Application of slurry bridging experiments at controlled water activities to predict the solid-state conversion between anhydrous and hydrated forms using theophylline as a model drug

Ticehurst, Martyn D.; Storey, Richard; Watt, C.M.

doi:10.1016/s0378-5173(02)00277-6

Cited by 87 publications

(83 citation statements)

References 18 publications

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“…In the case of TPa, the value of the critical RH is controversial and values ranging from 25% to 82% (for temperatures around 258C) have been reported. 44,47,70 Figure 6a shows the Raman spectra, in the region of 3060-3160 cm À1 , obtained for samples of TPa (commercial powder) stored at different RH values for 1 week at 228C, and illustrates the general behavior observed in all the studied regions. The corresponding plot of a h ratio versus RH is shown in Figure 6b.…”

Section: Critical Rh For Tpa Hydrationmentioning

confidence: 92%

“…0.1 g) were submitted to different temperatures (35,40,47, and 608C) during defined time periods, and sealed in glass capillary tubes in order to record their FT-Raman spectra.…”

Section: Sample Treatmentmentioning

confidence: 99%

“…TPh and TPh ! TPa transformations, and both processes have been studied for the bulk powder 38,[44][45][46][47][48][49][50][51][52][53][54][55][56] and for tablets. [57][58][59][60] The effects of different excipients on these hydration and dehydration processes have also been evaluated by different authors.…”

Section: Introductionmentioning

confidence: 99%

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Probing Pseudopolymorphic Transitions in Pharmaceutical Solids using Raman Spectroscopy: Hydration and Dehydration of Theophylline

Amado

Nolasco

Ribeiro‐Claro

2007

Journal of Pharmaceutical Sciences

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Theophylline is known to undergo vapor phase induced hydrate-anhydrate pseudopolymorphic transformations, which can affect its bioavailability. In this work, the kinetics of the pseudopolymorphic transitions of theophylline crystals in different storage conditions is studied using a vibrational spectroscopic technique. While the hydration is a single-step process with a half-life time of ca. 5 h, the dehydration occurs through a two-step mechanism. In addition, the phase stability of hydrate-anhydrate systems in different relative humidity (RH) conditions was probed. The critical RH for anhydrous teophylline was found to be at ca. 79%, while the critical RH for dehydration is ca. 30%. ß

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Section: Critical Rh For Tpa Hydrationmentioning

confidence: 92%

“…0.1 g) were submitted to different temperatures (35,40,47, and 608C) during defined time periods, and sealed in glass capillary tubes in order to record their FT-Raman spectra.…”

Section: Sample Treatmentmentioning

confidence: 99%

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Probing Pseudopolymorphic Transitions in Pharmaceutical Solids using Raman Spectroscopy: Hydration and Dehydration of Theophylline

Amado

Nolasco

Ribeiro‐Claro

2007

Journal of Pharmaceutical Sciences

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“…Hence, the presence of remaining anhydrous theophylline can be explained for the runs with lower liquid concentration. Adding less water, which results in a lower water activity, leads to a lower conversion rate of anhydrous theophylline to theophylline monohydrate [30,31].…”

Section: Gewijzigde Veldcodementioning

confidence: 99%

“…Ticehurst et al [30] stated that at higher temperature an increased water activity is required to transform anhydrous theophylline to theophylline monohydrate. This can explain why runs with a higher barrel temperature result in these small remaining amounts of anhydrous theophylline in the granules.…”

Section: Gewijzigde Veldcodementioning

confidence: 99%

Real-time assessment of critical quality attributes of a continuous granulation process

Fonteyne

Vercruysse

Díaz

et al. 2011

Pharmaceutical Development and Technology

104

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There exists the intention to shift pharmaceutical manufacturing of solid dosage forms from traditional batch production towards continuous production. The currently applied conventional quality control systems, based on sampling and time-consuming off-line analyses in analytical laboratories, would annul the advantages of continuous processing. It is clear that real-time quality assessment and control is indispensable for continuous production. This manuscript evaluates strengths and weaknesses of several complementary Process Analytical Technology (PAT) tools implemented in a continuous wet granulation process, which is part of a fully continuous from powder-to-tablet production line. The use of Raman and NIR spectroscopy and a particle size distribution analyzer is evaluated for the real-time monitoring of critical parameters during the continuous wet agglomeration of an anhydrous theophylline -lactose blend. The solid state characteristics and particle size of the granules were analyzed in real-time and the critical process parameters influencing these granule characteristics were identified. The temperature of the granulator barrel, the amount of granulation liquid added and, to a lesser extent, the powder feed rate were the parameters influencing the solid state of the active pharmaceutical ingredient (API). A higher barrel temperature and a higher powder feed rate, resulted in larger granules.

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Physicochemical Characterization and Oral Dosage Form Design and Selection

Dening

Amidon

et al. 2021

Burger's Medicinal Chemistry and Drug Discovery

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In order to initiate formulation development activities – that is the identification of a “marketable” product – important physical and chemical properties (physicochemical properties) as well as permeability properties need to be determined. Evaluation of these properties early in the discovery process can help discovery teams select which templates to pursue as well as identify the most promising leads. This information is also valuable “downstream” as decisions regarding dosage form design are being made. The focus of this article will be on the physicochemical properties that are most important in the evaluation of discovery leads and that provide the information needed as dosage form development is initiated and progresses. It will become apparent that the most appropriate dosage forms that make sense to consider are dictated by both the physicochemical and biopharmaceutical properties of the drug molecule. Throughout this article, there will be an emphasis on the tools and principles that will help the medicinal chemist during the drug discovery process, with particular emphasis on oral dosage forms.

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Application of slurry bridging experiments at controlled water activities to predict the solid-state conversion between anhydrous and hydrated forms using theophylline as a model drug

Cited by 87 publications

References 18 publications

Probing Pseudopolymorphic Transitions in Pharmaceutical Solids using Raman Spectroscopy: Hydration and Dehydration of Theophylline

Probing Pseudopolymorphic Transitions in Pharmaceutical Solids using Raman Spectroscopy: Hydration and Dehydration of Theophylline

Real-time assessment of critical quality attributes of a continuous granulation process

Physicochemical Characterization and Oral Dosage Form Design and Selection

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