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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
Q

CMC

A

Critical Micelle Concentration

After this point, can dissolve lipophilic drugs

26
Q

Liposome Physiochemical properties that can be altered and regulated

A

Size
Net charge
Membrane fluidity
Cell recognition

27
Q

Why Liposomal therapeutics?

A

Reduce toxic side effects of drugs

Tissue targeting

Urgent need for effective drug delivery systems

28
Q

Liposome routes of Admin

A

Cannot be given orally due to….
Degradation, Acidic gastric pH, Intestinal enzymes and Bile salts

Parenteral routes of delivery
IM, IV, Intraspinal

29
Q

Intraspinal Delivery of Liposomes

A

Admin of small doses over extended period

Local admin, Fewer side effects and pain relief

30
Q

DepoDur

A

Intraspinal Delivery Liposome

Approved 2004, Morphine sulfate liposome suspension good for 48 to 72 hrs

31
Q

Liposomes

A

Vesicle like structure composed of one or more lipid bilayers encapsulating an aqueous core

32
Q

Encapsulation of Drug into Liposomes

A

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
Q

Liposome for Drug Delivery

A

Has Homing peptide

Protective layer against immune destruction

34
Q

Liposome injections

A

Abelcet Injection - can directly inject

AmBisome for injection - powder that has to be reconstituted for injection

Both are Amphotericin B = Antifungal

35
Q

Hydration of lipid film/cake (Liposome prep)

A

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
Q

sizing of lipid suspension (liposome prep)

A

LMV suspension downsized by variety of techniques, including sonication or extrusion

37
Q

Sonication (Liposome prep)

A

Produces SUV from LMV

38
Q

Sonication (Liposome prep)

A

Produces SUV from LMV

39
Q

Extrusion (Liposome prep)

A

technique in which lipid suspension is forced through filter with defined pore size to yield particles with desired size

40
Q

Properties of Colloids

A

Optical properties

Electrical properties

41
Q

Optical properties of Colloids

A

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
Q

Electrical Properties of Colloids

A

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
Q

Significance of Zeta Potential

A

Between -30 and 30 = not stable
>-30 = stable
>30 = stable

44
Q

Liposomal Amphotericin B

A

Abelcet, AmBisome, Amphotec

Higher levels of nanoformualted AMB to penetrate infected areas

Decrease the exposure to kidney

45
Q

Abelcet and Ambisome allow…

A

faster infusion rates than conventional AMB with less infusion-related reactions

46
Q

DaunoXome

A

Active ingredient Daunorubicin

For advanced HIV-related Kaposi’s Sarcoma

PK of Daunoxome points to major retardation of clearance compared to free daunorubicin

47
Q

Stealth Liposomes

A

PEG modified Liposomes

Long circulation

Evasion of Reticuloendothelia System (RES)

48
Q

Limitations of conventional liposomes

A

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
Q

How to increase longevity of liposomes

A

Modify liposomal surface with PEG

50
Q

Doxil

A

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
Q

EPR effect

A

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
Q

EPR

A

Property of tumor, called enhanced permeability and retention effect

53
Q

Pegylated Drugs (non-liposome)

A

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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