2. Contents
๏ต Introduction
๏ต Excipients
๏ต Drug Excipient Interaction
๏ต Types of Drug Excipient Interaction
๏ต Thermal Techniques used to Detect Drug Excipient Compatibility
๏ต References
3. Introduction
๏ต Excipients play an important role in formulating a dosage form.
๏ต These are ingredients which along with active pharmaceutical ingredients make
up the dosage forms.
๏ต Excipients act as protective agents, bulking agents and can also be used to
improve bioavailability of drug.
4. Excipients
๏ต An excipient is a substance formulated alongside the active ingredient of a
medication, included for the purpose of long-term stabilization, bulking up solid
formulations that contain potent active ingredients in small amounts
๏ต Consistency of drug release and bioavailability.
๏ต Stability including protection from degradation
5. Drug Excipient Interaction
๏ต In pharmaceutical dosage forms the active pharmaceutical ingredients are in
intimate contact with the excipient which are greater quantity excipient and drugs
may have certain incompatibility which lead to drug excipient interaction.
6. Types of Drug Excipient Interaction
๏ต Physical interactions,
๏ต Chemical interactions.
๏ต Biopharmaceutical interactions.
7. Physical interactions
๏ต The physical interactions between the API and excipients do not involve
formation or breakage of chemical bonds in the drug molecular structure. These
interactions however, may lead to changes in the organoleptic properties,
polymorphic forms, crystallization behavior, or drug-release and stability profiles
8. Chemical interactions
๏ต The chemical interactions between the API and excipients involve changes in the
molecular structure of the API. These molecular changes can lead to degradation
of API or formation of new molecules called as โdegradantsโ.
9. Biopharmaceutical interactions.
๏ต These are the interactions which are observed after administration of medicine.
๏ถ The interaction is between the medicine (drug substance and excipients)
and the body fluids
๏ถ The interactions have the tendency to influence the rate of
absorption of the drug.
10. Thermal Techniques used to Detect Drug Excipient
Compatibility
๏ต Differential Thermal Analysis (DTA)
๏ต Differential Scanning Calorimetry (DSC)
11. Differential Scanning Calorimetry (DSC)
๏ต DSC is widely used to investigate and predict any physico chemical interaction
between drug and excipients involving thermal changes.
METHOD
๏ต The preformulation screening of drug-excipient interaction requires (1: 1)
Drug:excipient ratio.
๏ต To maximize the likehood of observing an interaction.
๏ต Mixture should be examined under N2 to eliminate oxidative and pyrrolytic
effects at heating rate on DSC apparatus.
12. Differential Thermal Analysis (DTA)
๏ต In this change in temperature between test sample and reference material is
measured under controlled and identical condition.
๏ต This differential temperature is plotted against time or temperature.
๏ต Interaction can be identified by comparing DTA curve obtained from the test
sample with those of reference material.
If Interaction occurs - Thermogram (DTA curve) of a mixture show appearance or
disappearance of one or more peaks corresponding to those of the component.
If no Interaction occurs- The thermogram of mixtures show same patterns
corresponding to those of the individual components
13. Conclusion
๏ต Excipients can initiate, participate in chemical or physical interactions with an
active substance, possibly leading to compromised quality or performance of the
medication.
