Dissolution

Question 1

Factors affecting drug dissolution

Answer 1

• Physiochemical properties (drug properties)
• Formualtion factors
• Physiological factors

Question 2

Physio chemical Drug properties affecting dissolution

Answer 2

• Surface area
• Particle size (milling micronisation)
• Solubility (salt formation, polymorphism)

Question 3

Formulation Factors affecting dissolution

Answer 3

• Dosage forms

- Excipients (Diluents/Surfactanats/Lubricants/Disintegration)

Question 4

Physiological factors in the GI tract affecting dissolution

these factors are also stimulated in in vivo in vitro correlation

Answer 4

• Ph/ionic composition/buffer capacity

- Agitation, viscosity, fluid volume

Question 5

Sink condition definition

Answer 5

Volume of dissolution medium, with or without a solubiliser, needed to provide complete dissolution of the expected amount of drug present in the product

Question 6

What is in-vevo performance dependent on

Answer 6

• Drug dissolution

- Drug permeation

Question 7

Data required for in vitro dissolution

Answer 7

%drug dissolved and time (min)

Question 8

Data required for in vivo plasma concentartion

Answer 8

% plasma drug concentration and time (hours)

Question 9

In vitro dissolution methods by pharmacopoeia standards

Answer 9

• Water
• Buffers
• Stimulated gastric fluid (0.1M HCL + pepsin)
• Stimulated intestinal fluid (pH 6.8 phosphate buffer + pancreases powder buffer capacity 23mmol)

Question 10

Why are in vivo test carried out

Answer 10

Quality assurance in pharmaceutical production
Stability assurance
Formulation development
Prediction of in vivo performance (via in vivo in vitro correlation)

Question 11

Three levels of IVIVC

Answer 11

1) Point to point relationship between in vitro dissolution rate and in vivo absorption rate
2) Comparison of mean in vitro dissolution time with the mean in vivo resident time
3) Single point relationship between one dissolution parameter (e.g. T50% , % dissolved in 4h and against one pharmaceutical paramater (AUC, Cmax)

Question 12

The four BCS classes

Answer 12

1) High solubility and high permeability
2) Low solubility and low permeability
3) High solubility and low permeability
4) Low solubility and low permeability

Question 13

In vitro dissolution media’ s

Answer 13

USP apparatus 1 (basket apparatus)

USP apparatus 2 (paddle apparatus)