Podcast
Questions and Answers
What is the overall order of a reaction if the individual orders are 2 for A and 3 for B?
What is the overall order of a reaction if the individual orders are 2 for A and 3 for B?
- 3
- 5 (correct)
- 2
- 1
Which of the following statements correctly defines a zero order reaction?
Which of the following statements correctly defines a zero order reaction?
- The rate is independent of the concentrations of the reactants. (correct)
- The rate increases as the concentration of the reactants decreases.
- The rate is directly proportional to the concentration of one reactant.
- The rate depends on the concentration of two reactants.
Which factor does NOT influence the stability of a drug?
Which factor does NOT influence the stability of a drug?
- Temperature
- pH
- Solubility
- Molecular weight (correct)
What is the purpose of determining the half-life of a drug?
What is the purpose of determining the half-life of a drug?
Which of the following describes solvolysis in the context of drug stability?
Which of the following describes solvolysis in the context of drug stability?
What designation is given to the period where 90% of the original drug concentration remains?
What designation is given to the period where 90% of the original drug concentration remains?
Which of the following is an example of an external factor affecting drug stability?
Which of the following is an example of an external factor affecting drug stability?
What is the significance of the sampling plan in stability testing?
What is the significance of the sampling plan in stability testing?
What does a first order reaction indicate about the relationship between reaction rate and reactant concentration?
What does a first order reaction indicate about the relationship between reaction rate and reactant concentration?
Which of the following best describes the term 'half-life' in the context of drug stability?
Which of the following best describes the term 'half-life' in the context of drug stability?
What do inherent factors in drug stability refer to?
What do inherent factors in drug stability refer to?
What is the meaning of shelf life (t90) for a drug?
What is the meaning of shelf life (t90) for a drug?
Which aspect of drug stability is NOT included as an external factor?
Which aspect of drug stability is NOT included as an external factor?
How is overall order of a chemical reaction defined?
How is overall order of a chemical reaction defined?
What is the significance of sampling time points in stability testing?
What is the significance of sampling time points in stability testing?
Which of the following best describes solvolysis related to drug stability?
Which of the following best describes solvolysis related to drug stability?
Flashcards
Law of Mass Action
Law of Mass Action
The rate of a reaction is directly proportional to the molar concentrations of the reactants, each raised to a power equal to the number of molecules involved in the reaction.
Zero Order Reaction
Zero Order Reaction
A reaction where the rate is independent of the concentration of reactants.
First Order Reaction
First Order Reaction
The rate of a reaction is directly proportional to the concentration of one reactant.
Solvolysis
Solvolysis
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Half-life (t½)
Half-life (t½)
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Drug Stability
Drug Stability
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Shelf Life (t90)
Shelf Life (t90)
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Sampling Plan for Stability Testing
Sampling Plan for Stability Testing
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Order of Reaction
Order of Reaction
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Study Notes
Law of Mass Action
- The reaction rate is proportional to the product of reactant concentrations, each raised to a power equal to the number of molecules undergoing reaction.
- Rate ∝ [A]a [B]b
- Rate = k[A]a[B]b
- Reaction order = sum of exponents (a + b)
- Order of A = a, Order of B = b
- Overall order = a + b
Reaction Order Examples
- Zero Order: Reaction rate is independent of reactant concentrations.
- First Order: Reaction rate is directly proportional to the concentration of one reactant.
Drug Stability
- Factors affecting drug stability:
- Inherent factors: Molecular changes due to energy changes & molecular breakdown (solvolysis, oxidation, photolysis, dehydration, racemization).
- External factors: pH, pKa, solubility/dissolution, excipient interactions, temperature.
Drug Stability Measures
- Half-life (t1/2): Time required for one-half of the material to degrade.
- Shelf life (t90): Time for 90% of the drug to remain at the original concentration (expiration dating period).
- The 10% loss criterion is generally based on negligible clinical consequences of such loss
- This is the time period during which a drug product is expected to remain within the approved specification for use, provided it is stored under the conditions defined on the container label.
- The 10% loss criterion is generally based on negligible clinical consequences of such loss
Stability Testing Considerations
- Sampling time points: Testing frequency must be sufficient to establish the stability profile of the new drug substance.
- Sampling plan: Sampling plan for stability testing involves planning for the number of samples to be charged to the stability chambers and sampling from the charged batch to cover the entire study.
- Test parameters: Stability test protocol should define the test parameters to evaluate stability samples. Chosen tests monitor quality, purity, potency, and identity which could be expected to change upon storage.
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Description
This quiz covers the Law of Mass Action and the concepts of reaction order as well as factors influencing drug stability. Explore the different order reactions and how various internal and external factors can affect the stability of pharmaceuticals. Test your understanding of these important scientific principles.
