PRACTICAL I : UNIFORMITY OF DIAMETER, THICKNESS AND HARDNESS

TITLE

Uniformity of diameter, thickness and hardness

OBJECTIVE 

To determine the uniformity of diameter, thickness and hardness of tablets

INTRODUCTION

Tablets and capsules represent unit dosage forms whereas liquid oral dosage forms such as syrups, suspensions, emulsions, solutions and elixirs usually contain one dose of medication in 5 to 30mL. Such doses are erratic by a factor ranging from 20 to 50% when the drug is self administered by the patient. The oral route of drug administration is the most important method for systemic effects. The parenteral route is routinely used in insulin therapy for self-administration of medication. The topical route of administration has only recently been employed with nitro-glycerine for the treatment of angina and scopolamine for motion sickness, but it suffers from effective drug absorption for systemic drug action of drugs that are administered orally, solid oral dosage forms (tablet and capsule) are the preferred class of products of the two forms, the tablet has a number of advantages such as the tablet is an essentially tamper proof dosage form.

Tablets and capsules, like other dosage forms, are subjected to those pharmacopoeial standards which deal with “added substances” with respect to their toxicity, interference with analytical methods and others. However, there are a number of procedures which apply specifically to tablets and capsules, and which are designed, not only to ensure that a tablet or a capsule exerts its full pharmacological actions, but also to determine the uniformity of the physical properties of the official tablet/capsule, irrespective of the manufacturer.

Such standards are found in the British Pharmacopoeia and United Pharmacopoeia and include the uniformity of diameter, uniformity of weight (mass), content of active ingredient, uniformity of content, disintegration and dissolution. Further, there are a number of quality control procedures, which, though widely applied, are not defined by the pharmacopoeias (non-pharmacopoeial standards) such as thickness, hardness and friability.

The following experiments is to demonstrate the application of a number of selected physical and dosage performance tests on samples of commercially available tablets and capsules.

PROCEDURES

1. 10 tablets selected and uniformity of diameter, thickness and hardness are determined using the Tablet Testing Instrument (PHARMATEST PTB 311).
2. The deviation of individual unit should not exceed ± 5% for tablets with diameter of less than 12.5mm and ± 3% for diameter of 12.5mm or more.

RESULTS

Tablet	Thickness (mm)	Diameter (mm)	Hardness	Deviation of diameter (%)
1	5.39	13.16	158.70	0.30
2	5.45	13.11	120.49	0.07
3	5.45	13.12	143.24	0.00
4	5.47	13.12	167.77	0.00
5	5.43	13.11	133.65	0.07
6	5.43	13.11	128.67	0.07
7	5.40	13.10	119.43	0.15
8	5.45	13.12	135.58	0.00
9	5.46	13.11	140.23	0.07
10	5.45	13.10	142.35	0.15
Mean	5.44	13.12	139.01	0.09

DISCUSSION

Tablet thickness is important for tablet packaging; very thick tablets affect packaging either in blisters or plastic containers. The tablet thickness is determined by the diameter of the die, the amount of fill permitted to enter the die and the force or pressure applied during compression.

In general, tablets should be sufficiently hard to resist breaking during normal handling, packaging and shipping, and yet soft enough to disintegrate properly after swallowing. Hardness of the tablet is controlled by (or is affected by) the degree of the pressure applied during the compression stage. Certain tablets such as lozenges and buccal tablets that are intended to dissolve slowly intentionally are made hard; others such as immediate-release tablets are made soft.

.In Experiment 1, uniform of diameter was introduced by the British Pharmacopoeia (BP) in 1958 to remove doubt. The test for diameter uniformity is only applied for coated and uncoated tablets. It is not applicable for enteric tablets, film coated tablets and sugar coated tablets. The tolerances for tablet with diameter of 12.55mm or less is ± 5% whereas for diameter of 12.55mm or more is ± 3%. However uniform of thickness and hardness is not required by BP and is also known as non- Pharmacopoeia tests. They are part of a manufacturer’s own product specifications. The tests are carried out to test the strength and resistant force to withstand mechanical shock during handling in production, packaging, distribution and storage. 

The Paralgin tablets are rather hard tablet as the mean of hardness is 139.01.   The diameter is more than 12.55mm and the deviation of individual unit from the mean diameter no exceed ±3%, at most only 0.3%. The mean thickness of the tablets  is 5.44mm.

CONCLUSION

In this experiment, Paralgin tablets have diameter bigger than 12.55mm. Deviation of individual unit from mean diameter of these tablets do not exceed ±3%. Therefore, it is found that all of Paralgin tablets undergoing uniformity test obey the rules and they are all pass the uniformity test.

REFERENCE

http://www.sadgurupublications.com/ContentPaper/2012/4_133_JCCPS_2(1)2012_P.pdf

(http://www.scribd.com/doc/47820668/Quality-Control-Tests-Tablets-Lecture-6)