API and dissolution

Question 1

By increasing surface area, dissolution is reduced. True or false?

Answer 1

False - increasing surface area increases dissolution

Question 2

What factors affect dissolution (Noyes-Whitney equation)?

Answer 2

Surface area
Diffusion coefficient 
Thickness of diffusion layer
Saturation conc in diffusion layer 
Concentration in GI fluid

Question 3

Lubricants increase dissolution rates. True or false?

Answer 3

False

Question 4

What are the 3 equipments that are approved by the BP and EP for intrinsic dissolution rate measurements?

Answer 4

Basket
Paddle
Flow through cell

Question 5

Paddle apparatus has a faster rotation rate than basket. True or false?

Answer 5

False - slower

Question 6

What are the experimental conditions for IDR measurements, as stated in BP?

Answer 6

Pre-formulation is determined in 0.1M HCl, 0.1M NaOH and water
UV-spec is the analytical method of choice
Solubility is measured at fridge temp (4), room temp (25) and body temp (37)

Question 7

Which equation governs dissolution?

Answer 7

Noyes-Whitney equation