mortar and pestle
Robert P. Shrewsbury
ROBERT P. SHREWSBURY PhD
Beard Hall, Room # 202B
Email: bob_shrewsbury@unc.edu
  Resources

HPLC Assays

Diphenhydramine Syrup

Diphenhydramine HCl

250 mg

Glycerin

   5 ml

Syrup NF

 30 ml

Vanillin Alcoholic Solution 67 mg%

0.2 ml

Distilled Water

qs 100 ml

Link to Formulation Record:

Process of Analysis:
Column: A 4.6 x 250 mm C18 10μ column
Flow rate: 1.4 mL/minute
Mobile Phase: 750 mL methanol, 50 mL tetrahydrofuran, 5.8 g sodium dioctyl sulfosuccinate, and 1 mL of 85% phosphoric acid per liter, adjusted to pH 4.6 with ammonium hydroxide.
Detector wavelength: 265 nm
Injection volume: 25 μL
Retention time of diphenhydramine: 7.0 minutes
Sample Preparation: One (1) mL samples of the student preparation were taken without shaking the preparation and were diluted with distilled water for HPLC analysis.
Standard Solutions: Solutions of 1-5 mg/mL were made in the same manner as the students’ preparation. A linearity standard curve was used to determine the preparations’ concentration.
Expected Concentration of API:  2.5 mg/mL

 

Ibuprofen Effervescent Powder

Ibuprofen

400 mg/tsp

Sodium Bicarbonate

52.4%

Tartaric Acid

28.6%

Citric Acid, Monohydrate

19.0%

Mft. 50 g

 

Link to Formulation Record:

Process of Analysis:
Column: 4.6 x 250 mm C18 10μ
Flow rate: 1.0 mL/minute
Mobile Phase: 400 mL citric acid and sodium hydroxide buffer and 600 mL acetonitrile. The citric acid and sodium hydroxide buffer was made by combining two solutions in a ratio of 40:60. The 40% solution was 23.0 g of citric acid anhydrous plus 200 mL of 1N NaOH in one liter of water. The other solution (60%) was 0.1 N HCl. The pH of the citric acid and sodium hydroxide buffer was 3.0.
Detector wavelength: 254 nm
Injection volume: 30 μL
Retention time of ibuprofen: 6.4 minutes
Sample Preparation: 0.3 g of the preparation was taken from the top of the container. 10 mL of water was added, and when the effervescence stopped, 10 mL of methanol was added. The sample was then hand shaken and injected into the HPLC.
Standard Solutions: Preparations of 1-4 g ibuprofen in 50 g of effervescent powder were prepared in the same manner as the student preparations. A linearity standard curve was used to determine the amount of ibuprofen.
Expected Concentration of API: 3.80 g ibuprofen in 50 g of the effervescent powder preparation.


 

Metronidazole Topical Solution

Metronidazole

1.0 g

HCl 10%

1.5 mL

Propylene Glycol

10.0 mL

Methylparaben

100 mg

Propylparaben

50 mg

Purified Water

qs 100 mL

Mft. 100 mL

 

Link to Formulation Record:

Process of Analysis:
Column: 4.0 x 250 mm C18 10μ
Flow rate: 1.2 mL/min
Mobile Phase: 60% methanol and 40% deionized water
Detector wavelength: 254 nm
Injection volume: 25 μL
Retention time of metronidazole, methylparaben, and propylparaben: 4 minutes, 6 minutes, and 11 minutes, respectively
Sample Preparation: Diluted 50 μL of the preparation in to 20 mL of deionized water. The sample was then hand shaken and injected into the HPLC.
Standard Solutions: Preparations of 0.85-1.15 g metronidazole per 100 mL were made in the same manner as the student preparations. A linearity standard curve was used to determine the amount of metronidazole.
Expected Concentration of API: 1 g of metronidazole


 

Promethazine PLO Emulsion

Promethazine HCl

10% w/v

Ethoxy Diglycol

20% v/v

Lecithin Isopropyl Palmitate Solution

22% v/v

Poloxamer 407 20% Gel

qs 100 mL

Mft. 10 mL

 

Link to Formulation Record:

Process of Analysis:
Column: 4.0 x 150 mm C18 5μ
Flow rate: 1.0 mL/min
Mobile Phase: 70% Acetonitrile, 29% dibasic potassium phosphate, and 1% tetrahydrofuran adjusted to pH 7.0 with phosphoric acid
Detector wavelength: 320 nm
Injection volume: 25 μL
Retention time of promethazine: 6.0 minutes
Sample Preparation: Dissolved 0.1 g in 20 mL of tetrahydrofuran and left samples to sit overnight. A second dilution was prepared by taking 1 mL of the first dilution and adding it to 10 mL of tetrahydrofuran. The sample was then hand shaken and injected into the HPLC.
Standard Solutions: Preparations of 0.5-1.25 g promethazine per 10 mL were made in the same manner as the student preparations. A linearity standard curve was used to determine the amount of promethazine.
Expected Concentration of API: 1 g promethazine per 10 mL of emulsion


 

Jessner's Solution (Combes Peel)

Salicylic Acid USP

14 g

Lactic Acid, 88%

14 ml

Resorcinol USP

14 g

Alcohol USP

qs 100 mL

Mft. 100 mL

 

Link to Formulation Record:

Process of Analysis:
Column: 4.6 x 250 mm C18 10μ
Flow rate: 1.0 mL/min
Mobile Phase: 60% Methanol and 40% 0.05M monosodium phosphate, adjusted to pH 3.2 with phosphoric acid
Detector wavelength: 280 nm
Injection volume: 25 μL
Retention time of resorcinol and salicylic acid: 3.5 and 7.9 minutes, respectively
Sample Preparation: Dissolved 50 μL in 20 mL of 50:50 methanol: deionized water. The sample was then hand shaken and injected into the HPLC.
Standard Solutions:  
Expected Concentration of API: 14% each of resorcinol and salicylic acid


 

Enalapril Suspension

Enalapril Maleate Tablets USP, 5mg

24 tablets

Syrup NF

qs 120 mL

Flavor

qs

Mft. 120 mL

 

Link to Formulation Record:

Process of Analysis:
Column: 4.6 x 150 mm C8 5μ
Flow rate: 1.8 mL/min
Mobile Phase: 35% acetonitrile and 65% 20 mM monobasic potassium phosphate (pH 3.5), adjusted to pH 2.2 with phosphoric acid
Detector wavelength: 215 nm
Injection volume: 20 μL
Retention time of enalapril: 5.8 minutes
Sample Preparation: Dissolved 0.5 mL in 19.5 mL of deionized water. The sample was then hand shaken and injected into the HPLC.
Standard Solutions: Preparations of 0.85-1.15 g enalapril per 1 mL were made in the same manner as the student preparations. A linearity standard curve was used to determine the amount of enalapril.
Expected Concentration of API: 1 mg of enalapril per mL of suspension


 

Misoprostol Suppositories

**Enalapril was substituted for misoprostol in the formulation**

 

Enalapril Maleate Tablets USP, 5mg

3 tablets

Silica Gel

35 mg/suppository

Witepsol H-15 Base

qs*

Mft. 12 suppositories

 

*calculated based on the calibration of the suppository mold

 

Link to Formulation Record:

Process of Analysis:
Column: 4.6 x 250 mm C18 10μ
Flow rate: 1.3 mL/min
Mobile Phase: 65% acetonitrile and 35% buffer (buffer: 204 mg of monobasic potassium phosphate per liter of deionized water), adjusted to pH 2.0 with phosphoric acid
Detector wavelength: 215 nm
Injection volume: 40 μL
Retention time of enalapril: 8.3 minutes
Sample Preparation: Dissolved 1 suppository in 20 mL of tetrahydrofuran. The sample was then hand shaken and left to sit overnight. A second dilution was prepared by extracting 1 mL of the supernatant from the first dilution and adding it to 19 mL of tetrahydrofuran and injected into the HPLC.
Standard Solutions: Lab staff (2) prepared suppositories at the same concentration as the student preparations. The average of the HPLC readings from the staff-prepared samples was calculated. HPLC readings from the student samples were assessed to see if they were within 15% of the determined average.
Expected Concentration of API: 1.25 mg of enalapril per suppository


 

Ciprofloxacin Otic Solution

Ciprofloxacin Hydrochloride

0.36 g

Hydrocortisone

0.5%

Glycerin

60 mL

Propylene Glycol

qs 120 mL

Mft. 120 mL

 

Link to Formulation Record:

Process of Analysis:
Column: 4.6 x 250 mm C18 10μ
Flow rate: 1.1 mL/min
Mobile Phase:1 L of mobile phase contains: 750 mL methanol, 50 mL tetrahydrofuran, 5.8 g sodium dioctyl sulfosuccinate, 1 mL 85% phosphoric acid, and a sufficient quantity of deionized water to bring the volume up to 1 L.
Detector wavelength: 280 nm
Injection volume: 20 μL
Retention time of enalapril: 6.5 minutes
Sample Preparation: Diluted 0.7 g in 20 mL of deionized water. The sample was then hand shaken and injected into the HPLC.
Standard Solutions: Preparations of 0.256% to 0.345% ciprofloxacin were made in the same manner as the student preparations. A linearity standard curve was used to determine the amount of promethazine.
Expected Concentration of API: 0.3% ciprofloxacin


 

Zonisamide Suspension

Zonisamide capsule, 100 mg

4 capsules

Syrup NF

qs 40 mL

OR

 

0.5% methylcellulose 1500 cps

qs 40 mL

Mft. 40 mL

 

Link to Formulation Record:

Process of Analysis:
Column: 4.6 x 250 mm C18 10μ
Flow rate: 1.4 mL/min
Mobile Phase:30% acetonitrile and 70% 20 mM monobasic sodium phosphate, adjusted to pH 3.5 with phosphoric acid.
Detector wavelength: 240 nm
Injection volume: 25 μL
Retention time of zonisamide and methylparaben: 4.8 and 6.0 minutes, respectively
Sample Preparation: Diluted 0.5 mL of student preparation in 19.5 mL of mobile phase (see above) that contained 0.5 mg/mL of methylparaben as an internal standard. Dilution was vortexed for 10 seconds and left to sit for 5 minutes. A second dilution was prepared by extracting 1 mL of the supernatant from the first dilution and adding it to 9 mL of mobile phase that did not contain any internal standard. The second dilution was shaken well and injected into the HPLC.
Standard Solutions:
Expected Concentration of API: 10 mg/mL zonisamide


 

Diclofenac Gel

Diclofenac Sodium

1 g

Propylene Glycol

10 mL

Carbomer 940

1.25 g

Ethanol 95%

50 mL

Trolamine

20 drops

Purified Water

qs 100 mL

Mft. 100 mL

 

Link to Formulation Record:

Process of Analysis:
Column: 4.6 x 250 mm C18 10μ
Flow rate: 1.0 mL/min
Mobile Phase: 60% acetonitrile and 40% deionized water, adjusted to pH 3.0 with phosphoric acid
Detector wavelength: 280 nm
Injection volume: 10 μL
Retention time of diclofenac: 5.8 minutes
Sample Preparation: Dissolved 0.5 g in 20 mL of solvent (solvent can be water, propylene glycol, 50% isopropanol and 50% water, 50% acetonitrile and 50% water, or 60% methanol and 40% water). The sample was then hand shaken and injected into the HPLC.
Standard Solutions: Preparations of 0.85-1.15 g diclofenac per 100 mL were made in the same manner as the student preparations. A linearity standard curve was used to determine the amount of diclofenac.
Expected Concentration of API: 1% diclofenac