other dosage forms part 1 Flashcards
reasons for failure of contraceptive?
compliance
accessibility
efficacy and effectiveness
types of polymers used?
homopolymer
alternating copolymer
block copolymer
graft copopolymer
what is a vaginal ring?
reservoir device
how does vagina ring work?
inserted in vagina on first day of period and stays for three weeks and removed for a week and withdrawal bleed experienced.
ovulating is inhibited and mucus of the cervix altered so sperm can’t impenetrate it
the endometrium is unfavourable for implantation
what is contraceptive patch?
cervical mucus altered and ovulation is inhibited
endometrium is unfavourable to implantation
how is contraceptive patch used?
takes the transdermal route of delivery
after three weeks no patch is used and withdrawal bleed experienced
hodiagram of contraceptive patches?
slide 8
what are the three layers of matrix patch?
polyethylene and polyester backing layer
a middle layer of adhesive
release liner that is removed before application
what are the two types of patches
matrix and reservoir
what are the design consideration for patches?
adhesive polymer
backing
reservoir
membrane
what is adhesive polymer for?
making sure its:
non-irritating
medically approved
water resistant-showering
elastic- so you can move your arm
easily removed
no reaction with drug
what is the backing for?
impermeable so reservoir doesn’t evaporate to alter drug release
what does the reservoir contain?
contains solution of drug or suspension making reservoir self replenish
what is the membrane on patches for?
permeable so drug released into the skin
how do IUD’s work?
inserted through cervical canal
lifespan of 5 years
strings used to check if they’re in place in uterus
what deos IUD’s do as a contraceptive?
stops sperm from surviving
causes release of endometrial prostaglandins and leukocytes, enzymes and copper ions
endometrium becomes uncapable for the implantation of an embryo
advantages of IUDs
no interaction with drugs
high and immediate effect
reversible
disadvantages of IUDs
menorrhagia risk
If IUD fails then increase risk of ectopic pregnancy
risk of pelvic infection
what is the IUS
progestogen secreting device
hormone reservoir which consists of levonorgestrel
what does levonorgestrel do?
supresses endometrium preventing implantation
thickening of cervical mucus so sperm can’t penatrate it
what does PDMS do?
the core of the IUS and has an outer-membrane that controls release of levonorgestrel
what is the advantages of IUS?
reduced menorrhagia
highly effective
reversible
relieved menstrual problems without hysterectomy
disadvantages of IUS?
it it fails increases ectopic pregnancy
irregular bleeding
IUS wider that IUD so cervix needs to be dilated
what is nexplanon?
implant rod that is inserted with sterile applicator
uses ethylene vinyl acetate membrane reservoir system
release rate of drug changes over time
disadvantages of nexplanon?
professional needed to insert/remove
side effects like headache
can cause irregular bleeding
advantages of Nexplanon?
no user action
no side effects
effective
easy to reverse
in matrix systems how is the drug release?
drug is distributed evenly throughout polymer matrix and release follow Higuchi equation
in reservoir system how is the drug release?
the core controls release of drug and has a more constant release rate
follows Fick’s Law of diffusion
what are suppositories?
dosage delivered to the body via rectum
what are pessaries?
dosage delivered to the body via vagina
how are drugs released in suppositories and pessareis?
melt, disintegrate at body temperature releasing the drug and then drug enters the systemic circulation
process of suppositories fatty base diffusing across membrane?
melts and spreads, the drug dissolves in mucus and diffuses through the membrane
what has to be considered with fatty bases in supositories?
melting point should be slightly below body temperature
should be able to remove from the mold
properties to consider with water soluble suppositories?
Include glycerinated gelatin and polyethylene glycol
preservatives are needed
PEG can have different melting points by differing the molecular weight
types of vehicles for supposittories?
fatty and water soluble
process of water soluble suppositories diffusing into membrane?
absorbs the water and dissolves in fluid
drug dissolves in mucus and diffuses through membrane
