Osmosis Flashcards
Define osmosis
The solvent (e.g. water) moves from an area of low concentration of solute to high concentration of solute
Define osmotic pressure
The external pressure that must be applied to a solution to prevent dilution by water
What is a hypertonic solution?
Conc of dissolved components (e.g. salts,) is higher in blood serum compared to RBC’S - through osmosis water moves out into the blood serum to balance the solute conc –> cell shrinks –> fatigue;sleepiness
just remember cell SHRINKS and the WHY will come automatically
What is a hypotonic solution?
Conc of dissolved components (e.g. salts,) is lower in blood serum compared to RBC’S –> cell BURSTS as water moves into the cell (i.e. a higher conc. of solute)
CELL BURSTS
When preparing IV bags the solution needs to be as isotonic as possible (i.e. 308 mOSM). Is this a true statement
YES
What’s the outermost layer of the skin and what does it contain?
Epidermis and it contains the strateum corneum, granular cell layer, spinous cell layer, basal cell layer
What is the second outermost layer of the skin and what does it contain?
Dermis and it contains glands, nerves, hair follicles, muscle fibres
Theres 5
Describe the barriers the skin acts act? (MMMTR)
- Mechanical:
- Microbiological: stops infection
- Radiation: protects againsts UV light
- Temperature regulation but not a good barrier against hot or cold
- Mechanical shock: protects against blows and shocks
Outline the trans-appendael route of drug asborption through the skin
Travels into the internal layers of skin through sweat ducts and **hair follicles **
outline the transcellular route (main route) of drug absorption through the skin
Travels through dead keratinocyte’s by passing the lipid membrane and cytoplasm
- travels through CELLS
outline the intercellular route of drug absorption through the skin
Travels via the spaces between the skin cells
Pimple treatment options
Salicyilic acid, benzoyl peroxide and azaliac acid
There are 5
List the properties of an effective topical dosage form
- Stable
- High Safety Range
- Easy to apply
- non-irritating excipients
- Contains an anti-septic
Does a topical dosage form need to be isotonic?
Does it need to be one particular formation
No and No
Are systematic treatments for the inner ear possible? How does it pose a problem?
Possible, however:
1. blood labyrinth of the ear = higher doses
2. Systematic treats both ears however infectoin may be in only one ear
What does ‘auricular’ refer to?
The ear
What happens in the turbinates of the nose?
Drug absorption takes place
‘Dosage forms for the ear must be sterile’. Is this a true statement
YES
There are 4
List the benefits of nasal drug delivery (AAPA)
- Avoids hepatic first pass metabolism
- Avoids the blood-brain barrier
- Promotes both localised and systematic drug delivery
- A new way to deliver vaccines
There are 4
List the disadvantages of nasal drug delivery (AAPA)
- Nasal metabolism via P450 enzymes
- Mucus becomes a physical barrier. Need to make sure the drugs are soluble in the mucus
- Rapid clearance time of mucus (half of the mucus gets cleared in 15 minutes) so drugs have a very short time to get absorbed
- Ilness can result in inflammation and swelling which reduces the surface area of the nasal cavity –> harder drug delivery and less likely the drugs will be absorbed
Write the layers of the eye in the order in which ocular dose forms are absorbed.
- Lipid layer
- Aqeous layer
- Mucin layer
- Epithelium
- Bowmans layer
- Stroma
- Descemets membrane
- Endothelium
**Tear film **consists of lipid, aqeuous and mucin layer
‘Cornea’ consists of the epithelium layer and the rest of the components following that
List the problems when it comes to absorption of ocular drugs in the eye
- Rapid dilution in tear fluid
- rapid solution drainage
- binding to extra-orbital tissues
- Cornea is very lipophilic which becomes a problem when it comes to absorption of hydrophilic drug
What is glaucoma (eye condition) and which drugs treat this condition?
Optic nerve at the back of the eye is slowl y destroyed
1. Adrenaline
2. Physotigmine
Which drug treats laser eye surgery
Cocaine hydrochloride
Which drug promotes pupillary dilation? - (ocular dosage form)
Homatropine hydrobromide
Does an ideal ocular dosage form need to be isotonic?
YES
