2. General Considerations
• Pharmaceutics – branch of Pharmacy
that deals with drug formulations
• Pharmaceutical products need to be
presented in a form that can be
administered to an organism
• Formulation takes into consideration
easy delivery as well as guaranteed
desired action (drug reaches target,
achieves therapeutic action)
3. Oral Preparations
Pill – round or ovoid solid body; may be coated
with sugar or other substance
• Tablet – granulated powder containing one or
more medications, compressed into a disc;
must disintegrate in the GIT, so starch is
often incorporated; + sugar-/film- coating;
• Dragees – chewable tablets
• Enteric-coated tablets – coated with a
substance that is stable at acidic pH (will not
disintegrate in the stomach) but breaks down
rapidly at higher pH (small intestines)
4. Oral Preparations
• Capsule – an outer “shell” holds the drug
inside
– Hard gelatin capsule – contains solid drug in powder
form; may be opened
– Soft gelatin capsule – contains the drug in liquid or
semi-liquid form; cannot be opened; useful for drugs
that are insoluble in water
• Sustained/Slow-release preparations – drug is
formulated in such a way that it releases very
slowly in the GIT; a single dose suffices for
delivery of the drug over a period of hours,
ensuring sustained action.
5. Oral Preparations
Liquid preparations – for children & for adults
who have difficulty swallowing pills; usually
flavored to make them palatable;
• Elixirs – drugs insoluble in water are
dissolved in Alcohol
• Syrups – sugared liquid preparations
• Suspension – drug in solid form, not
dissolved in Alcohol
• Emulsion – drug in liquid form, not dissolved
in Alcohol
6. Topical Preparations
Topical – application of a drug to the skin/ mucosa
overlying the area to be treated
• Drops – isotonic solutions – ophthalmic, nasal, otic
(eardrops – formulated as oily solutions for
adherence to the aural cavity)
• Creams – water-based, poorly absorbed; drug is left
on skin surface as water evaporates
• Ointments – lipid-based, greasy appearance & feel;
drug penetrates deeply into tissues, especially if
with “occlusive” dressing
• Pastes – have a very high powder content; water-
repellent.
• Gels & Lotions – used on hairy parts of the body.
8. Topical Preparations
• Intranasal sprays – often
metered to deliver precise
doses of the drug; can be
absorbed systemically
• Transdermal patches – useful
for administering lipophilic
drugs & those that are active in
very small amounts
• Suppositories – useful in
nauseous or vomiting patients,
unconscious patients, patients
with difficulty of swallowing;
may be administered rectally or
vaginally (Pessaries)
12. Routes of Administration
Oral
• most convenient, most economical
• rate & extent of absorption determines
onset of drug action/effect
• usual site of absorption: small intestines
• nonionized lipid-soluble forms favor
absorption
– weak acids are highly ionized in small intestinal alkaline pH
– weak acids are readily absorbed in the stomach
13. Oral administration
• First pass effect:
– Drugs absorbed from the GIT passes through the portal
venous system, then through the liver before finally reaching
the systemic circulation, to the receptors & target tissues
– Extensive hepatic metabolism/extraction results in minimal
drug delivery to the systemic circulation
(e.g.propranolol,Demerol, INH)
– poor liver extraction, ↑bioavailability e.g. diazepam, warfarin
• Disadvantages
– emesis due to GIT irritation
– destruction of drug by gastric acid/ GI enzymes
– unreliable or inconsistent absorption
– metabolism of drug by intestinal flora
14. Sublingual
administration
• Sublingual literally means 'under the tongue'. It
is a method of administering substances by
placing the medication under the tongue to gain
rapid and direct entry into the blood vessels
rather than via the digestive tract. Medically,
sublingual drug administration is applied in the
field of cardiovascular drugs.
• sublingual drugs : Calcibloc, Nitroglycerin,
Polypeptide K,
15. • comes in contact with the mucous membrane, or buccal mucosa, it
diffuses into the epithelium beneath the tongue, the sublingual areas
act like a blotting paper, readily soaking up the substance. This
region contains a high density of blood vessels, and as a result, via
osmosis, the substance quickly enters the blood stream at the
sublingual artery and thereafter, polypeptide-k ® is carried by blood
flow to the connected lingual artery.
• Can all substances be administered sublingually?
Not all substances are permeable and accessible to the buccal
mucosa. In order for a nutrient to be effectively absorbed
sublingually, it needs to be able to travel accross the buccal mucous
membranes; by a process of diffusion known as osmosis and
factors, such as pH, molecular weight, and lipid solubility of a
substance may determine whether the route is possible.
17. Transdermal administration
Advantages
• Sustained therapeutic plasma levels
• Reliable drug absorption
– Molecular wt < 1000
– pH range 5 – 9 in aqueous medium
– No histamine-releasing action
– Daily drug requirement < 10 mg
• Smaller doses, so lower incidence of side
effects
• Generally good patient compliance
• Examples: scopolamine, nitroglycerin,
nicotine, methylphenidate (or ADHD)
18. Rectal administration
• Proximal rectum administration – absorption
into superior hemorrhoidal veins portal
venous system - liver - systemic
circulation
• Low rectal administration – entry into the
systemic circulation without passing through
the liver
• Generally unpredictable pharmacological
responses
• Rectal mucosal irritation possible
• Examples: antipyretics, anticonvulsants
19.
20. Parenteral Administration
Parenteral – mode of drug administration that avoids the
GIT. Drug injections. Use of ASEPTIC TECHNIQUE
very very important!!
• Intravenous (IV) injections – fast action due to
avoidance of GI absorption
• Intradermal – injected into the dermis; very slow
absorption; only small quantities of the drug can be
given this way.
• Subcutaneous – just beneath the skin; very slow route;
poor blood supply
• Intramuscular – into the fleshy part of the muscle:
gluteus, deltoid, anterior thigh;
23. Parenteral administration
• Intravenous, Intramuscular, Subcutaneous,
• Ensures active drug absorption
• More rapid drug delivery than Oral
• Only route acceptable for unconscious
patients, uncooperative patients
• Systemic absorption depends on capillary
membrane surface area, drug solubility in
interstitial fluid
• Advantages:
– Rapid precise blood drug levels
– Irritant drugs more comfortably administered
– Drug is rapidly diluted
24.
25.
26. Specialized Modes of Administration
• Intrathecal – drug is introduced into the
CSF-filled space surrounding the spinal
cord; for giving of drugs directly into the
CNS, avoiding the blood-brain barrier e.g.
Baclofen, Morphine
• Epidural – drug is introduced into the space
above the dura; useful in administering local
anesthetics for surgical procedures in the
pelvic area & below
• Intra-articular – injection directly into joint
spaces
