Pharmaceutics

Question 1

What are the 3 Solid Lipid Nanoparticles (SLN) types?

Answer 1

Homogenous Matrix –> A release form from day 1

Drug Enriched Shell –> A fast compound delivery system (due to the particles being at the edge)

Drug Enriched Core –> A slow, controlled released form (as the drug is in the middle)

Question 2

What are the 3 forms of Nanostructured Lipid Carriers (NLCs)

Answer 2

Imperfect –> A blend of solid and liquid lipids with different molecular structures

Amorphous –> Lipid solid matrix in the amorphous state

Multiple Type (O/F/W) –> The drug solubility in oils (liquid lipids) is greater than in solid lipids

Question 3

What does cross-linking do in hydrogels?

Answer 3

Increases the hydrophobicity of the gel

Decreases the diffusion rate of the drug

Question 4

What is one of the main disadvantages with in using natural polymers in wound healing?

Answer 4

Batch to batch variability

Question 5

How can we easily get drugs to the brain?

Answer 5

Via the nose

The olfactory epithelium is an area in which the BBB is not present, so drugs can move through this and into the brain via paracellular diffusion (eg, cocaine)

Question 6

What are niosomes?

Answer 6

Bilayered structures that are made of non-ionic surfactant, and cholesterol

These are able to entap a wide range of chemicals

Question 7

What are pericytes?

Answer 7

Cells that can migrate from the vasculature and into the wound site

They contract and deposit down collagen

Similar to myofibroblasts

Question 8

What are the negatives of SLNs?

And how do Nanostructured Lipid Carriers (NLCs) fix these?

Answer 8

The crystalline structure causes little space for the actual drug, with it becoming more ordered time goes along (to go to its lowest energy form), expelling the drug!

NLCs have a more diverse matrix structure, so there is more room for the active compound

Question 9

What affects the rigidity/fluidity of liposomes?

And what does this cause?

Answer 9

The alkyl-chain length and degree of unsaturation (saturation = rigid)

Cholesterol –> Makes it more rigid

The more rigid the structure the more stable it is, and so the longer the encapsualted drug will stay inside of the liposome (prolonged release)

Question 10

What are…

Organogels

Xerogel

Jelly

Answer 10

Organogels –> Organic liquid containing (eg, petrolatum)

Xerogel –> When the liquid is removed, and so only the matrix remains (eg, gelatin sheets)

Jelly –> When the matrix is rich in liquid (ephedrine sulphate jelly)

Question 11

What are the advantages of Lipid Nanoparticle Carriers?

Answer 11

Low toxicity

Small particle size

Increase skin hydration

Reduce skin irritation

Act as a sunscreen

Question 12

What are the 3 types of closed wounds?

Answer 12

Contusions (Bruises) –> Blunt force trauma causing tissue damage under the skin

Hematoma –> Damage to the blood vessles under the skin, causing blood accumulation

Crushing Injuries –> Blunt force causing a pressure injury over a long period of time

Question 13

What are nanomedicines?

Answer 13

The application of technologies on the scale of 1-500nm to diagnose and treat diseases

They are too small to be detected by the immune system

Allow the drug to be delivered to the site of action with smaller doses… so less side effects

Increased drug penetration and stability

Question 14

What is a big problem when giving drugs inter-otically, to the middle ear, to children?

Answer 14

Childrens membranes may be more permeable than adults, causing an increase in absorption…..and so possibly more side effects!!

Question 15

Explain macromolecular compound gels

Answer 15

Either formed with covalent bonds (thermally irreversible) or phyisical interactions (thermally reversible)

Type 1 –> 3D network formed with covalent bonds between the macromolecules (thermally irreversible)

Formed by the polymersiation of monomers of water soluble polymers (in the presence of an X-linker)

Type 2 –> Held together by weak intermolecular bonds (thermally reversible)

When cooled below point T, PVA is formed….which are viscous in water –> Allowing for use in topical applications

Question 16

In nasal drug delivery, when would a drug be absorbed via the paracellular route?

Answer 16

When hydrophillic and a MW less than 1kDa

Question 17

Explain the 3 phases of the wound healing process

Answer 17

Inflammatory Phase –> Bleeding occurs to remove toxins before vasoconstriction occurs

The clotting mechanism then kicks in, along with inflammatory mediators much as histamine release. Vasodialation happens allowing phagocytes to enter the wound

Proliferative Phase –> Granulation occurs, which is the effect of fibroblasts and macrophages stimulating the production of fibrous tissue

Fibroplasia creates a new collagen bed, pulling the wound edges together…. whilst new capillaries are formed (angiogenesis)

The Remodelling Phase –> Fibroblasts create collagen to increase tensile strength. As the collagen matures it X-links

Question 18

What are the main characteristics of liposomes?

Answer 18

Biodegradable

Biologically inert –> So weakly immunogenic and has a low toxicity

Can alter tissue distribution of the drug they are carrying

Question 19

What is a wound?

Answer 19

Any defect, or damage, to the skin as a result of physical/chemical/thermal factors, or as a result of an infectious disease

Question 20

Explain what occurs as the concentration of ampiphille increases

Answer 20

Phospholipids become ordered into vesicles

Then into a hexagonal columnar phase (middle soap phase)

Then into a lamella phase (neat soap phase) –> where sheets of ampiphilles are seperates by water

Question 21

Describe what hydrogels are, and how drugs are released from them

Answer 21

They can retain large quantities of water (100x their dry weight) but are still water insoluble

Highly hydrated –> Diffusion occurs through pores

Low Hydration –> Drug is dissolved in the polymer, and is transported between the chains

Hydrogels can also swell and cause the drug to be released…dependent on Heat/pH/Application/Electrical current

Question 22

What is the difference between an incision and a laceration?

Answer 22

Incision –> A regular wound thats caused by a clean sharp-edged object

Laceration –> A rough irregular wound caused by crushing or ripping forces

Question 23

What’s the difference between Unilamellar and Multilamellar liposomes?

Answer 23

Unilamellar –> One bilayer surrounds an aqueous core

Multilamellar –> A multitude of concentrically orientated bilayers surronding the aqueous core

Question 24

What are the 3 types of ethosome?

Answer 24

Classical –> Soft-liquid vesicles composed of phospholipids, water and ethanol (in high concs)

Binary –> The addition of another type of alcohol (PG or isopropyl alcohol (IPA))

Transethosomes –> The addition of a penetration enhancer or surfactant (edge activator) to a classical ethosome

Question 25

Which type of drugs/molecules are suited to **nasal delivery**?

Answer 25

Acid sensitive drugs Polar drugs with low BA Small lipophillic drugs

Question 26

What are the **4 types of classification of liposomes**?

Answer 26

**Conventional** --\> Neutral or negatively charged, and used for targetting of the cells of the mononucelur phagocyte systems (MPS). Contain mainly phospholipids and/or cholesterol **Sterically Stabilised ('Stealth')** --\> Has hydrophobic coatings (commonly PEG) to prolong circulation times **Immunoliposomes ('Antibody-targeted')** --\> These can be conventional or sterically stabilised. Specific antibodies on their surface to enhance target site binding **Cationic** --\> Positively charged, used for transporting genetic material. These can cause complement to be activated

Question 27

What is the definiation of a **Gel**?

Answer 27

Viscoelastic, solid-like materials comprised of an elastic cross-linked network and a solvent Mainly composed of the solvent Relatively unaffected by thermal motion

Question 28

What are **physical/supramolecular** gels?

Answer 28

Gels that are derived from low molecular mass compounds Formed through self-aggregation of small gelator molecules to form Self-Assembled Fibrillar Networks (SAFINs) These SAFINs are formed via many non-covalent interactions, so they are thermally reversible

Question 29

What is the **intial hurdle in nasal drug delivery**?

Answer 29

Drug deposition in the nasal cavity

Question 30

Name 4 ways that we can **improve nasal drug delivery**

Answer 30

Alter the mucous layer Increase the contact time with the nasal epithelium (using mucoadhesives) Use of penetration enhansers Specialised devices

Question 31

What are **always added to nasal sprays**?

Answer 31

Very small amounts of co-solvents --\> to improve solubility Viscosity-modifying agents Preservatives Anti-oxidants

Question 32

Name 3 characteristic **features** of **water soluble gels**

Answer 32

Large increase in viscosity above gel point (critical polymer concentration) Appearance of rubber-like elasiticty The gel retains shape under low stress, but will deform at higher stress

Question 33

When will dry phospholipids spontaneously **swell**?

Answer 33

When in water above Tm

Question 34

What are **transfersomes**?

Answer 34

Ultra-deformable liposomes, composed of phospholipids and additional surfactant/emulsifier (**'edge activator'**) Elastic vesicles that can permeate in-tact skin Localised at higher concentrations (in the SC) Can cause some irritation if the edge activators aren't very pure