encapsulation in double emulsions fundamental analysis of ... · experimental setup for...

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Encapsulation in double emulsions Fundamental analysis of stability S. Nachtigall, C. Holtze, A. Laurenzis, S. Bachmann, M. Vranceanu, G. Oetter, F. Runge (BASF SE) V. Götz, S. Hosseinpour, W. Peukert (FAU Erlangen) N. Leister, H. P. Karbstein (KIT Karlsruhe) Formula X I Manchester I 24-27 th June 2019

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Page 1: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Encapsulation in double emulsions Fundamental analysis of stability

S. Nachtigall, C. Holtze, A. Laurenzis, S. Bachmann, M. Vranceanu, G. Oetter, F. Runge (BASF SE)V. Götz, S. Hosseinpour, W. Peukert (FAU Erlangen)N. Leister, H. P. Karbstein (KIT Karlsruhe)

Formula X I Manchester I 24-27th June 2019

Page 2: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Potential applications - Encapsulation of… …enzymes, proteins or peptides for detergents …hydrophilic bioactive ingredients (e.g. vitamins) for

cosmetic and food applications …hydrophilic crop protecting agents and active

ingredients in pharmaceuticals

Double emulsions: promising structures to encapsulate hydrophilic active ingredients

04.07.2019 Formula X I Manchester I 24-27th June 20192

Inner aqueous phase (W1)including active ingredients

Outer aqueous phase (W2)

Hydrophobic shell material (liquid or solid)

W/O-emulsifierO/W-emulsifier

Benefits Stability/protection of active ingredients Triggered or retarded release Taste/smell masking Drift and washing-out prevention

Page 3: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Double emulsions – example “Hollow microcapsules”

200 µm

Curing

Closedcapsule

Activeloading

Porous capsule

Concept Filling of empty, porous capsules with active

material Pores of capsules to be closed after filling

Benefits Universal capsules for various active ingredients Biodegradable capsule matrix

@BASF @customer

200 µm

04.07.2019 Formula X I Manchester I 24-27th June 20193

Page 4: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Lipophilic surfactant (W/O-emulsifier) High energy input (e.g. gear rim

dispersing device)

Polymer and solvent

H2O

FiltrationDistillation of solvent

Washing

Step 1: W1 in O emulsification Step 2: (W1/O) in W2 emulsification

Hydrophilic surfactant (O/W-emulsifier) Low energy input (e.g. stirred vessel)

Double emulsions – example “Hollow microcapsules”

04.07.2019 Formula X I Manchester I 24-27th June 20194

Page 5: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Double emulsions: challenges

04.07.2019 Formula X I Manchester I 24-27th June 20195

Advantages Various different applications

Preparation with common equipment

DiffusionCoalescence

BUT Big challenge to keep active inside

No guidelines for process and product development

Page 6: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Double emulsions: challenges Analysis of coalescence- and diffusion phenomena in W1/O/W2-double emulsions

04.07.2019 Formula X I Manchester I 24-27th June 20196

New analytical approaches for investigating instability mechanisms

Influence of process parameters

Identification of structure/property-relationships

Guidelines for faster formulation and process development

Formulation and process development based on molecular understanding

W/O-emulsifierO/W-emulsifier

Page 7: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Diffusion and coalescence at interfaces: single drop experiments & interfacial tension measurements

Characterization of interfaces via nonlinear spectroscopy (SFG, SHG)

Supported by molecular modeling (BASF)

Analysis of double emulsions in different scales

Methods to investigate instability mechanisms

04.07.2019 Formula X I Manchester I 24-27th June 20197

tcoalescence tdiffusion*

*S. M. Neumann, CC BY

Page 8: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Diffusion and Coalescence Time Analyzer*Influence of emulsifier systems

04.07.2019 Formula X I Manchester I 24-27th June 20198

*S. M. Neumann, U. van der Schaaf, H.P. Schuchmann: The Diffusion and Coalescence Time Analyzer (DCTA): A novelExperimental setup for investigating instability phenomena in double emulsions. Food Structure 12 (2017) 103 – 112.

OW2

Water - MCT TO8 - MCT TO8 - PGPR Water - PGPR0

15

30

45

60

Coa

lesc

ence

tim

e in

s

>300 sOil phase: Miglyol® 812O/W-emulsifier: Lutensol® TO8, 0.1 wt%W/O-emulsifier: PGPR, 0.1 wt.%

Without emulsifier

+ Lutensol TO8 ®

+ PGPR+ PGPR+ Lutensol®

TO8

> 300 s

Page 9: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Diffusion and coalescence at interfacesInfluence of emulsifier system

04.07.2019 Formula X I Manchester I 24-27th June 20199

1E-7 1E-6 1E-5 1E-4 0,001 0,01 0,1 10

10

20

30 10-6wt%TO8 10-3wt%TO8 10-1wt%TO8

IFT

in m

N/m

PGPR concentration in wt%1E-7 1E-6 1E-5 1E-4 0,001 0,01 0,1 1

0

10

20

30

IFT

in m

N/m

PGPR concentration in wt%

Oil phase: Miglyol® 812W/O-emulsifier: PGPRO/W-emulsifier: Lutensol® TO8tcoal = 5 s

tcoal = 35 s

tcoal > 300 stcoal = 30 s

tcoal = 25 s

tcoal = 23 s

0

OW2

O/W-emulsifier disturbs stability

Page 10: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Analysis of emulsifier diffusionInterfacial tension measurements

04.07.2019 Formula X I Manchester I 24-27th June 201910

1 wt% 0.1 wt%

10 100 1000 10000 1000000

2

4

6

8

10

12

14

16

18

20

IFT

in m

N/m

Time in seconds

Oil phase: Miglyol® 812O/W-emulsifier: Lutensol® TO8

Determination of emulsifier diffusion via interfacial tension

Page 11: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Characterization of interfaces Nonlinear spectroscopy (SFG, SHG)

04.07.2019 Formula X I Manchester I 24-27th June 201911

Experimental SFG setup

Planar setup Scattering setup

Experimental SHG setup

Fundamental analysis Learning about systems

Analysis of real emulsions

Interfacial emulsifier composition

Second Harmonic Generation (SHG): amount of molecules at interface (intensity)

Sum Frequency Generation (SFG): type and orientation of molecules (spectra)

Page 12: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

2800 3000 3200 3400 3600

SFG

nor

m. s

igna

l (a.

u.)

IR Wavenumber (cm-1)

water MCT on water

Characterization of interfaces Planar SFG spectra I Influence of O/W-emulsifier

04.07.2019 Formula X I Manchester I 24-27th June 201912

Distinction between Miglyol® 812 and Lutensol® TO 8 is possible

Lutensol ® TO 8 dominates at interface

Ordered and covering layer of surfactant

Detection of O/W-emulsifier at interface

2800 3000 3200 3400 3600

SFG

nor

m. s

igna

l (a.

u.)

IR Wavenumber (cm-1)

water MCT on water 0.1 wt% Lutensol TO 8 in water

2800 3000 3200 3400 3600

SFG

nor

m. s

igna

l (a.

u.)

IR Wavenumber (cm-1)

water MCT on water 0.1 wt% Lutensol TO 8 in water MCT + 0.1 wt% Lutensol TO 8 on water

Water spectrumWater I Miglyol® 812Water + 0.1 % Lutensol® TO8Water + 0.1 % Lutensol® TO8 I Miglyol® 812

Page 13: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Characterization of interfaces Scattering SHG analysis I Adsorption of Malachite green

04.07.2019 Formula X I Manchester I 24-27th June 201913

0 2 4 6 8 10 12 14 16 18 20

4000

8000

12000

16000

20000

24000

28000

MCT-SDS (0.3 mM, 190 nm)

Hexadecane-SDS (0.3 mM, 180 nm)

MCT-Texapon (24 mM, 182 nm)

SHG

cou

nts

Malachite green (µM/l)

Miglyol® 812 I Texapon® NSO(24 mM, d = 182 nm)Miglyol® 812 I SDS (0.3 mM, d = 190 nm)Hexadecane I SDS (0.3 mM, d = 180 nm)

Emulsion production: UltrasoundDispersed phase: Miglyol® 812 (φ=1 %)Continuous phase: water + surfactantAddition of malachite green

Different types of adsorption depending on emulsion properties

Surfactant molecules: replacement, binding on, relocation…

Page 14: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –

Double emulsions - Summary & Outlook

04.07.2019 Formula X I Manchester I 24-27th June 201914

Advantages Various different applications

Preparation with common equipment

Challenges Keeping the active inside → stability issues

No guidelines for process and product development

Analysis of instability mechanisms New technical approaches to analyze instability mechanisms and for the characterization of interfaces

Applicability of analytical approaches shown

Next steps: screening of different emulsifiers and transfer of gained knowledge to real systems

Page 15: Encapsulation in double emulsions Fundamental analysis of ... · Experimental setup for investigating instability phenomena in double emulsi ons. Food Structure 12 (2017) 103 –