Experiment 4B - Particle Size and Shape Analysis using Microscope

Tittle: Particle size and shape analysis using microscope.

Date of experiment: 24^th November 2016

Objective:

1.      To analysis and interpret the particle size and shape with 5 different size of sands and powders (MCC, Lactose)

2.      To observe and compare the differences of the particles in size and shape from each sample.

Introduction:

            In order to achieve equivalent particle size and shape for drug (medicine) manufacturing, there are few methods can be used one of that is by using microscope. When using microscope, the particle size and shape can be seen clearly to ensure they in same size and shape. It is easier for industry pharmaceutical to manufacturing effective medicine for community. Powders also can be observed by using microscope, the particles have smaller size and shape to increase rate of dissolution.

Materials and apparatus:

Microscope compound, different size of sand particles and powders (MCC, Lactose).

Procedure:

      1.      Five different size of sand and powders are placed in a weighing boat.

    2.      The particles were analyzed to emphasis on the size and shape of the particles through the compound microscope.

     3.      Once the particles were observed microscopically the general shape for the particular material was determined.

RESULT – MICROSCOPIC VIEW

TYPE OF SANDS	MICROSCOPIC VIEW
150 MIC
355 MIC
500 MIC
850 MIC
VARIOUS SIZE
TYPE OF POWDERS	MICROSCOPIC VIEW
Microcrystalline Cellulose (MCC)
Lactose

DISCUSSION

Nowadays, particle size control of pharmaceutical manufacture of product quality becoming increasingly apparent in the pharmaceutical industry.

Particle size is a parameter having the dimension of length and defined by one or another of several arbitrary criteria such as:

1. The width of the smallest square opening, or the diameter of the smallest circular opening, through which the particle can pass

2. The diameter of a circle having an area equal to the maximum projected area of a particle

3. The diameter of a sphere whose volume is equal to that of the particle

4. The diameter of a sphere whose density and settling velocity are equal to those of the particle.

Several methods can be used in order to determine the particle size such as microscopy, sieving, sedimentation technique, Electrical sensing zone method- Coulter Counter, Laser Diffraction method and permeametry technique. The important of determine the size of particle are the release and dissolution of a drug. The release of drug that large in surface area much quicker because the size of drug is finer and particles dissolve quicker. Next, the dosage. The dosage of a particular drug might be altered if the particle size is too big or too small. In addition, if the particle sizes that aren't uniform may result in coagulation and improper dosages. Thus, improper dosages of certain drugs may result in severe reactions or even death in some cases.

In the experiment of Particle size and shape analysis using microscope, the particles that chosen to be observed are 5 different size of sand which are 150 mic, 315 mic, 500 mic, 850 mic and various siz and 2 type of powder which are lactose and MCC.

Compound Microscope is used in the experiment because compound microscope has sufficient magnification to allow adequate characterization of the smallest particles. The magnification which we used during this experiment set to be constant for all 7 samples which is 4x0.10 magnification. This is important so that we can compare the size and shape of the particle clearly and easily.

 Precaution when using the microscope is to ensure that the compound microscope is stable and is placed on a surface protected from vibration. From the experiment, we found out that the particles have different shape for different size of particles. The general size of each particles are very different from each other especially MCC and lactose which are smaller than the size of sand.

The particle size analysis can be done further by determine the diameter of the particle. The diameter of the particle can be calculated using 2 methods such as Feret's diameter or Martin's diameter. Feret's diameter is refers to the mean distance between two parallel tangents to the projected particle perimeter. Martin's diameter is the mean chord length of the projected particle perimeter. Advantages of this method are the particles can be examined individually.

CONCLUSION

From the observation in the experiment, we successfully analysis and interpret the particle size and shape with five different types of sands and powders (MCC, Lactose) through the compound microscope. We also successful observed and compared the differences of the particles in size and shape from each sample.

QUESTIONS FOR

1. Explain in briefly the various methods that you can use to measure the diameter of a particle.

There are several statistical methods which can be used to measure the diameter of a particle, such as Martin's diameter (dM), Ferret's diameter (dF), projected area and projected perimeter diameter (da or dp), sieve diameter (dS), volume diameter, longest dimension, and maximum chord.

Martin's diameter (dM) is the mean chord length of the projected particle perimeter, which can be considered as the boundary separating equal particle areas. The lines may be drawn in any direction which must be maintained constant for all image measurements. Martin’s diameter measures the chord of a particle and is useful for estimating the surface area of an irregular non-spherical particle. Ferret's diameter (dF) is the mean distance between two parallel tangents on opposite sides of the particle. This measure is used in the analysis of particle sizes, for example in microscopy, where it is applied to projections of a three-dimensional object on a 2D plane.

Next, projected area diameter (da) is the diameter of a circle having the same area to that of the projected image of a solid particle while projected perimeter diameter (dp) is based on the circle having the same circumference as the perimeter of the particle. Both of these methods are independent upon particle orientation. They only take into account of two dimensions of the particle, thus inaccurate for unsymmetrical particle.

A sieve diameter (dS) is defined as the width of the minimum square aperture through which the particle will pass. A common sizing device associated with this definition is a series of sieves made with square woven meshes. This diameter is frequently used in sieving experiment analysis. Volume diameter is a diameter of a sphere that has the same volume or surface area ratio as a particle of interest. Example of method that used this diameter is coulter counter machine.

In addition, longest dimension is a measured diameter equal to the maximum value of Ferret's diameter. Last but not least, maximum chord is a diameter equal to the maximum length of a line parallel to some fixed direction and limited by the contour of the particle.

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

The best statistical method that can be used for every sample is Ferret’s and Martin’s diameter. This is because both methods can give us the average diameter over many different orientations of the particles. As the result, a mean diameter value for each particle can be obtained. Thus, these methods are more accurate in analyzing the samples that we used (in this case sands, lactose and MCC) compare to other methods. Other than that, considering the orientation and shape of the image, we can use the electron microscope since Ferret’s diameter accesses the three-dimensional image of particles.