Martina Sahre1, Sreedharan Sabarinath1, PhD

Maria Grant2, MD, Christoph Seubert3, MD, PhD,

Carisa deAnda4, PharmDHartmut Derendorf1, PhD

University of Florida, College of Pharmacy, Departments of

Pharmaceutics1, Therapeutics and Pharmacology2, Anesthesiology3,

Trius Therapeutics4, San Diego, California

Evaluation of Tissue Distribution of TR-Evaluation of Tissue Distribution of TR-700 in Healthy Volunteers Using 700 in Healthy Volunteers Using

MicrodialysisMicrodialysis

OverviewOverviewIntroduction

TR-700 / TR-701RationaleMicrodialysis

Study DesignResultsConclusion

TR-700TR-700

Oxazolidinone classLimited water solubilityPhosphate ester prodrug (TR-701)Rapid conversion to active drug

N O

O

HN

O

F

N

O

Linezolid

N O

OH

O

F

N

NN

N

N

N O

O

F

N

NN

N

N

OP

O

ONa

ONaIn VivoPhosphatases

TR-700

TR-701

TR-700TR-700

Oxazolidinone classIndication complicated skin and skin

structure infections (cSSSI)In vitro activity against:

S. aureus (MS and MR), Linezolid-resistant MRSA carrying binding-

site mutations, cfr geneS. pneumoniae (PS, PR), S. pyogenes, S.

agalactiae, Enterococci (inc.. VRE)

Rennie et al. (2003), Im et al. (2007), Jones et al. (2009), Shaw et al. (2007), Schaadt et al. (2009)

RationaleRationale

Plasma concentrations linked to PK/PD indices

Free drug in tissue more relevantDrug molecules need to reach tissue

Total Plasma, Muscle Tissue, Adipose Tissue, --- Free Plasma

Barbour et al. (2009), Deghanyar et al. (2005)

Mean Ceftobiprole Concentrations After Single 500 mg i.v. Dose

C(tissue) < fc(plasma) C(tissue) > fc(plasma)

Mean Linezolid Concentrations After Single 600 mg i.v. Dose

RationaleRationale

Biopsy, skin blisters, imaging techniques AUC of Moxifloxacin after 400 mg p.o single

dose:

Measure unbound PK parameter in tissue using microdialysis

Mueller et al. (1999)

Plasma Muscle

Tissue

Subcutaneous Tissue

Saliva Capillary Blood

Blister

AUC [µg*h/m

L]19.8 8.5 8.0 17.6 18.7 12.3

Microdialysis PrincipleMicrodialysis Principle

Diffusion through a semipermeable membrane

“Mimics” blood vesselSampling tool Assess free drug directly

Courtesy of CMA

RecoveryRecoveryProbe is continuously perfused → no

equilibriumcdialysate < cmedium

Recovery defined as ratio cdialysate/cmediumDialysate: liquid recovered from probeMedium: tissue or solution containing

compound of interestFactors influencing recovery:

Temperature, Membrane length, Flow-rate, Molecular size, Membrane properties, Tissue properties

Probe calibration → recovery factor

RetrodialysisRetrodialysis

Perfusate contains known concentration of compound

Dialysate concentration measuredCalculated recovery used to

adjust drug concentrations from experiment

100*100]Recovery[%perfusate

dialysate

c

c

Courtesy of CMA

Study DesignStudy DesignTR-700 measured in plasma, s. c. adipose and

muscle tissue15 healthy volunteers Pilot (n = 3) and Main Study (n = 12)

Two microdialysis probes implantedRetrodialysis to calibrate probeWashout period

Main StudySingle dose of study drug, 600 mg p.o.Dialysate samples every 20 minutes for 12 h,

blood samples for 24 h after dosingProtein binding samples 0, 2, 12h post dose

CMA 60 probe, Courtesy of CMA, Sweden)

Pilot Study ResultsPilot Study Results

Recovery > 90%Washout period 4 h

Main Study: ResultsMain Study: ResultsProtein Binding 87 % (1.3%)

TR-700 Levels in Plasma (Total and Unbound), Adipose and Muscle Tissues

Time [h]

0 4 8 12 16 20 24

Co

nce

ntr

atio

n [n

g/m

L]

0

1000

2000

3000

4000

5000

6000

7000

Adipose Tissue Muscle Tissue Total Plasma fPlasma

TR-700 Levels in Plasma (Unbound), Adipose and Muscle Tissues

Time [h]

0 4 8 12 16 20 24

Co

nce

ntr

atio

n [n

g/m

L]

0

200

400

600

800 Adipose Tissue Muscle Tissue fPlasma

Mean PK Parameters (SD)Mean PK Parameters (SD)

Parameter Unit Plasma fPlasmaAdipose Tissue

Muscle Tissue

Cmax (µg/mL) 5.37 (1.51) 0.70 (0.27) 0.66 (0.16) 0.74 (0.15)

Tmax§ (hr) 2 (1-4) 2 (1-4)

3.33 (2.33-10.3)

3.67 (1.67-7)

AUC0-12(µg*h/mL)

38.8 (7.55) 4.96 (1.09) 5.27 (1.28) 5.95 (1.11)

AUC0-24(µg*h/mL)

57.1 (14.7) 7.28 (1.91) - -

AUC∞(µg*h/mL)

70.0 (24.8) 8.89 (3.06) 16.6 (15.8) 14.6 (10.5)

t½§ (hr)

8.13 (5.94-12.8)

8.13 (5.94-12.8)

9.22 (5.98-85.9)

9.59 (6.15-48.2)

CL/F (L/hr) 9.46 (2.91) * * *Vz/F (L) 113 (19.3) * * *

fAUC0-12, tissue/fAUC0-12, plasma 

1.08 (0.22) 1.22 (0.18)

Protein Binding % 87.2 (1.3) * * ** Not applicable; § Median (Range); λz: terminal elimination rate constant

ConclusionConclusion

TR-700 conc. in observed tissues similar to unbound plasma concentrations

No significant difference between AUC0-12 for unbound plasma, adipose and muscle tissues

Drug and microdialysis well tolerated

AcknowledgementsAcknowledgements

Prof. Hartmut DerendorfMaria Grant, MD and Christoph Seubert,

MD, PhDSreedharan Sabarinath, PhDGeneral Clinical Research Center at the

University of FloridaPhilippe Prokocimer, MDTrius Therapeutics, Inc.

Individual Adipose Concentrations

Time [min]

0 60 120 180 240 300 360 420 480 540 600 660 720 780

Con

cent

ratio

ns [

ng/m

L]

0

100

200

300

400

500

600

700

800

900

1000123456789101112

Individual Muscle Concentrations

Time [min]

0 60 120 180 240 300 360 420 480 540 600 660 720 780

Co

nce

ntra

tion

[n

g/m

L]

0

100

200

300

400

500

600

700

800

900

1000