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Pharmaceutics I > Exam 2 - Powerpoint 7 (Novel Drug Delivery Technologies) > Flashcards

Exam 2 - Powerpoint 7 (Novel Drug Delivery Technologies) Flashcards

1
Q

Benefits of NDDS

A 
Improved patient compliance
Improved outcomes
Reduction of adverse effects
Patients acceptance to treatment
Lower cost of treatment
Allowing patients to receive medication as outpatient
Reduction of overall medicinal resources
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2
Q

Categories of NDDS

A

Physical Mechanism

Biochemical Methods

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3
Q

Physical Mechanism

A 
Osmosis
Diffusion
Iontophoresis
Sonophoresis
Microneedles
Electroporation
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4
Q

Biochemical Methods

A

Monoclonal antibodies
Gene Therapy
Polymer-drug products
Liposomes

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5
Q

Iontophoresis

A

Uses constant low electric current to push a charged drug through skin

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6
Q

Mechanism of Iontophoresis

A

Electrorepulsion

Electroosmosis

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7
Q

Electrorepulsion

A

Drug reservoir is placed on the skin under the active electrode with the same charge as the drug

A counter electrode is positioned elsewhere on the body

Active electrode effectively repels the active substance and forces it into the skin

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8
Q

Electroosmosis

A

Results when electric field is applied to charged membrane (skin) and causes solvent to flow across this membrane from anode to cathode

Skin pH 3-4, natural negatively charged

It is selectively permeable to cations, as they move into the skin, they carry mass flow of solvents/water molecules…known as electroosmosis

Due to electroosmotic flow, flux of anodal iontophoresis is typically higher

It enhances the penetration of uncharged (neutral) polar, and larger molecules

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9
Q

What determines iontophoretic drug passage through skin?

A 
Drug concentration
Molecular size (upper limit 10kDa)
Current density (max 0.5 mA/sq cm
Application time
Ionic competition
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10
Q

Iontophoresis Patches

A

Lidosite from Vyteris
Ionsys by ALZA
Iontopatch

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11
Q

Iontophoresis Advantages

A

Promising technique for delivery of hydrophilic drugs

Programmed delivery, delivery is proportional to applied current

Improved patient compliance, mens to remind patient the dose can be built into the system

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12
Q

Electroporation

A

High voltage, very short (fraction of a second)

Produces hydrophilic pores across the skin barrier

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13
Q

Skin Microporation

A

Involves minimal invasive technique in which micron sized pathways are created in skin

Holes big enough for drugs to pass

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14
Q

Microneedles

A

needles that can pierce into skin to create pore big enough for drugs to enter but small enough to avoid pain.

Only pierce top layer

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15
Q

Thermal Microporation

A

Applies short duration electrical current through array of tiny resistive elements to the skin surface

Cells of stratum corneum are flash vaporized, leaving microscopic holes

Openings are formed temporarily

Other methods to create holes involves physical removal of cells

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16
Q

Phonophoresis

A

Transport of drug molecules through skin under the influence of ultrasound pulses

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17
Q

Ultrasound Mechanism

A

Cavitations
Acoustic Streaming
Thermal Stress

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18
Q

Ultrasound Info

A

Need a coupling medium ie Gel

Medium transfer energy from device to skin

High Fhz = bad delivery of payloads
Low Fhz = good delivery of payloads

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19
Q

Dispersed Systems

A

Molecular dispersion (true solution)
Colloidal dispersion
Coarse dispersion

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20
Q

Molecular dispersion

A

Particle size < 1nm

can pass semipermeable membrane and ultra filter

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21
Q

Colloidal Dispersions

A

Particle size = 1 nm - 500 nm (0.5 micron)

Can pass filter paper but not semipermeable membrane

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22
Q

Coarse Dispersions

A

Particle size > 0.5 microns

Do not pass normal filter or semipermeable membrane

23
Q

Classification of Colloids

A

Lyophilic (liquid loving)
Lyophobic (Liquid Hating)
Association Colloids

24
Q

Association Colloids

A

Formed by association of dissolved molecules of a substance to creat particles of colloid dimensions

Ex. Surfactant micelle, liposome and microemulsion

Interact in such a way to minimize contact between lipophilic portion of amphiphile and water

25
CMC
Critical Micelle Concentration After this point, can dissolve lipophilic drugs
26
Liposome Physiochemical properties that can be altered and regulated
Size Net charge Membrane fluidity Cell recognition
27
Why Liposomal therapeutics?
Reduce toxic side effects of drugs Tissue targeting Urgent need for effective drug delivery systems
28
Liposome routes of Admin
Cannot be given orally due to.... Degradation, Acidic gastric pH, Intestinal enzymes and Bile salts Parenteral routes of delivery IM, IV, Intraspinal
29
Intraspinal Delivery of Liposomes
Admin of small doses over extended period Local admin, Fewer side effects and pain relief
30
DepoDur
Intraspinal Delivery Liposome Approved 2004, Morphine sulfate liposome suspension good for 48 to 72 hrs
31
Liposomes
Vesicle like structure composed of one or more lipid bilayers encapsulating an aqueous core
32
Encapsulation of Drug into Liposomes
Both water and lipid soluble drugs can be encapsulated Hydrophilic drugs encapsulated in aqueous core, the area between bilayers Hydrophobic drug can be entrapped in bilayer strcuture
33
Liposome for Drug Delivery
Has Homing peptide Protective layer against immune destruction
34
Liposome injections
Abelcet Injection - can directly inject AmBisome for injection - powder that has to be reconstituted for injection Both are Amphotericin B = Antifungal
35
Hydration of lipid film/cake (Liposome prep)
Add aqueous medium to container of dry lipid film and stir During hydration, LMV (like onion) are formed Each lipid bilayer separated by water layer
36
sizing of lipid suspension (liposome prep)
LMV suspension downsized by variety of techniques, including sonication or extrusion
37
Sonication (Liposome prep)
Produces SUV from LMV
38
Sonication (Liposome prep)
Produces SUV from LMV
39
Extrusion (Liposome prep)
technique in which lipid suspension is forced through filter with defined pore size to yield particles with desired size
40
Properties of Colloids
Optical properties Electrical properties
41
Optical properties of Colloids
Light scattering uses Light scattering measurements are used for estimating particle size, shape and MW and interactions Tyndall effect not exhibited by true solutions as particles in a true solution are too small to scatter light
42
Electrical Properties of Colloids
Colloidal particles carry same type of charge in sol, while the dispersion medium has an equal but opposite charge Colloidal particles repel each other due to same charge, cant combine to form larger particles
43
Significance of Zeta Potential
Between -30 and 30 = not stable >-30 = stable >30 = stable
44
Liposomal Amphotericin B
Abelcet, AmBisome, Amphotec Higher levels of nanoformualted AMB to penetrate infected areas Decrease the exposure to kidney
45
Abelcet and Ambisome allow...
faster infusion rates than conventional AMB with less infusion-related reactions
46
DaunoXome
Active ingredient Daunorubicin For advanced HIV-related Kaposi's Sarcoma PK of Daunoxome points to major retardation of clearance compared to free daunorubicin
47
Stealth Liposomes
PEG modified Liposomes Long circulation Evasion of Reticuloendothelia System (RES)
48
Limitations of conventional liposomes
Readily taken up by phagocytic cells of RES Localized predominantly in liver and spleen Made of natural lipids that cells can ID and engulf
49
How to increase longevity of liposomes
Modify liposomal surface with PEG
50
Doxil
Doxorubicin HCL Liposome injection Specially coated doxorubicin with 2 layers of protective coating Coating allows DOXIL to evade detection and destruction by immune system, increase time of drug in body and letting it reach tumor tissue where its released
51
EPR effect
Blood vessels of growing tumors are more "leaky" to macromolecules and large particles allowing them easy access to tumors interior Normally macromolecules would quickly drain back to circulatory system but tumor tissues trap them and prevent escape Clearance form tumor tissue is delayed due to poor lymphatic drainage
52
EPR
Property of tumor, called enhanced permeability and retention effect
53
Pegylated Drugs (non-liposome)
NEUPOGEN (filgrastim) - replenishes neutrophils, have to go to doctor after every chemo session. Nulasta (pegfilgraastim) - same effect, but since Pegylated, lasts longer and you can give it just once and it'll last for awhile

Pharmaceutics I (11 decks)

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