T2 - Drug Stability Calculations

Question 1

Why is drug degradation considered decomposition?

Answer 1

A → B + C

Question 2

What determines the rate of a chemical reaction?

Answer 2

Number of collision between reactions that is dependent on the concentration of reactants, reaction temperature, and presence of catalyst

Question 3

What is the Arrhenius equation?

Answer 3

Used to quantify the rate of a reaction by measuring reactant and product concentrations over time

Question 4

What are variables of the Arrhenius equation?

Answer 4

K(T) is the rate constant at temperature
A is the constant for a reaction
Ea is activation energy
R is the gas constant 8.314 J/k x mol

Question 5

According to Arrhenius equation, what happens if T increases?

Answer 5

Higher T → larger k → increased rate of reaction

Question 6

How is activation energy achieved?

Answer 6

An energy threshold that the reaction molecules must achieve in order to react

Question 7

What determine the stability of drug products?

Answer 7

The maximum anticipated shelf-life that the drug product can maintain the specified strength of the drug under environmental conditions likely to be encountered in actual use

Question 8

What is shelf-life?

Answer 8

The time interval that a drug product is expected to remain within the approve shelf-life provided it was stored under the conditions specified on the product label in the specified containers and closure-system

Question 9

How do we quantify shelf-life?

Answer 9

The time period where 90% of the original strength in the product

Question 10

What happens to a product once shelf-life is reached?

Answer 10

Drug is considered expired, shelf-life is used to determine expiration date of drug products

Question 11

What is the importance of shelf-life studies?

Answer 11

Used to determine how long a drug product can reasonably by expected to maintain its quality, safety, and character

Question 12

What are the test methods of conducting shelf-life studies?

Answer 12

Direct and indirect

Question 13

What is the direct method of testing?

Answer 13

Storing the product under specific conditions for a longer period of time and checking it at regular intervals to see when it degrades

Question 14

What are the 2 indirect methods of shelf-life study?

Answer 14

1. Predictive models development
2. Accelerated shelf-life studies

Question 15

What is predictive models development?

Answer 15

Based on info from databases to calculate shelf-life

Question 16

What is accelerated shelf-life studies?

Answer 16

Performed for 6 months by increasing the rate of degradation by increasing temperature (40C) and relative humidity (75%)

Question 17

What happens if degradation is too significant in accelerated shelf-life studies?

Answer 17

Temperature and relative humidity is reduced (30C and 60%)

Question 18

What is Q10?

Answer 18

The rate of drug/product degradation increases when the temperature is raised by 10C (rule of ten)

Question 19

What is the purpose of Q10?

Answer 19

Allows for the prediction of a drug product’s shelf-life under real-life conditions based on results of testing at high temperatures

Question 20

What is the typical Q10 value of biological conditions?

Answer 20

2-3 (assume 3 if value was not given)

Question 21

How do we calculate Q10?

Answer 21

Question 22

How do we calculate shelf-life?

Answer 22

Question 22

How do we calculate shelf-life?

Answer 22

Question 23

What are the equations associated in calculating zero-order?

Answer 23

Question 24

What are the equations associated in calculating first-order?

Answer 24