LABORATORY MANUAL PHM 2143 PHYSICAL PHARMACY II

Transcription

1 DEPARTMENT OF PHARMACEUTICAL TECHNOLOGY LABORATORY MANUAL PHM 2143 PHYSICAL PHARMACY II NAME MATRIC NO. Please read the instructions, carry out the lab practical and answer the questions. You may be requested to re-sit if the lab work and the responses are not satisfactory.

2 1/9 Practical 1 Emulsion Formation Task Question Response 1. Prepare oil-in-water a. Describe your emulsion. emulsion. i) Use the formulation given in Table 1 or Table 2 of Appendix A. You are required to do ONE emulsion only. - type of oil, concentration - type of surfactants, concentrations, HLB b. What was the temperature before and after emulsification? ii) Homogenise for 10 minutes at room temperature. Depending on the homogenizer given, set speed at a minimum. Do not change the speed during the homogenization. Wait for 5 minutes. If there is phase separation, continue homogenisation. Discuss with your group members the speed and time required to produce stable emulsion. iii) Upon completion, cover the beaker. c. Describe the homogenizer used. What was the speed of the homogenization? What happen if you increase the speed? d. What was the duration of homogenization? What happen if you increase the duration? e. Did you get an oil-in-water emulsion? Explain. 2. Heat 50 g of emulsion in a beaker until 70 C. Put aside. Observe. a. Explain your observation.

3 2/9 Task Question Response 3. Pour 100 ml of the emulsion into a 100 ml graduated cylinder. Cover. Keep at 30 C. Observe and record the separation of the phases after 10 min, I, 2 and 24 hours. a. Draw a histogram indicating the phase separation. Indicate the volume of oil if any, turbid phase and watery. Label y and x axes. Table 1 Phase separation of emulsion Phase Time (h) volume (ml) Yellow oil White emulsion Slightly turbid Clear watery Legend: Symbol Description Oil Emulsion Water b. Indicate the relative oil content in each phase (which phase has more oil?). Figure 1 Phase separation of emulsion c. Why does phase separation occur? d. Can phase separation be minimized? Explain. e. Why do you need to cover the measuring cylinder?

4 3/9 Practical 2 Viscosity Task Question Response 1. Measure the viscosity of the remaining emulsion using a rotational viscometer. a. How many days lapsed after emulsion preparation did you measure the viscosity? Measure viscosity at different speeds. Record the readings and indicate in your response. b. Plot the viscosities at the different speeds. Label y and x axes. Note: Read the instructions and handle the viscometer with care. Start with the smallest spindle until you find a spindle that is suitable (Hint: 20% < torque < 80%). DO NOT exert pressure while mounting the spindle. This may damage the instrument. c. Which spindle did you use? Figure 2 Viscosities of emulsions at different rotational speeds d. How does the shape of the spindle affect viscosity? e. Explain the results observed in Figure 2.

5 4/9 f. How does viscosity affect the stability of an emulsion? g. Why is control of viscosity important to the end user? h. What type of excipient can be used to modify the viscosity? 2. ADD 1 ml of 1% w/v of Carbopol 940 solution into 100 ml emulsion. Stir. Pour into 100 ml measuring cylinder. a. Plot the phase separation Compare with Figure 1. Label y and x axes. i) Observe phase separation and record. Table 2 Phase separation of emulsion with viscosity modifier Phase Time (h) volume (ml) Yellow oil White emulsion Slightly turbid Clear watery Yellow oil ii) Determine viscosity. Use smallest spindle and highest speed first. b. Compare Figure 3 with Figure 1. c. Compare the viscosity before and after the addition of Carbopol 940 solution. Figure 3 Phase separation of emulsion after adding viscosity modifier

6 5/9 Practical 3 Particle size analysis Task Question Response 1. Measure the particle size of the remaining sample using laser diffraction technique. a. Plot the size distribution and label your graph. Label y and x axes. Repeat your measurement. Your results will be the average of these two readings. Note: Read the instructions and handle the sizer with care. Ensure that you have the correct information about your emulsion before you use the results given by the programme: Confirm the refractive index of the dispersed phase and the continuous medium. b. What is the average diameter and standard deviation? c. What is the mean diameter? Figure 4 Particle size distribution of oil droplets d. What is the mode? e. What is the polydispersity index. f. Is your emulsion a polydisperse sample? Explain. g. Why do you need to know the refractive index of your sample?

7 6/9 Practical 4 Chemical stability Task Question Response 1. Observe the remaining emulsion under an optical microscope. Did you see any coalescence? Explain. i) Take a picture and indicate the scale, sample identification, microscope model and magnification. ii) Attach the picture to this working manual. 2. Add 5 ml of 0.5 M aluminum chloride to 50 ml of emulsion. Stir. Observe under microscope after 30 min. 3. Add 5 ml of 0.5 M sodium chloride to 50 ml of emulsion. Stir. Observe under microscope after 30 min. 4. Add 5 ml of 0.5 M hydrochloric acid to 50 ml of emulsion. Stir. Observe under microscope after 30 min. 5. Observe the emulsions under the microscope after 30 minutes. What happened to the emulsion? What happened to the emulsion? What happened to the emulsion? Did you see any coalescence? Explain. i) Take a picture and indicate the scale, sample identification, microscope model and magnification. ii) Attach the picture to this working manual.

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9 8/9 Lab report Based on your lab practical, submit ONE laboratory report PER GROUP within TWO weeks. Late submission will not be entertained. The report is worth 8 % of total assessment for the course. Each practical when executed successfully with satisfactory responses may contribute a maximum of 3% each. Attach this working manual as your Appendix. Please refer to the following links for acceptable format of report and contents: and Report format Abstract Introduction Materials and methods Results Discussion Conclusion References In Discussion, include the following: Relate your experimental results to known theories. Include errors made during the practical. Include safety issues and precautions.

10 9/9 APPENDIX A TABLE 1: HLB AND RATIO OF SPAN 20 AND TWEEN 20 HLB Emulsion amount (g) Oil content (20% of emulsion) (g) w1 + w2, Total emulsifier (10% to oil) (g) HLB SPAN HLB TWEEN f1, weight fraction of SPAN f2, weight fraction of TWEEN w1, weight of Surfactant 1 (g) w2, weight of Surfactant 2 (g) Perfume/colour q.s. q.s. q.s. q.s. q.s. Water (g) TABLE 2: HLB AND RATIO OF SPAN 20 AND TWEEN 80 HLB Emulsion amount (g) Oil content (20% of emulsion) (g) w1 + w2, Total emulsifier (10% to oil) (g) HLB SPAN HLB TWEEN f1, weight fraction of SPAN f2, weight fraction of TWEEN w1, weight of Surfactant 1 (g) w2, weight of Surfactant 2 (g) Perfume/ colour q.s. q.s. q.s. q.s. q.s. Water (g)