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Solid Particles And Particle Size Flashcards

1
Q

Why is Particle Size Important?

Biopharmaceutics

A

Rate of Dissolution of solids INCREASE

as Surface area INCREASES

Small particles = Large surface area

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2
Q

Toxicity

Why is Particle Size Important?

A

Small rod-shaped insoluble particles

~1um x 5um long

CARCINOGENIC if inhaled

  • –> attack immune system if they are similar to bacteria
    • failed attackks lead to lung tissue damage
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3
Q

Inhalation Drug Delivery

Why is Particle Size Important?

A

Particles must be within a critical size of

1-5um

to reach deep recess of lungs (aleovi)

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4
Q

Poorly Soluble Drugs

Why is Particle Size Important?

A

Particle Size REDUCTION

–> increase surface area

INCREASES dissolution rate

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5
Q

Nanoparticle Technology

Why is Particle Size Important?

A

Extra solubility enhancement can be achieved

W/ colloidal particles

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6
Q

Aseptic Processing

Why is Particle Size Important?

A

Filtration is Important

–> REMOvE MICROORGANISMS

laminar air flow hoods

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7
Q

Liquid Filtration Process

Why is Particle Size Important?

A

Filter pore size related to Microorganism / drug particle size

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8
Q

Compounding

Why is Particle Size Important?

A

Organoleptic Properties

Tase / Smell ENHANCED by particle size

Large particles = gritty and visually unaesthetic

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9
Q

Nanometer to Angstrom

A

1nm

= 10 angstroms

1angstrom = 1x10-10m

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10
Q

Micrometrics

A

Describes the SCIENCE & TECHNOLOGY

of Small particles

  • Range in size from .5um - 3000um (3mm) in size
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11
Q

Physical Characteristics of Powder

Molecular Level

A
  • Characteristics of individual molecules studied by:
    • UV/VIS absorption spectroscopy
    • Fluorescence spectroscopy
    • Vibrational Spectroscopy
    • ​IR / NMR
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12
Q

Particulate Level

Why is Particle Size Important?

A
  • Characteristics that pertain to a small group of particles are studied by:
    • Particle Morphology
      • ​SEM
    • ​Sieving / Laser Diffraction
    • Crystallography / X-ray diffraction
    • Thermal Methods
      • ​DSC / DTA
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13
Q

Bulk Level

Why is Particle Size Important?

A
  • Characteristics pertain to a large group of particles
    • ​Solubility / dissolution rate
    • adsorption / flow
    • Angle of repose
    • Bulk packin / tap density
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14
Q

Objective of Size Reduction

Large Particle Size

A

Uniform Particle size/ shape for processing

  • Control of raw materials
  • Process uniformity
  • uniform flow of particles
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15
Q

Milling / Comminution

Large Particle Size

A

Comminution = Crush / grind into powder

Hammer Mill / Fitzmill

  • Happer = wedge shaped hatchet blade
  • Mill speed –> more small particles
  • Feed Rate:
    • TOO FAST –> choke mill –> BURNING
    • too slow –> starve mill –> small particle size
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16
Q

Analysis of

Large Particle Size

A
  • SIEVING
    • ​Mesh, GREATER NUMBER = Smaller the size
    • screen openings per inch
  • ​Microscopy
  • Bulk Density / Tap Density
  • Angle of Repose
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17
Q

How to measure / characterize Solids

Large Particle Size

A
  • Count particles
  • Measure longest dimension:
    • Surface Area
    • Volume
    • Mass
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18
Q

Equivalent Sphere Method

Large Particle Size

A

Express dimensions in ONE NUMBER

Dimension / Surface Area / Volume

MEAN DIAMETER

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19
Q

Number-Length mean

D[1,0]

Large Particle Size

A

Sum of diameter / n

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20
Q

Number-Surface mean

D[2,0]

Large Particle Size

A

SURFACE AREA

SQUARE ROOT OF Sum[d2] / n

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21
Q

Number Volume or Number-Weight mean

D[3,0]

Large Particle Size

A

Sum of diameters to the 3rd power / n

All to the 1/3 power

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22
Q

Particle Characterization

Large Particle Size

A

What matters is

WHAT TYPE OF INSTRUMENT PROVIDES THE DATA

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23
Q

Monodisperse Vs Polydisperse

Large Particle Size

A

Mono = all particles are same size and shape

Poly = particles range from small to large

look for an AVERAGE particle size to measure

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24
Q

Unimodal vs Bimodal

Large Particle Size

A

Unimodal = Mean size has 1 PEAK

Bimodal = 2 sizes 2 peaks

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25
Q

Bulk Density

Large Particle Size

A
  • Not an intrinsic property
    • Changes depending on how the material is handled
  • ​Disturbing a cylinder
    • –> powder particles will move and settle closer together
    • –> Increased bulk density
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26
Q

Different ways to compute average/mean particle size

Large Particle Size

A
  • Average the longest length
  • surface area
  • volume
  • weighted combination
    • ​arithmetic mean / geometric/ harmonic mean)

JUST MAKE SURE U COMPARE THE SAME THANG

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27
Q

Tapped Density

Large Particle Size

A
  • ​Refers to the bulk density of the powder
    • ​AFTER a specified compaction process
      • ​VIBRATION
  • ​​Cylinder is TAPPED
    • until the volume reaches a MINIMUM
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28
Q

Angle of Repose

Large Particle Size

A
  • Bulk materials poored onto a horizontal surface
    • –> form conical pile
  • Angle of repose
    • = Internal angle between surface of the pile
    • & the horizontal surface
  • ​Related to:
    • density / surface area / shapes
    • & STICKINESS (coefficient of friction)
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29
Q

Product / Process Considerations

Large Particle Size

A
  • ENCAPSULATION
    • ​VOLUMETRIC FILL INTO CAPSULE
    • Dispensed by weight but filled by volume
  • ​Solid Mixing / blending
    • ORDERED MIXING = of same size in order
    • segregation / volume of material
  • SOlids Milling
    • ​Uniformity of particle size
  • ​Tablet compressing
  • Product Dissolution performance
  • Solid granulation proces
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30
Q

Target Size Reduction

Small Particle Size

A

1 micron = 1mm

Uniform size/ shape

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31
Q

Ball Mill

Small Particle Size

A
  • Grinder consisting of cylindrical container
    • ​–> Solids –> FINE POWDERS
  • ​Rotate around horizontal axis
    • Material to be ground + GRINDING MEDIUM
      • ​ceramic/steel balls
32
Q

Micronizer (Jet Mill)

Small Particle Size

A

Sturtevant Micronizer = Fluid Energy Mill

  • Compressed air/gas
    • –> produce particles LESS THAN 1 micron (1mm)
  • ​Fine particles move towards center –> exit through vortex finder
    • use centrifugal force
33
Q

Analysis of

Small Particle Size

A
  • Microscopy
  • Electrozone Sensing
  • Laser Diffration = LALLS
  • Photon Correlation Spectroscopy = PCS
  • Cascade Impactors
  • BET isotherm analysis
34
Q

Microscopy

Analysis of Small Particle Size

A

Measurement Slide

Logarithmic scarle

Image analysis software needed

same technique as w/ larger particles

35
Q

Electrozone Sensing = Coulter Counter

Analysis of Small Particle Size

A

Particle size determined by VOLTAGE CHARGE

Must measure using an electrolyte

CAN NOT MEASURE DRY POWDER / SPRAYS

requires calibration

lower limit = 2mm

36
Q

Laser Diffraction = LALLS

Malvern

Analysis of Small Particle Size

A

Low angle laser light scattering

Range >.05um

Laser is stable/reliable

NO calibration

CAN measure dry powders / liquid in suspension / sprays

37
Q

Photon Correlation Spectroscopy

PCS

Analysis of Small Particle Size

A

For particles BELOW <1nm

Brownian motion to measure particle size

CAN NOT use on particles that are sedementing

DENSITY dependent

large molecules = slower movement

38
Q

Cascade Impactors

Analysis of Small Particle Size

A

Use to measure particle size in AEROSOLS

Stokes Law

Particle size serparation is carrried out by Inertial impaction

based on particle mass

39
Q

Product / Process Considerations

of Small Particle Size

A
  • Product dissolution Performance –> BIOAVAILABILITY
    • ​Micron particle size –> Dissolution –> More Absorption
  • Solid Micronization
    • uniformity of size
  • Tablet Coating
  • Suspension/cream / ointments
    • Opthalmics
  • ​AEROSOL DOSAGE FORMS
40
Q

Aerosol Dosage Forms

of Small Particle Size

A

​Goal is to get aerosol particles –> DEEP LUNG ALVEOLI

not into upper respiratory

Particle Size is the key to success

  • pMDI’s or MDI
    • has propellant
    • pressurized container with drug –> actuation
  • DPI (dry powder inhalation)
    • ​no propellant no pressure
    • Admin by ACTUATION
      *
41
Q

Ideal Respiratory Delivery System

Small Particle Size

A
  • Respirable particle Delivery:
    • Particle Size -<2um
    • Reproducible Plume Pattern
    • Consistant dose UNIFORMITY
    • no electrostatic issues
  • ​Stable & Compatable formulation
    • ​stable particle size
    • free from extractables/microbials
42
Q

Biopharmaceutics

on Particle Size

A

​Increasing particle size can delay drug release in suspension

  • Rate of Dissolution
    • ​related to particle size / total surface area
  • Solubility is INCREASED
    • if particle is extremely small <100nm
  • ​M-Cells (associated w/ lymph tissue / intestinal wall)
    • absorb nanoparticles
43
Q

Griseofulvin

A
  • Antifungal that was POORLY ORALLY ABSORBED
    • ​Reduced particle size
      • ​–> Decreased the dose
44
Q

Fenofibrate

A

Reduction of particle size

Allowed for a lower dose needed

45
Q

Potassium Chloride / Nitrofurantoin

A

Sustained Release drug created from

MICROENCAPSULATING the product

reduce the rate of absorption

individual crystals covered w/ semipermeable coatin

46
Q

Insulin

Biopharmaceutics

A

Insulin is typically RAPIDLY elminated from the body

due to high water solubility

Formation W/ zinc-insulin suspensions

–> PROLONGS BIOLOGICAL ACTIVITY

47
Q

Uses of Nanoparticles

A
  • Primarily used for Nanotechnology
    • ​DRUG DELIVERY SYSTEMS
      • ​Protective encapsulation
      • Target specific tissues
      • Act as water-soluble carriers
        • ​ for poorly soluble drugs
  • Secondary used to ENHANCE dissolution rates
    • ​–> to improve Bioavailability
      • ​Ex. greseofulvin / Fenofibrate
48
Q

Top Down Formation of

Nanoparticles

A
  • Top-Down comminution
    • Ball Milling / Jet Milling
    • REDUCE solid particles –> colloid size
      • ​200-500nm range​​
49
Q

Bottom-Up Technique

Nanoparticles

A
  • Assemble nanopartcles from MOLECULAR COMPONENTS
    • Self-Assembly
      • polymeric surfactants / dendron-substrate complexation
    • Precipitation
    • Polymerization of Monomers
50
Q

Dendrimers

​Nanoparticles

A
  • Highly branched polymers
    • –> molecular complexing agents that
      • ​WRAP AROUND
        • the API
  • Similar to chelating agents = tiny burritos
    • ​Encapsulation of a single drug molecule
      • inside a SINGLE dendrimer shell
  • Size is similar to micelles
51
Q

Solvent-Displacement Methods

​Nanoparticles

A
  • Adding anti-solvent
    • –> reduces the solubility of the drug-polymer complex
  • Salting Out
  • Emulsion-Diffusion / SOlvent evaporation
  • Supercritical fluid vaporizattion
  • Coacervation reactions
52
Q

In-Situ Polymerization

​Nanoparticles

A
  • Sme polymers undergo polymeraztion reactions under special conditions
    • –>Formation of polymer nanoparticles that
      • ​ENTRAP the drug
53
Q

Membrane Filtration Requirements

Air Filtration

A

HEPA = High Efficiency Particulate Arrestance

used to remove bacteria (allergens)

  • MUST remove 99.97%
    • ​ of all particles GREATER THAN >0.3um
      • from the air it passes through
  • Pre-filters used before this membrane
    • protects the membrane filter
    • traps larger molecules
54
Q

Containment

Positive Air Flow

Air Filtration

A
  • Airflow INTO the facility must be filtered to remove any particulate contaminants
    • ​anything LARGER THAN > 300nm
  • ​Positive Air Pressure
    • ​Air flows OUT to reduce contamination
55
Q

Aseptic Compounding Considerations

A
  1. Wash Hands Well
  2. Wear gloves / cover skin
  3. Use the right LFH
  4. in a clean facility
  5. work within hood / clean & non obstructed
  6. FIlter and hood should be properly maintained
56
Q

Glove Box

RABS

CAI

Pharmacy Aseptic Practice

A

Glove box = Isolator = RABS = CAI

  • Similar air flow & fxn of Laminar Flow Hoods
    • ​particle filtration is the same as well​
  • CAI = Compounding Aseptic Isolator
  • RABS = Restricted Access Barrier Systems
58
Q

Macrofiltration

A

10um-100um

POLLEN / RBC / Sand

  • Contain Large Particles
    • wet chemical analysis
      • fiberglass/cellulose filters
      • Coffee filters
59
Q

Microfiltration

A

1um - 10um

Most bacteria / yeast / some virus (polio)

STERILE

​

60
Q

Dialysis / Ultrafiltration

A

1nm - 100nm (0.1um)

Include most particulates / molecules

VIRUS / Proteins

61
Q

Liquid Filtration Process

A
  • Membrane FIltration
  • Depth Filters
    • protect mebranes / prolong filter lfife
  • Filter Aids
    • diatomaceous earth / cellulose / perlite
  • Decolorization
    • ​activated charcoal adsorption
62
Q

Aseptic Filtration

liquid filtration

A

0.22mm FILTER

  • Hydrophilic filters for aqueous solutions
    • ​cellulosic
  • ​HydroPHOBIC filters for non-aqueous solutions
    • PTFE
63
Q

Particle Size Considerations

Non-Aseptic Compounding

A
  • Mix w/ mortar & pestle
  • Materials might have different particle size
    • mill first (reduce size before mixing)
    • different particle sizes will segregate
  • Moisture Levels
    • affect particle agglomeration
  • Ordered Mixing = Geometric Mixing
    • begin with smallest amount of powder –> add increasing ammounts
  • Suspension Settling
    • ​Increase particles size –> increase settling rate
64
Q

Mixing Powders

A
  • NOT possible to produce an ideal mixture of 2 powders
    • there is ALWAYS some content of nonuniformity
    • ideally = low entropy
    • really = high entropy
65
Q

Demixing

A

Little Particles –> Bottom

Large –> top

  • Powders have the tendency to SEPERATE during processing:
    • Percolation
      • gravity –> small particles move into voids between large particles
    • Vibration speeds up demixing
      • ​Transportation​
66
Q

Demixing Occurs More Readily if…

A

NOT in uniform SIZE & DENSITY

  • reduce particle size first
  • uniformity can not be assumed esp when batch size increases
    • always have to MEASURE
67
Q

Eutectic System

A
  • Mixture of chemical compounds or elements that have
    • A Single chemical composition that SOLIDIFIES @ lower temp than the other compositions
  • Liquified
    • ​Has a LOWER Melting Point
68
Q

Desirable Function of

a Eutectic

A
  • HAVE A LOWER MELTING POINT
    • than either of the individual components
    • –> Eutectics Dissolve more rapidly as well
  • HIGHER BIOAVAILABILITY
    • from higher solubility –> faster dissolution –> faster absorption
69
Q

UNDESIREABLE

function of Eutectics

A
  • Trituration –> Pressure on the mixture
    • low melting point –> two materials can
      • MELT TOGETHER
  • Making a blend of the powders is difficult or imposible
    • Can Solve by
      • ​–> Reduce the particle size SEPERATELY
      • Mix seperately
      • Add dry blend component with INTERT FILLER
        • ​MgO / MgCO3
        • minimize opportunities for contact
70
Q

Particle Size

Large

Small

Nano

A

1mm

1um(1micron)

1nm

71
Q

Size Reduction

Large

Small

Nano

A

Hammer Mill

Micronizer / Fluid Energy Mill / Ball Mill

Top-Down/Bottom-Up

72
Q

Analysis

Large

Small

Nano

A

Screens / Bulk Density / Mesh Size

Laser Diffraction / Equivalent Sphere

Same as Small

73
Q

Pore Size / Filtration

Large

Small

Nano

A

Wet Chemistry / Coffee Filters

Aseptic Processing / Soutions (0.22um) / Air

Ultrafiltartion / Semipermeable Membranes

74
Q

Applications for Large Particles

A

Manufacturing Processing

Capsule Size

Mixing Powders

Topical dosage forms

75
Q

Applications for Small Particles

A

Dissolution

Bioavailability

Aseptic compounding

LFH

INHALATION DOSAGE FORMS

76
Q

Applications for NANOparticles

A

Hemodialysis

Peritoneal Dialysis

Bioavailability

Ceutics Final (5 decks)

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