Mixing of powders. Wim Oostra - PDF Free Download

Mixing of powders Wim Oostra

Introduction Concepts of mixtures Statistics Mechanisms of mixing Segregation Equipment Practice Scale - up References Content

Types of Mixtures

Ordered Mixture

A good mixture?

Clusters

Simulation 1 0 2 4 6 8 10 fraction of clusters [-] 0.1 0.01 0.001 0.0001 2% 5% 10% cluster size [# spheres] Yi, Y.-B, C.-W. Wang and A. M. Sastry (2004), J. Electrochem. Soc., 151 (8), A1292-A1300, 2004.

NIR imaging 0 1 2 millimeters 3 4 5 6 0 1 2 3 4 5 6 millimeters

Measurements 1000 E2: Cluster distribution: Good vs Poor (concentration pixel > 8.1 w/w %) 100 Cluster frequentie 10 1 good poor 0.1 0.0 0.5 1.0 1.5 Cluster size [mm]

Statistics, ideal case Two component system Particles differ only in color Binomial statistics

Statistics Average: y n = 1 y i n Standard deviation: σ = n 1 ( y i n 1 y) 2

Statistics, ideal case At complete segregation: 2 σ = p q Fully randomized for A particles: 2 σ = p A q

Statistics, real life Two component, multisized: Multi component with one key component: + = q a a p a a W f p W f q W p q ). ( ). (. 2 σ ( ) ( ) ( ) + + + =....... 1 2 2 2 r a a q a a p a a W f r W f q W f p p p W p σ

Mixing indices Lacey: M σ σ 2 2 0 = 2 2 σ 0 σ r mixing occurred = mixing possible Poole, Taylor, Wall: σ M = σ r

Mixing indices 0.25 0.2 sigma2 Lacey poole 4 3.5 3 sigma [-] 0.15 0.1 0.05 0 2.5 2 1.5 1 0.5 0 0 5 10 15 20 25 revs. [#] index [-]

Mechanisms of mixing Diffusion- redistribution of particles by random motion Convection - transfer from one location to another by external force Shear formation of slip planes

Diffusion

Convection

Shear dispersion

Segregation can be caused by: Difference in particle size Difference in density Difference in shape or a combination of these

Segregation Mechanisms Trajectory segregation

Segregation Mechanisms Percolation

Segregation Mechanisms Elutration

Segregation

Types of mixers Tumbling mixers Convective mixers High shear mixers Fluidized mixers Hopper mixers Multi-purpose mixers

Tumbler mixers:

V-mixer

Bin blender

Double cone blender

Drum

Ribbon blender

Nauta mixer

High shear mixer

Static mixer

Mixer selection

Ribbon blender

Rotocube

V-blender

Influence of size ratio

Mixing Strategies > 5-10% Direct blending 1-5% Preblending (non-geometric) <1% Preblending (Geometric) < 0.1% Solvent addition or Ordered mixing

Preblending (Nongeometric) Use KC 0.5 Example: 4% loading 0.04 0.5 =20%, preblend 1 part in 4 parts and subsequently make final blend

Preblending (geometric) Mix equal parts of key component and other component ( Mixture 1) Mix equal parts of Mixture 1 and other component ( Mixture 2) Mix equal parts of Mixture 2 and..

Scale up of blenders Rotational velocity is key blending parameter Try to keep tip speed and momentum the same during scale-up As mass increases tip speed decreases

Scale up of blenders Small scale: Develop sampling methods, sample sizes and locations Evaluate blending times Production scale: Verify blending time and rotational speed

Sampling Powder should be in motion when sampled Better sample the whole stream for many short times than part of the stream for a long time Use revolving sample splitter for reduction

Sample splitters Method rsd [%] cone and quartering 6.81 scoop sampling 5.14 table sampling 2.09 Chute riffler 1.01 Spinning Riffler 0.125

Sample thieves Several different designs are available Accuracy varies strongly, not only between different designs but also in one design between different mixtures!

A Sample thief

Test the thief

Use the thief Consistent and standardized technique Angle of insertion Swivel Fast or slow Personnel training Glass vs plastic containers (static) Test entire sample Weigh sample containers before sample is added Rinse sample container with extra diluent Lab training

Blend Sampling 115 110 Content [%] 105 100 95 90 85 80 0 5 10 15 20 25 30 sample # P/T: 60%

Tablet sampling

Blend sampling

Modern sampling (PAT), end point control On line NIR On line Raman Acoustic emission Effusivity.

PAT (1) 60 mg Gepirone Mixed 3-4 days after weighing HPMC Mixing time 15 minutes RSD HPLC 4.1% (after 3 wks) NIR spectra (immediately) 80 mg Gepirone Immediately mixed after weighing HPMC Mixing time 15 minutes RSD HPLC 1.3% (after 3 wks) NIR spectra (immediately) Gepirone NIR mengen 60 mg cp 0.06 NIR mengen Gepirone 80 mg gemiddelde absorptie [SNV 2nd-der] 0.04 0.02 0 1600 1605 1610 1615 1620 1625 1630 1635 1640 1645 1650-0.02-0.04-0.06 m60-01 m60-02 m60-03 m60-04 m60-05 m60-06 m60-07 m60-08 m60-09 m60-10 m60-11 m60-12 m60-13 m60-14 m60-15 m60-16 m60-17 m60-18 m60-19 m60-20 NIR spectrum [nm] Gemiddelde absorptie [snv 2nd-der] 0.1 0.08 0.06 0.04 0.02 0 1600 1605 1610 1615 1620 1625 1630 1635 1640 1645 1650-0.02-0.04 m80-01 m80-02 m80-03 m80-04 m80-05 -0.06 m80-06 m80-07 m80-08 m80-09 m80-10 m80-11 m80-12 m80-13 m80-14 m80-15 -0.08 m80-16 m80-17 m80-18 m80-19 m80-20 -0.1 NIR spectrum

Risk management and PAT (2) 0.25 NIR Mengen Gepirone (spectrum; 1600-1650) 60% som stdev 1600-1650 [NIR 0.2 0.15 0.1 0.05 NIR HPLC Parameter control (time) Quality-based Control (NIR value) 50% 40% 30% 20% 10% RSD Gepirone gehalte [HPLC] 0 0 5 10 15 20 mengtijd [min] 0% Solution; change from parameter-based process control to quality-based control

A control strategy INPUTS Parameters Mixing time Mixing speed PSD Excipients PSD Active Moisture content excipients MIXING Blend uniformity RH Batch size Mixer type Critical

The desired control strategy INPUTS Parameters Mixing time Mixing speed NIR PSD Excipients PSD Active Moisture content excipients MIXING Blend uniformity RH Batch size Mixer type Not critical Critical for this unit operation Critical for other unit operation

A variety of mixers

Analyzer on V-blender

Result Mixing in Vrieco Nauta blender 0.0012 0.001 MBSD (AU) 0.0008 0.0006 0.0004 12 kg 35 kg 40 kg 0.0002 0 0 5 10 15 20 25 30 Time (Minutes)

Full scale F.04 A. Gerich, et.al. A generic in-line NIR method for blend uniformity control using a moving F-test.

Full scale data, batch 2, 29, 62 Sulub et.al.

Modern scale up Bin blender, two sizes 2 two component mixtures On line assesment of mixture quality through NIR probe Data used to determine effective mixing volume of mixers

Small scale

Large scale

Results Formulation Critical rotations Scale up coeff. Ditab 130 3.33 Ditab 106 2.72 Dihydrate 92 3.41 Dihydrate 90 3.33

Modern approaches

References Powder Mixing, Brian Kaye, Chapman&Hall, 1997, ISBN 0412403404 Introduction to Particle Technology, Martin Rhodes, Wiley, 2000, ISBN 0471984825 Modelling of Powder Blending using On-line Near-Infrared Measurements, Drug. Dev. and Industrial Pharmacy, 27(7), 719-729 (2001) Powder Mixing and Segregation, F.J. Muzzio, T. Shinbrot, Final Report IFPRI, May 2001. Sampling and characterisation of pharmaceutical powders and granular blends, F.J. Muzzio et. al., Int. J. Pharmaceutics, 250, 51-64, 2003 Particle size measurement, T. Allen, 5th ed. Chapman&Hall, 1994 A review on the continuous blending of powders, L. Pernenkil and CL.L. Cooney, Chemical Engineering Science, 61, 720 742, 2006 Blend uniformity end-point determination using near-infrared spectroscopy and multivariate calibration, Journal of Pharm. and Biomed. Analysis, In Press, Accepted Manuscript, Available online 18 February 2011 Yusuf Sulub, Michele Konigsberger, James Cheney