Sieving

TITLE
Sieving

OBJECTIVES
1. To detrmine the particle size of solid lactose and microcrystalline cellulose (MCC) by using sieve nest
2. To odentify the particle size distribution of a particular powder.

INTRODUCTION

Sieve is an essential part of every pharmaceutical production process, particularly as product quality and integrity are so important. The use of a sieve gets rid of oversized contamination to ensure that ingredients and finished products are quality assured during production and before use or despatch. In basic terms, a sieve consists of a housing containing a removable wire mesh of a defined aperture size. This assembly is vibrated by an electric motor so that small particles can pass through the mesh apertures and any particles or contaminations that are too big remain on the top. Most units used in the pharmaceutical industry tend to be circular and of a high-quality good manufacturing practice (GMP) design by ensuring accurate separation. Stainless steel mesh with a high tolerance on the apertures is also specified to give excellent product quality

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In this experinment, student are given two common excipient used in tablet formulations, namely Lactose anfd Microcrystallipe (MCC). The objectives of the experinment is to determine the particle size and the size distribution of both powder.

MATERIALS

Lactose, Microcrystalline Cellulose (MCC)

APPARATUS

Sieve nest, weighting boat, and spatula

PROCEDURE

1. Firstly, 100 g of Microcrystalline Cellulose (MCC) is weighing.

2. The sieve nest was prepared and arranged in descending diameter to the smallest, from top a bottom.

3. The Microcrystalline Cellulose (MCC) was placed at the uppermost sieve and the sieving process in 10 minutes.

4.  Next, the Microcrystalline Cellulose (MCC) collected at every sieve was weighed and the particle are distribution was plotted in the form of histogram

5. Step 1-4 was repeated by using Lactose

RESULT

Size (diameter), μm	Particle size range, μm	MCC
		Weigh (g)	Frequency (%)
<50	0 ≤x <50	2.8780	2.88
50	50 ≤x <150	91.2385	91.24
150	150 ≤x <300	4.4295	4.43
300	300 ≤x <425	0.1026	0.10
425	425 ≤x <500	0.0022	2.20 x 10-3
500	500 ≥	0.0009	0.90 x 10-3

Size (diameter), μm	Particle size range, μm	Lactose
		Weigh (g)	Frequency (%)
<45	0 ≤x <45	0.2537	0.26
45	45 ≤x <150	4.5063	4.54
150	150 ≤x <300	26.5859	26.81
300	300 ≤x <425	67.7878	68.35
425	425 ≤x <500	0.0046	4.64 x 10-3
500	500 ≥	0.0392	0.040

QUESTIONS

1. What are the average particle size for both lactose and MCC?

The average particle size of lactose is between the ranges of 32 µm to 400 µm. The average particle size of microcrystalline cellulose (MCC) is average particle size 50µm.

2. What other methods can you use to determine the size of particle?

Laser diffraction is another method that can be used to determine the size of particles for the duo.  For the measurement the powder is passing a laser beam. The light of the laser beam is diffracted in different directions and the scatter pattern is recorded by detectors. The scatter pattern is strongly related to the particle size and the size distribution of the particles.

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

Conventional solid dosage forms such as tablets are administered orally for local and systemic action. The local activity (acid neutralizing capacity) attributed by antacid formulations is proportional to the particle size of the ingredient. Particle size is having a pronounced effect on the absorption of drugs with low aqueous solubility. This was demonstrated with tablets, capsules, suspensions and suppository dosage forms. Particle size of the pharmaceutical semi-solid dosage forms influences the efficacy, safety and performance of the dosage form. It affects skin penetration and can also influence the flux rate of the active ingredient. In addition, particle size is a key factor in determining process ability, spread ability and the rheological behaviour of a formulation

References:

http://www.pharmainfo.net/tegkmurthy/blog/influence-particle-size