Considerations on the quantitative analysis of apparent amorphicity of milled lactose by Raman spectroscopy

Pazesh, Samaneh; Lazorova, Lucia; Berggren, Jonas; Alderborn, Göran; Gråsjö, Johan

doi:10.1016/j.ijpharm.2016.07.001

Cited by 23 publications

(10 citation statements)

References 33 publications

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“…In addition, the crystal size calculation suggests lactose amorphization. 36 XRD results are compatible with the hypothesis that the trituration process would be able to induce change in the properties of particles, such as plastic deformations. 16 The observed enthalpy variation (►Fig.…”

Section: Discussionsupporting

confidence: 86%

Physicochemical Properties of Zinc and Lactose in Solid Mixtures: Influence of Trituration Process

et al. 2021

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Background Recent experimental results supporting the dynamization process show modification in the characteristics of solid mixtures. Objective The present work aims to evaluate the physicochemical properties of metallic zinc and lactose, evidencing the interactions between all chemical components presented in dynamized solid mixtures by analytical techniques. Methods Mixtures of zinc and lactose (1:9 w/w) were successively triturated at the same proportion according to the Brazilian Homeopathic Pharmacopoeia, receiving the designation of 10−1 – 10−6 (1dH – 6dH). All samples were submitted to the following characterization techniques: Atomic Absorption Spectrometry (AAS), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), and Raman Spectroscopy (RS). Results AAS results detected 97.0% of zinc in the raw material, and the triturated zinc lactose system (ZnMet) presented mean values similar to those expected for the physical mixtures: i.e., 9.94%, 1.23%, and 0.11% in the three first proportions (10−1, 10−2, 10−3), respectively. SEM images showed particle size reduction due to the trituration process. The XRD assays of ZnMet 10−3 and 10−6 indicated peak changes at 12.3° and 43.26°, probably associated with modifications of inter-atomic crystalline spacing. The thermal analysis results of dynamized samples suggest modifications in the chemical interaction between zinc and lactose induced by the physical forces applied. RS experiments showed variation in vibration frequencies due to the dynamization procedure, in which marked ZnMet 10−6 spectral modifications were detected at 357, 477, 1086 and 1142 cm−1, and in the wavelength range 860–920 cm−1. Conclusion These results highlight the importance of applying suitable characterization methods to improve our understanding of the properties of homeopathic solid mixtures, whereas the uses of sensitive tools evidence the influence of trituration on the crystalline properties and in the enthalpy variation of dynamized samples.

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Section: Discussionsupporting

confidence: 86%

Physicochemical Properties of Zinc and Lactose in Solid Mixtures: Influence of Trituration Process

et al. 2021

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“…To further reduce the size of the particles (below 1 μm), a longer milling time or a higher speed needs to be applied. However, milling may produce the amorphous form via mechanical activation, but typically this requires significantly longer time scales (20). In this study, the thermograms showed no changes in the thermal properties of the milled material compared to those for the received materials, which indicates that the compounds are still in their original crystalline form after this processing.…”

Section: Discussionmentioning

confidence: 99%

Controlled Suspensions Enable Rapid Determinations of Intrinsic Dissolution Rate and Apparent Solubility of Poorly Water-Soluble Compounds

2017

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PurposeTo develop a small-scale set-up to rapidly and accurately determine the intrinsic dissolution rate (IDR) and apparent solubility of poorly water-soluble compounds.MethodsThe IDR and apparent solubility (Sapp) were measured in fasted state simulated intestinal fluid (FaSSIF) for six model compounds using wet-milled controlled suspensions (1.0% (w/w) PVP and 0.2% (w/w) SDS) and the μDISS Profiler. Particle size distribution was measured using a Zetasizer and the total surface area was calculated making use of the density of the compound. Powder and disc dissolution were performed and compared to the IDR of the controlled suspensions.ResultsThe IDR values obtained from the controlled suspensions were in excellent agreement with IDR from disc measurements. The method used low amount of compound (μg-scale) and the experiments were completed within a few minutes. The IDR values ranged from 0.2–70.6 μg/min/cm2 and the IDR/Sapp ratio ranged from 0.015 to 0.23. This ratio was used to indicate particle size sensitivity on intestinal concentrations reached for poorly water-soluble compounds.ConclusionsThe established method is a new, desirable tool that provides the means for rapid and highly accurate measurements of the IDR and apparent solubility in biorelevant dissolution media. The IDR/Sapp is proposed as a measure of particle size sensitivity when significant solubilization may occur.

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“…The apparent amorphous content (AAC) of each compact was quantified directly after compaction with Raman spectroscopy as described previously (Pazesh et al, 2016). Raman spectra were obtained using Raman Ewave Opetronics Inc. (SLSR-ProTT analyser, Irvine, CA, USA), equipped with TE cooled CCD detector and a laser source operating at an excitation wavelength of 785 nm.…”

Section: Methodsmentioning

confidence: 99%

Atypical compaction behaviour of disordered lactose explained by a shift in type of compact fracture pattern

Pazesh

Persson

Alderborn

2019

International Journal of Pharmaceutics: X

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The objective was to investigate tabletability and compactibility for compacts of a series of α-lactose monohydrate powders with different degree of disorder. Regarding the tabletability, the powders of high degree of disorder displayed similar behaviour that deviated markedly from the behaviour of the crystalline powders and the milled powder of modest degree of disorder. The Ryshkewitch-Duckworth equation, describing compactibility, was nearly linear for the crystalline powders, while for the disordered powders the model failed to describe the relationships, i.e. the disordered powders were characterised by a plateau in the Ryshkewitch-Duckworth plots over a relatively wide range of compact porosities. It was concluded that the difference in compaction behaviour of the milled particles compared to the crystalline powders was primarily explained by the increased particle plasticity of the disordered particles. The plateau in the Ryshkewitch-Duckworth plots obtained for the disordered powders was explained by a change in the fracture behaviour of the compacts, from an around grain to an across grain fracture pattern. This implied that the disordered particles can be described as a type of core-shell particles with an amorphous shell and a defective crystalline core.

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Considerations on the quantitative analysis of apparent amorphicity of milled lactose by Raman spectroscopy

Cited by 23 publications

References 33 publications

Physicochemical Properties of Zinc and Lactose in Solid Mixtures: Influence of Trituration Process

Physicochemical Properties of Zinc and Lactose in Solid Mixtures: Influence of Trituration Process

Controlled Suspensions Enable Rapid Determinations of Intrinsic Dissolution Rate and Apparent Solubility of Poorly Water-Soluble Compounds

Atypical compaction behaviour of disordered lactose explained by a shift in type of compact fracture pattern

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