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Routes of Drugs.ppt

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					  ROUTES OF DRUG
  ADMINISTRATION

                     By
                 Zubair Latif
Pharmacology and Toxicology
UVAS, Lahore
Drug Absorption

   Absorption is the process by which a drug
    enters the bloodstream without being
    chemically altered
                or
   The movement of a drug from its site of
    application into the blood or lymphatic
    system
Factors affecting route of drug
administration
   Physicochemical properties of the drug
   Onset of action required
   Type of response required
   Site of desired action
   Nature and Formulation of drug
   Circulation at the site of absorption
   Biotransformation
   Condition of patient
     Routes of Drug Administration

   The possible routes for drug entry into the
    body may be divided into two classes:

       ENTERAL

       PARENTERAL
          ENTERAL ROUTES

   ENTERAL Drug placed directly in the GI
            tract:

     Oral       swallowing (p.o., per os)
     Sublingual placed under the tongue

     Rectum     Absorption through the rectum
     Oral
   Administration of drug by ingestion.
   Not very much preferred in animals because of
    restraining of animals is difficult.

   Given in the form of drench or mixed with feed or
    water.

   Applied with the help of stomach tube, or
    Nasogastric tube.

   If rapid effect is required drug may be
    administered before meal if drug causes irritation
    may be administered after meal.
    Advantages of oral route
   Can be self- administered, pain free, easy to
    take.
   Absorption takes place along the whole length
    of the GI tract.
   The drugs preparations needs no sterilization.
   Both solid and liquid dosage forms can be
    given through this route.
   Most suitable route for GIT Infections and GI
    parasites
   Cheap as compared to most other parenteral
    routes.
Disadvantages of oral route
   Drug action has slower onset son not suitable
    in case of emergency.

   Drug absorption is irregular and unpredictable
    due to presence of ingesta.

   First-pass effect - drugs absorbed orally are
    initially transported to the liver via the portal
    vein.

   Irritation to gastric mucosa - nausea and
    vomiting.
    First-pass Effect
   The first-pass effect is the term used for the
    hepatic metabolism of a pharmacological
    agent when it is absorbed from the gut and
    delivered to the liver via the portal circulation.
    The greater the first-pass effect, the less the
    agent will reach the systemic circulation when
    the agent is administered orally
    Disadvantages of oral route

   Destruction of drugs    by   gastric    acid   and
    digestive juices.

   Unpleasant taste of some drugs.

   Unable to use in unconscious patient.

   Poor administration techniques may lead to
    intratracheal   delivery   and  subsequent
    aspiratory bronchopneumonia
    Sublingual/Buccal
  Drugs are taken as solutions or smaller tablets
  which are held in the mouth or under the tongue.
Advantages
  Rapid absorption
  Drug stability
  Avoid first-pass effect
Disadvantages
  Inconvenient

  Small doses

  Unpleasant taste of drugs
Rectal route of drug administration

 1. Unconscious patients and children.
 2. If patient is nauseous or vomiting.
 3. Easy to terminate exposure.
 4. Absorption may be variable.
 5. Good for drugs affecting the bowel
 such as laxatives.
    Parenteral
   Intravascular
    Intravenous
    Intra-arterial

   Extravascular        Other Extravascular
    Intramuscular         Inhalation
    Subcutaneous          Topical Application
    Intra-articular
                          Other Mucous Membranes
    Intraperitoneal       (Vagina, Nose…)
    Intracardial
    Intrapleural
    Epidural
    Intradermal
    Intrathecal
    Intraoosseous
  Intravascular
Intravenous
Intra-arterial
Absorption phase is bypassed
 (100% bioavailability)
1.Precise, accurate and almost immediate
onset of action,
2. Large quantities can be given, fairly pain
free
3. Greater risk of adverse effects
    a. high concentration attained rapidly
    b. risk of embolism
Intravenous route of drug
administration
Drug solution is injected directly in one         of
superficial vein either as bolus or infusion.
In cattle and Horses vein is jugular, In sheep and
goat jugular, Caphaneous and cephalic, vein is
and in dog vein is Caphaneous and cephalic.
Identify the vein to be used in some animals this
is straightforward, others may have to palpate
(feel for) veins. Always inject with the blood flow.
Clean the site with soap and water, or an alcohol
swab.
Introduce the needle into the vein at a shallow
angle.
    Intravenous route of administration

   Pull back the plunger to identify that the needle
    is in a vein a small amount of dark red venous
    blood should trickle into the syringe.
   Inject slowly to reduce the likelihood of damage
    to the vein and to lower the overdose risk.
   Remove the needle slowly       if the needle is
    removed too quickly, the vein may collapse.
   Immediately apply pressure to the site bruising
    is caused by bleeding into the surrounding
    tissues. Immediate firm pressure will limit the
    amount of bruising caused.
    Advantages of Intravenous route
   Quick onset of action.

   This route is used when precise control of the
    drug effect is required.

   Highly irritating and non isotonic solutions can
    be given by slow IV because dilution provided
    by circulating blood.

   Large volume of fluids can be administered
    through this route.
    Disadvantages of Intravenous route
   This route required special technique.

   Air embolism may put life of animal in danger.

   Extra vascular accumulation of irritant drugs
    may cause necrosis of peripheral tissues and
    phlebitis.

   Not suitable for insoluble drugs like oils and
    suspensions.
Intramuscular route of administration

   Drug is injected deep
    between the layers of
    one of large skeletal
    muscle        because
    these    are    richly
    supplied with blood
    and less with nerves.

   This route is used for
    providing     systemic
    effects of drugs.
Advantages of Intramuscular route
Route of choice in animals.
Very rapid absorption of drugs in aqueous solution and
oleaginous suspensions.
Absorption of drug is rapid except for oily and depot
preparations.
The duration of action is longer than for IV injection, but
usually a little shorter than for subcutaneous
administration.
Mostly suitable route for fractious, wild and zoo animals,
which may be difficult to restraint.
Disadvantages of Intramuscular route

   Large volume of fluids cannot be injected.

   There is possibility of improper deposition of
    drug in nerve, blood vessels, fat or connective
    tissues.

   It is not suitable for emergency situations
    because    conditions   like cardiovascular
    collapse or shock may impede absorption of
    drugs.
Subcutaneous route of administration

The drug preparation is deposited in the loose
subcutaneous tissue (Under skin).It is richly supplied with
nerve but less blood supply.
Advantages
Large volume of non irritating drugs may be administered.
Absorption of drugs is slower than
IM and IV.
It is suitable for depot preparations.

Disadvantages
Not suitable for irritant drugs
 Intradermal route of administration
The drug preparation is injected in the dermis of skin.
Injection is applied on the skin of most sensitive part of
body.

Advantages
Used for diagnostic purposes, like tuberculin test, Malein
test, Antibiotic sensitivity test.

Disadvantage
Painful condition.
Intra articular Injection

   Inject the drug in Joints

    For the treatment of arthritis
    More skill is required
    Painful application

Damage the cartilage
    Intraperitoneal drug administration
   Injection into Peritoneum      (body
    cavity).

   IP injection is more often applied to
    animals than humans.

   It is generally preferred when large
    amounts of blood replacement fluids
    are needed, or when low blood
    pressure or other problems prevent
    the use of a suitable blood vessel
    for Intravenous Injection.
Advantages
 Rapid absorption

 Large volume of drug may be injected.

 Used frequently in lab animals.

Disadvantages
 Not suitable for irritating compounds because it
  causes chemical peritonitis.
 There is possibility of puncturing of intestine or
  other abdominal organs.
Intra Cardiac Injection

   Drug is injected directly in to the
    heart
    Epidural Injection

   An injection in the epidural space.
   It is a space located in the spine between
    the vertebrae and the dural sac, which
    surrounds the spinal cord.
     Intrathecal Injection


   Drugs which
    cannot cross BBB
    are administered
    through this route
Intraoosseous Injection

   Injection in Bone marrow
Other Extravascular
Inhalation

  1.Gaseous and volatile agents and aerosols
  2.Rapid onset of action due to rapid access to
  circulation
       a. Large surface area
       b. Thin membranes separates alveoli from
          circulation
       c. High blood flow
Topical route of drug administration
SKIN
Absorption is directly proportional to the lipid solubility of drugs.
  Absorption through skin can be enhanced by use of dressing,
  inunctions or special drug delivery devices like ear tags and
  transdermal patches.
BATH
It is immersion of the body in medicated water. Baths are given
    generally for their local effects upon the skin in cutaneous
    disorders.
DIPS
It is type of bath in which body is dipped in medicated fluid for a
    certain time. In vet. Dips are used in small animals to kill
    ectoparasites.
Topical route of drug administration
INUNCTIONS
It is the application of semisolid or liquid drug on the body by
   rubbing.
DUSTING
It is application of fine particles of solid on surface of body.
    APPLICATION ON MUCOUS MEMBRANES
Intramammary Administration.
Intra ocular Administration.
Intra aural Administration.
Intranasal Route.
Intravaginal
Intrauterine
Intra Prepucial
Specialized drug delivery systems
Transdermal Drug delivery system
Transdermal drug delivery system are topically
administered medicaments in the form of patches that
deliver drugs for systemic effects at a predetermined and
controlled rate.
 Specialized drug delivery systems
Liposomes.
Liposomes are minute vesicles of lipid bilayers
enclosing and aqueous compartment. They are utilized
for the transportation of drugs to areas not normally
accessible to free form of drug.
Specialized drug delivery systems
Dermojet/Hypospray
It is a special form of subcutaneous administration in
which needle is not used. A high velocity jet of drug
solution is projected from a micro fine orifice using a
gun like device. It is painless method for insertion of
drug in the body.
           Route for administration
              -Time until effect-


   Intravenous 30-60 seconds
   Intraosseous 30-60 seconds
   Inhalation 2-3 minutes
   Sublingual 3-5 minutes
   Intramuscular 10-20 minutes
   Subcutaneous 15-30 minutes
   Rectal 5-30 minutes
   Ingestion 30-90 minutes
   Transdermal (topical) variable (minutes to
    hours)
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