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Chapter 7 notes

Chapter 7 Routes and Formulations

QuestionAnswer
The way in which the body absorbs and distributes drugs varies with what? the route of administration and the dosage form used
Enteral or Parenteral Routes of administration
Any route other than oral, sublingual, buccal or rectal is considered a Parenteral route of administration
Parenteral Next to, or beside the enteral. Refers to any sites of administration that are outside of or beside the alimentary tract
for each route of administration there are various formulations used to deliver the drug via that route
Different dosage forms affect onset times, duration of action or concentrations of a drug in the body
a consideration for selecting a particular route of administration or dosage form is the type of effect desired
Local effect occurs when the drug activity is at the site of administration (eg. eyes,ears,nose,skin)
systemic effect occurs when the drug is introduced into the circulatory system from the route of administration and carried by the blood to the site of the activity
List the 4 enteral routes Oral, sublingual, buccal, rectal
Dosage forms for oral Tablets, capsules, bulk powders, solutions, suspensions, elixirs, syrups,emulsions
Dosage forms for buccal Tablets, solutions
dosage forms for sublingual Tablets, lozenges
dosage form for rectal solutions, ointments, suppositories
List 7 parenteral routes Intraocular, intranasal, inhalation, intravenous, intramuscular, intradermal, dermal
dosage forms for intraocular Solutions, suspensions, ointments, inserts
dosage forms for intranasal Solutions, suspensions, ointments, gels
dosage forms for inhalation solutions, aerosols, powders
dosage forms for intravenous, intramuscular, intradermal Solutions, suspensions, colloids, emulsions
Dosage forms for dermal Solutions, tinctures, collodions, linimints, suspensions, ointments, creams, gels, lotions, pastes, plasters, powders, aerosols, transdermal patches
intraocular eye
intranasal nose
buccal inside the cheek
sublingual under the tongue
dermal through or on the skin
inhalation lungs
oral stomach or intestines
intravenous venous circulatory system
intradermal dermal layer of skin
vaginal vagina
rectal rectum
subcutaneous subcutaneous
intramuscular muscle
Subcutaneous dosage form solutions, suspensions, emulsions, implants
vaginal dosage form solutions, ointments, cream, aerosol foams, powders, suppositories, tablets, IUDs
Oral administration is the most frequently used route administration
oral dosage forms are easy to use and administer
PO means by mouth which came from the term Peroral which means the dosage will be swallowed and the absorption will be primarily from the stomach and the intestine
the stomach is very acidic and has a PH of 1-2
certain drugs cannot b taken orally because they are degraded or destroyed by stomach acid and intestinal enzymes
degraded chemically changed to a less effective form
the absorption of many drugs is affected by the presence of food in the stomach
Drugs administered in liquid dosage forms generally reach the circulatory system faster than drug formulated in solid dosage forms. this is because disintergration and dissolution are not required
oral liquids include solutions, suspensions, gels and emulsions
solid dosage forms include tablets, capsules, and bulk powders
PH the ph scale measures acidity or alkalinity of a substance.
ph of 7 represent neutral
ph of 1-6 represent increasing acidity
ph of 8-14 increasing alkaline, base
inactive ingredients in medicines include binder, lubricants, fillers, diluents, disintegrants
Why are inactive ingredient like Binders, fillers, lubricants, diluents, etc. used in medicines? to help the dosage form disintegrate and dissolve when administered
PH of small intestine 6-7
PH of large intestine 7-8
the disintegration and dissolution of tablets, capsules and powders generally begins to occur in the stomach but will continue to occur when the contents of the stomach empty into the intestine
Enteric coated tablets are used when the drug can be degraded by the stomach acid
What does the enteric coating enable the tablet to do? wait until it reaches a higher level of PH in the intestine before it disintergrates
Disintegration the breaking part of a tablet into smaller pieces
dissolution when the smaller pieces of a disintegrated tablet dissolve in solution
Tablets are hard formulations in which the drug and other ingredients are machine compressed under high pressure to form into shape.
depending on their intended use tablets vary in size, weight, hardness, thickness, disintegration and dissolution characteristics
Multiple compressed tablets contain one drug in an inner layer and another drug(or the same drug) compressed at a lower pressure around it as an outer layer
a multiple compressed layer can also have 2 layers adjacent to eachother
Repeat action tablets initially release one dose of the drug and then release a second dose some time later
types of tablets sugar coated, film coated, multiple compressed, repeat action, chewable, and effervescent
Capsules contain the drug and other ingredients are packaged in a gelatin shell.
what is the capsule size based on? the amount of material to be placed in the capsule
what does the capsule do once taken the gelatin shell dissolves in the stomach and the medicine is released. then it undergoes disintegration and dissolution before the drug is dissolved into the circulatory system
Soft or Soft gel capsules contain liquid instead of powders in a gelatin shell. the active drug is already dissolved in liquid
Bulk powders contain the active drug in a small paper or foil envelope. The patient empties the contents of paper or envelope into water or juice and drinks the contents. Most of the drug and ingredients dissolve before the patients drinks it
Modified release drug products several oral formulations that release a drug so that a longer duration of action is achieved compared to conventional tablets
what is the goal of modified release drugs? to reduce the number of doses a patient needs to take during the day
SR sustained release
SA sustained action
ER or XR Extended release
PA prolonged action
CR controlled release
TR time release
LA long acting
Solution A clear liquid (not ness. colorless) made up of one or more ingredients dissolved in a solvent
solvent a liquid that can dissolve another substance to form a solution
Aqueous solution most common oral solution. means water was used as the solvent
types of solvents water, alcohol, glycerin, propylene glycol or any combo of these
Syrups Concentrated or nearly saturated solutions of sucrose in water. more viscous than water, contains less than 10% alcohol
flavoring syrups syrups containing flavoring agents
medicinal syrups contain drugs ie. guaifenesin syrup
Nonaqueous solutions solutions which predominantly contain solvents other than water either alone or in addition to water
Nonaqueous solvents alcohol, glycerin, and propylene glycol
Elixirs clear, sweetened, hydroalcoholic liquids intended for oral use. can either contain alcohol soluble or water soluble drugs.
Elixirs are usually less viscous and less sweet than syrups
alcoholic content of elixirs is between 5%-40% alcohol or 10-80 proof
Spirits or essence are alcoholic or hydroalcoholic solutions of volatile substances,
alcoholic content of Spirits or essence between 62%-85% or 124-170 proof
Sprits or essences are mainly used as flavoring agents, some spirits ae used for medicinal effect
Tinctures are alcoholic or hydroalcoholic solutions of nonvolatile substances.
Tinctures of potent drugs have how many grams of the drug per 100ml? 10g they are called 10% tinctures
Tincture of nonpotent tinctures generally have how many grams per 100ml of tincture? 20g
Suspensions formulations in which the drug does not completely dissolve in the solvent. the drug particles are suspended in the formula. sweetened and flavored
primary concern in formulating suspensions they tend to settle over time leading to a lack of dose uniformity. a well formulated suspension will remain suspended or settle very slowly and can easily be redispersed with shaking
Some commercial suspensions are packaged as lyophilized powder.
Reconstitution when water is added to lyophilized powder in a container and a suspension is made
Advantages of solutions -completely homogenous doses, immediately available for absorption, for patients who cant swallow pills, doses can be easily adjusted
Disadvantages of solutions drugs and chemicals are less stable in solution than dry dose, some drugs are not soluble in solvents that are acceptable for therapeutic use, may require special additives or techniques to mask objectionable taste, difficult to handle, transport + store
Advantages of suspension Can orally administer drugs that are insoluble in acceptable solvents, can be taken or administered when cant swallow,masks objectionable taste, drug are chemically more stable than in solution
Disadvantages of Suspension tend to settle over time leading to lack of dose uniformity, unpleasant oral texture
emulsions some formulations contain both aqueous and oleaginous components. These two can be formulated into n homogenous mixture when and emulsifying agent is used
oleaginous oil based
Emulsifier enable one of the components to be dispensed in the other in the form of little tiny globules or droplets
If the oleaginous component is present as droplets the emulsion is called an oil in water (o/w) emulsion
if the aqueous component is present as droplets the emulsion is called water in oil (w/o) emulsion
Emulsions are used in many routes of administration. which route do patients complain about the oily feel? Oral
Why would an emulsion be the formula of choice? To mask the taste of a very bitter drug, or when the oral solubility or bioavailability of a drug is to be dramatically inceased
How can you find an emulsion in the topical form? As a cream, lotion, or ointment base
Emulsions used for oral administration are: physically unstable and tend to separate into two distinct phases over time.
When does creaming with an emulsion occur? when dispersed droplets merge and rise to the top or fall to the bottom of the emulsion.
A creamed emulsion can easily be redispersed by shaking. Coalescence is the irreversible separation of the dispersed phase.
Coalescence Breaking or cracking
What substances are Gels made from Gelling agents that the increase viscosity (thickness)of the liquid in which they are placed
Gelling agents form an interlacing three dimensional network of particles that restricts the movement of the solvent
Common known gelling agents Acacia, Alginic acid, Carbopols (carbomers), gelatin, methylcellulose, tragacanth, xanthan gum
Even though each gelling agent has some unique properties, there are some generalizations that can be made. Most GA require 12-24 hrs to reach max viscosity and clarity, GA are used in concentrations of .5% up to 10% depending on the agent, its easier to add the active drug before the gel has formed, only some are recommended for oral administrtion
The only gels recommended for oral administration Carbopol 934P, methycellulose, hydroxypropylmethylcellulose, and sodium caboxymethylcellulose
An emulsion is a mixture of two liquids that do not mix with eachother in which one liquid is dispersed through the other by using a stabilizer called an emulsifier
When rapid action is desired what route of administration is preferred? The mouth- Buccal or Sublingual
formulations used in the mouth are usually: Fast dissolving, uncoated tablets which contain highly water soluble drugs
When a tablet is placed under the tongue, what kind of administration is that? Sublingual
When a tablet is placed into the cheek to dissolve, what kind of administration is that? Buccal
In a SL administration, when the drug is released from the tablet, it is quickly absorbed into what system? the circulatory system, since the membranes lining the mouth are very thin and there is rich a blood supply to the mouth
What medication is the best example of a sublingual administrated tablet formation? Nitroglycerin
Where is Nitroglycerin degraded in the body after being taken SL? degraded in the stomach and intestines
Another type of administration for Nitroglycerin is a translingual aerosol that permits a patient to spray droplets under the tongue
Because of the bitter taste of holding tblets under the tongue, what other SL form of administrion can be used? Lozenges, which are generally formed with sweetening agents
Why is the buccal cavity used? It allows for rapid absorption of drugs and bypasses first pass metabolism in the liver
Sub, Trans, and lingua are Latin words meaning Under, across or over and tongue.
Water soluble the property of a substance being able to dissolve in water
Steps in using a SL tablet 1. Take a sip of water 2. pleace tab under tongue 3. mouth must remain closed until the tab is dissolved and absorbed.
why would drugs be administered rectally? For a local effect or to avoid degradation after oral administration
Local effects from a rectal administration Soothing inflamed hemmorhoids or promoting laxation
Rectal administration is preferred when the drug is degraded by stomach acid or intestinal enzymes, or if oral administration is unavailable.
Systemic effects of rectal administration Asthma control, antinausea, motion sicknes and anti infective therpy
Most common rectal forms of administration Suppositories, solutions, and ointments
Suppositories are a semisolid dosage form that dissolves or melts when inserted
Suppositories are manufactured in many shapes, and are used in other routes of administration like vaginal or urethral
Rectal ointments are intended to be spread round the anal opening and are most often used to treat inflamed hemorrhoidal tissue
Disadvantages of rectal doses Not preferred by patients, inconvenient, rectal absorption of most drugs is frequently erratic and unpredictable
Enemas can create an urge to deficate due to the placement of fluid into the rectum.
types of enemas cleansing enema uses water or cleaning solution, retention enema uses an oil
hemorrhoid painful swollen veins in the anal rectal area, generally caused by strained bowel movements from hard stools
Parenteral routes of administration that are injection independent ophthalmic, intranasal, inhalation, dermal, vaginal, otic
Parenteral routes of administration that are injection dependent intravenous, intramuscular, intradermal, subcutaneous, epidural, intrathecal
A parenteral route may be indicated when an orally administered drug is poorly absorbed or is degraded by stomach acid or intestinal enzymes
A parenteral route of administration comes in handy when When a patient is uncooperative or unconscious or otherwise unable to take a drug.
Disadvantages to parenteral routes of administration Many are more expensive than enteral route formulations, many require skilled personnel to administer them, once a parenteral drug is administered, it is difficult to remove the dosage if there is an adverse or toxic reaction
name 2 types of risks associated with parenteral administration of dosages with a needle infection, thrombus
What is a requirement for some types of parenteral administration? a needle and some type of propelling device such as a syringe or pump to administer the drug
Several characteristics that injectable routes have in common formulations limited to solutions,suspensions and emulsions. Formulation must be sterile. Formula PH must also be carefully maintained, limited volumes of the formula can be injected
Sterile Bacteria free
How is the PH of formulas carefully maintained? Commonly done by adding ingredients to the formulation called buffer system.
What happens if too much volume of the formulation is injected pain and increased cell death
necrosis increased cell death
Where are intravenous injections located? directly into the veins and therefor into the circulating blood
Types of IV injections large volume, slow infusions with aqueous solutions such as D5W, or NS, small volume single injections, fat emulsions, blood tranfusions and patient controlled analgesia solutions
NS 0.9% sodium chloride in water
PCA Patient controlled analgesia
1st layer of IV injection epidermis
2nd layer of IV injection dermis
3rd layer of IV injection Subcutaneous
4th layer of IV injection vein
5th layer of IV injection Muscle
Intramuscular injections are administered into the muscle tisue
IM injections generally result in slower onset but longer duration of action compared to IV admin.
Subcutaneous injections are administered where the subcutaneous tissue
SC administration provides slower absorption than IM admin. and faster absorption than oral
Intradermal injections are administered where the top layer of skin, at a slight angle using short needles
Most intradermal injection are used for what reason mostly diagnostic determinations, desensitization or immunization
buffer system ingredients in a formulation designed to help control the PH
How long does it take an IV administered drug to circulate throughout the body 20 seconds
What is the most common IV administration? Solution.
What types of solutions are there most are aqueous, but they may have glycols, alcohols or other non aqueous solvents in them
Why are injectable suspensions difficult to formulate? They must possess suitable syringeability and injectability
Syringeability Refers to the ease with which the suspension can be drawn from a container into a syringe
injectability refers to the properties of the suspension while being injected, such as flow evenness, freedom from clogging, etc.
What are fat emulsions for Formulations used in TPN solutions to provide triglycerides, fatty acids and calories for patients who cannon absorb them from the gastrointestinal tract
Dry powder formulations are manufactured for IV use, but what has to be done to them they must be reconstituted with a suitable dilutent to make a liquid formulation
what can be done to drugs that are not stable in liquid form? lyophilized into a powder
lyophilized freeze dried
What is a lyophilized powder reconstituted with a solvent called a dilutent
Common dilutents for IV formulas Sterile water + bacteriostatic water
IV site arm veins 1. Basilic, 2. cephalic, 3. median cubital, 4. median ante- brachial
IV site hand veins 1. Cephalic 2. Dorsal venous arc 3. metacapal
IV site Foot veins Dorsalis pedis
3 parts of a syringe syringe plunger, syringe barrel, needle
IV administration complications Thrombus, phlebitis, air emboli, particulate material
Why would blood clot be a problem with an IV injection site? extreme in solution PH, particulate material, irritant properties,needle or catheter trauma, to small a vein for volume of solution
Air Emboli occurs when air is introduced into the vein
particulate material can include small glass chips from product vial or rubber pieces from vial closure,
simple syringe and needle setups can be used to inject formulations of a short period of time (generally up to 2 min.)
What is syringe size based on The volume of the formulation to inject
What is the needle size based on the route of administration being used (IV,IM,SC,ID)
Infusion the gradual process of IV injection of a volume of fluid into a patient
What volume would a infusion generally be a large volume - 500ml-1000ml
Infusion solutions are generally an electrolyte solution such as D5W or 1/2 NS
1/2 NS one half normal saline, .45% sodium chloride in water
what is the rate of normal infusion? 2ml-3ml per min
What are the 2 ports on an infusion bag for? An administration set port, a medication port
What is the administration set port on an infusion bag for? Provides the connection between the solution bag and the needle in the patient. May also be connected to an infusion pump to control the flow rate.
What is the medication port on an infusion bag for? where a simple syringe and needle may be used to inject a drug through the medication port into the solution bag
What is a minibag? A second small bag containing the drug that an be piggybacked onto the administration set through an infusion pump
Infusion pump an administration device to deliver medication through IV
Why are infusion pumps dependent on gravity flow stopped being used? They have variable delivery rate
What are elastomeric pumps useful for Very slow or continuous infusions
What are elastomeric pumps? Balloon like reservoirs filled with medication that is forced out of the reservoir through a flow restrictor
IM injections are made are preformed where into the muscle fibers that are under the subcutaneous layer of skin
IM injection needles are generally how long 1"- 1.5"
What gauge needles are generally used for IM injections? 19-22 gauge
What are the principal injection sites of an IM injection? Gluteus Maximus (butt), Deltoid (Upper Arm), and Vastus Lateralis muscles (thigh)
When giving an IM injection into the gluteus maximus what is one thing to consider The thickness of gluteal fat, particularly in female patients.
If an appropriate sized needle isn't used when giving an IM injection into the gluteal fat of the gluteus maximus, what will happen? The injection will not reach the muscle
What should you know about the injection site for an IM injection It should be as far away as possible from major nerves and blood vessels to avoid nerve damage and accidental intravenous administration
Vastus Lateralis muscle thigh muscle
Injuries that could occur rom IM injections are abscesses, cysts, embolism, hematoma. skin sloughing and scar formation
To void injury when giving IM injections, what is recommended? to rotate or change the injection site
How many ML can be injected intramuscularly in deltoid and thigh? 2ml
how many ML can be injected intramuscularly in the gluteus maximus? 5ml
Does IM injection or IV administration usually result in lower but longer lasting blood concentrations? IM injections
What does the absorption step do for an IM injection? Delays the time to peak concentration
When a formulation is injected, what happens? A depot is formed inside the muscle tissue where the drug is injected
What factors into absorption from the depot Muscle exercise,particle size of the drug, and the salt form of the drug used in the formulation
Formulations for IM injections include Solutions, suspensions, colloids, oil in water or water in oil emulsions
what two formulations contain insoluble particles Colloids and suspensions
Which formulation has smaller particles, colloids or suspensions? the particles in colloids are 100 times smaller
Why are different salt forms of some drugs used? to take advantage of a slower dissolution rate or a slower solubility.
Why would you want to vary the amounts of particle size, the type of emulsion, and the salt form? to achieve the desired absorption rate
Which has a faster absorption rate, aqueous solutions or oleaginous solution? Aqueous. both are faster than colloids or suspension.
depot area in the muscle where the formulation is injected during an IM injection
Colloids Particles of up to a hundred times smaller than those in suspensions that are, however, likewise suspended in a solution.
What is a Z tract injection and why is it used? A technique used for medications that stain the skin or irritate tissues.
How is a Z tract injection performed? The skin is pulled to one side prior to injection. Then the needle is inserted and the injection is performed. Once the needle is removed the skin is released so that the injection points in the skin and muscle are no longer aligned
In a z tract injection why do you not want the skin and injection site to line up after the injection is made? This keeps the drug from entering the subcutaneous tissue and staining or irritating the skin.
How deep is z tract injection usually? 2-3" deep
Why choose the subcuteous route of administration? Versatile and can be used for both short and long term therapies.
Subcutaneous injection sites Lower abdomen, front of thigh, upper back, back of upper arm,
The injection of a drug or implantation of a device beneath the surface of the skin is made in the loose tissues of the upper arm, the front of the thigh, and the lower portion of the abdomen. As well as the upper back.
The maximum amount of subcutaneous injection is 2ml
needles are generally 3/8 - 1" in length and 24-27 gauge
What influences the absorption of drugs in the subcutaneous tissue? muscle exercise, salt form used, size of particles
Fewer blood vessels in SC or in IM? SC
Subcutaneous administration is generally more rapid and predictable than with oral administration
Using heat or massaging the injection site do what? they have ben found to increase the absorption rate
which is the most common drug administered SC? insulin
What kind of precautions should be observed when giving someone a SC inj? drugs which are irritating or very viscous may produce serious adverse effects and be painful to the patient.
Implant One of the most popular ways to achieve very long term drug release is to place the drug in a delivery system or device that is implanted into the body tissue
where is the implant preferred? into the SC layer of skin
Implantation generally requires a surgical procedure or a specialized injection syringe
implants are required to be biocompatible
an advantage to using the subcutaneous implantation? it can be easily removed if nessescary
what type of SC implants can be used? Birth control, prostate cancer treatment, degradable microspheres, vapor pressure devices for morphine delivery, osmotic pressure devices for insulin and magnetically activated pellets
biocompatibility not irritating; does not promote infection or abscess
wheal a raised blister like area on the skin caused by an ID injection
Intradermal injections involve small volumes that are injected into the top layer of skin
An ID injection does what once the formula is injected? forms a wheal or blister like area from which the drug will slowly be absorbed into the dermis.
the dermis is the layer of skin below the epidermis, containing more blood vessels than the epidermis but fewer than most other injection sites
what is the rate of absorption in an ID injection absorption is gradual
Where would you give an ID injection? The anterior surface of the forearm.
When giving an ID injection how long are the needles? generally 3/8" long
what gauge are the needles for an ID injection? 25 to 26 gauge
How is the ID injection made? the needle is inserted horizontally into the skin with the bevel facing up. The injection is mde when the bevel disappears under the skin
max. volume administered by ID injection 0.1 ml
Ophthalmic drugs used for things like various eye conditions and for anesthesia
ophthalmic formulations are aqueous solutions, aqueous suspensions, ointments, and implants
every ophthalmic product must be sterile in its final container
because of the sensitivity of eyes, what must be closely monitored? PH and viscosity
normal volume of tears in the eye 7 microliters
if blinking occurs the eye an hold 10 mcl
normal commercial eye droppers hold 50 mcl
what would the dose lost from overflow percentage? 80%
the ideal volume of a drug solution to administer would be 5-10 mcl
Some disadvantages to ophthalmic administration lacrimal drainage and very rapid absorption by the eyelid lining
where do the tears that wash the eyeball flow from? the lacrimal gland across the eye and rain into the lacrimal canalicula.
tear production for the average man is 2mcl per minute
the entire ear volume in the eye turns over every 2-3 minutes
systemic absorption is caused by rapid washing of the eye by tears
the drug is rapidly carried away from the eye after being absorbed by the eyelid and enters the circulatory system
ophthalmic ointment tubes are typically small, holding and fitted with approx. 3.5g with a narrow gauge tip which permit the extrusion of a ribbon or ointment
Lacrimal gland the gland that produces tears for the eye
lacrimal canicula the tear ducts
conjunctiva the eyelid lining
transcorneal transport drug transport into the eye
the capacity of the Intranasal cavity is approx. 20 ml
benefits from Intranasal administration large surface area for absorption and a very rich blood supply
what are the most common intranasal drugs used for? used for decongestant activity on nasal mucosa
other popular intranasal drugs antihistamines and corticosteroids
the intranasal absorption of some drugs produces what blood concentrations similar to when the drug is IV administered
Intranasal administration serves as a possible route of administration for drugs that are seriously degraded or poorly absorbed after oral administration.
IN formulations include solutions, suspensions, ointments and gels
IN solutions or suspnsions are generally administered as drops or a fine mist from nasal spray or aerosol container
why are nasal sprays preferred to drops drops are more likely to drain into the back of the mouth and throat and be swallowed.
what have plastic bottles been replaced by glass containers with a metered dose inhaler actutor
MDI actuator metered dose inhaler actuator
3 types of IN Devices for administration Nasal spray with MDI actuator, nasal aerosol, nasal inhaler
Nasal inhaler a device which contains a drug that is vaporized by inhalation
a nasal inhaler includes a cylindrical tube with a cap, that contains fiberous material impregnated with a volatile drug
how does a nasal inhaler work? the cap is removed, the inhaler is tip is placed inside the nostril, as the paient inhales air is pulled through the tube and the vaporized drug is pulled into the nasal cavity
nasal mucosa the cellular lining of the nose
nasal cavity the cavity behind the nose and above the roof of the mouth that filters air and moves mucous and inhaled contaminants outward and away from the lungs
3 ways an IN dosage can be lost the nasal linings enzymes can degrade and metabolize some drugs, normal mucous flow will carry the drug with it, some amounts of IN administered drugs are swallowed
if IN dosages are used for long periods of time, may lead to chronic swelling of the nasal mucosa
how long should you use IN doses? 3-5 days
edema chronic swelling
what are inhalation dosage forms for intended on delivering drugs to the pulmonary system
why use an inhalation dosage? the lungs have a large surface area for absorption and a rich blood supply. also, avoids problems of degradation and poor absorption
Inhalation is not considered n alternative route of administration to IV because inconsistency in the absorption of drugs from the lungs
The most important drugs administered by the inhalation route Gaseous or volatile anesthetics
other drugs administered by the inhalation route affect lung function, act as bronchodilators and antiallergic
Most inhalation dosages are MDI aerosols that depend on the power of compressed or liquefied gas to expel the drug from the container
aerosols are easy to use and have no danger of contamination, but are not very effective in delivering a drug to the respritory tract
aerosols are not effective in delivering the drug to the respiratory tract not due to the poor design of aerosol design, but to the physical bariers of the airway and lungs that any inhalation dosage form must overcome to be effective
What is a critical factor with an inhalation dose? particle size.
Large particles (20 microns)hit the back of the throat and mouth and are eventually swallowed rather than inhaled
Particles from 1-10 microns reach the bronchioles
smaller particls (.6 microns) penetrate the alveolar sacs of the lung where absorption is rapid but retention is limited sine a fraction of the dose is inhaled
breathing patterns and the depth of breathing also play important roles in the delivery of what the delivery of drugs into the lung by inhalation aerosols
Alveolar sacs (alveoli) the small sac of specialized tissue that transfer oxygen out of inspired air into the blood and carbon dioxide out of the blood and into the air for exhlation
inspiration breathing
places an inhalation dose is absorbed in the lungs alveoli and bronchioles
inhalation administering devices an atomizer, diskus, nebulizer, MDI aerosol, MDI aerosol with spacer
MDI aerosols for inhalation admin. Used to administer drugs by inhalation and have special metered doses when the aerosol is activated. The amount of medicine released is regulated by a valve that has a fixed capacity or fixed dimensions
Adapters and spacers Developed to assist patients who cannot coordinate the breathing in and atuation of the aerosol
Dry powder inhalers Administered in powder form using a special inhalation device. The device automatically releases the drug when the user inhales. The powdered drug is supplied in hard gelatin caps, cartridges, or disks
Atomizers and nebulizers Devices which break up liquid into a spray. As the liquid vaporizes the air stream created carries the spray out of the vessel and into the mouth
what is the largest, heaviest organ skin, accounts for 17% of a persons weight.
what does skin do preforms a barrier that protects the underlying organ systems from trauma, temp, humidity, harmful penetrations, moisture, radiation and micro organisms
What do you call dosage forms that are applied to the skin? Dermal dosage formulations
What are most dermal dosage forms used for? local effects on or within the skin
what are dermal formulations used for protectants, lubricants, emollients, or drying agents, or as a delivery vehicle for a drug
what do some dermal formulations promote? Percutaneous Absorption
Percutaneous Absorption Absorption through the skin
Advantages to dermal administration ease of administration, usage by patients is generally good, can provide continuous drug delivery, dermal administration an be easily removed
major disadvantages of dermal administration amount of drug that can be absorbed is limited to about 2/mg per hr.
skin is generally how thick 3-5 mm
where is skin thicker palms and soles of feet
where is skin thinner eyelids and genitals
other structures with the skin hair follicles, sebaceous glands, sweat glands and nails
what is the outer layer of epidermis called Stratum corneum
How is the stratum corneum continually replaced by skin cells underneath
what is the turnover time of skin cell from cell development to shedding of the dead cells? 21 days
Sloughing Shedding of dead cells
The stratum corneum is the primary barrier to drug penetration
How thick is the stratum corneum? 10 micrometers thick but can swell up to approx. 3x that by absorbing as much as 5x its weight in the water.
What happens when the stratum corneum hydrates, or absorbs water? it becomes easier for drugs to penetrate
percutaneous absorption the absorption of drugs through the skin, often a systemic effect
Dermal formulations are Solutions, tinctures, collodions, liniments, ointments, creams, gels and lotions, pastes, powders and plasters, transdermal patches, tape and gauzes
Dermal solutions and tinctures are generally used as antiinfective agents, generally dispensed in small volumes
collodions are liquid preperations of pyroxylin dissolved in a solvent mixture of alcohol and ether
Liniments are alcoholic or oleaginous solutions generally applied by rubbing
What are the most popular dermal formulations? Ointments, creams, gels and lotions
Advantages to vaginal administration Avoids degradation of dosage,doses can be retrieved, has the potential of providing long term drug absorption
disadvantages to vaginal administration leads to vaiable absorption rates, administration of formula during menstruation could predispose patient to TSS. Also a tendency or some dosages to be expelled after insertion into the vagina
Vaginal formulations include solutions, powders for solutions, ointments, creams, aerosol foams, suppositories, tablets and IUDs
IUD intrauterine device
contraceptive device or formulation designed to prevent pregnancy
TSS Toxic shock syndrome, rare and potentially fatal that results from a severe bacterial infection of the blood, caused when bacteria natural to the vagina enters the blood stream
Systemic something that is wide spread throughout, system wide, affecting the whole boy
Created by: megancarter
 

 



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