drug polymorphs: Aspects of pharmaceutical properties and selective crystallization

Drug polymorphism, an established term used to describe the phenomenon that a drug can exist in different crystalline phases, has attracted great interests in pharmaceutical field in consideration of its important role in affecting the pharmaceutical performance of oral formulations. This paper presents an overview of recent advances in the research on polymorphic drug systems including understandings on nucleation, crystal growth, dissolution, mechanical properties, polymorphic transformation, etc. Moreover, new strategies and mechanisms in the control of polymorphic forms are also highlighted in this review. Furthermore, challenges and trends in the development of polymorphic drugs are briefly discussed, aiming at developing effective and efficient pharmaceutical formulations containing the polymorphic drugs.

A Review of Pharmaceutical Nano-Cocrystals: A Novel Strategy to Improve the Chemical and Physical Properties for Poorly Soluble Drugs

Nowadays, many commercial drugs have poor solubility and bioavailability. Cocrystals are formulated to modulate active pharmaceutical ingredients’ properties with improved solubility, dissolution, and bioavailability compared to their pristine individual components in the pharmaceutical industry. Nano-cocrystals, crystals in the nano range, can further enhance these properties because of not only the cocrystal structure, but also the large surface to volume ratio of nanocrystals. Even though there are many studies on cocrystals, the research of pharmaceutical nano-cocrystals is still in the initial stage. Thus, it is necessary to conduct a systematic study on pharmaceutical nano-cocrystals. In this review, the possible preparation approaches of nano-cocrystals have been reported. To have a comprehensive understanding of nano-cocrystals, some analytical techniques and characterizations will be discussed in detail. In addition, the feasible therapeutic application of nano-cocrystals will be presented. This work is expected to provide guidance to develop new nano-cocrystals with commercial value in the pharmaceutical industry.

Preparation and characterization of dicarboxylic acids salt of aripiprazole with enhanced physicochemical properties

The focus of present work was to prepare salt of aripiprazole (APZ) with dicarboxylic acids to improve physicochemical properties the drug. Dicarboxylic acids used in the study were malonic acid, maleic acid and succinic acid. The salts were prepared with solubilization-crystallization method. The salts were characterized for pH-solubility, dissolution, and stabilities. The Fourier infrared spectroscopy, X-ray powder diffraction, differential scanning calorimetry and near infrared chemical imaging indicated formation of new solid phase. pH-solubility profiles of the salts were similar to the drug except higher solubility were observed in the salts at all tested pH. The highest solubility was observed for APZ-Malonate salt among all the prepared salts. The solubility curve was inverted 'V' shape for APZ-maleate and APZ-succinate while it was inverted 'U' shape for APZ-malonate. The water solubility of APZ, APZ-malonate, APZ-maleate and APZ-succinate were 0.07 ± 0.02, 3503.9 ± 37.4, 269.3 ± 6.9 and 729.4 ± 9.4 µg/mL, respectively. The dissolution was 2.9 ± 0.4, 18.4 ± 3.9, 19.5 ± 1.4 and 36.6 ± 4.0% in 45 min for APZ, APZ-maleate, APZ-malonate, and APZ-succinate. The stabilities of the salts were similar to the drug. Thus, salts improved the physicochemical properties of the drug, and have similar stability profiles as that of APZ.

Mifepristone polymorph with enhanced solubility, dissolution and oral bioavailability

Mifepristone is one of potent anti-progesterone agents, which binds to progesterone receptors and glucocorticoid receptors. Until now, there are a lot of research focusing on enhancing the solubility and oral bioavailability of Mifepristone. However, poor solubility and oral bioavailability has some undesirable consequences. In this work, Mifepristone in form D was discovered for the first time and characterized by PXRD, TGA, DSC, FT-IR, SEM and SS NMR. Form D was a metastable crystal type which manifested favorable stability under ambient conditions. Form D had better dissolution characteristic compared with commercial Mifepristone in 0.5% SDS solution. In addition, Mifepristone in form D exhibited a 1.43-fold higher peak plasma concentration (C_max) and 1.46-fold higher area under the curve (AUC) in rats. The work in this paper is a complement to the present understanding of drug polymorphism on the in vitro and in vivo behavior, and establishes the ground work for future development of Mifepristone in form D as a promising drug for the market.

Biological properties of two enantiomorphic forms of N-(2,6-dimethylphenyl)-4-hydroxy-2,2-dioxo-1H-2λ6,1-benzothiazine-3-carboxamide, a structural analogue of piroxicam

The title benzothiazine-3-carboxamide, C₁₇H₁₆N₂O₄S, crystallized in two enantiomorphic crystal forms with the space groups P3₂ and P3₁ despite the absence of a classic stereogenic atom. The molecular structures are mirror images of each other. Only one sulfonyl O atom takes part in intramolecular hydrogen bonding as a proton acceptor and this atom is different in the two enantiomorphic structures. As a result, the S atom becomes a pseudo-stereogenic centre. This fact is worth taking into account due to the different biological activities of the enantiomorphic forms. One form possesses a high analgesic activity, while the other form revealed a high anti-inflammatory activity.

Optimization of the Production Process and Product Quality of Titanate Nanotube-Drug Composites

Recently, there has been an increasing interest in the application of nanotubular structures for drug delivery. There are several promising results with carbon nanotubes; however, in light of some toxicity issues, the search for alternative materials has come into focus. The objective of the present study was to investigate the influence of the applied solvent on the composite formation of titanate nanotubes (TNTs) with various drugs in order to improve their pharmacokinetics, such as solubility, stability, and bioavailability. Composites were formed by the dissolution of atenolol (ATN) and hydrochlorothiazide (HCT) in ethanol, methanol, 0.01 M hydrochloric acid or in ethanol, 1M sodium hydroxide, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), respectively, and then they were mixed with a suspension of TNTs under sonication for 30 min and vacuum-dried for 24 h. The structural properties of composites were characterized by SEM, TEM, FT-IR, differential scanning calorimetry (DSC), thermogravimetric (TG) analysis, and optical contact angle (OCA) measurements. Drug release was determined from the fast disintegrating tablets using a dissolution tester coupled with a UV-Vis spectrometer. The results revealed that not only the good solubility of the drug in the applied solvent, but also the high volatility of the solvent, is necessary for an optimal composite-formation process.

Investigation of an Unusual Crystal Habit of Hydrochlorothiazide Reveals Large Polar Enantiopure Domains and a Possible Crystal Nucleation Mechanism

The observation of an unusual crystal habit in the common diuretic drug hydrochlorothiazide (HCT), and identification of its subtle conformational chirality, has stimulated a detailed investigation of its crystalline forms. Enantiomeric conformers of HCT resolve into an unusual structure of conjoined enantiomorphic twin crystals comprising enantiopure domains of opposite chirality. The purity of the domains and the chiral molecular conformation are confirmed by spatially revolved synchrotron micro-XRD experiments and neutron diffraction, respectively. Macroscopic inversion twin symmetry observed between the crystal wings suggests a pseudoracemic structure that is not a solid solution or a layered crystal structure, but an unusual structural variant of conglomerates and racemic twins. Computed interaction energies for molecular pairs in the racemic and enantiopure polymorphs of HCT, and the observation of large opposing unit-cell dipole moments for the enantiopure domains in these twin crystals, suggest a plausible crystal nucleation mechanism for this unusual crystal habit.

Pharmaceutical cocrystals, salts and polymorphs: Advanced characterization techniques

The main goal of a novel drug development is to obtain it with optimal physiochemical, pharmaceutical and biological properties. Pharmaceutical companies and scientists modify active pharmaceutical ingredients (APIs), which often are cocrystals, salts or carefully selected polymorphs, to improve the properties of a parent drug. To find the best form of a drug, various advanced characterization methods should be used. In this review, we have described such analytical methods, dedicated to solid drug forms. Thus, diffraction, spectroscopic, thermal and also pharmaceutical characterization methods are discussed. They all are necessary to study a solid API in its intrinsic complexity from bulk down to the molecular level, gain information on its structure, properties, purity and possible transformations, and make the characterization efficient, comprehensive and complete. Furthermore, these methods can be used to monitor and investigate physical processes, involved in the drug development, in situ and in real time. The main aim of this paper is to gather information on the current advancements in the analytical methods and highlight their pharmaceutical relevance.