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ASSESSING THE DRUG RELEASE FROM NANOFORMULATIONS – WHEN, WHY AND HOW?

Matthias G. Wacker, PhD

matthias.wacker@ime.fraunhofer.de

Pharma Test Workshop Series 2016

NANOTECHNOLOGY IN THE PHARMACEUTICAL

INDUSTRY

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DRUG RELEASE FROM NANOFORMULATIONS

• Dissolution rate increases with surface area (Noyes-Whitney)

• Rising saturation solubility for small particles occurs (Ostwald ripening)

• Nanocrystals are synthesized to achieve high dissolution pressure

• “Burst release“ is a common problem of nanocarrier technology

Surface area

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DRUG RELEASE TESTING

• Quality control

Testing dosage forms in a standardized setup

Detecting different formulation qualities from batch to batch

• Biorelevant release testing

Discriminating between different formulations

Simulating physiological environment

Predicting the in vivo performance of dosage forms (IVIVC)

• In vitro digestion testing of nanomaterials

Investigating material degradation in biorelevant medium

Simulating physiological environment

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QUALITY CONTROL

• Discriminating between batch qualities in a low-cost procedure

with simple medium composition

• Detect changes in manufacturing process, excipients or stability issues

• Short release interval and automated setup where possible

Source: Pharmatest Apparatebau GmbH

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BIORELEVANT RELEASE TESTING

• Simulate physiological environment, e.g. by using biorelevant media

containing physiological dissolution enhancers (proteins, bile salts)

• Simulate effects that were be observed in vivo (e.g. gastric emptying)

• Predict in vivo data based on in vitro experiments

Source: Pharmatest Apparatebau GmbH; AGW

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IN VITRO DIGESTION MODELS

Confirming particle size properties to characterize nanomaterials after

exposure to biorelevant media

Detect particle dissolution, aggregation or degradation in biorelevant media

Comply with EU and US guidelines

Particle size

Dynamic light scattering

Powder diffration

Electron microscopy

AFM

TEM

SEM Analytical

ultracentrifugation

Field flow fractionation

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DRUG RELEASE MEDIA

• Quality control

Aqueous buffer media

Surfactants and other excipients to support dissolution process

• Biorelevant release testing

Physiological fluids (e.g. blood, plasma, intestinal fluids)

Simulated physiological fluids

• In vitro digestion models

Physiological fluids optimized to monitor degradation

Enzymes and proteins

Optimized to allow size measurement from medium

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DRUG RELEASE MEDIA FOR NANOFORMULATIONS

Medium Setup for drug release Reference

Human plasma Non-compendial flow-through cell setup (Gido, Langguth et al. 1993;

Gido, Langguth et al. 1994)

HEPES buffer 7.4

Dialysis bag (USP2)

Reverse dialysis bag (USP2)

Flow-through cell(USP4) with A4D adapter

(Bhardwaj and Burgess 2010)

Phosphate buffer saline 7.4 Modified basket (USP1) (Abdel-Mottaleb and

Lamprecht 2011)

Phosphate buffer 7.4 supplemented

with fetal calf serum (10-90%) Dispersion releaser (USP2) (Janas, Dressman et al. 2013)

Phosphate buffer 7.4 supplemented

with fetal calf serum (50%) Dispersion releaser (USP2) (Villa Nova, Janas et al.)

FaSSGF / FaSSIF / FaSSIF V2

FeSSGF / FeSSIF / FeSSIF V2 USP apparatus 2 with syringe filters

(Juenemann, Jantratid et al.

2010)

FaSSIF V2 USP apparatus 2 with syringe filters (Beyer, Moosmann et al.

2015)

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METHODOLOGY FOR DRUG RELEASE TESTING

• Nanoformulations require optimized separation technology

• Methods must discriminate between nanoparticles and dispersed drug

molecules

• Careful sampling is required to detect drug release without disrupting

formulation structure

Methodology for drug release testing includes

Sample and separate

Dialysis

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SAMPLE AND SEPARATE

• Separation techniques such as mechanical filtration or solid phase

extraction are applied

• Both methods may affect stability of the carrier

• Accurate selection of filter pore size, SPE or filter material and medium

Disruption

Separation (Cut-off)

Adsorption

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SAMPLE AND SEPARATE

Mechanical filtration devices

• Careful selection of filter membrane

and pore size required

• Not applicable to sensitive formulations

such as micelles, liposomes, emulsions

• Relevant for solubility-driven release

• Applicable to many peroral IR

nanocrystal formulations

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SAMPLE AND SEPARATE

• Biorelevant release test of microsized fenofibrate by applying sample and

separate with syringe filters of different pore sizes

• Microparticle are well-separated by different filter pore sizes

Source: Juenemann et al. 2011, Eur. J. Pharm. Biopharm.

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SAMPLE AND SEPARATE

• Release samples collected with nanoparticles from FaSSIF

• Only one filter reflects equilibrium solubility of fenofibrate over 24 h

Source: Juenemann et al. 2011, Eur. J. Pharm. Biopharm.

Filte

r pore

siz

e

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SAMPLE AND SEPARATE

• Solid particle formulation of poorly soluble compound TMP001 (logP=10,417)

• Microparticle formulation and nanoparticle formulation

○ Free drug

■ Nanoformulation

● Microformulation

Setup USP2/syringe filter 0.1 µm

pH 6.8

Medium FaSSIF V2

Source: Beyer et al. 2015, Pharm Res

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SAMPLE AND SEPARATE

Solid phase extraction

• Affinity-based separation technique

• SPE column must have poor affinity to

formulation excipients

• Applicable to some core-loaded liposome

formulations

• Requires careful validation to separate

excipient and API by affinity

Source: Guillnot et al. 2015, Pharm Res

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DIALYSIS

• Separation by dialysis in combination with the compendial equipment

such as USP apparatus 2 (paddle) or USP apparatus 4 (flow-through cell)

• Sensitive when k1 << k2

• k2 is higher for compounds with moderate or good solubility

k1 k2

Source: Ashtikar et al. 2016, J Pharm Pharmacol (In preparation)

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DIALYSIS

• Evaluating different membranes in a continously

monitored dialysis setup (optimal data collection)

• Membrane transport for one compound

comparing CE and RC membranes

• Calculation of k2 from the release profile

Source: Xie et al. 2015; Int J Pharm

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DIALYSIS

• Same pore size but different

membrane materials

• Sensitivity of measurement with

cellulose ester (CE) is much higher

than with RC (regenerated cellulose)

• Pore size and membrane material are

essential

Source: Xie et al. 2015; Int J Pharm

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DIALYSIS

• Membrane transport k2 needs to quick when release rate is high

• Comparing dialysis techniques needs to be done with fast and slow-releasing

drug delivery systems

Source: Xie et al. 2015; Int J Pharm

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DIALYSIS

Dialysis bag

• Dialysis membrane closed by two

clamps

• Poor membrane penetration

and partitioning

• High variability at high dissolution rates

• Works well for slow-releasing dosage forms or

drugs with moderate or good solubility

Source: Ashtikar et al. 2016 (In preparation)

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DIALYSIS

Flow-through cell

• USP4 allows release testing in

open-loop and closed loop systems

• Sotax offers the A4D adapter for

nanoformulations

• High cell-to-cell variability in flow rate

when used at a pumping rates of

below 1 mL/min

• Works well for API with moderate or

good solubility and/or high flow rate (low k2)

• No evaporation in open-loop configuration

Source: Ashtikar et al. 2016 (In preparation); European Pharmacopeia; www.sotax.com

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DIALYSIS

• Investigation of Dexamethasone liposomes in different systems compared to

A4D

• Sink conditions were applied

• Reduced sensitivity especially when release rate is high

Source: Bhardwaj et al. 2010, Int J Pharm

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DIALYSIS

Dispersion releaser

• USP2 is a robust standard setup

used for quality control of IR

formulations

• Pharma Test offers the “dispersion

releaser”

• High sensitivity for fluctuations in

release rate

• Works well for compounds with poor,

moderate and good solubility (high k2)

• Evaporation occurs in long-term

experiments

Source: Ashtikar et al. 2016 (In preparation); Janas and Wacker 2013, DE102013015522.3

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DIALYSIS

• Parenteral polymeric micelle formulation of poorly soluble API (logP=9,57)

• Batch-to-batch reproducibility in quality control

• Formulation highly sensitive to shear forces

○ Batch 1

● Batch 2

Setup USP2/dispersion releaser

pH 7.4

Medium phosphate buffer saline

foetal calf serum 10%

Source: Villa Nova et al. 2015, Int J Pharm

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DIALYSIS

• Dialysis bag vs. dispersion releaser tested with free compound assuring sink

conditions

• Solid particle formulation with sustained release properties

● Free drug, dispersion releaser

● Free drug, dialysis bag

●/○ SR formulation 1 /2

Setup USP2 / dialysis bag or

dispersion releaser

pH 7.2

Medium phosphate buffer saline

10% FCS

Source: Janas et al. 2016 (In preparation)

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DIALYSIS

• Sampling from inner compartment during dialysis-based release test

• Particle aggregation and dissolution effects after administration

• Biorelevant media specifically designed to monitor degradation but to allow

size measurement

Source: Modified from Janas et al. 2013, AAPS Annual Meeting & Exposition

F1-4 0h 24 h

Water Medium 1-2 Medium 1-2

200 nm200 nm

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SUMMARY

Nanoformulations have high dissolution pressure compared to other

formulations

Release rate can be quantified by sample and separate or dialysis

Sample and separate approaches require careful sampling to avoid shear

forces and “forced extraction“

Dialysis requires additional care in membrane selection and needs to be

optimized to increase membrane transport

Biorelevant release testing can also be employed for nanomaterial testing to

comply with EU guidelines

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NANOMETRX

NanoMetrX is a Fraunhofer IME project setting up methodology for testing

nanomaterials, e.g.

Analytical technology identifying nanomaterials

Analytical technology identifying degradation and dissolution behavior

Analytical technology identifying routes of release

Open platform is provided to all manufacturers

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Analytical technologies provided on a „fee-for-service“ basis

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Join the collaboration and support NanoMetrX financially and with your

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Use our methodology for your products free of charge

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ACKNOWLEDGEMENTS

Dr. Mukul Ashtikar Prof. Dr. Jennifer Dressman

Dr. Bassam Al Meslmani Prof. Dr. Marcos Bruschi

Susanne Beyer Prof. Dr. Michael Parnham

Monica Villa Nova

Christine Janas

Aline Moosmann

Xie Li

Laura Jablonka

Manuela Thurn