Drug Stability Flashcards
(42 cards)
What is accelerated stability testing?
Accelerated stability testing involves subjecting a product to conditions that simulate time over a shorter period to assess its stability and estimate shelf life.
This testing is done under more severe conditions like high temperature and humidity to speed up the degradation process.
Why is accelerated stability testing important?
It helps in quickly identifying potential issues with a product before it goes to market and is essential for ensuring product quality and safety.
This is particularly crucial in industries where stability is vital.
Define amorphous solids.
Amorphous solids lack a defined shape and arrangement of particles, offering increased solubility and bioavailability compared to crystalline forms.
These solids have a disordered molecular structure.
What advantages do amorphous solids have in drug formulations?
Amorphous solids enhance dissolution rate and absorption in the body, leading to faster dissolution and higher drug concentrations in the blood.
Their increased surface area compared to crystalline solids contributes to these effects.
What is a key characteristic of amorphous solids?
Amorphous solids are thermodynamically unstable and tend to convert to more stable crystalline forms over time.
What does the Arrhenius equation describe?
The Arrhenius equation describes the relationship between temperature and reaction rates, stating that for every 10°C increase, the rate of reaction approximately doubles.
It is often used to calculate rate constants in chemical reactions.
What does the Arrhenius equation help predict?
It helps predict how environmental changes, like temperature, can impact reaction rates.
True or False: The Arrhenius equation assumes a linear relationship between temperature and reaction rate constant.
True
Fill in the blank: Amorphous forms are commonly used in drug formulations to improve _______.
[drug delivery and therapeutic effectiveness]
What does the Bronsted-Bjerrum Equation describe?
The relationship between pH, pKa, and the ratio of ionized to unionized drug molecules in solution
The equation helps in predicting drug ionization at different pH values.
How is the Bronsted-Bjerrum Equation expressed?
pH = pKa + log A-1/[HA]
This equation is fundamental for understanding drug behavior in different environments.
What is the significance of the Bronsted-Bjerrum Equation in pharmacology?
It helps in understanding drug absorption, distribution, and elimination
Knowledge of this equation can aid in optimizing drug formulations for desired pharmacokinetic properties.
Define chemical stability.
The ability of a substance to maintain its chemical composition under various environmental conditions
Factors affecting stability include exposure to light, heat, humidity, and pH.
What are common causes of chemical degradation?
- Oxidation
- Hydrolysis
- Photolysis
These processes can significantly affect the stability of chemical substances.
How can chemical stability be enhanced?
By using antioxidants to prevent oxidation
Additionally, storing substances in a cool, dry place can help maintain their stability.
What are crystalline solids?
Substances with an ordered arrangement of atoms or molecules, displaying a repeating pattern in their crystal lattice structure
They have sharp melting points due to their organized structure.
What effect do different crystalline forms have?
They can exhibit varying solubility and bioavailability
This is crucial for the effectiveness of pharmaceutical compounds.
What method is commonly used to determine the crystalline structure?
X-ray diffraction
This technique provides detailed information about the crystal lattice arrangement.
How do impurities or defects in the crystal lattice affect crystalline solids?
They can affect the physical and chemical properties of crystalline solids
This highlights the importance of purity in drug formulation.
What is the dielectric constant?
A measure of a solvent’s ability to decrease the electric field strength, indicating a solvent’s polarity
It is crucial for predicting solubility and stability of drugs.
How does the dielectric constant relate to ionic compounds?
A higher dielectric constant generally indicates better solvent ability to dissolve ionic compounds
This is important for formulating effective drug delivery systems.
What can affect the dielectric constant of a solvent system?
Temperature and pressure
Variations can impact drug solubility and overall formulation effectiveness.
How is the dielectric constant used in drug delivery systems?
To optimize drug solubility
Understanding dielectric properties helps in the formulation of effective drug delivery systems.
What is drug stability?
The ability of a drug to retain its chemical composition and effectiveness over a specific period
Influenced by factors like temperature, light, and moisture.
