Katarzyna Adamska

Monika Pietrzyńska

Adam Voelkel

POZNAN UNIVERSITY OF TECHNOLOGYPoland

Inverse liquid chromatography in the study

of physicochemical properties of

hydroxyapatite-polymer monolithic columns

INTRODUCTION

2

Monolithic bed

Continuous homogeneous, porous structure, in the

form of a backbone, prepared by polymerisation or

other consolidation (sintering, deposition,

compression) of the material inside the capillary.

3

particle-packed columns

monolith

Monolithic materials

HPLC separation,

purification.

Sorbents for sample

preparation (solid

phase extraction -

SPE).

High surface area and

high stability.

Highly permeable to

liquid flow.

High efficiencies with

low back pressures.

Reduced run times

with high flow rate.

4http://www.lifescience.ca

https://www.thermofisher.com

https://www.phenomenex.com/

http://www.glsciences.com

Classification of monolithic HPLC columns

Function

guard

capillary

fast

preparative

Separationmechanism

RP

NP

affinity

ion-exchange

Columnmaterials

silica

polymer

carbon

5

MATERIALS AND METHODS

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Hydroxyapatite-polymer monolithic material

7

Investigation of the interactions between

drugs and hydroxyapatite

Bisphosphonates

• high affinity for hydroxyapatite

• bind to calcium

Hydroxyapatite (HA)• major component and

essential ingredient of

bone

26410 OHPOCa

Bisphosphonates

Bisphosphonates (BPs) inhibit

bone resorption and are

widely used for the treatment

of bone diseases, including

osteoporosis.

8R. Graham, G. Russell,. Bisphosphonates: The first 40 years. Bone, 49 (2011) 2–19

The differences among BPs in binding to

hydroxyapatite are associated with the long

duration of action.

It was proved, that BPs can be found in

plasma and urine many months after

dosing.

This means, that BPs must be present in

the circulation and available for reuptake

into bone for prolonged periods.

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Bisphosphonates

10G.H. Nancollas et al. / Bone 38 (2006) 617–627

Bisphosphonates

Bisphosphonates cause several

complications.

Oral ingestion is associated with

rhinitis gastritis or esophagus and

abdominal pain.

Additionally BPS cause disease

known as bisphosphonate-related

osteonecrosis of the jaw (BRONJ).

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Bisphosphonates

Monolithic materials preparation

Monomer [%] Porogen [%] HA [%]

HEH0 30 70 0

HEH1 27 70 3

HEH2 24 70 6

HEH3 21 70 9

HEH4 18 70 12

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Porogens: Dodecanol, cyclohexanol, toluene

◦ Poly(2-hydroxyethyl methacrylate-co-ethylene

dimethacrylate)

HEMA / EDMA/ Hydroxyapatite (HEH)

Material BET

[m^2/g]

Pore size

[Å]

HEH0 4.41 74.5

HEH3 35.72 119.4

Physicochemical characterisation

of HEH material

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Dionex Ultimate 3000 LC; RI, UV-VIS detectors,

The stainless steel column (2.1mm i.d. x 100mm) filled with HEH,

Mobile phase: methanol, dichloromethane, acetonitrile.

TEST SOLUTES:

Cyclohexanone, 1,4-dioxane, Aniline, Pyridine,

Benzonitrile, THF, DMF, Cyclohexanole, 1,3-Propanediol,

Butanone, Diethyl ether, Propylamine, Acetofenone,

1,3-diaminopropane, Acetic acid, Ethyl acetate, Geraniol,

Phenol, Ibuprofen, Acetonitrile, Propan-1-ol.

Inverse Liquid Chromatography

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Inverse Liquid Chromatography

Linear solvation energy relationship - Abraham model

log SP = eE + sS + aA + bB + vV + c

SP - is some free energy related solute property such as a distribution constant, retention factor, specific retention volume.

• e - dispersion and induction interactions,

• s - dipole-type interactions,

• a - hydrogen-bond basicity,

• b - hydrogen-bond acidity,

• v - a measure of the difference in cavity formation in thetwo condensed phases together with any residual dispersion interactions, that are not selfcanceling.

RESULTS

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ILC - Surface properties / Abraham

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ILC - Surface properties / Abraham

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Examination of

sorption and desorption

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Risedronate sodium

Principal Component Analysis (PCA) /

materials characterisation

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Eigenvalues

72,53%

20,38%

7,09%

0,0 0,5 1,0 1,5 2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5 6,0

Number

-0,5

0,0

0,5

1,0

1,5

2,0

2,5

3,0

3,5

4,0

Eig

envalu

e

Principal Component Analysis (PCA) /

materials characterisation

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Projection of variables ( 1 x 2)

Active

Additional

e

s

a

b

v

*sorption*desorption

-1,0 -0,5 0,0 0,5 1,0

Variable 1 1 : 72,53%

-1,0

-0,5

0,0

0,5

1,0V

ariable

2 :

20,3

8%

Principal Component Analysis (PCA) /

materials characterisation

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Projection of cases ( 1 x 2)

Active

HEH0

HEH1

HEH2

HEH3

-4 -3 -2 -1 0 1 2 3 4

Variable 1: 72,53%

-2,5

-2,0

-1,5

-1,0

-0,5

0,0

0,5

1,0

1,5V

ariable

2:

20,3

8%

Conclusions Inverse liquid chromatography technique can be applied for

characterization of the hydroxyapatite-polymer monolithic

columns.

LSER provide a relatively unambiguous understanding of the

importance of the various interactions governing the

thermodynamics of the system being studied.

All materials shows ability to the dispersive interactions,

through π/n-electrons pairs (e parameter) – the higher

content of HA, the higher ability to such type of interactions.

According to PCA data, the highest correlation of Risedronate

sorption/desorption process onto HEH has been found for a

parameter – the ability to accept a hydrogen bond could

make the most contribution to the sorption/desorption proces,

probably.

HEH monolithic column would provide a useful tool to

investigate newly synthesized BPs for better understanding

process of their action. 22

Thank you for your attention

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