LOCAL ROUTE OF DRUG

ADMINISTRATION

Dr. AJAY SINGHGSVM medical college kanpur

INTRODUCTION• the first step in pharmacokinetic is the administration and

absorption of drug • now day most of the drug can be administreted by

varitey of routs• choice of appropriate rout in a given situation depends

both on drug as well as patient related factors -physical and chemical properties of drug. -site of desired action. -rate of extent of absorption of the drug from different

routes. -effect of digestive juices and first pass metabolism on the

drug. -condition of patient.

DEFINITION

• systemic route • local routes

→a routes of drug administration is the path by which a drug fluid, poision or other substance is brought into contact with the body.→on the basis of local and systemic action routes can be broadly divided into→

LOCAL ROUTE

• These routes can only be used for localized lesions at accessible sites.

• Systemic absorption of the drug from these routes is minimal or absent.

• Thus high concentrations are attained at the desired site without exposing the rest of the body.

DIVISION OF LOCAL ROUTE

LOCAL ROUTS

TOPICALDEEPER TISSUES

ARTERIAL SUPPLY

Topical route:

This refers to external application of the drug to the surface for localized action.

EXAMPLES• Ointments, creams ,lotions

and powders used for Mucous membrane of eye, ear, nose throat, mouth, urinary bladder, vagina and rectum

TYPE OF TROPICAL ROUTES

• enepidermic routes

• epidermic routes

• insufflation

• instillation

• irrigation or douching

• painting or swabbing

enepidermic route• when the drug is simply

applied to the outer skin, it is called enepidermic route of drug administration.

• Examples → ointment and antiseptic lotion

Epidermic route :• When the drug is rubbed into

the skin, it is known as epidermic route. Examples include different oils

insufflation• the blowing of a powder, vapor,

or gas into a body cavity.• a drug administered by this

method, especially are powder or aerosol carried into the respiratory passages.

example→ salbutamol, cromolyn sodium

Instillation• the introduction of a

liquid (by pouring or injection) drop by drop into the conjunctival sac, ear, nose and wounds.

Irrigation or Douching

• This method is used for washing a cavity e.g. nasal cavity, urinary bladder, uterus, vagina and urethra. It is also used for application of antiseptic drugs.

example→ lidocane applied to urethra

Painting/Swabbing• Drugs are simply applied in

the form of lotion on cutaneous or mucosal surfaces of buccal, nasal cavity and other internal organs.

• example- vancomycine for g.i. mucosa

DEEPER TISSUES• Certain deep areas can be

approached by using a syringe and needle, but the drug should be such that systemic absorption is slow;

example• intra-articular

injection(hydrocortisone acetate) • intra-thecal injection(lidocaine) • retrobulbar injection(hydrocortisone

acetate)

ARTERIAL SUPPLY

• Close intra-arterial injection is used for contrast media in angiography, anticancer drug can be use in femoral or bronchial artery to localise the effect for limb malignancies.

• In these cases the drug is injected into the artery that is supplying the blood to the desired site .

advantages • Convenient and easy to apply.• For a skin rash or something of the sort, a

topical medication acts locally to where it is applied, whereas an oral medication works throughout the entire body.

• There is also a smaller chance of having an allergic reaction because it only acts where it has been applied.

disadvantages• Skin irritation of contact dermatitis may

occur due to the drug. • Drugs of larger particle size not easy to

absorb through the skin.• Because topicals act locally, they do not

distribute themself throughout the body and are quite useless as pain relievers.

REFERENCE

• KD tripathi

• wikipedia