Utensils Used in Pharmacy Practicals
Dispensing Scale (Balance)
is used to weigh the ingredients used in dispensing of pharmaceutical preparations. Minimum weighble quantity is taken as 100mg (60mg or one Grain Erlier). Weighings are done to the nerest 3rd decima pace.
e.g. 1.335g = 1g + 355 mg
1.3555g = 1g + 356 mg
1.3554g = 1g + 355 mg
When the 4th decimal place is 5 or more,one is added to the front number. If it is less than 5, the 4th number is ignored. In weighing, do not directly weigh on the pan, but on a piece of paper. For this fist put two equal pieces of paper on either pan and balance before starting to weigh. Always put the weights on the eft side pan and the drugs on the right side pan. When putting the drugs keep the pans raised. when taking out the drugs lower the pans to sit on the platform of the balance.
The Counter Scale : ( Balance)
Is used ti weigh larger amounts of drugs, and ointment bases and liquids in making semi solid preparations and solid preparations.
Rhis balance works on the same principles as the dispensing scale; but the pans are supported on the base of the balance., instead of being hung from the bridge of a balance.
The pans may not look the same. In this case, to find whether the balance point is reached look whether the balance point is reached look whether 'D' is of the same height.
Measure Glass :
This is the glass where solutions are made. Usually the graduations start with 30 mL and increase in 30s going up to 240 mL in a medium size measure Glass. In making simple solutions, - everything is dissolved in this glass. The base should be added, usually half the final volume, before adding any other ingredients.The lower meniscus (Level) should be in line with the graduation for correct measurement and accuracy. For preparations, where the final volume is more than 30 mL., this glass can be used.
Minim Glass:
This is used to prepare preparations where the final volume is less than 30 mL.
Measuring Cylinder:
this is used to measure small quantities of liquid ingredients to be added to the liquid preparations. This is graduated usually from one to ten mL. Each mL is divided into 5 equal portions of 0.2 mL. Less than 1mL will have to be taken in drops using a pipette (Dropper).
For this take 1mL = 15 drops.
Therefore 0.5 mL - 15* 0.5 - 7.5 drops,
taken approximately as 8 drops.
Mortars and Pestles:
01. Composition mortar and pestle:
This is used to grind (crystals) and lumps of substances into smaller particles. This is also used to make dispersion, suspensions and emulsions.
02. Powder mortar and pestle ( Double composition Mortar and pestle:
This mortar has two sides. The shallow side is used for making powders, and the deep side for pills.
Powder Folder:
Is a device to fold the powders, so that the powders are of equal shape and size.
Spatulas :
01 Ointment Spatula:
Made of stainless steel and used to make ointments by simple mixing or trituration.
02. Vulcanite / Horn' or Bone Spatula:
These are used to make ointments and to take ingredients from the reagent bottles
03. Powder Spatula:
These are usually made of metals and are used for taking ingredients out of regent bottles.
Generally for acidic substances and for salts of silver and mercury, vulcanite or bone or hon or stainless steel spatulas should be used.
Water Bath
It is a metal vessel on which are placed removable metal rings with a centre hole on which can be placed a porcelain dish. Water is put into the vessel and boil using a ring gas burner. When drugs need to be melted they are placed in the porcelain dish and heated over the hot water dish.
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