PRACTICAL 2 (PART B)

TITLE:
Practical size and shape analysis

OBJECTIVE:
 To observe and study the sizes and shapes of different type of sands.

DATE OF EXPERIMENT:
20th November 2014

INTRODUCTION:

The sizes of the solid medicines are very important in order to achieve suitable rate of absorption by the body. Powder with different particle sizes have different flow and packaging properties, which alter the volumes of powder during each encapsulation or tablet compression event. The particles which are having small dimensions will tend to increase the rate of solution. There are many methods can be used to analyse the size and the shape, one of the methods is microscopy. 

MATERIALS AND APPARATUS:

1. Microscope
2. Five (5) different samples of sand  (A=150µm, B=355µm, C=500µm, D=850µm, E=Various, lactose and MCC)

PROCEDURE:

1. Microscope was set up.
2. Five different particle samples were labelled with A,B,C,D.E, lactose and MCC.
3. A pinch of sample A was taken and put on the slide. The particles were separated one with another to prevent from redundant particle on one place. 
4. The sample was put on the slide and observed the particles size and shape using microscope with magnification x10.
5. The shape and size of particles had been analysed.
6. The experiment was repeated by changing the particles and used sample B,C,D and E. MCC and lactose are then analyzed with 40 times magnification.

RESULT: 

Sample A (10X)

Sample B (10X)

Sample C (10X)

Sample D (10X)

Sample E (10X)

Lactose (10X)

Lactose (40X)

MCC (10X)

MCC (40X)

QUESTIONS:

1) Explain in brief the various statistical methods that you can use to the diameter of the particle.

              The particles that consists of spheres or equivalent spheres of same diameter is to be mono sized, but most powders contain particles that have different diameters. The size of distribution can be broken down into different size ranges as it can be presented in the form of a frequency (histogram) and cumulative frequency form. The histogram method will expose to show the distribution of size particles in three types which are normal distribution, positively skewed distribution and bimodal distribution. The cumulative frequency usually for undersize and oversize.

       The mode and median diameters can be obtained for incomplete particle size distribution while the mean can only be determined from complete size distribution and upper and lower size limits is known. There are 3 ways to determined mean of particle size which are Arithmetic means, Geometric means and interconversion mean. Arithmetic means are achieved by summation of particular parameter for all the individual particles in a sample and divided and dividing the value achieved by the total number of particles. Geometric mean follow a log-normal distribution. Interconversion of mean are using Hatch-Choate equations.

2) State the best statistical method for each of the samples that you have analyzed.

                The best method that should be use is histogram.          

CONCLUSION:

In conclusion, the sand particles have various size and irregular shape that combine angular and rounded edges. It is the same for MCC but lactose has more angular edges rather than rounded edges and look likes prism. Every particles has its own shape and different sizes that can be obtain by using suitable method. For pharmaceutical industry, this is very practical for them to produce efficient medicines.

REFERENCE:

• http://www.horiba.com/fileadmin/uploads/Scientific/Documents/PSA/PSA_Guidebook.pdf
• http://www.horiba.com/scientific/products/particle-characterization/education/general-information/data-interpretation/understanding-particle-size-distribution-calculations/
• http://cma.tcd.ie/misc/particle_size.pdf

PRACTICAL 2 (PART A)

TITLE:
 Sieving

OBJECTIVE:
 To determine the particle size distribution of the powder material and the size of the solid particles by using sieve nest. 

DATE OF EXPERIMENT:
20th November 2014

INTRODUCTION:  

Sieve analysis helps to determine the particle size distribution of the coarse and fine aggregates. A sieve analysis can be performed on any type of non-organic or organic granular materials including sands, crushed rock, clays, granite, feldspars, coal, soil, a wide range of manufactured powders, grain and seeds, down to a minimum size depending on the exact method. A sieve test is performed by first assembling a stack of interlocking sieves. In this stack the sieve with the largest openings is at the top each lower sieve will have a smaller opening than the one above it. A pre-weighed sample of the material to be tested is placed in the top sieve. This sieve stack is the shaken until all the material has either been retained on a sieve or passed through. The material retained in each sieve is weighed and compared to the weight on the other sieves. A sieve test analysis or distribution is calculated which shows the proportion of each particle size category in the sample.

Test Sieve Machine

The materials which are tested in this experiment are lactose and microcrystalline cellulose. The lactose is first weighed and is poured into the sieve stack before being sieved  by using mechanical shaker for a fixed amount of time. At the end of the experiment, the weight of lactose is recorded and the experiment is repeated by using microcrystalline cellulose. The overall results are then  presented in histograms.

MATERIALS:

·         Lactose powder

·         Microcrystalline cellulose (MCC)

APPARATUS:

·         Sieve nest

·         Spatula

·         Weighing boats

·         Electronic balance

PROCEDURE:

1.      100g lactose was weighed.

2.      A 'sieve nest' was prepared in ascending order and the given size of the sieve.

3.      The lactose powder was put into the uppermost sieve.

4.      The lactose powder was sieved for 10 minutes.

5.      The weight of lactose powder collected at every sieve was recorded at the end of the experiment and histograms of particle size distribution was plotted.

6.      The above process was repeated using MCC.

  

DISCUSSION:

From this experiment, there are two materials that have been observed which are lactose and microcrystalline cellulose (MCC). The method used was sieving method, where we able to determine the particle size distribution. Sieve analysis consists of shaking the lactose and MCC sample through a set of sieves that have progressively prepare in descending order which is, larger diameter on the top while smaller diameter on the bottom. The sieve that have diameter of 500 µm are on the top and followed by 425 µm, 300µm, 200 µm, 150 µm, 53 µm, <53 µm. The results of sieve analysis are generally expressed as the frequency of total weight of lactose or MCC/ particle size distribution of the powder that passed through different sieve.

From this experiment it shows that most particles size of lactose are in the range of 50 - 150µm followed by range of 0 – 50µm respectively. While as for MCC, most particles size are in the range of 0 – 53 µm followed by a range of 53 – 150 µm.

At the end of the experiment, lactose and MCC used were collected back and were weighed. It was found that the total mass sample for lactose after sieving was 99.7419 g compare to the initial mass which was 99.9779 g. The total mass change from 99.9779 g to 99.7419. Meaning that, 0.2360 g was missing during sieving process. Meanwhile, same goes to MCC. The results for the total mass sample for MCC after sieving is smaller than the total mass before sieving. The initial weight for MCC was 101.0179 g while, upon completion, the weight was 100.1651 g. This mean, 0.8528 g of MCC was missing. This is probably because of the small particles of sample powder might missing during the sieves are being vibrated. Besides, some particles, especially the finer ones, might still adhesive attached to the sieve nest thus were not weighed. From this experiment, we found that, most particles in MCC is smaller than those of lactose.

As the recommendation, the screen on the sieves should be clean carefully in order to remove all the sample powders. The stack of the sieves on the sieve nest must be locked tidily to avoid them from moving away during shaking process. Beside, make sure that all the left over sample powders in each sieve is transferred to the container use in weighing process for a better result.

RESULT:

Size diameter of aperture (µm)	Particle size range (µm)	Lactose
		Weight (g)	Frequency (%)
<50	0<x≤50	4.9536	4.9547
50	50<x≤150	93.1901	93.2107
150	150<x≤200	1.2056	1.2057
200	200<x≤300	0.3625	0.3626
300	300<x≤425	0.0082	0.0082
>425	425<x≤500	0.0000	0.0000
Total weight (g)		99.7419

  

Size diameter of aperture (µm)	Particle size range (µm)	MCC
		Weight (g)	Frequency (%)
<53	0<x≤53	60.0473	59.9484
53	53<x≤150	34.1569	34.1106
150	150<x≤200	3.2373	3.2320
200	200<x≤300	1.7847	1.7818
300	300<x≤425	0.9293	0.9278
>425	425<x≤500	0.0096	0.0096
Total weight (g)		100.1651

 QUESTION:

1.      What are the average particles size of lactose and MCC?

The average particles size of lactose is 50<x≤150 µm while for MCC is 0<x≤53 µm

2.       Are there any other methods that can be used to determine certain particle size?

Yes. The methods that can be used to determine certain particle size are microscope methods, coulter counter, laser light scattering method, dynamic light scattering method, sedimentation method, air elutriation, photo analysis and optical counting methods.

3.      What is the importance of particle size in a formulation?

Particle size in a certain formulation is important in achieving optimum production of efficacious medicines especially in pharmaceutical phase. It can influence the bioavailability and activity of drug. For example, it can influence segregation behaviour, the ease with which powder flows through the press and the compressibility of a formulation. This factor of formulation also can influence the disintegration and dissolution rate in the body cavity.

CONCLUSION:

The objective to determine the size distribution of the sample of powders by sieve analysis is achieved. Most particles size of lactose are in the range of 50 - 150µm followed by range of 0 - 50µm respectively. While as for MCC, most particles size are in the range of 0 - 53µm followed by a range of 53 – 150µm. This shows that most particles in MCC is smaller than those of lactose.

REFERENCES:

1.      http://www.cscscientific.com/particle-size/sieves

2.      https://www.scribd.com/doc/18998525/Sieve-analysis

3.      http://www.slideshare.net/jeufier/screening-sieve-shaker

4.      http://www.pharmaceutical-int.com/article/particle-size-is-important-particle-analysis-techniques.html

5.      http://www.engineeringcivil.com/sieve-analysis.html