Vaginal Route Flashcards
Are vaginal routes less common than rectal routes?
YES
What effect can they have?
Local BUT systemic is possible
Are formulation designs similar to rectal?
YES
What is the drug absorption for systemic?
Passive diffusion into bloodstream
What physiological factors influence absorption?
Vol Viscosity pH Stage of menstrual cycle Age Sexual activity
What drug related factors influence absorption?
Drug solubility Ionisation behaviour Molecular weight Release characteristics Dosage form
What are the advantages?
Smaller doses Systemic possible Suitable when oral restricted Avoids GI tract + 1st-pass metabolism Self administration + removal Overcomes inconvenience + pain caused by parenterals route
Why can smaller doses be used?
Local action
Why is systemic absorption possible?
Large SA + highly vascularised
What are disadvantages?
Gender specific
Systemic treatment not popular
Menstruation cycle + hormones affect systemic
Vaginal fluid vol variations affect local
Acidic pH of vagina affect degradation of drug
Require use of special applicator
Describe ideal vaginal dosage forms
Long-acting Easy to apply No local irritation Colourless, odourless + don't leak Not affect sexual activity Don't stain pants
What are the semi-solid formulations?
Creams, ointments + gels
Why is pH of semi-solid formulations modified?
To match vaginal pH
What do semi-solid formulations require?
Collapsible tubes, with suitable applicator
What is an issue with semi-solid formulations?
Delivery of accurate dose is hard
Applicators cost to produce
What is the size of semi-solid formulations?
Single dose containers in 3-5ml dose per application
Describe vaginal tablets
Solid, single dose preparations similar to oral tablets
What is the shape of vaginal tablets?
Ovoid
What are advantages of vaginal tablets?
Ease of storage + use
Low cost
Well-controlled large-scale production
Rapidly disintegrate in small vol of vaginal fluid
What may be added to vaginal tablets?
Disintegrants
Lactose as filler
Why is lactose as a filler added to vaginal tablets?
Natural substrate for vaginal microflora that converts lactose to lactic acid
Describe vaginal suppositories
Similar to rectal
Solid, single dose
API dissolved/dispersed in base
1g
What base is used for vaginal suppositories?
Glycerol-gelatin base
What must glycerol-gelatin base be dispersed in for vaginal suppositories?
H2O
What do vaginal suppositories require?
Applicator + suitable training for insertion
Describe vaginal rings
Solid formulation that provide controlled release of drug over time
Flexible, circular system containing drug in polymer network
What is an example of a vaginal ring?
NuvaRing
What is a vaginal ring used for?
Contraception
Describe process of a vaginal ring
Insert
Leave in for 3 weeks
Replace after 7 day break
What are the drug-release mechanisms?
Melting
Disintegration
Describe what happens in melting
Melt at body temp
= release drug + molten mass disperses into available space
Describe what happens in disintegration
SOLID dosage form
Release drugs by dissolution or disintegration, followed by dispersion contents in vaginal fluid
Describe what happens in disintegration
SEMI-SOLID dosage form
Release drugs by diffusion + dispersion of contents from formulation to vaginal fluids
How are vaginal + rectal suppositories manufactured?
Use moulding method Base heated to above melting temp Drug dispersed in heated liquid Molten product poured into mould Cooled OR directly injected into final packaging (mould strips)
