Medicinus - Dexa Medica

dosage and the effectiveness of a drug describes as
its biological activity in animals or in men. Both safety
and effectiveness are primarily a quality of drug
substance to show that they are not of prime interest
within the scope of pharmaceutical technology. Acceptability
of a drug is a more complex notion since
it comprises both properties which make it easier to
take a medicine, such as its taste, its smell, its appearance
and qualities contamination. 1
DOSAgE FORM DESIgN
Drug substances are seldom administered alone,
but rather as part of formulation in combination
with one or more nonmedical agents that serve
varied and specialized pharmaceutical functions
referred to pharmaceutical ingredients. The functions
of pharmaceutics’ ingredients may be served
as: filler, binder, desintegrant, glidant, lubricant, anti
adherant, solubilize, suspend, thicken, dilute, emulsify,
stabilize, preserve, color, flavor, etc.
The proper design and formulation of a dosage
form requires consideration of the physical, chemical
and biological characteristics both of the drug substances
and pharmaceutical ingredients to be used in
fabricating the product. The drug and pharmaceutical
material utilized must be compatible with one another
to produce a dosage forms product that is safe,
effective and acceptable. Dosage forms are needed
for many reasons as follows:
1. For the protection of a drug substance from the
destructive influences of atmospheric oxygen or
humidity
2. For the protection of a drug substance from destructive
influence of gastric acid after oral administration
3. To conceal the bitter, salty, or offensive taste or
odor of a drug substance
4. To provide liquid preparations of substances that
are either insoluble or unstable in the desired vehicle
5. To provide clear liquid dosage forms of substances
6. To provide time-controlled drug action
7. To provide optimal drug action from topical administration
sites
8. To provide for the insertion of a drug into one of
the body’s orifices
9. To provide for the placement of drugs directly
into bloodstream or into body tissues
10. To provide for optimal drug action through inhalation
therapy.
Before formulating a drug substance into dosage
form, it is important to predetermine the desired
technology
product type insofar as possible in order to establish
the framework for product development. Most
commonly, a pharmaceutical manufacturer prepares
a drug substance in several dosage forms and
strengths for the efficacious and convenient treatment
disease. The formulation of modern drug that
best meet the goals for the product, normally consist
of one active substance in combination with one or
more pharmaceutical ingredients , and there are several
dosage forms into which a combination active
substances are needed. 2
Active substance should be checked for identity,
purity and potency, prescription for which can be
found in pharmacopoeias or comparable compendia.
Sometimes these prescriptions have to be completed
with specific ones when special requirements
have to be set for the preparations to be made of
these.
Modern drug treatment uses preparations that
are frequently prepared by manufacturer and which
require no further manipulation in the pharmacy.
Most modern drugs are available in tablets, capsules
or injections. The efficacy of the drug in the body depends
on the dose of active substance. The dose of
a drug has been appropriately described as amount
which is “enough but not too much”, the idea being
to produce the drug’s optimum therapeutic effect
in a particular patient with the lowest possible dose.
The dose of a given drug is specific to the patient,
with many factors contributing to its size and effectiveness.
Table 1 presents examples of some drugs
with relatively low usual doses.
Table 1. Examples of some drugs with relatively low
usual doses 3
No. Drug Usual
dose
(mg)
Category
1 Lithium carbonate 300 Antidepressant
2 Ferrous sulfate 300 Hematinic
3 Cimetidine 300 Antiulcer
4 Ibuprofen 300 Antiinflamatory
5 Amoxicillin 250 Antibacterial
6 Erithromycin 250 Antibacterial
7 Nitrofurantoin 100 Antibacterial
8 Propoxyphene HCl 65 Analgesic
9 Hidrochlorothia-zide 50 Diuretic
10 Codeine phosphate 30 Analgesic
11 Phenobarbital 30 Sedative
12 Diphenhydramine
HCl
25 Antihistaminic
MEDICINUS 24(1), January 2011 35