Environmental Harmonizationin Multi-Application Sunscreen Use:

In Vitro Permeation Testing to Healthy Volunteers

Audra L. Stinchcomb, RPh, PhDProfessor

Department of Pharmaceutical Sciencesastinchc@rx.umaryland.edu

Disclaimer & Disclosure• The views expressed in this presentation do not reflect

the official policies of the U.S. Food and Drug Administration or the U.S. Department of Health and Human Services; nor does any mention of trade names, commercial practices, or organization imply endorsement by the United States Government. This study is not FDA funded.

• Chief Scientific Officer and Co-Founder of

– A company developing and testing topical drug products

Acknowledgements

• Lab Members– Sagar Shukla, PharmD, PhD– Sherin Thomas, PhD– QingZhao Zhang– Paige Zambrana– Dana Hammell, M.S.– Danielle Fox

Paige Zambrana PhD thesis project

Methods of Assessment of Bioavailability

Blood levels

Microdialysis Tape strippingIVPT

In vitro permeation test

Pharmacodynamic assay (vasoconstriction) Urine levels

7

In-Line Diffusion Cells

http://permegear.com/in-line-cells/ 8

IVPT (In vitro permeation test)1. Dermatome 2. Assemble setup 3. Record TEWL

4. Dose Product

Positive displacement pipette

Inverted HPLC vial 9

Multiple Dosing• Oxybenzone permeation with multi-application

use of sunscreens on 1) in vitro permeation of oxybenzone across

excised human skin2) design an in vivo study, under harmonized

conditions, to evaluate the pharmacokinetics of oxybenzone absorption in healthy human volunteers for four sunscreen products each containing 6% oxybenzone

Sunscreen Products

IVIVC: In Vitro In Vivo Correlation

• Value of IVIVC– Facilitate testing of drug candidates and

optimization of formulation– Assist in quality control – Serve as a surrogate for bioequivalence studies,

scale-up and postapproval changes

→ Minimize/Reduce in vivo clinical studies (Save & )

Influence of Heat

• Evaluate the effect of heat exposure• 37°C vs standard skin surface temperature of 32°C

Influence of Heat on Percutaneous Absorption

1) ↑ Diffusivity of Drug from its Vehicle

11

+ Heat ➜

Influence of Heat on Percutaneous Absorption

2) ↑ Fluidity of Stratum Corneum Lipids

https://biochemistry3rst.wordpress.com/tag/phosphodiate/

Influence of Heat on Percutaneous Absorption

3) ↑ Cutaneous Vasodilation

Body temperature regulation

When the body is too hot

Initial MiniMUsT Study Design

37°CB Dose 1 Dose 2 Dose 3

Time

80 min 160 min 4h 6h 8h 10h 12h 16h

A Dose 1 Dose 2 Dose 3

Time

80min 160min 4h 6h 8h 10h 12h 16h

Baseline arm

Heat arm

Both arms will be performed for Lotion 1 and Lotion 2IVPT carried out for 24 hours

30

IVPT Data: Lotion 1 (Cream Emulsion)Flux profile from human skin for Lotion 1 (mean ± SD)

(3 replicates/donor)Donor 1a

0 6 12 18 240.0

0.5

1.0

1.5

Time (h)

Flux

( µg/

cm2 h

)Donor 2a

0 6 12 18 240.0

0.5

1.0

1.537°C for 8h32°C

Time (h)

Flux

( µg/

cm2 h

)

Donor 3

0 6 12 18 240.0

0.5

1.0

1.5

Time (h)

Flux

( µg/

cm2 h

)

Donor 4

0 6 12 18 240.0

0.5

1.0

1.5

Time (h)

Flux

( µg/

cm2 h

)

IVPT Data: Lotion 2 (Water washable lotion) Flux profile from human skin for Lotion 2 (mean ± SD)

(3 replicates/donor)Donor 1b

0 6 12 18 240.0

0.2

0.4

0.6

0.8

1.0

Time (h)

Flux

( µg/

cm2 h

)

Donor 2b

0 6 12 18 240.0

0.2

0.4

0.6

0.8

1.037°C for 8h32°C

Time (h)

Flux

( µg/

cm2 h

)

Donor 3

0 6 12 18 240.0

0.2

0.4

0.6

0.8

1.0

Time (h)

Flux

( µg/

cm2 h

)

Donor 4

0 6 12 18 240.0

0.2

0.4

0.6

0.8

1.0

Time (h)

Flux

( µg/

cm2 h

)

Flux profile comparison of Lotion 1 vs Lotion 2 for two human skin donors (mean ± SD)

Donor 3

0 6 12 18 240.0

0.5

1.0

1.5

37°C for 8h (Lotion 1)32°C (Lotion 1)37°C for 8h (Lotion 2)32°C (Lotion 2)

Time (h)

Flux

( µg/

cm2 h

)

Donor 4

0 6 12 18 240.0

0.5

1.0

1.5

Time (h)

Flux

( µg/

cm2 h

)

Lotion – 2 mg vs 10 mg Single Dose IVPT

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 3 6 9 12 15 18 21 24

Flux

(µg/

cm2 )

Time (h)

Lotion 10 mg off setup8h heatno heat

10 mg lotion-off setup

heat no heat

avg. cum (µg/cm2) 9.21 5.86

avg dose (mg) 9.8 10.35

avg skin thickness (µm) 313.3 306.7

0.000.020.040.060.080.100.120.14

0 3 6 9 12 15 18 21 24

Flux

(µg/

cm2 )

Time (h)

Lotion 2 mg off setup8h heatno heat

2 mg lotion-off setup

heat no heat

avg. cum (µg/cm2) 1.39 1.91

avg dose (mg) 2.02 2.07

avg skin thickness (µm) 290 300

Conclusions: When dosing 2 mg the no heat condition had a similar flux and avg cumulative amount permeatedWhen dosing 10 mg the heat condition had a higher flux and avg cumulative amount permeated

Lotion – 2 mg multidose IVPT

0.0

0.1

0.2

0.3

0.4

0.5

0 3 6 9 12 15 18 21 24

Aver

age

Flux

(µg/

cm2 )

Time (h)

Lotion 8 h heat vs no heat8h heat

no heat

Conclusions: For this study used a new membrane support system but heat flux goes back to being higher when multiple doses are applied

~potential for higher humidity environment occurring since cell insert dosing area is tall not allowing for adequate evaporation??? Potentially need to make a new version of a cell insert so that skin is more exposed to air (see above)

Current cell insert

Proposed cell insertTop Bottom

Human Pharmacokinetic Study• 12 h open-label, randomized, four-way crossover

pharmacokinetic study in healthy human volunteers• Harmonized to the previously mentioned IVPT parameters• During heat application, skin temperature of 37 ± 2oC was

achieved by placing a heating pad adhered to the underside of a 3D printed dome over the top of the volunteers' thighs

• Serum samples were analyzed for oxybenzone using a validated LC-MS/MS method

• 2 mg/cm2 application 800 cm2

Design of Standardized Heat Dome

Setup during clinical trial heat procedure days

Record of average skin temperature recorded from four separate skin sensors placed on the

thighs covering an area of 800 cm2

Skin temperature

0 100 200 300 400 50030

32

34

36

38

40

42Sensor 1Sensor 2Sensor 3Sensor 4Average

Time (min)

Tem

pera

ture

( °C

)

Serum PK profiles for volunteers treated with Lotion 1 sunscreen and Lotion 2 sunscreen

Lotion 2

Lotion 10, 80, and 160 min application

Evaporation Rate of Excipients Influences Percutaneous Absorption

https://innovareacademics.in/journals/index.php/ijcpr/article/download/25886/14261/119954

Temperature and Relative Humidity Influence Formulation Evaporation Rate

https://qph.fs.quoracdn.net/main-qimg-1d3774bfe2610597783cda119b8c1233

Temperature Control (31-33°C (87.8-91.4°F)

Humidity Control (humidifier set at 45% RH)

miniMUsT Clinical Design

Temp 31-33°C (87.8-91.4°F) Humidity 45% RH

(0, 80 and 160 min) Sunscreen Application Procedure Day (hour) zero 1 2 3 4 5 6 7 8 9 10 11 12

Sampling time points 18 total predosing

2:00

3:00

3:30 4:00

4:30 5:00

5:30 6:00

6:30 7:00

7:30 8:00

8:30 9:00

9:30 10:00

12:00

Temp 31-33°C (87.8-91.4°F) Humidity 45% RH

(0, 80 and 160 min) Sunscreen Application

Procedure Day (hour)

zero

1

2

3

4

5

6

7

8

9

10

11

12

Sampling time points

18 total

predosing

2:00

3:00

3:30

4:00

4:30

5:00

5:30

6:00

6:30

7:00

7:30

8:00

8:30

9:00

9:30

10:00

12:00

In Vitro ResultsHuman Skin Profile for All Products to be Tested In Vivo

(Mean ± SD) (3 replicates/donor)

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6 8 10 12 14 16 18 20 22 24

Mea

n Fl

ux (µ

g/cm

2 h)

Time (h)

Donor 1

29

0.0

0.2

0.4

0.6

0.8

1.0

0 2 4 6 8 10 12 14 16 18 20 22 24

Mea

n Fl

ux (µ

g/cm

2 h)

Time (h)

Donor 2

Goals• Develop a streamlined testing method that is more clinically and environmentally

harmonized for quantifying sunscreen UV filter safety levels– Extrapolate full body exposure data from surrogate 800 cm2 thigh study– Make sure that skin surface temperature and relative humidity are controlled so that products

can be compared to each other

• Generate more accurate information as to the potential total permeation of oxybenzone in worst-case scenarios

• Show the difference that formulation makes advocating for final formulation testing for permeation

• Optimized in vitro study protocols may help to decrease the number of clinical trials required for UV filter product testing

36

U01FD004947Dr. Annette L. BungeDr. Richard H. GuyDr. Tom Franz

Clinical Study TeamDr. Jeff FinkUMB GCRC nursesClinical Study Participants

U.S. FDA Funding

• Dr. Caroline StrasingerTDS Strength/Dose Study

• Dr. Sam Raney, OGDTDS Heat Effects & OGD IVIVC

• Dr. Priyanka Ghosh, OGDTDS Heat Effects & OGD IVIVC

• NIPTE-U01-MD-2015 U01FD004275• NIPTE-U01-MD-2016-003 + MCERSI• U01FD004947• U01FD004955

DisclaimerThe views expressed in this presentation do not reflect the official policies of the Department of Health and Human Services; nor does any mention of trade names, commercial practices, or organization imply endorsement by the United States Government.

Current Lab MembersContributors to the work presented:• Sherin Thomas (Lidocaine,

buprenorphine, diclofenac)• Dana Hammell, MS (Lab Manager and

Document Control)• Dani Fox (Clinical Coordinator)• Sagar Shukla (Lidocaine)• Paige Zambrana (Sunscreens & glucose

monitoring, fentanyl)• Qingzhao Zhang (Metronidazole &

rivastigmine)

Sunscreen Funding• Dr. Maureen Kane CoI• University of Maryland Baltimore,

School of Pharmacy Mass Spectrometry Center (SOP1841-IQB2014), and the University of Maryland, Baltimore, Institute for Clinical & Translational Research (ICTR) Voucher Program

Acknowledgments

This project has been approved by the UMB Institutional Review Board for human subject research

Environmental Harmonization� in Multi-Application Sunscreen Use: �In Vitro Permeation Testing �to Healthy VolunteersDisclaimer & DisclosureAcknowledgementsMethods of Assessment of BioavailabilityIn-Line Diffusion CellsIVPT (In vitro permeation test)Multiple DosingSunscreen ProductsIVIVC: In Vitro In Vivo Correlation Influence of Heat Influence of Heat on Percutaneous AbsorptionInfluence of Heat on Percutaneous AbsorptionInfluence of Heat on Percutaneous AbsorptionInitial MiniMUsT Study DesignIVPT Data: Lotion 1 (Cream Emulsion)�Flux profile from human skin for Lotion 1 (mean ± SD) �(3 replicates/donor)�IVPT Data: Lotion 2 (Water washable lotion) �Flux profile from human skin for Lotion 2 (mean ± SD) �(3 replicates/donor)�Flux profile comparison of Lotion 1 vs Lotion 2 for two human skin donors (mean ± SD) Lotion – 2 mg vs 10 mg Single Dose IVPTLotion – 2 mg multidose IVPT�Human Pharmacokinetic StudyDesign of Standardized Heat DomeSetup during clinical trial heat procedure days Record of average skin temperature recorded from four separate skin sensors placed on the thighs covering an area of 800 cm2�Serum PK profiles for volunteers treated with Lotion 1 sunscreen and Lotion 2 sunscreenEvaporation Rate of Excipients Influences Percutaneous AbsorptionTemperature and Relative Humidity Influence Formulation Evaporation RateTemperature Control �(31-33°C (87.8-91.4°F)�Humidity Control �(humidifier set at 45% RH)miniMUsT Clinical DesignIn Vitro Results�Human Skin Profile for All Products to be Tested In Vivo� (Mean ± SD) (3 replicates/donor)GoalsSlide Number 31