NFNF2283 : EFFECT OF DIFFERENT AMOUNT OF PEG ON THE PHYSICAL CHARACTERISTICS OF SUPPOSITORY

DATE: 7^TH MARCH 2017

TITLE: The Effect of Different Amount of PEG On The Physical Characteristics of Suppository

INTRODUCTION:

Suppository is another way to deliver a drug besides than oral or injections. It is a solid dosage form of various sizes, appearances and weight intended to be administered by rectal route where it will melt, soften or dissolve to produce its effects.

The suppository is usually composed of medicament that is dissolved or suspended in a suppository base. Suppository is intended for systemic action in paediatric patients and in patients who cannot swallow or tolerate oral medication due to a variety of reasons.

The base of the suppository must be suitable for the spread of drugs. Ideal suppository bases should be easily formed by compression or molding, can release any medicaments readily, able to melt at body temperature or can be dissolved or dispersed in body fluids, still in shape when handled, compatible with the drugs, non-irritant and non toxic.

For this experiment, we are using polyethylene glycol (PEG) polymers that have received much attention as suppository bases due to its desirable properties; chemically stable, non irritant, miscible in water and mucous secretions and can be formulated by either molding or compression in a wide range of hardness and melting point. In addition, they do not melt at body temperature but dissolve to provide a prolonged release.

Certain PEG polymers may be used as singly as suppository bases but commonly we use two or more molecular weights mixed in various proportions as needed to yield a finished product with satisfied hardness and dissolution time.

OBJECTIVES:

1.      To calibrate suppository mould with PEG before preparing medicated suppositories.

2.      To determine the effect of different compositions of PEG base on the physical characteristics of suppositories.

MATERIALS AND METHODOLOGY:

APPARATUS:

ü  Analytical balance

ü  Water bath at 37℃

ü  Hotplate

ü  4 x50mL beakers

ü  1 x 5mL pipette and pipette bulb

ü  1 x 5mL measuring cylinder

ü  1 x suppository mould set

ü  1 x spatula

ü  4 x weighing boats

ü  2 x glass rod
MATERIALS
ü  Polyethylene glycol 1000
ü  Polyethylene glycol 6000
ü  Paracetamol
ü  Distilled water
ü  Liquid paraffin

METHODOLOGY

1.      Calibration of suppository moulds with PEG base

For this calibration exercise, 10 g of the following proportions of PEG 1000 and PEG 6000 were used:

Ingredients	Percentage	Weight Basis
PEG 1000	60%	6g
PEG 6000	40%	4g

2.      To calibrate the mold with PEG suppository base:

1.      A clean and dry mold was taken and was lubricated with liquid paraffin.

2.      PEG 1000 was melted on a hot plate, then PEG 6000 was mixed into the hot plate after reducing the heat.

3.      The mixture was removed from the heat and was allowed to cool before pouring into the mold.

4.      The cavities was overfilled in the mold and let in room temperature until solid.

5.      The excess was carefully removed with a hot spatula and then the suppository was removed from the mold.

6.      The suppositories were weighed and the total weight was recorded. The average suppository weight was calculated.

RESULT

Mold #	1350
Total weight for 6 suppositories	6.1670 g
Average weight  for one suppository	1.028 g

3.      Preparation of paracetamol suppositories

1.      Saturated stock solution of paracetamol was prepared by adding 10g of paracetamol in 5 Ml distilled water.

2.      The paracetamol suppository (10g) was prepared using following formulation:

Suppository	PEG 1000 (g)	PEG 6000 (g)	Paracetamol stock solution (mL)	Total (g)
I	9	0	1	10
II	6	3	1	10
III	0	9	1	10

3.      PEG 1000 was melted on the hot plate, then the heat was reduced and mixed with PEG 6000.

4.      The mixture was removed from the heat and was allowed to cool before pouring into the mold.

5.      The cavities was overfilled in the mold and was let in the room temperature until it was solid.

6.      The excess was carefully removed with a hot spatula, the suppositories were removed from the mold.

7.      The shape, texture and colour of the suppositories was observed.

8.      Each of the suppositories was put into a separate beaker containing distilled water (10Ml and pre-warmed at 37℃).

9.      The time for the suppositories to melt was recorded.

DISCUSSION

1.Describe the importance of calibrating suppository mould before preparing medicated suppository.

It is important to calibrate the suppository mould before preparing the medicated suppository to ensure that the medicated suppository have the supposed amount of medicine. This is due to the ability of the medicinal substances to alter the density of the base material thus resulting in slight changes in the weight of the suppository when compared to the one without the medicine.

2.Compare the physical appearance of suppositories that are formed and discuss.

Suppositories	Observations	Shape	Texture	Colour
I		Bullet	Greasy, hard	White
II		Bullet	Greasy, hard	White
III		Bullet	Less greasy ,hard	Transparent white

All the suppositories are bullet-shaped as they are moulded in the same type of mould . Suppository I have PEG 1000 as its base whereas suppository III have PEG6000 as its base. Due to this factor, suppository I is more greasy than suppository III. Melting point for PEG 1000 is 37-40⁰c whereas melting point for PEG 6000 is 60-63⁰c.Melting point for PEG 1000 is lower than PEG 6000 because PEG 1000 have smaller molecular weight compare with PEG 6000. There is less hydrocarbon chain in PEG 1000 compare with PEG 6000 ,thus, less energy is needed to break the hydrocarbon chain. Hence, melting point of PEG 1000 is less than PEG 6000.

3. Plot a graph of time required to melt the suppository vs. the amount of PEG 6000 in the formulation. Compare and explain the results.

PEG 6000 amount (g)	0	3	9
Time (min)	4.58	6.63	8.20

 
   Polyethylene glycol (PEG) is a polyether compound that has a wide array of application ranging from industrial manufacturing to medicine. It is an inert, non-ionic and long-chain polymer which is commonly expressed as H−(O−CH2−CH2)n−OH. In this experiment, it is used as water soluble or water miscible bases for the manufacture of suppository. In this context, different molecular weights of PEG will contribute to differences in the physical parameters such as solubility, freezing point, melting point, surface tension and the time taken for the suppository to melt in our body.

From the aspect of physical characteristic, we observed that PEG 1000 with a lower molecular weight exist as a greasy semisolid while PEG 6000 with a higher molecular weight exist as a waxy solid. In this experiment, we are also required to examine the time needed for the suppository to melt with different composition of PEG 6000 in the formulation. Theoretically, the suppository with higher composition of PEG 6000 will take a longer time to melt compared to that with a lower composition of PEG 6000.  From the graph above, it show that the higher composition of PEG 6000 (9g) will take a longer time to melt as compared to the lower one which are 0g and 3g respectively. At first, the time required for suppository that consists of 0g of PEG to melt is 4 minutes and 35 seconds whereas the suppository consisting 3g of PEG 6000 takes 6 minutes and 38 seconds to melt. The time needed for the suppository consisting 9 g of PEG 6000 to melt is the longest, which is 8 minutes and 12 seconds. Thus, this experiment shows that the time needed for the suppository to melt increases with increasing amount of PEG 6000 in the formulation. This is due to the high composition of PEG 6000 which has lower water solubility as compared to PEG 1000, causing it to take longer time to melt. Thus, we can conclude that the suppository with higher amount of PEG 6000 should take longer time to melt in the body’s fluid as the suppositories in this experiment are melted at 37  in water bath which is similar to our body temperature.

4.Describe function(s) of each ingredients used in the suppository formulation.

The suppository contains of PEG 1000 and PEG 6000 as the base; chosen due to their stability chemically,  non-irriating and miscible with water and mucous secretion properties, paracetamol as the medicinal ingredient and water for the paracetamol stock solution.

CONCLUSION

1.    Calibration method was done by  using PEG 1000 and PEG 6000 in this experiment and the average weight of one suppository was 1.028 g.

2.   Different compositions of PEG bases gave different physical characteristics of the suppositories. Our hypothesis was, increase in PEG 6000 bases increases the hardness of the suppositories, thus increases the melting time. The hypothesis was accepted as seen in our results.

REFERENCE

1. http://pharmlabs.unc.edu/labs/suppository/bases.htm

2. https://www.slideshare.net/PHARMACISTS/suppository

3. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&cad=rja&uact=8&ved=0ahUKEwiK0tWq19_SAhWIrI8KHc6XDToQFggrMAM&url=http%3A%2F%2Fwww2.syphu.edu.cn%2Fsyzx%2Fyjx%2Fmaterials%2Fjc_english%2F06.doc&usg=AFQjCNFGDH6W3hrSZkbkzLzrIbK897OiAA&sig2=cBIU9NbBeH07TVdTJoziiw&bvm=bv.149760088,d.c2I