25 Questions
What is the primary structure of the human growth hormone (hGH)?
191 amino acids
Which amino acid is the principle site of deamidation in alkaline pH for hGH?
asparagine (asn)
Which amino acid undergoes major oxidative site at methionine residue for hGH?
methionine
Where does deamidated hGH occur inside our bodies?
Pituitary gland in brains
Which technique can counteract hGH aggregation due to hydrophobic interactions when unfolded?
Polysorbate-20
How do sugar and glycine stabilize proteins in liquid state?
By interacting with water
What is the purpose of refrigerating reconstituted hGH?
To prevent concentration-induced aggregation
What is the key step in freeze-drying process to produce proteins in a dry form?
Evaporating water
How can phosphate buffers impact pH during freezing?
By decreasing solubility at lower temperatures
What can low temperature and dehydration during freezing and drying cause to proteins?
Protein degradation
What is the purpose of spray drying in producing inhalable insulin powder?
To turn liquid into powder
What factors impact the dry capacity of gas in spray drying?
Inlet temperature and drying gas humidity
How do high temperature and low humidity affect the drying rate in spray drying?
Increase the drying rate
What is the likely outcome to the residual water content in the powder using a drying gas with high temperature and low humidity at a high aspirator flow?
High
What method can be used to detect aggregation in proteins?
Size Exclusion HPLC
Which spectroscopic method provides insights into aromatic residues, disulfide bonds, and tertiary structures?
Circular dichroism (CD) spectroscopy
Which method separates molecules according to charge?
Isoelectric focusing gel electrophoresis
What does increasing aspirator flow lead to in terms of cyclone efficiency to collect powder?
Increase
What is the likely outcome of decreasing liquid feed rate in terms of drying speed?
Faster drying
What information does Far UV CD (190-240nm) reveal about proteins?
Amide bonds and secondary structures
What does high spray gas flow (atomizing pressure) lead to in terms of powder fineness?
Finer powder
What does a higher solid concentration in liquid lead to after evaporation of the liquid?
Bigger dry particles
What method separates molecules according to size?
Size Exclusion HPLC
What does Fourier transform infrared (FTIR) spectroscopy focus on?
Amide 1 region (1600-170 cm^-1) related to secondary structures
What is the likely outcome of using a drying gas with low humidity for powder drying?
Efficient evaporation of water
Study Notes
Protein Stabilization and Formulation Techniques
- Proteins, including hGH, can aggregate due to hydrophobic interactions when unfolded.
- Zn binding sites and surfactants like polysorbate-20 can counteract hGH aggregation.
- Sugar and glycine stabilize proteins in liquid state by interacting with water.
- Amorphous sugar states can trap proteins, stabilizing the formulation through glass stabilization.
- Reconstituted hGH should be refrigerated to prevent concentration-induced aggregation.
- Freeze-drying involves creating a vacuum, freezing, and evaporating water to produce proteins in a dry form.
- Phosphate buffers can impact pH due to lower solubility at lower temperatures.
- Phosphate buffers can affect the stability of molecules during freezing.
- Low temperature and dehydration during freezing and drying can cause protein degradation.
- Spray drying is a one-step process to turn liquid into powder, used for producing inhalable insulin powder.
- Controlling factors for spray drying include inlet temperature, drying gas humidity, and aspirator air flow.
- High temperature and low humidity increase the dry capacity of gas, increasing liquid evaporation and drying rate.
Test your knowledge of protein stabilization and formulation techniques with this quiz. Learn about methods to prevent protein aggregation, the role of surfactants and sugars in stabilizing proteins, and the processes of freeze-drying and spray drying. Understand the impact of temperature, humidity, and buffers on protein stability and formulation.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
