L23 - Hormonal drug delivery Flashcards
DOSAGE FORMS
i) what are they?
ii) give four examples
iii) what are powder forms of drugs in small doses bulked up with? give two examples
iv) give four reasons we need different dosage forms
v) what would a drug that cannot pass through cell membranes need to be formulated as?
i) pharma products in the form in which they are marketed for use
ii) creams, pill, injection, inhaler, patch
iii) excipients eg water and lactose
iv) different clinical conditions, different types (age) of patient, different routes of admin, different drug properties
v) wont be orally active so need to be formulated as an injection
DRUG DELIVERY/ROUTES OF ADMIN
i) give six routes of admin
ii) where is the site of action of a locally delivered drug? how quick is its onset? what can absorption into the blood stream lead to?
iii) how is a drug transported to site of action in systemic delivery?
i) oral, oral cav (mucosa, buccal, subling), rectal, parenteral (injec), epicutaenous, pulm, vaginal
ii) site of action is site of delivery
- quick onset
- entry to blood stream may cause unwanted side effects
iii) by the blood
SYSTEMIC DELIVERY - BIOAVAILABILITY
i) what two things does bioavailability relate to?
ii) what is the min effective dose and the maximum safe dose?
iii) when will the patient feel the effects of the drug?
iv) which two parameters is the magnitude of effect or intensity of the drug fall between?
v) what does the AUC represent?
vi) at the peak concentration ( C max) what are the levels of the drug in the small intestine and the blood?
i) bioavail relates to the rate and extent of drug absorption into the blood
ii) min effective dose = onset of drug effect
max safe dose = above this there is side effects
iii) patient will feel effects of the drug after the min effective dose is reached
iv) mag of effect/intensity falls between the min effective dose and the peak conc
v) AUC represents the bioavailability of the drug (how much of the drug given is absorbed/reaches the circulation)
vi) at C max there is low levels of drug in the SI and high levels in the blood
label A-E on bioavailability curve
A = peak concentration (C max)
B = onset
C = magnitude of effect or intensity
D = therapeutic window
E = AUC = bioavailability of drug
TYPES OF HORMONE
i) what are modified amino acid derivatives derived from? (2) name two? are they big or small molecules?
ii) name three peptides and proteins - are these big or small
iii) what are steroids derived from? name two examples
iv) what are eicosanoids derived from? name two? are they hydrophobic or phillic?
i) tyrosine or tryptophan
- dopamine and thyroxine
- small molecules
ii) neuropeptides eg vasopressin, pit hormones and GI hormones
- large molecules
iii) steroids are derived from cholesterol
- corticosteroids and hydrocortisone
iv) eicosanoids are dervied from lipids
- prostaglandins and leucotrienes
- hydrophobic
MODIFIED AA DERIVATIVES & STEROIDS
i) what dose is required?
ii) what route are they bioavail?
iii) what are they usually mixed with? give two examples
iv) why may different dosage forms of steroids be needed?
i) very small doses
ii) orally bioavail
iii) usually mixed with excipients because very low doses
- fillers, lubricants, surfactants, flavours
iv) need different dosage forms to avoid systemic side effects
PEPTIDE HORMONE - INSULIN
i) are these small or large molecules? can they be given orally?
ii) what type of insulin does long acting insulin give? how many times per day is it injected?
iii) what makes long acting insulin long acting?
iv) what does a continuous subcut insulin infusion do?
v) what other route allows systemic drug delivery? what two things does this avoid?
vi) how quickly does inhaled insulin act? when is it taken?
i) large
ii) long acting insulin provides baseline insulin
- injected once or twice a day
iii) long acting insulin is formulated so its less water soluble
- self aggregates and precipitates into microcrystals which acts as a depot that allow slow release insulin over time
iv) subcut insulin infusion detects glucose levels and pump injects required levels of insulin
v) pulmonary
- avoids GI tract and first pass hepatic metabolism
vi) inhaled insulin has quick onset of action and is taken before meals
SEX HORMONES
i) what are they based on?
ii) do they have good absorption after oral admin? are they suscep to first pass metab? how long is their half life
iii) name three ways that can increase bioavail (which routes of admin)
iv) how may testosterone/progesterone be given? what does this allow?
i) steroids
ii) poor absorption post oral admin
- extensive first pass metab
- short half life
iii) give parenterally (im injection), transdermal, intranasal, buccal
iv) given im injections which allows sustained release
TESTOSTERONE ESTERS
i) what properties do esters have?
ii) how does the ester affect the testos molecule? what happens when it enters the blood?
iii) how long is it released over?
iv) how many esters may be in a molecule? what does this allow?
i) low water solubility and high oil solubility
ii) ester deactivates the testos molecule (stops it binding the androgen receptor)
- when it enters the blood the ester is cleaved/hydrolysed which restores OH group and makes it active again
iii) released over long time period - 2-3wks
iv) can have four different esters which allows steady release over long time period
INTRANASAL ADMINISTRATION
i) name three advantages
ii) does it avoid first pass metabolism?
iii) name three disadvantages
iv) name a product on the market that is given intranasally
i) large SA for absorption, highly vascularised and good bioavail for low MW compounds
ii) avoids first pass metab
iii) mucocillary clearance, drug is metab active before it gets to the blood, poor bioavail for high MW compounds
iv) desmopressin
BUCCAL ADMINISTRATION
i) how does it work?
ii) how many times is buccal testos applied?
iii) where is it absorbed to? does it bypass first pass metabolism?
i) mucoadhesive polymer stticks to mucus membrane in mouth
ii) twice daily
iii) abs straight into systemic circ and bypasses first pass metab
VAGINAL ADMINISTRATION
i) what type of medication is used to assist reproduction and has systemic delivery?
ii) which device allows local delivery of oestradiol? what may this be used for?
iii) what may a vaginal pessary of estradiol be used for?
iv) over what time period can an IUD release hormone into the uterine cavity? is there high levels of hormone in the blood?
i) vaginal progesterone gel
ii) vaginal ring used for post menopausal vaginal atrophy
iii) pessary of oestradiol can be used for post meno HRT
iv) IUDs can work for 3-5 years and hormone doesnt get into systemic circ so low side effects
EICOSANOID HORMONES
i) give three examples
ii) systemic or local delivery?
iii) what may they be used for?
i) prostaglandin E2, vaginal gel and vaginal pessary
ii) local delivery
iii) PG E2 ca be used to ripen the cervix over 12 hrs
