Lecture 1 Flashcards
Methods used to evaluate particle size and distribution?
Sieving or screening, Optical Microscopy,Sedimentation, Stream Scanning, Laser diffraction
Surface morphology?
It is observed by Scanning Electron
Microscopy (SEM)
Surface morphology of drug can
provide greater area for various
surface reactions such as
degradation, dissolution, or
hygroscopicity
Surface roughness leads
to poor powder flow characteristics of
powders due to friction and
cohesiveness
Hygroscopicity Tests
Gravimetry
Karl Fischer Titration
Gas chromatography
Hygroscopicity influences?
chemical stability, flowability, and compatibility.
AMORPHOUS DRUG example?
Novobiocin: It is inactive when administered in crystalline form, but
when they are administered in the amorphous form, absorption from the
gastrointestinal tract proceeds rapidly with a good therapeutic response.
Crystalline drug example?
crystalline forms of penicillin G as K
or Na salt is considerably more stable and result in
excellent therapeutic response than amorphous forms.
POLYMORPHIC DRUGS?
Chloramphenicol exist in A,B
& C forms, of these B form is
more stable & most preferable.
Pseudomorphic crystalline drugs ?
The anhydrous and trihydrate forms of ampicillin were
administered orally as a suspension to human subjects. The more
soluble anhydrous form (10 mg/ml) produced higher and earlier
peaks in the blood serum levels than the less soluble trihydrate
form.
Conditions to screen
for crystallinity and
polymorphism?
Precipitation, lyophilization, spray drying, grinding & compression
Characterization of crystallinity
and polymorphic forms
- Scanning electron microscopy.
- X-ray diffraction.
- Differential scanning calorimetry (DSC).
- Thermogravimetric analysis (TGA)
- Dissolution and solubility analysis.
Thermogravimetric analysis (TGA) measures?
Desolvation & decomposition
THERMAL ANALYSIS application?
-Purity, polymorphism, solvation, degradation, and excipient compatibility.
- investigate and predict any
physicochemical interactions between components in the formulation.
-It is used for the selection of chemically compatible excipients
Hygroscopicity depends on?
atmospheric humidity,
temperature, surface area, exposure and the mechanism of moisture
uptake.
