matthias g. wacker, phd

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HOW TO DESIGN NANOCARRIERS FOR DRUG DELIVERY?

Matthias G. Wacker, PhD

[email protected]

Pharma Test Workshop Series 2016

NANOTECHNOLOGY IN THE PHARMACEUTICAL

INDUSTRY

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NANOTECHNOLOGY FOR THE MARKET

• Enhancing solubility of poorly soluble compounds

• Administer high doses of API in a liquid dosage form (e.g. tox studies)

• Target API to a specific site of action (e.g. Doxil®)

Source: Cumming et al. 2013, Nature Reviews Drug Discovery; www.accademia.org

I‘m more

soluble

than you!

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• Nanocrystal formulations are produced by milling, HPH or nanoprecipitation

• Bioavailability of compounds from BCS classes II and IV (e.g Tricor®) is

enhanced, signficantly

• Immediate release is desirable for most nanocrystal formulations

100 nm

500 nm

2 µm

5 µm

Source: Liversidge and Liversidge 2011, Adv Drug Del Rev

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Formulation

name

Technology Compound BCS class

Rapamune® NanoCrystal®

(Elan Drug Technologies)

Sirolimus II

Emend® NanoCrystal®


Aprepitant IV

TriCor® NanoCrystal®


Fenofibrate II

Megace®ES NanoCrystal®


Megestrolacetat

e

IV

TriglideTM DissoCubeTM

(SkyePharma)

Fenofibrate II

Source: Modified from Wacker 2016, Springer Books

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• Nanocarriers are applied to transport API to their target

• Encapsulation of compounds into a (protective) shell

with sustained release properties

• Distribution and interaction with physiological environment

is controlled by excipients

A B

Source: Wacker et al. 2016, Beilstein J Nanotechnol

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• Release rate affects drug distribution profile of nanocarriers

• Sustained release is required to fulfill the drug delivery paradigm

Kidney

(Compartment 2)

Blood plasma

(Compartment 1)

Lungs

(Compartment 4)

Liver

(Compartment 3)

kel

…

Carrier Free drug

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Formulation name Technology Compound Type

Abraxane® Nanoparticles Paclitaxel Parenteral nanocarrier

Ambisome® Liposomes Amphothericin B Parenteral nanocarrier

DaunoXome® Liposomes Daunorubicin Parenteral nanocarrier

Depocyt® Liposomes Cytarabin Parenteral nanocarrier

DepoDUR® Liposomes Morphoine Parenteral nanocarrier

Doxil® / Caelix® PEGylated Liposomes Doxorubicin Parenteral nanocarrier

Source: Modified from Wacker 2016, Springer Books

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WHY DO NANOMEDICINES FAIL?

• Complexity of drug delivery approaches is beyond the reality of GMP

production (e.g. method transfer and scale-up)

• Translation of existing knowledge into defined product characteristics

(e.g. particle size distribution)

• Maintaining pharmaceutical quality in small and large-scale production

(e.g. in vitro tools for formulation development and quality control)

• “Trial and error“ development instead of rational formulation design

(No predictive models for the in vivo performance)

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RATIONAL FORMULATION DESIGN

Source: Wacker 2013, Int J Pharm

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CASE STUDY 1: FROM SMALL SCALE TO MEDIUM SCALE

• Perorally administered drug formulation of

mTHPC

• Optimizing formulation design and transfer

to GMP compliant manufacturing technology

• Low systemic availability but high intracellular

activity

Source: www.biolitec.com

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CASE STUDY 1: FROM SMALL SCALE TO MEDIUM SCALE

• Nanocarriers demonstrating

mucoadhesion and penetration

through the mucus layer in the

colon

• Size-controlled targeting mechanism

by epithelial enhanced

permeability and retention (eEPR)

• Demonstrating sustained release

and uptake into cancer cells

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FORMULATION DESIGN

• Define specifications with major impact on therapeutic aim

• Set up analytical methods to support early formulation development

• Choose an initial formulation design (process technology and composition)

reflecting technical and therapeutical needs

Nanoparticle formulation

Nanocarriers

Active drug targeting

Drug load / Release rate

Particle size/ shape

Specific surface design

Passive drug targeting

Drug load/ Release rate


Surface charge/

Hydrophilicity

Nanocrystals

Particle size Release rate

Source: Modified from Wacker MG 2015, Springer Books

Nanoparticle formulation

Nanocarriers

Active drug targeting

Drug load / Release rate


Specific surface design

Passive drug targeting

Drug load/ Release rate


Surface charge/

Hydrophilicity

Nanocrystals

Particle size Release rate

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FORMULATION DESIGN

• Drug load and encapsulation efficiency

dose 0.15 mg/kg

non-critical parameter

• Particle size and size distribution

more than 95% within 50 - 200 nm

• Net charge

> + 30 mV

• Release rate and profile

< 20% over 5 h

Release

rate

Particle

size

Drug

load

Net

charge

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FORMULATION DESIGN

• Organic solution of drug and polymer (Eudragit® RS 100)

• Addition of non-solvent and stabilizer under defined conditions

• Precipitation of drug-loaded nanoparticles

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FORMULATION DESIGN

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FORMULATION DESIGN

• Identify most important formulation and process parameters

• Monitor the impact of process parameters on nanocarrier formulation

• Optimize process for intended manufacturing and analytical procedures

Polymer concentration

Flow rate Type of solvent

Small scale

[mg/h] Medium scale

[g/h]

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FORMULATION DESIGN

Source: Beyer et al. 2015a, Pharm Res

• Optimizing formulation design for all of the three defined parameters

• Implementing DoE to study synergies between polymer concentration and

flow rate

Solvent 1 Solvent 2

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FORMULATION DESIGN

• Validation of analytical technology required before process optimization

• Combinations of different techniques are mandatory for determining particle

size


Solvent 2

Solvent 1

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FORMULATION DESIGN

• Current regulations for food, cosmetics and medical devices reflect this

analytical problem

• Two different methods that are based on two different principles

• At least one method based on electron microscopy

Particle size

Dynamic light scattering

Powder diffration

Electron microscopy

AFM

TEM

SEM Analytical

ultracentrifugation

Field flow fractionation

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IN VITRO SELECTION

• Many nanocarrier devices fail to cross the mucus barrier before

being taken up by cells

• Ussing chamber experiment with a mucin-producing T84 cell layer confirms

penetration depth and uptake

Source: Beyer et al. 2015b, Pharm Res

Donor Acceptor

+

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IN VITRO SELECTION

• Fluoresence activated cell-sorting (FACS) demonstrated quantitative

accumulation of the nanocarriers

• Method is showing association

but not the uptake into the cells

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IN VITRO SELECTION

• Polymeric particles have to enter

the cytosol before releasing the

API

• Uptake of nanocarriers into the

cells will be essential for the

therapeutic approach

Source: Beyer et al. 2015b, Pharm Res

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IN VITRO SELECTION

• No standard procedure to assess

the drug release from polymer nanoparticles

• Biorelevant release testing makes it more

difficult due to colloidal excipients

• Dialysis is applied when systems are sensitive to

shearing forces

Source: Al Meslmani et al. 2015 (In preparation), J Pharm Pharmacol

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IN VITRO SELECTION

• Drug release of mTHPC was studied by online measurement under sink

conditions in a dialysis setup

• Membrane kinetics is a factor to consider for dialysis processes

Source: Xie et al. 2015, Int J Pharm

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IN VITRO SELECTION

• Biorelevant dissolution testing is more predictive for in vivo performance

• Sample and separate method for nanocrystals was applied to nanocarriers

• Sustained release was confirmed for nanoformulation 2

Source: Modified from Al Meslmani et al. 2015 (In preparation), J Pharm Pharmacol; Beyer et al. 2015b, Pharm Res

○ Pure drug ● Microformulation

■ Nanoformulation 1 □ Nanoformulation 2

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IN VITRO SELECTION

• Low dark toxicity of the formulation design

• High efficacy after uptake into cancer cells and illumination

(photosensitizer therapy)


mTHPC

No mTHPC

Purified nanocarriers

Non-purified nanocarriers

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INDUSTRIAL MANUFACTURE

• Transfer to medium-scale process with initial formulation parameters

obtained from DoE screening

• Manufacture in a continous-flow process

• Confirming product characteristics by TEM/SEM and DLS

Source: Beyer et al. 2015, Pharm Res

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INDUSTRIAL MANUFACTURE

• Transfer to GMP facilities of a pharmaceutical

manufacturer

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CASE STUDY 2: IN VITRO SELECTION OF BLOCK-CO-POLYMERS

• Synthesis of new blockcopolymers

• Developing polymeric formulations of model compound Dexamathasone

• Screening and selection of polymeric micelle formulations by using an

optimized set of in vitro tools

• Finding tendencies in the drug binding behavior of polymeric micelles

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FORMULATION DESIGN

• Synthesis of blockcopolymers by using a hydrophilic PEG chain and various

lipophilic side chains

• Determining composition by NMR analysis

Polyethyleneglycol

Buthylmethacrylate (BuMA)

Benzylmethacrylate (BzMA)

Acrylamidobenzylacrylate (AAmBzA)

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IN VITRO SELECTION

• Determination of plasma halflife via fluorescence resonance

energy transfer (FRET) assay

• Determination of CMC

Polymer CMC [mg/L] Plasma t1/2 [h[

BP001 0,43 23,1

BP002 0,36 11,6

BP003 0,25 11,6

BP004 0,93 28,9

BP005 0,53 14,4

BP006 0,69 16,5

BP007 0,55 -

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FORMULATION DESIGN

• Optimizing preparation process for nanocarrier formulations

• Loading Dexamethasone to blockcopolymers by using solvent

evaporation method

• Characterization by DLS and Cryo-TEM

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IN VITRO SELECTION

• Polymers have been loaded with

highest drug load

• Samples are sensitive to filtration

procedures

• No standard technology can be

applied

Source: Modified from Al Meslmani et al. 2015 (In preparation), J Pharm Pharmacol

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IN VITRO SELECTION

• Drug release was determined by using dialysis bag method

• Complete release of compounds from the polymeric material was determined

in presence of 10% of foetal calf serum

• Significant differences in the release profiles under accelerated conditions

● Pure drug

♦ BP002

■ BP006

Source: Janas et al. 2015, J Pharm Sci (In preparation)

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CASE STUDY 3: OPTIMIZING MEDIUM-SCALE MANUFACTURE

• Long-circulating parenteral nanocarriers for drug delivery with optimal toxicity-

to-efficacy ratio

• Accumulation by taking advantage of enhanced permeability and retention

(EPR) effect

• Optimized medium-scale manufacturing process

• Confirm efficacy and pharmaceutical quality

Formulation design/

Preformulation

Process optimization

Quality and efficacy

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CASE STUDY 3: OPTIMIZING MEDIUM-SCALE MANUFACTURE

• Formulation of the photosensitizer mTHPC for

intravenous injection

• Embedding compound into PLGA-PEG

nanoparticles

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FORMULATION DESIGN

• Drug load and encapsulation efficiency

dose 0.15 mg/kg

> 60% acceptable for administration

• Particle size and size distribution

50 - 150 nm, PDI < 0.1

High in vitro stability in serum

• Net charge

< -15 mV

• Release rate and profile

< 20% in 1 h

Release

rate

Particle

size

Drug

load

Net

charge

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FORMULATION DESIGN

• Selection of PLGA-PEG as long-circulating drug carrier material

• Preformulation studies confirmed the use of Pluronic F68 as stabilizing agent

• Solvent-to-non-solvent ratio was set 1:10 to enable freeze drying of the final

suspension

• Preformulation studies confirmed an absolute flow rate of 2.2 mL/min

Preformulation studies

Solvent-to-non-solvent (SNS) ratio

Absolute flow rate

Type of stabilizer

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FORMULATION DESIGN

• Identify a group of process parameters that may be relevant to product

characteristics

• Optimization of process parameters in two steps

Polymer

conc.

Stabilizer

conc.

Gas

pressure

Drug

conc.

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PROCESS OPTIMIZATION

• Screening for independent variables with greatest impact on encapsulation

efficiency

• Selecting independent variables for further optimization

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

Stabilizer and

polymer concentration

N2 pressure

and drug concentration

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• Optimizing formulation by testing various levels for a limited number of

variables

• Selecting optimal formulation design for further processing

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

Polymer concentration

Stabilizer concentration

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QUALITY AND EFFICACY

• Quality parameters

in vitro stability in physiological media

in vitro release in an optimized release test

• Efficacy parameters

Light and dark toxicity

in vivo distribution

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• Currently no compendial release test for nanoformulations available

• Dispersion releaser technology allows micellar and liposomal structures by

using dialysis technique in a USP1/2 system

Source: Janas and Wacker, German Patent Application No. DE102013015522.3

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• Stability of formulations in presence of 0 to 90% of serum

• No aggregation in physiological medium observed

• Drug release testing by using an optimized dialysis method

• Reproducibility of manufacturing process within the defined specification

range has been demonstrated

○ Batch 1

● Batch 2

Source: Villa Nova et al 2015, Int J Pharm; Janas and Wacker, German Patent Application No. DE102013015522.3

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• High efficacy of formulation design when illuminated

• Lower toxicity observed compared to the existing drug formulation (Foscan®)

Source: Villa Nova et al 2015, Int J Pharm

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• Photosensitizers have fluorescent

properties but they are decreasing

with photodynamic activity

• No signal in deeper compartments

observed but no precipitation or

depot formation at the injection site

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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

matthias g. wacker, phd

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