Vaginal Drug Delivery Flashcards
Mucosal surface areas of different administration sites
GI tract - 350,000
Skin - 20,000
Oral - 200
Vaginal - 90
Units in cm squared
Vaginal is lowest among these 4
Describe the cell type in the vaginal mucosa epithelium
Stratified squamous epithelial cells
Non-keratinised
Describe the structure of the laminate propria
Loose
Highly vascularised
Connective tissue
What period of the menstrual cycle shows significant change in number of vaginal epithelial cells
Days 19 - 24
What are the two sections of the cervix
Endocervix
Ectocervix
What type of cells make up the endocervix
Columnar epithelial
What type of cells make up the ectocervix
Squamous epithelial
How does hormonal influence compare between cervical and vaginal epithelial
Cervical epithelia are less sensitive to hormonal influence than vaginal epithelia
What arteries are involved in vaginal blood supply
Common iliac artery > hypogastric artery > vaginal arteries
What veins are involved in vaginal drug drainage
Vaginal venous plexus > vaginal veins > internal iliac veins
Do vaginally administered drugs undergo hepatic first pass metabolism
No
The internal iliac vein does not transport blood to the liver
Describe the uterine first pass effect
Vaginally administered drugs are directly transported to the uterus
Drugs move from vaginal vein to uterine artery
Extent of uterine first pass effect is depends of location of administration in the vagina
How does vaginal fluid affect drug delivery
Influences :
1. drug solubility
2. dissolution
3. ionisation
4. distribution
What is healthy vaginal pH levels
pH 3.5 - 5
How is vaginal pH maintained
Maintained by bacteria by L acidophilus
Converts glycogen to lactic acid
What 2 purposes does acidic environment of vagina serve
Protection from infection
Promote growth of lactobacilli
How does vaginal pH change during the menstrual cycle
Increases during mentruation
Falls during ovulation
How does cervical pH change during menstrual cycle
Stays relatively constant
Advantages of vaginal drug delivery
Accessible and non-invasive
Good blood supply
Local and systemic effects
High permeability
Avoids first pass metabolism
Disadvantages of vaginal drug delivery
Hygiene issues
Poor retention of delivery device
Permeability is influenced by oestrogen levels
Local irritation
Semi-solid preparations can be messy
Poor patient compliance
What are the indications for vaginal drug delivery
- Women’s healthcare e.g. vaginal infection, cervicovanginal cancers
- Reproductive issues
- Oestrogen replacement therapy
- Contraception e.g. spermicidal, steroidal
What is the active drug, formulation and indication for the product Vagifem
Estradiol
Tablet
Vaginal atrophy
What is the active drug, formulation and indication for the product Canestan
Clotrimazole
Cream
Vaginal/Vulval candidiasis
What is the active drug, formulation and indication for the product NuvaRing
Ethinylestradiol
Ring
Hormonal contraception
Describe a vaginal ring delivery system
Diffusion controlled
Controls the release of drug over a long period of time
Provides local or systemic effect
What are the two main indications for vaginal rings
- Oestrogen replacement therapy (Estring)
- Contraception (NuvaRing)
Name the two types of vaginal rings
- Matrix type vaginal ring
- Reservoir type vaginal ring
Describe a matrix type vaginal ring
Drug is dispersed through entire ring volume
Made by one step injection moulding
Describe a reservoir type vaginal ring
Drug is only dispersed through central core
Made via multi step injection moulding
Describe the composition of a vaginal gel
Water
Gelling agent e.g. carbomer
Preservative
Active drug agent
Describe a thin polymer film drug delivery system
Water soluble polymer film
Dissolves rapidly in vagina with minimal fluid present
Provides rapid drug release
What are thin polymer films used for
Vaginal contraceptive
Vaginal cleansing
What is a vaginal pessary
Small plug of medication
Designed to dissolve at body temperature
Used in the rectum or vagina
