Kulliyyah of Pharmacy, IIUM

PHM2213 Physical Pharmacy 2

Preparation of surfactants and determination of surface tension

Objective

To prepare anionic surfactants and to measure the surface tension of the surfactant solutions.

Introduction

Surfactants are widely used in pharmaceutical and cosmeceutical preparations. Even though anionic surfactants are known to be toxic, the simplicity of their preparation, which leads to low production cost, deems these anionic surfactants popular as a choice in numerous formulations.

In this practical, students will prepare a solution of potassium oleate and potassium caseinate.

Experimental procedure

1.  Preparation of 10% potassium oleate solution

  1. weigh 10 g oleic acid in a clean glass beaker.
  2. weigh 10 g of KOH.
  3. dissolve KOH in 80 g double distilled water.
  4. warm the KOH solution to 40°C
  5. while maintaining the temperature at 40°C, add oleic acid slowly and stir.
  6. pour solution in a 100 ml volumetric flask. Add double distilled water to the mark. Invert the flask three times.

2.  Preparation of 10% potassium caseinate solution

  1. weigh 10 g casein in a clean glass beaker.
  2. weigh 10 g of KOH.
  3. dissolve KOH in 80 g double distilled water.
  4. warm the KOH solution to 40°C
  5. while maintaining the temperature at 40°C, add casein slowly and stir.
  6. pour solution in a 100 ml volumetric flask. Add double distilled water to the mark. Invert the flask three times.

3.  Determination of surface tension

Refer to PHM1213 practical. Plot your results and determine the c.m.c.

Write a report and submit one week after the practical.

Include the following in your discussion:

  1. Can we use ammonium hydroxide or sodium hydroxide as the base?
  2. Explain the reason for the difference in c.m.c.
  3. What is the mechanism of colloidal stabilisation when using potassium oleate as the emulsifier?

Prepared by: Kausar Ahmad

Date created: 8-November-2004

Date of revision: 16-December-2004

Status: not finalised

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