Supramolecular chemistry and crystal engineering

Nangia, Ashwini

doi:10.1007/s12039-010-0035-6

Cited by 91 publications

(55 citation statements)

References 70 publications

(30 reference statements)

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“…7 Surprisingly, barring the crystal structures of PZA polymorphs, which date back to the 1960s and 1970s, 4 there is a dearth of spectroscopic and phase stability information on PZA. Polymorphism was noted in PZA long before this phenomenon became important to the pharmaceutical industry, which is usually taken as the 1990s decade, 8 when litigation took place surrounding forms 1 and 2 of ranitidine hydrochloride (Zantac) and the accidental appearance of a stable, less soluble form II of Ritonavir (Norvir).…”

Section: Introductionmentioning

confidence: 99%

Pyrazinamide Polymorphs: Relative Stability and Vibrational Spectroscopy

Cherukuvada

Thakuria

Nangia

2010

Crystal Growth & Design

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102

109

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The stability of four polymorphs of pyrazinamide, R, β, γ, and δ, was studied under solvent-mediated crystallization, neat and liquid-assisted grinding, polymorph seeding, and ambient storage conditions. In contrast to a recent report that the δ polymorph is the most stable modification (Castro et al. Cryst. Growth Des. 2010, 10, 274), we find that the R polymorph is the thermodynamic form. β, γ, and δ transform to the R phase in the above-mentioned conditions as monitored by infrared, near-infrared, and Raman spectroscopy, differential scanning calorimetry, and X-ray powder diffraction. Transformation to the high temperature γ phase is monitored by thermogravimetric analysis-infrared (TG-IR) spectrometry. A semischematic energy-temperature diagram consistent with phase transformation experiments, thermal measurements, and crystal structure data gives the order R < δ < γ < β at 25°C (R is the most stable form), whereas at 160°C γ < R < δ < β (γ stable modification), but at absolute zero δ < R < β < γ (δ stable modification). Even though the δ polymorph has the lowest free energy at absolute zero temperature, the R polymorph is the thermodynamic form under the ambient conditions regime more relevant to crystallization and handling of pharmaceuticals. The intrinsic dissolution rate of the γ form is faster than R and δ polymorphs, but R is the preferred polymorph of pyrazinamide considering both stability and bioavailability criteria. We also report high quality X-ray crystal structures of all the four polymorphs of pyrazinamide (R = 0.0387, 0.0340, 0.0392, and 0.0372 for R, β, γ, and δ).

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Section: Introductionmentioning

confidence: 99%

Pyrazinamide Polymorphs: Relative Stability and Vibrational Spectroscopy

Cherukuvada

Thakuria

Nangia

2010

Crystal Growth & Design

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102

109

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“…The primary goal of crystal engineering is to understand the intermolecular covalent and non-covalent interactions in terms of self assembly towards the design of novel functional materials [1][2][3][4][5][6]. Appreciable amount of work has been done to understand the molecular packing and structure-property relationship.…”

Section: Introductionmentioning

confidence: 99%

“…In order to do so, we have designed a number of multidentate N-heterocyclic ligands (shown in Scheme 1) and exploited them with different Cu I -halides in presence of PPh 3 and synthesized six new complexes (1)(2)(3)(4)(5)(6) which were characterized by SC-XRD and PXRD studies.…”

Section: Introductionmentioning

confidence: 99%

Predesigned synthesis of dinuclear to unusual hexanuclear to 1D coordination polymer of Cu(I)-halides and their and photophysical properties

Patra

Pal

Mondal

et al. 2016

Inorganica Chimica Acta

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“…In the last decade, several approaches to attain multicomponent pharmaceutical forms have been used and different kinds have been obtained. The most notorious cases are undoubtedly co‐crystals and molecular salts[1] and their design, using crystal engineering principles, strategic and synthetic approaches have been the subject of different reviews [2–5]. Also, their characterization and implications for regulatory control and intellectual property protection have been presented and discussed.…”

Section: Preamblementioning

confidence: 99%

New forms of old drugs: improving without changing

Domingos

André

Quaresma

et al. 2015

Journal of Pharmacy and Pharmacology

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Objectives In a short approach, we want to present the improvements that have recently been done in the world of new solid forms of known active pharmaceutical ingredients (APIs). The different strategies will be addressed, and successful examples will be given. Key findings This overview presents a possible step to overcome the 10-15 years of hard work involved in launching a new drug in the market: the use of new forms of well-known APIs, and improve their efficiency by enhancing their bioavailability and pharmacokinetics. It discusses some of the latest progresses. Summary We want to present, in a brief overview, what recently has been done to improve the discovery of innovative methods of using well-known APIs, and improve their efficiency. Multicomponent crystal forms have shown to be the most promising achievements to accomplish these aims, by altering API physicochemical properties, such as solubility, thermal stability, shelf life, dissolution rate and compressibility. API-ionic liquids (ILs) and their advantages will be briefly referred. An outline of what has recently been achieved in metal drug coordination and in drug storage and delivery using bio-inspired metal-organic frameworks (BioMOFs) will also be addressed. PreambleIn the last decade, several approaches to attain multicomponent pharmaceutical forms have been used and different kinds have been obtained. The most notorious cases are undoubtedly co-crystals and molecular salts [1] and their design, using crystal engineering principles, strategic and synthetic approaches have been the subject of different reviews.[2-5] Also, their characterization and implications for regulatory control and intellectual property protection have been presented and discussed. Here, we go one step forward and taking into account the recent definition of pharmaceutical co-crystal; from the published outcome of the Indo-US bilateral meeting in 2012 [6] and the FDA guidance draft for co-crystals, [7] which classifies co-crystals as 'dissociable API-excipient molecular complexes' where the co-former is the excipient, we call pharmaceutical companies' attention to the fact that following FDA rules, co-crystals can be treated as drug product intermediate, offering the potential of abbreviated new drug application rather than the full new drug application. This can be looked upon as not only a prompt process involving fewer risks, but also a less cost-effective process. Different steps have also been given to enhance drug properties through API metal coordination, generating metallodrugs and metallopharmaceuticals and more recently bio-inspired metal-organic frameworks (BioMOFs) for drug storage and controlled delivery. Here, we briefly present and discuss some of the recent published work, giving examples where the proposed routes proved to be beneficial.

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Supramolecular chemistry and crystal engineering

Cited by 91 publications

References 70 publications

Pyrazinamide Polymorphs: Relative Stability and Vibrational Spectroscopy

Pyrazinamide Polymorphs: Relative Stability and Vibrational Spectroscopy

Predesigned synthesis of dinuclear to unusual hexanuclear to 1D coordination polymer of Cu(I)-halides and their and photophysical properties

New forms of old drugs: improving without changing

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