Drugs /Dosage Forms Lecture Flashcards
quiz creams and other 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
The Need for Dosage Forms
- 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)
General Considerations in Dosage Form Design:
▪ Determine desired product type – the framework for product
development.
▪ 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.
Master Formula
a formulation that best meets the goals of the product
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
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
- MICROSCOPIC EXAMINATION
- 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
MELTING POINT DEPRESSION
- Determines the: purity of the substance compatibility of various substances before inclusion in the
dosage form - Pure substance: sharp melting point
- Impure substance: depressed melting point
PARTICLE SIZE
- Affects the physical–chemical properties of drug substances, particularly in:
a. Dissolution rate
b. Bioavailability
c. Content uniformity
d. Stability
e. Taste
f. Texture
g. Flow properties
h. sedimentation rate
i. Absorption
- Particle size may affect the formulation and efficacy of the dosage form
POLYMORPHISM
- substances can exist in more than one crystalline form
- Polymorphic forms – usually exhibit different physicochemical properties
(including melting pt and solubility)
SOLUBILTY
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
* Determined by equilibrium solubility method
- excess amount of drug + solvent = shaken at constant temp. over a
prolonged period of time until equilibrium is obtained
A drug must possesses aqueous solubility - for therapeutic efficacy.
* Insoluble compounds: incomplete/erratic absorption
