Solid-State Characterization of Amorphous and Mesomorphous Calcium Ketoprofen

Atassi, Faraj; Chen, Mao; Masadeh, Ahmad S.; Byrn, Stephen R.

doi:10.1002/jps.21925

Cited by 28 publications

(23 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is important in pharmaceutical science because the properties (solubility, dissolution rates) and function (bioavailability) of stable or metastable amorphous gels are often significantly different from their crystalline counterparts [22,23]. Previously, for example, Calcium Ketoprofen dehydrate could only be vitrified by quenching from the melt in liquid nitrogen and is known to crystallize from water-ethanol supersaturated solutions in containers [24]. Similar containerless amorphization behavior is found here for Clotrimazole, Dibucaine, and Clofoctol.…”

Section: Fig 2 Insertsupporting

confidence: 71%

Amorphization of Molecular Liquids of Pharmaceutical Drugs by Acoustic Levitation

Benmore

Weber

2011

Phys. Rev. X

View full text Add to dashboard Cite

It is demonstrated that acoustic levitation is able to produce amorphous forms from a variety of organic molecular compounds with different glass forming abilities. This can lead to enhanced solubility for pharmaceutical applications. High-energy x-ray experiments show that several viscous gels form from saturated pharmaceutical drug solutions after 10-20 min of levitation at room temperature, most of which can be frozen in solid form. Laser heating of ultrasonically levitated drugs can also result in the vitrification of molecular liquids, which is not attainable using conventional amorphization methods.

show abstract

Section: Fig 2 Insertsupporting

confidence: 71%

Amorphization of Molecular Liquids of Pharmaceutical Drugs by Acoustic Levitation

Benmore

Weber

2011

Phys. Rev. X

View full text Add to dashboard Cite

show abstract

“…In the material science community the PDF technique has been used for several decades (101-105) and has more recently been applied by the pharmaceutical community to study short-and long-range order amorphous glassy materials (106)(107)(108)(109)(110)(111). It has been used in studies to investigate crystalline defects, help in the crystal structure determination (106,107,110), characterization of polymer/drug systems (111)(112)(113) and the use of multivariate data analysis has alleviated the interpretation of PDF (108,111). It could be a possible route to gain a deeper insight into the degree of disorder in a milled sample.…”

Section: Atomic Pairwise Distributionmentioning

confidence: 99%

Methods of amorphization and investigation of the amorphous state

Einfalt¹,

Planinšek²,

Hrovat³

2013

Acta Pharmaceutica

114

View full text Add to dashboard Cite

.g., polymorphs) provides pharmaceutical scientists with an opportunity to select the preferred form of the material to be used in a formulation. This is very useful since critical properties, such as particle morphology and dissolution properties, are frequently different in the different physical forms of a material. The amorphous form of pharmacologically active materials has received considerable attention because, in theory, it represents the most energetic solid state of a material, and should thus provide the biggest advantages in terms of dissolution rate and bioavailability (1). However, the amorphous form also shows various disadvantages, such as lower physical stability compared to crystals.The structure of an amorphous solid is usually described as possessing a crystal--like short-range molecular arrangement, but lacking a long-range order. As illustrated by Fig. 1, the immediate environment of a molecule (m) in an amorphous solid may not differ significantly from that in a crystal (e.g., similar number of and distance to nearest neighbors), but an amorphous solid lacks any long-range transational-orientational symmetry that characterizes a crystal (1). However, this is only true when we are dealing The amorphous form of pharmaceutical materials represents the most energetic solid state of a material. It provides advantages in terms of dissolution rate and bioavailability. This review presents the methods of solid--state amorphization described in literature (supercooling of liquids, milling, lyophilization, spray drying, dehydration of crystalline hydrates), with the emphasis on milling. Furthermore, we describe how amorphous state of pharmaceuticals differ depending on the method of preparation and how these differences can be screened by a variety of spectroscopic (X-ray powder diffraction, solid state nuclear magnetic resonance, atomic pairwise distribution, infrared spectroscopy, terahertz spectroscopy) and calorimetry methods.

show abstract

“…Limiting r-region to 20 Å of amorphous pharmaceuticals avoids fitting artifacts (Newman et al 2008). The PDF amplitude of amorphous materials falls rapidly along r compared to crystals and the r leasing to the virtual loss of G(r) oscillation yields the size of coherent domains (Atassi et al 2010). Benmore et al (2013) characterized amorphous APIs using synchrotron X-ray diffraction and spallation neutron diffraction.…”

Section: Local Structure Of Amorphous Pharmaceuticals Using Total X-rmentioning

confidence: 99%

“…Indeed, a synchrotron source is preferable to generate total scattering data with the highest resolution consisting of minimal statistical uncertainties. The PDF data with Q max < 18 Å −1 constitute all structural features for pharmaceuticals (Atassi et al 2010). Dykhne et al (2011) found that the PDF fingerprint of amorphous carbamazepine is unambiguously correlated with that of crystalline form when recorded using synchrotron radiation (Q max = 20 Å −1 ), silver-anode (Q max = 15.9 Å −1 ) or molybdenum-anode (Q max = 12.5 Å −1 ) while statistically poor and suboptimal resolution was obtained with Cu-anode (Q max ≤ 8 Å −1 ).…”

Section: Local Structure Of Amorphous Pharmaceuticals Using Total X-rmentioning

confidence: 99%

“…Multivariate analysis (MVA)-PDF can efficiently assess the degree and the nature of disorder during milling, storage time/temperature-mediated crystallization of milled amorphous material (Bøtker et al 2011;Naelapää et al 2012;Boetker et al 2012). The rapid acquisition PDF using synchrotron radiation of Ca-ketoprofen uniquely discriminated amorphous and mesomorphous structures of the crystalline phase (Atassi et al 2010). Total diffraction data of a drug candidate, GNE068, were used for the in-depth investigation of the disordered mesophase (Chakravarty et al 2013).…”

Section: Local Structure Of Amorphous Pharmaceuticals Using Total X-rmentioning

confidence: 99%

See 1 more Smart Citation