Biorelevant Experiment

Two Stage Dissolution: FaSSGF→FaSSIF

  • Simulate how a drug product behaves when it contacts the stomach fluid (FaSSGF) and then when it is converted into intestinal fluid (FaSSIF)

  • Results will reveal the drug’s tendency to either supersaturate or precipitate

  • Particularly important for basic drugs with a higher solubility at acidic stomach pH compared to higher intestinal pH

  • Will help you make important formulation development decisions to optimize gastrointestinal absorption of poorly water-soluble drugs in the fasted state

Background

For a drug to be absorbed, it has to dissolve in vivo in intestinal fluids. To investigate drug supersaturation/precipitation, we recommend two different dissolution studies:
 
1) Establish dissolution of the drug product in FaSSIF (Fasted State Simulated Intestinal Fluid) to understand drug dissolution without interference from stomach fluids. 

               

2) Carry out dissolution of the drug product when it first contacts FaSSGF (Fasted State Simulated Gastric Fluid) and then when it is converted into FaSSIF. This is known as 'two stage' biorelevant dissolution. 

The value of these experiments is considerable. After a patient has taken their drug with a glass of water:

                                                                        

1) Drug dissolution starts in gastric fluid   2) Bile juice converts transferred gastric fluid...   3)...into small intestinal fluid. Drug dissolution continues

Biorelevant’s 'two stage' dissolution experiment simulates this in vivo transfer process. It is based on the USP two stage dissolution method but uses in vitro biorelevant media that simulate in vivo fasted state stomach (FaSSGF) and intestinal fluids (FaSSIF):

                                                                                           

1) Drug dissolution starts in 450mL of FaSSGF   2) Adding 450mL of FaSSIF Converter...   3)...transforms it into FaSSIF. Drug dissolution continues 

Which type of drug and formulation is this experiment suitable for?

The FaSSIF dissolution and two stage biorelevant dissolution experiments are particularly useful for poorly water-soluble basic drugs where absorption may be influenced by gastrointestinal drug supersaturation or precipitation. It is suitable for both immediate release and enteric coated formulations. These experiments help you to understand:

  • Intestinal dissolution without the influence of gastric fluids
  • Gastric drug dissolution and stability before and after the transfer process
  • Potential gastrointestinal precipitation or supersaturation behaviour in simulated small intestinal fluid (FaSSIF)
  • Results can reveal supersaturation or crystallisation behaviour within intestinal fluids from which absorption occurs to help monitor magnitude of supersaturation
  • How these properties can influence and improve absorption of your drug

We have produced step-by-step guides to help you conduct drug analysis, filter adsorption, FaSSIF dissolution and two stage biorelevant dissolution which you can download below. These guides will help you standardize your experiments and achieve consistent results.

METHOD

Two Stage Biorelevant Dissolution Drug Analysis Guide

Establish the HPLC analytical setup for a drug product before carrying out FaSSIF and two stage biorelevant dissolutions

FormulationImmediate Release
MediaFaSSGF and FaSSIF
EquipmentUV (DAD or PDA) Detector
AnalysisHPLC
Two Stage Biorelevant Filter Adsorprtion Study Guide

Determine % of drug adsorption and required volume of dissolution sampling before carrying out biorelevant dissolutions

MaterialDrug Substance
MediaFaSSGF and FaSSIF
FilterGMF 13mm 0.45μm
AnalysisHPLC
FaSSIF Dissolution Guide

Carry out dissolution of formulation in fasted state simulated intestinal fluid before two stage biorelevant dissolution

FormulationImmediate Release
MediaFaSSIF
EquipmentUSP II
AnalysisHPLC
Two Stage Biorelevant Dissolution Guide

Simulate the in vivo to in vitro process to observe drug behaviour during the shift from FaSSGF to FaSSIF

FormulationImmediate Release
MediaFaSSGF→FaSSIF
EquipmentUSP II
AnalysisHPLC

MATERIALS

FaSSIF
Medium
FaSSIF
Prandial State
Fasted
Fluid Simulated
Small Intestinal
pH
6.5
FaSSIF

300mL is required of FaSSIF for drug analysis. We recommend running a dissolution test in FaSSIF (900mL/vessel) before the two stage biorelevant dissolution experiment. This is to understand drug dissolution in fasted intestinal fluids without interference from stomach fluids. 

FaSSGF
Medium
FaSSGF
Prandial State
Fasted
Fluid Simulated
Gastric
pH
1.6
FaSSGF

We recommend 300mL of FaSSGF for drug analysis. To simulate fasted state stomach fluid, 450mL of FaSSGF is required per vessel for the two stage biorelevant dissolution experiment. 

FaSSIF Converter (For Two Stage Dissolution)
pH
1.6→6.5
Prandial State
Fasted
Fluid Simulated
Gastric→Small Intestinal
Medium
FaSSIF Converter
FaSSIF Converter (For Two Stage Dissolution)

FaSSIF Converter is used with 3F Powder to transform 450mL of FaSSGF into 900mL of FaSSIF

Biorelevant Dissolution Filters
Material
Glass Microfibre (GMF)
Pore Size
0.45µm
Diameter
13mm
Origin
UK
Features
Minimal drug adsorption
Biorelevant Dissolution Filters

For optimal results, we strongly advise using a fresh filter at each sampling time point to halt the dissolution process. Our boxes of custom-made dissolution filters contain 72 pieces.

RECOMMENDED BUYS

3F Powder
FFF02
70g
Buy 4, Save 20%
$499.99
FaSSIF Buffer
FASBUF
250g
Buy 10, Save 10%
$29.99
FaSSGF Buffer
FASGBUF
250g
Buy 10, Save 10%
$29.99
FaSSIF Converter
FASCONV
280g
$29.99
BRL Disso Filters (13mm)
GMF13
72 pieces
Buy 4, Save 25%
$199.99

We recommend 1 x FFF02, 1 x FASBUF, 1 x FASGBUF, 1 x 2ST-FASBUF and 1 x GMF-13

X
X
X
X
X
3F Powder
FFF02
70g
FaSSIF Buffer
FASBUF
250g
FaSSGF Buffer
FASGBUF
250g
FaSSIF Converter
FASCONV
280g
BRL Disso Filters (13mm)
GMF13
72 pieces
In stock
$499.99
Buy 4, Save 20%
- +
In stock
$29.99
Buy 10, Save 10%
- +
In stock
$29.99
Buy 10, Save 10%
- +
In stock
$29.99
- +
In stock
$199.99
Buy 4, Save 25%
- +

RESULTS

Answer the following questions and the Biorelevant Support Team will help interpret your results by explaining what they mean for the development of your drug product.  

                                                                                                                              

We aim to respond within 5 working days but more complex results can take longer for us to process.