DOSAGE FORMS AND ROUTES OF ADMINISTRATION
Intro Introduc ductio tion n to route routess of admin administ istra ratio tion: n: Drug Drug substa substance nces s are rarely rarely
administered in their natural or pure state. They are usually administered in combination with one or more nonrnedicinal agents that serve different and sp speci eciali alized zed pharm pharmace aceuti utical cal functi functions ons.. The select selective ive us use e of these these nonrnedicinal
agents,
called
as
pharmaceutical
ingredients
(compone (components nts /parts), /parts), helps, helps, adjuncts adjuncts (supports (supports), ), or necessiti necessities es different different pharmaceutical preparations. The pharmaceutical ingredients are used to solubilize (dissolve), suspend, thicken (harden), dilute, emulsify, stabilize, and preser preserve ve the pharm pharmaceu aceutic tical al prepar preparati ations ons.. Some Some pharm pharmaceu aceutic tical al ingr ingred edie ient nts s are are also also us used ed as colo colori ring ng agen agents ts and and flav flavor orin ing g agen agents ts (flavoring agents are used to hide or mask the bitter test of drugs). Every intent intentio ion n to use pharm pharmace aceuti utical cal ingre ingredie dients nts is to impr improve ove the quali quality ty (efficacy) and also to make the pharmaceutical preparations attractive for the consum consumer er (user (user). ). The pharm pharmace aceuti utical cal prepar preparati ations ons with with parti particul cular ar characteristics presented (given) to the patients are called as dosage forms .
[Pharmaceutics: The general area of study related with the physical, chemical and biolog biologica icall facto factors rs influe influenci ncing ng the formul formulati ation, on, manufa manufactu cturin ring, g, stabi stabilit lity y and effectiveness effectiveness of pharmaceutical pharmaceutical dosage forms is called as pharmaceutics].
Import Importanc ancee or nee need d for dosage dosage form: form: Most Most of the the drug drugs s are are high highly ly
biologically active and hence exact dosage (quantity) of every drug is to be administered. Further, age of patients, condition of patients, general liking (choice) of patients, site of application etc. are different factors that made the pharmacists to design (plan to prepare) dosage forms. The impor importan tance ce or need need to prepar prepare e dosage dosage forms forms may be summa summari rized zed as follows1) To provide provide safe and convenient convenient administ administrati ration on of drug substance substance in accurate dosage (quantity). 2) For For prot protect ectio ion n of drug drug su subs bsta tanc nces es from from dest destru ruct ctiv ive e infl influe uenc nce e of atmo atmosp sphe heri ric c oxyg oxygen en and and mois moistu ture re (e.g (e.g.. coat coated ed tabl tablet ets, s, seal sealed ed ampules etc.). 3) For For prot protect ectio ion n of drug drug su subs bsta tanc nces es from from dest destru ruct ctiv ive e infl influe uenc nce e of
gastric acid after oral administration (e.g. enteric coated tablets). 4) To conceal conceal (hide (hide or mask) mask) the bitter, bitter, salty, salty, or obnox obnoxiou ious s (hate (hateful ful)) taste or (smell) of a drug substance (e.g. capsules, coated tablets, flavored syrups etc.). 5) To provid provide e liqui liquid d prepar preparati ations ons of substa substance nces s that that are insolubl insoluble e or unstable in the desired vehicle (medium), (medium), (e.g. suspensions). 6) To provide provide liquid liquid dosage forms forms of substances substances that that are soluble soluble in the desired vehicle (medium), (e.g. solutions). 7) To
pro provid vide
mech mechan anis ism m
exten xtende ded d (e.g (e.g..
dru drug
vari variou ous s
act action thro hrough ugh
cont contro roll lled ed
rele releas ase e
con contro trolled relea elease se tabl tablet ets, s,
caps capsul ules es
andsuspensions). 8) To provi provide de optim optimal al drug drug actio action n from from topica topicall admin administ istrat ration ion sites (e.g. ointments, creams, ophthalmic (related to eye), ear and nasal preparations). 9) To provi provide de for for the the inse insert rtio ion n of a drug drug su subs bsta tanc nce e into into one one of the the body's body's
orifices orifices
(opening/ (opening/
aperture aperture//
outlet) outlet) (e.g.
rectal rectal
or
vaginal suppositories). suppositories). 1 0)
To provide for the placement of drugs within body tissue
(e.g.injections). 1 1)
To provide optimal drug action through inhalation therapy
[e.g.inhalants
(vicks)
and
inhalation
aerosols
(used
asthmatic patients).
Rout Routes es
of
admi admini nist stra rati tion on::
admi dminist nistrrati ation, (i.e. .e.
The route ute
There by
are
different
whi which the dru drug
routes is
of
placed aced
(regulated/given (regulated/given or taken). The
list
term
(name/designation) (name/designation) and the site of routes of
administration administration of drugs are given as :-
by
S. No.
Term
Site
1)
Oral
Mouth
2)
Per-oral
Gastro intestinal tract (via mouth)
3)
Sublingual
Under the tongue
4)
Parenteral
4) a) Intramuscular 4) b) Intravenous
Other than gastro intestinal tract (by injection) Muscle Vein
4) c) Intraarterial
Artery
4) d) Intracardiac
Heart
4) e) Intra synovial
Joint-fluid area
4) f )
Joints
Intraatrticular
4) g) Intr Intrac acut utan aneo eou us or Skin intradermal 4) h) Subcutaneous Beneath the skin 5)
Skin surface
6)
Epicutaneous (topical) Conjunctival
7) 8)
Intraocular Intranasal
Eye Nose
9)
Aural
Ear
10)
Intrarespiratory
Lung
11)
Rectal
Rectum
12)
Vaginal
Vagina
13)
Urethra!
Urethra
Conjunctiva
Variety of Dosage Forms: There are different forms into which a drug
may be placed (regulated/given or taken) for convenient and effective treatment of disease. Drugs can be prepared for administration by very conceivable (convincing) route and the suitable preparation is formulated to insu insure re maxi maximu mum m ther therap apeu euti tic c (cur (curat ativ ive) e) resp respon onse se.. Thes These e may may be tablets, tablets, capsules, capsules, solution solutions, s, syrups, syrups, elixirs, elixirs, suspensi suspensions, ons, gels, gels, powders, powders, troches or lozenge, ointments, creams, pastes, aerosol, lotions, sprays, inhalants inhalants,, emulsio emulsions ns and supposit suppositorie ories. s. The preferred preferred dosage dosage forms forms in different routes of administration is listed as:-
S.
Term
1)
Oral
2)
Sublingual
3)
Parenteral
4)
Epicutaneous (topical)
5) 6)
Conjunctival
Tablets Capsules Solutions Syrups Elixers Suspensions Gels Powders Tablets Troches or Lozenge Solutions and Suspensions Solutions Suspensions Gels Powders Ointments Creams Pastes Aerosol Lotions Sprays Ointments and Solutions
Intrao Intraocul cular/ ar/Int Intraa raaura urall Soluti Solutions ons and Suspensions
7)
Intranasal
8)
Intrarespiratory
9)
Rectal Vaginal
10)
11)
Site
Urethra!
Solutions Ointments Aerosol Sprays Inhalents Aerosol Solutions, Ointments and Suppositories Tablets Solutions Ointments Emulsions and Suppositories Solutions and Suppositories
Advantages and Disadvantages of oral rout of administration: Drugs are usually
taken by oral route of administration. The Advantages and disadvantage of oral route of administration administration are discussed below Advantages of oral route of administration:
1) It is most natural natural route route of adminis administrat tration. ion. 2) It is most easy route for administration administration of drug for patients. 3) It is safest safest route route of of administ administrati ration. on. 4) It is most convenient convenient for patien patients. ts. 5) This route route can take take large large variety variety of dosage dosage forms. forms. 6) Nursing Nursing for admini administra stration tion is not requi required. red. 7) An allergic allergic reaction reaction of the drug (toxicity) (toxicity) is delayed and hence safe. 8) It is economic economical al to the the patients patients..
Disadvantages Disadvantages of oral route of administration:
1) The onset onset of action action of drug is late late and hence recov recovery ery is not fast. fast. Therefore oral route of administration administration not preferred in emergency. 2) As it is absorbed absorbed from from gastroint gastrointestin estinal al tract the the quantity quantity of doses of drug required is more. 3) It
is
difficul difficultt
route route
of
adminis administra trati tion on
of
drug drug
for
nonnon-
cooperative patients like babies and children. 4) It is also also diffi difficul cultt route route of admini administr strati ation on of drug drug for uncons unconscio cious us patients. 5) The absorpti absorption on of drug from gastro gastrointe intestin stinal al tract is not not assured assured by patients suffering from gastrointestinal gastrointestinal disorder. 6) Oral Oral route route of admin administ istrat ratio ion n may may cause cause gastro gastroint intest estin inal al disor disorder ders s like acidity, loss of appetite, etc. 7) The
uncertain uncertainty ty of maintena maintenance nce
of the
prescrib prescribed ed
dosage dosage
of
drug is possible in oral route of administration. 8) Drug enzyme
may
be be
destroye destroyed d
or
inactivat inactivated ed
by
the the
in gastrointestinal gastrointestinal tract.
Advantages and Disadvantages of parenteral rout of administration: Taken by
parenteral route of administration, administration, The Advantages The Advantages and Disadvantages
of parenteral rout of administration are discussed belowAdvantages of parenteral route of administration:
1) The The onse onsett of acti action on of drug drug is fast fast and and henc hence e reco recove very ry is fast fast.. The Therrefo efore
paren arente terral
route oute
of
admi dministr strati ation
pref prefer errred
in
emergency. 2) As it is admini administe stered red direct directly ly on the site site or nearer nearer to the site, site, the quantity of doses of drug required is less. 3) It is easy easy rout route e of admi admini nist stra rati tion on of drug drug for for thos those e pati patien ents ts like like babi abies
a nd
children
who
normall ally
resist
to
oral
route
of
administration. 4)
It is the only possible route of administration administration of drug for unconscious patients.
5) The absorpti absorption on of drug from gastroin gastrointesti testinal nal tract is not assured assured by pati patien ents ts
suff su ffer erin ing g
from from
gast gastro roin inte test stin inal al
diso disord rder er
and and
henc hence e
parenteral route of administration administration is preferred. 6) Parent Parentera erall route route of admini administr strati ation on is prefer preferred red for those su suffe fferi ring ng from gastrointestinal gastrointestinal disorders like acidity, loss of appetite, etc. 7) The certain certainty ty of maint maintena enance nce of the prescr prescrib ibed ed dosage dosage of drug is possible in parenteral! route of administration. administration. 8)
There is no chance of drug getting destroyed or inactivated as by the enzyme in gastrointestinal gastrointestinal tract.
Disadvantages of parenteral route of administration: 1)
It is not natural route of administration.
2) It is riot easy route route for administra administration tion of drug for patients patients and selfselfadministration administration is not possible. 3) It is painful painful route route of adminis administrati tration. on. 4) Prepar Preparati ation on of dosage dosage form form for parenter parenteral al route route of admini administr strati ation on requires highly sophisticated instrumentation and condition. 5) The verity verity of dosage dosage form form by which the drugs drugs,, an be taken taken by this this route route is restr restrict icted ed and are in liqui liquids, ds, soluti solutions ons and sus suspen pensio sions ns form. 6) Nursing Nursing for admini administra stration tion is require required. d. 7) An allergi allergic c react reactio ion n of the drug (toxici (toxicity) ty) is fast and hence is not safe.
8) It is not econom economical ical to to the patien patients. ts.
