PHAR 600:  Principles of Drug Design and Development (PD3)
University of Maryland School of Pharmacy

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Learning Facilitator

R. Gary Hollenbeck, Ph.D.
Associate Professor of Pharmaceutical Sciences
Professor of Pharmaceutical Sciences
Room 740, Pharmacy Hall
Phone: (410)-706-7670
e-mail: ghollenb@rx.umaryland.edu

Drug Solubility Unit:
Assignment

Presented below is information on Naproxen and Sodium Naproxen. Using this information, provide a spreadsheet with:

1.  estimated ideal solubility values for each pH specified

2.  a single graph showing the variation of solubility vs pH for naproxen that includes both the weak acid and salt regions.

Forward the completed spreadsheet as an e-mail attachment to: ghollenb@rx.umaryland.edu

pH - Solubility Profile

Naproxen

Estimated Parameters

Literature Values

Max Dose (mg) =

500

molec wt =

230.3

molec wt sodium salt =

252.2

Salt So (M) =

Acid So (M) =

pKa =

4.2

Solubility Data

pH

(H+)

FDA

FDA

(mg/mL)

(M)

1

0.1

1.35

0.04466

0.0

0.000

2.04

0.00912

0.0

0.000

3.07

0.00085

0.0

0.000

4.66

2.187E-05

0.0

0.000

5.03

9.332E-06

0.0

0.000

6

0.000001

6.55

2.818E-07

1.8

0.008

6.85

1.412E-07

4.1

0.018

6.95

1.122E-07

5.3

0.023

7.1

7.943E-08

4.8

0.021

7.31

4.897E-08

10.3

0.045

7.4

3.981E-08

7.7

1.995E-08

Data from Experiments with Sodium Naproxen

7.72

1.905E-08

208.2

0.826

7.78

1.659E-08

306.7

1.216

7.8

1.584E-08

222.0

0.880

7.84

1.445E-08

234.0

0.928

7.85

1.412E-08

229.8

0.911

7.87

1.348E-08

233.3

0.925

7.89

1.288E-08

314.0

1.245

8.1

7.943E-09

346.8

1.375

8.25

5.623E-09

8.8

1.584E-09

9.23

5.888E-10

307.5

1.219

10.2

6.309E-11

295.6

1.172


 

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