DOSAGE FORM DESIGN CONSIDERATIONS Flashcards
study on the: formulation, manufacture, stability, and
effectiveness of pharmaceutical dosage forms
Pharmaceutics
-Selective use of these non-medicinal agents
- Pharmaceutical ingredients or excipients
Uses of Pharmaceutical ingredients or excipients
Solubilize
Thicken
Stabilize
Flavor
Suspend
Dilute
Preserve
Efficacious
Emulsify
Color
Appealing closure forms
Requirements of a proper design & formulation
of dosage form
a. Consideration of drug substances: Physical, chemical and biological
characteristics
b. Compatible with one another - stable, efficacious, attractive, easy to
administer, and safe
c. Manufactured under appropriate measures of quality control and packaged in
containers to make the product stable
d. Labeled to promote the correct use and stored under conditions to maximize
shell life
To protect the drug substance from the
destructive influences of atmospheric
oxygen or humidity.
Coated tablets
To protect the drug substance from the
destructive influence of gastric acid after oral
administration.
Enteric-coated
To conceal the bitter, salty or offensive taste
or odor of a drug substance.
Capsules,
Flavored syrups
To provide liquid preparations of substances
that are either insoluble or unstable in the
desired vehicle.
(Suspension)
To provide clear liquid dosage forms of
substances.
Syrups, Solutions
To provide rate-controlled drug action.
Controlled-release tablets
To provide optimal drug action from topical
administration sites.
Ointments, Creams,
Transdermal patches
To provide for insertion of a drug into one of
the body’s orifices
Suppositories
To provide placement of drugs directly in the
bloodstream or body tissues
Injections
To provide for optimal drug action through
inhalation therapy
Inhalants, Inhalation
aerosols
the framework for product
development.
Determine desired product type
Develop and examine initial formulations of the product:
a. desired features: drug release profile bioavailability
clinical effectiveness
b. pilot plant studies and production scale-up.
a formulation that best meets the goals of the product
Master Formula
Factors to consider before formulation of a medicinal agent in
one or more dosage forms:
a. Therapeutic matters (nature of the illness)
b. manner it is treated (locally or through systemic action)
c. age and anticipated condition of the patient.
Before the formulation of a drug substance into a dosage form, it is
essential that:
- It is chemically and physically characterized
- It defines the nature of the drug substance
This information provides the framework for the drug’s combination
with pharmaceutical ingredients in the preparation of the dosage
form
Considerations for physical characteristics:
- Particle size
- Crystalline structure
- Melting point solubility.
Determination of chemical properties
-Structure form
- Reactivity
Evaluation of the purity of the chemical substance for:
- Identification and for evaluation of its chemical, physical, and biological properties
Three ways liquid drugs be given in solid form
- Sealed in soft gelatin capsule
- Developed into a solid ester or salt form suitable for tablets or drug
capsules - Mixed with a solid or melted semisolid material
- melted mixture is poured into hard gelatin capsules to harden &
capsules sealed
It gives an indication of particle size and size range of the raw material
along with the crystal structure.
Provide information in formulation processing attributable to
changes in particle or crystal characteristics of the drug.
* Example: spherical and oval powders flow more easily than needle-shaped
powders and make processing easier
MICROSCOPIC EXAMINATION
Determines the: purity of the substance
compatibility of various substances before inclusion in the
dosage form
MELTING POINT DEPRESSION
depressed melting point
Impure substance
sharp melting point
Pure substance:
*Phase diagrams constructed determine:
- existence and extent of the
presence of solid and liquid phases in
binary, ternary and other mixtures
substances can exist in more than one crystalline form
POLYMORPHISM
usually exhibit different physicochemical properties
(including melting pt and solubility)
Polymorphic forms
- Evaluation of: a. Crystal structure (Techniques: microscopy, IR spectroscopy,
thermal analysis, x-ray diffraction)
b. Polymorphism
c. Solvate form
- Changes in crystal characteristics can influence bioavailability and chemical and physical stability
can cause implications in dosage forms process functions
Polymorphic forms
POLYMORPHISM
is defined as the maximum concentration of a substance
that can be completely dissolved in a given solvent at a certain
temperature and pressure level
Drug solubility
Determined by equilibrium solubility method
- excess amount of drug + solvent = shaken at constant temp. over a
prolonged period of time until equilibrium is obtained
for therapeutic efficacy.
A drug must possesses aqueous solubility
incomplete/erratic absorption
Insoluble compounds
The smaller the particle size
the greater the solubility
If a drug product is formulated into a liquid product:
adjustment of pH of solvent to enhance solubility
require extremes in pH outside of accepted physiologic
limits or that may cause stability problems with formulation ingredients.
Weak acidic or basic drugs
Adjustment of pH usually has
little effect on the solubility of substances other than
electrolytes.
The use of cosolvents or other techniques such as complexation,
micronization, or solid dispersion
may improve aqueous solubility