Effect of Cryogrinding on Physico-Chemical Properties of Drugs. I. Theophylline: Evaluation of Particles Sizes and the Degree of Crystallinity, Relation to Dissolution Parameters

Gubskaya, Anna V.; Lisnyak, Yury V.; Blagoy, Yury P.

doi:10.3109/03639049509065880

Cited by 13 publications

(4 citation statements)

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“…[30] The occurrence of these two opposite phenomena is dependent on the process parameters. [38] Often after a certain time point the particle size has achieved a constant level and continuing the milling does not further decrease the particle size. In some cases an increase in grinding time may even lead to a gradual increase of particle size and heterogeneity of the material, while decreased particle sizes are achieved with decreased milling speeds ( Figure 3).…”

Section: Process Variables In Nanomillingmentioning

confidence: 99%

“…During milling, two opposite processes are interacting in the milling vessel: fragmentation of material into smaller particles and particle growth through interparticle collisions [30] . The occurrence of these two opposite phenomena is dependent on the process parameters [38] . Often after a certain time point the particle size has achieved a constant level and continuing the milling does not further decrease the particle size.…”

Section: Introductionmentioning

confidence: 99%

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Pharmaceutical nanocrystals by nanomilling: critical process parameters, particle fracturing and stabilization methods

Peltonen

Hirvonen

2010

Journal of Pharmacy and Pharmacology

335

194

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Objectives Wet milling is a common technique to produce drug nanocrystals. Stability of the nanocrystals is a critical question, and different kinds of stabilizers, e.g. polymers, celluloses, surfactants and lipids, have been tested for various drugs. Still, the question about how to select the best stabilizer to a certain drug material and also to a selected process is open. Key findings Many different factors, such as surface energy, hydrophobicity, solubility, viscosity and functional groups, affect the stability of the formed nanosuspensions. Affinity of the stabilizer to the particle surfaces seems to be the most important parameter. This affinity is partly related to the surface energy and hydrophobicity of the surfaces and stabilizers. Summary In this review the most important factors affecting nanocrystal formulation and efficacy of stabilizers are presented. In order to widen understanding of the milling process, the most important variables related to milling techniques and particle fracturing processes during the milling are briefly presented.

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Section: Process Variables In Nanomillingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pharmaceutical nanocrystals by nanomilling: critical process parameters, particle fracturing and stabilization methods

Peltonen

Hirvonen

2010

Journal of Pharmacy and Pharmacology

335

194

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“…By using the integrated peak intensities, the variations in the lattice strain and particle size, which can have significant influences on the line shape, will not be reflected in the final result. Other examples of quantitative analysis using integrated peak area include digoxin,36 cefazolin sodium,42 raffinose,43 B02669,44 β‐lactam,30 α‐lactose monohydrate; β‐lactose,45 cromolyn sodium,23 acetaminophen,46 cefditoren pivoxil,47 lactose,48 microcrystalline cellulose,49 β‐cyclodextrin,27 cephalothin,50 theophylline,51 TAT 59,20 and lactose 52…”

Section: Quantification Techniquesmentioning

confidence: 99%

Analytical techniques for quantification of amorphous/crystalline phases in pharmaceutical solids

Shah

Kakumanu

Bansal

2006

Journal of Pharmaceutical Sciences

329

235

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“…Additionally, cryo-milling, which consists in grinding particles at temperatures below room temperature, has proven to be a very simple and effective technique for reducing drug particle size to micrometric or even submicron ranges, thus improving particle dissolution rates [13][14][15][16][17] . However, some researchers have reservations about grinding because it may induce unwanted reactions in the drug, affecting its physicochemical stability [18][19][20] .…”

Section: Introductionmentioning

confidence: 99%

Changes in the Solid State of Nicergoline, a Poorly Soluble Drug, Under Different Grinding and Environmental Conditions: Effect on Polymorphism and Dissolution

Censi

Gigliobianco

Casadidio

et al. 2019

Journal of Pharmaceutical Sciences

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Nicergoline native crystals (Form I) were subjected to different grinding methods for 15, 30, 45, and 60 minutes: Method A, grinding at 20 °C under air atmosphere; Method B, grinding in presence of liquid nitrogen under air atmosphere; Method C, grinding at 20 °C under nitrogen atmosphere; and Method D, grinding in presence of liquid nitrogen under nitrogen atmosphere. Scanning electron microscopy, differential scanning calorimetry, X-ray powder diffractometry, thermogravimetry, and infrared spectroscopy were used to follow changes in the particle size and in crystalline structures. Batches from Methods A and C underwent partial amorphization immediately after grinding; form II was obtained by heating these partially amorphous forms or after spontaneous crystallization of A and C after 1 and 5 months storage. Method B promoted the hydration of nicergoline to a monohydrate form. Batch D was stable under grinding and neither amorphization nor hydration were observed. The best Intrinsic Dissolution Rate was that of metastable Form II, followed by Form I, while the worst was that of the Method B monohydrate form. The slowest particle dissolution was observed for hydrated particles, because of the lowest IDR, while the most rapid was exhibited by batch D, because of the very small particle size.

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Effect of Cryogrinding on Physico-Chemical Properties of Drugs. I. Theophylline: Evaluation of Particles Sizes and the Degree of Crystallinity, Relation to Dissolution Parameters

Cited by 13 publications

References 5 publications

Pharmaceutical nanocrystals by nanomilling: critical process parameters, particle fracturing and stabilization methods

Pharmaceutical nanocrystals by nanomilling: critical process parameters, particle fracturing and stabilization methods

Analytical techniques for quantification of amorphous/crystalline phases in pharmaceutical solids

Changes in the Solid State of Nicergoline, a Poorly Soluble Drug, Under Different Grinding and Environmental Conditions: Effect on Polymorphism and Dissolution

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