other solid dosage forms Flashcards
describe design of a patch
adhesive polymer - medically approved, non irritant, elastic, must not react with drug
backing - impermeable reservoir must not leak
reservoir - solution or suspension - makes reservoir self replenishing.
membrane - permeable so that the drug can be released
ADV of patch
weekly application, which is easier than daily pills.
can regulate cycles and reduce menstrual symptoms.
disadvantages of patches
possible skin irritation
not recommended for women with certain health risk eg high BP
describe the design of a vaginal ring
flexible ring which releases estrogen and progestin.
reservoir device
ovulation is inhibited and cervical mucus is altered so that it is impenetrable to sperm
advantage of vaginal ring
monthly application, offering convenience
can improve menstrual cycle regularity and reduce cramps.
disadvantage of vaginal ring
may cause discomfort
describe the design of an IUD
small T-shaped device inserted into the uterus.
hormonal and non-hormonal
advantage
long term contraception up to 10 years
minimal maintenance after insertion and highly effective.
reversible
disadvantage of IUD
cause discomfort during insertion and spotting initially
may cause heavier periods or hormonal side effects.
can result in menorrhagia
contraceptive implant
a small rod inserted under the skin of the upper arm that release progestin to prevent ovulation
Advantages
last up to 3 years
safe for women who cannot use estrogen based contraceptives
reversible
highly effective
disadvantages of contraceptive implant
can cause irregular bleeding
requires minor procedure for insertion and removal.
condoms design
barrier method made of latex worn or inseted
advantages of condoms
provides protection against STIs
easily accessible, inexpensive and non-hormonal
disadvantage
may slip or break
some people may have allergies to latex or discomfort
what are the 2 drug release kinetic types
matrix
reservoir
describe the drug release in a matrix system
drug is uniformly distributed throughout the polymer matrix
rate of release is more rapid initially and slows as the concentration of the drug decreases.
reservoir release
a rate limiting membrane controls release of drug from a core.
more constant release rate
filling of hard shells
hard shell in two halves
filled with powder
shell is gelatine
soft shells
soft polymer shell
filled with liquid - oil
shell is gelatine with plasticisers
name the two type of pellets
- coated non-pareil pellets
- extruded spheronised pellets
advanatage of using a pellet over DR and ER
- very reliable
-spreads through GI tract
-can provide mixed drug release rates - can dose two incompatible drugs together
advantage of coated non-pareils
- does not require new equipment or training
- complicated release profiles are possible
disadvantage of coated non-pareils
time - especially if multi-layered - complicated process
each different layer requires validation.