In Vivo Predictive Dissolution – Flux

Measurements

Konstantin Tsinman, PhD

Chief Scientific Officer

Pion Inc

ktsinman@pion-inc.com

What do we mean by IVIVC?

FDA2:IVIVC is a predictive mathematical model describing the

relationship between an in vitro property of a dosage

form and a relevant in vivo response.

USP1:The establishment of a rational relationship between a

biological property, or a parameter derived from a

biological property produced by a dosage form, and a

physicochemical property or characteristic of the same

dosage form.

1. United States Pharmacopoeia. In vitro and In vivo Evaluations of Dosage Forms,

27th edition, Revision, Mack Publishing Co., Easton, PA., 2004.

2. Guidance for industry, extended release oral dosage forms: development,

evaluation and application of an in vitro/in vivo correlation. FDA, CDER, 1997.

FDA2:IVIVC is a predictive mathematical model describing the

relationship between an in vitro property of a dosage

form and a relevant in vivo response.

In Vitro

Property

Math.

Model

In Vivo

Response

In Vitro

Property

In Vivo

Response

The Holy Grail of in vitro assay

≈

What is Our Goal?

Chasing the Perfect Model

“Plumbing” Man“Real” Man

Small intestine of

“Absolutely

Cylindrical Man”

Looking for a Robust Predictive Model

Stomach of

“Absolutely

Cylindrical Man”

“Real” Man “Absolutely Cylindrical” Man

Absorption is related to

mass transport

of drug compound from GIT

through membranes

t

ABS dAdttimelocationGITJMass ),(

Fluxis a measure of transport:

the net number of moles of particles

crossing unit area per unit time

perpendicular to unit area

)(1

tcPdt

dc

A

V

dt

dM

AJFlux De

AA

Definition Fick’s First Law

pH

Permeability

Suppressed

Solubility

Enhanced

Flux

Unchanged

Permeability, Solubility –Excipients

Classification Gradient Map

Collaborative Effort of Pion and H. La RocheAvdeef et al. Eur J Pharm Sci. 2008;33(1):29–41; Avdeef et al. Pharm. Res., 2007, 24, 530-545;

Bendels et al. Pharm. Res. 2006, 23, 2525-2535.

pH

Permeability

Suppressed

Solubility

Enhanced

Flux

Enhanced

Permeability, Solubility –Excipients

Classification Gradient Map

Collaborative Effort of Pion and H. La RocheAvdeef et al. Eur J Pharm Sci. 2008;33(1):29–41; Avdeef et al. Pharm. Res., 2007, 24, 530-545;

Bendels et al. Pharm. Res. 2006, 23, 2525-2535.

Why Dissolution Study May Not Predict

In Vivo Data?

M. Kataoka, et al., Pharm. Res., 2012, 29, 1485-1494

Flux Studies using µFLUX™ Setup

)()( tcPdtA

dmtJFlux De

Combining benefits of in situ concentration monitoring

with parallel dissolution-permeability setup

Fiber Optic Probes

Donor

CompartmentSGF->FaSSIF

transitionReceiver

Compartment

Sink buffer

pH 7.4

Separating

Membrane

Pion GIT-PAMPA

Dissolution/Flux in FaSSIF

Research Compound

SGF – FaSSIF transformation

after 30 min of the assay

Winner formulation

performed best in dog model

Andy Z. X. Zhu, et. al. Utilizing In Vitro Dissolution-Permeation Chamber for the Quantitative

Prediction of pH-Dependent Drug-Drug Interactions with Acid-Reducing Agents: a Comparison with

Physiologically Based Pharmacokinetic Modeling AAPS J., 2016, DOI: 10.1208/s12248-016-9972-4

Risk Assessment of pH Modifying DrugsSmall Volume Flux Measurements

1. Stewart AM et al. Development of a Biorelevant, Material-Sparing Membrane Flux Test for Rapid

Screening of Bioavailability-Enhancing Drug Product Formulations. Mol Pharm [Internet]. 2017

Jun 5;14(6):2032–46.

2. Stewart AM, et al. Impact of Drug-Rich Colloids of Itraconazole and HPMCAS on Membrane Flux in

Vitro and Oral Bioavailability in Rats. Mol Pharm [Internet]. 2017 Jul 3;14(7):2437–49.

Rela

tive M

ax A

bs

Rate

In V

ivo

Relative Flux In Vitro Fed Conditions

“Vessel-in-Vessel” Flux Setup

Relating Flux Increase In Vivo

Absorption Rate

Itraconazole

Bend Research (Lonza)

Formulations of Itraconazole1

1Tsinman et al. Ranking Itraconazole Formulations Based on the Flux through Artificial

Lipophilic Membrane. Pharm Res. 2018;35(8).

µFLUX Results (in vitro) Correlation with Rat PK data

(in vivo)

Dose Number

)()/(

)(0

mLVmLmgS

mgDoseD

GITGIT

Dissolution Number

Permeability Number

Can Flux Data Predict Absorption?

1(min ) (min)n Diss tranD k t

1(min ) (min)n Perm tranP k t

nn

a

P

D

D

F01

1exp1

Sugano K. Biopharmaceutics Modelling and Simulation. Wiley & Sons. 2012

Permeability Number

How to Capture Biorelevance for Absorption Numbers

1(min ) (min); GITn Perm tran Perm eff

GIT

AP k t k P

V

For Biorelevance

either

( ) ( )Perm Permk in vitro k in vivo

or

( ) ( )

( )

eff eff

GIT

GIT

P in vitro P in vivo

Ain vivo isused

V

How Biorelevant is Double-Sink™ PAMPA?

Avdeef et al. J Pharm Sci. 2007 96(11):2893-909.

The same membrane is used in FLUX Measurements!

For HJ Permeability

absorption rate was

measured and the

cylindrical model

was applied, i.e.𝐴𝐺𝐼𝑇𝑉𝐺𝐼𝑇

≈2

𝑅𝑆𝐼

Solubility/Permeability in FormulationDevelopability Classification System (DCS)

J. Buttler, J. Dressman. The Developability Classification System: Application of Biopharmaceutics

Concepts to Formulation Development. J. Pharm. Sci., Vol. 99, 4940–4954 (2010)

SPJFlux e Solubility Limited Cases:

DCS and Flux

)min(102.1

)(500

)()/(10

215

3

4

cmmgDose

cm

mgDosescmSPJ e

What Flux value should be a target to be Class 1 of DCS?

Assumptions:

Permeability through PAMPA membrane represents human jejunum permeability;

Flux does not change (no supersaturation/precipitation phenomenon)

Example:

Q. Projected Dose is 200 mg. What flux should we target by

changing formulations?

A. J = 1.2*200*10-5 = 2.4*10-3 mg/(min cm2) = 2.4 µg/(min cm2)

Projected Dose and Flux

Assumptions:

Permeability through PAMPA membrane represents human jejunum permeability;

Flux does not change (no supersaturation/precipitation phenomenon)

What is the Dose limit to stay DCS Class 1 for a

particular Flux value

)(103.8 4 mgJDose

Example:

Q. The measured flux for my formulation is 0.1 µg/(min cm2). What

dose would still be classified as DCS Class 1?

A. D0 = 8.3*104*0.1*10-3 = 8.3 (mg)

Estimation of the Fraction Absorbed

Solubility-Permeability Limiting Cases

0

( )SItransit

n SIa

Dose

SI

AJ T

P VF

mDV

For the Case of Absolutely Cylindrical Man

2 2; ( ) / 250( )

1.5( )SI Dose

SI SISI

A mDose mg mL

V VR cm

%43%100*4.0

21033.100045.0(max)

aF

%6.2%100*4.0

21033.1000032.0(min)

aF

Formulations of Itraconazole1

1Tsinman et al. Ranking Itraconazole Formulations Based on the Flux through Artificial

Lipophilic Membrane. Pharm Res. 2018;35(8).

Maximum and Minimum Absorbable Dose Supersaturating-Precipitating Formulations

Supersaturating

Formulation

Initial Flux

Late Flux

t

lateABS

t

initABS

dAdtJkM

dAdtJkM

min

max

FLUX

Donor Chamber Receiver Chamber

MacroFLUX to Study Final Dosage Forms

USP compatible Vessel

250 mL – 900 mL

FO Probe connected

to Rainbow

instrument

Absorption Chamber

FO Probe connected

to Rainbow

instrument

Overhead

stirrer

Separating lipophilic

membrane

BioFLUX

Bioequivalence Study for Generics

Brand and Generic Formulations of Telmisartan

N

N

N

N

OH

O

CH3

CH3

CH3

Borbás E, et al. The effect of formulation additives on in vitro dissolution-absorption profile and in vivo

bioavailability of telmisartan from brand and generic formulations. Eur J Pharm Sci. 2018;114(1):310–7.

Formulations Ingredients

LactoseSorbitol Mannitol

Predicting Risks in Bioequivalence Studies

“Normal” SGF → FaSSIFpH 1.6 – pH 6.5

pH 1.6 – pH 6.5

Type-I

“Alkalized” SGF →FaSSIF pH 4.0 – pH 6.5

pH 4.0 – pH 6.5

Type-II

Drug-Drug Interaction (Drug Products)

pH Modifying Agents

Li et al. Using pH Gradient Dissolution with In-Situ Flux Measurement to Evaluate Bioavailability and DDI for Formulated Poorly Soluble Drug Products. AAPS PharmSciTech (in publication)

Pang J, Dalziel G, Dean B, Ware JA, Salphati L. Mol Pharm. 2013;10(11):4024–31.

GDC-09411, BCS Class IIbStrong DDI Expected in Clinical Studies

• >90% reduction in flux and absorbed amount

in vitro

• ~80% reduction in AUC due to DDI of ARA in

dog PK studies

Compound C (BCS Class IIb)Product Formulated to Minimize DDI from ARA

Food Effect

To eat or not to eat…

Commercial Itraconazole Formulations

BioFLUX 250 mL

FaSSIF

FeSSIF

Brouwers J, Geboers S, Mols R, Tack J, Augustijns P. Int J Pharm. 2017;525(1):211–7.

In Vitro – In Vivo

In Vivo:Positive Food Effect for Capsules

Slight Negative for Solution

Positive

Negative

Conclusions

•Flux assays allow investigation of complex formulations and

building realistic PK predictions

•Introduction of absorption chamber into dissolution setup can

lead to more biorelevant dissolution studies

•It was demonstrated that relatively simple and robust flux

measurements can provide great in vitro tool capable of

capturing major factors related to absorption thus leading to

realistic IVIVC

•Complication of the in vitro model does not necessary mean

that better IVIVC can be achieved

Select Your “Man” Wisely

For Biorelevance Study

Acknowledgements

Oksana Tsinman

Bálint Sinko

Enikó Borbas

Zsombor K. Nagy

Larry Wigman

Jane Li

Bernd Riebesehl

Michael Juhnke

Arnaud Grandeury

Bernard Van Eerdenbrugh

Saijie Zhu

Thank You!

Konstantin Tsinman, Ph.D.

Chief Scientific Officer

Pion Inc.

ktsinman@pion-inc.com