[ps2id id=’background’ target=”/]
BACKGROUND
Lycopodium spores are obtained from club moss, Lycopodium clavatum Linn., belonging to family Lycopodiaceae. The spores are yellow in colour, spheroidol, tetrahedral in shape with reticulate surface. They have uniform average diameter of 25 microns. One milligram contains average 94000 spores. They have uniform moisture content, hence the weight remains the same. This is the reason, why these spores are used to evaluate powdered drugs by comparison. The spores are also resistant to pressure.1
[ps2id id=’requirements’ target=”/]
REQUIREMENTS
Balance
Watch glass
Small flexible spatula
Microscope with mechanical stage or a counting square
Suspending agent: Fixed oil or suspending agent; glycerine: tragacanth mucilage: water (2:1:2). This keeps the spores and particles in a suspension. Dilution of the suspension should give about 10 to 20 spores in a field.
[ps2id id=’procedure’ target=”/]
PROCEDURE
Determine the loss on drying for the powder at 1050C. Mix a weighed amount of air-dry powder of the drug and a weighed amount of lycopodium spores in a small watch glass (100 mg drug and 50 mg lycopodium spores). Mix with a small flexible spatula. Add oil or suspending agent. Mix for 10 min till a smooth paste is obtained.
Transfer the suspension to a small glass tube by draining with the help of a glass rod. Add more suspending agent, washing down the mixture into the tube. (about 4 ml of the suspending agent is required for 50 mg of lycopodium spores). This should give about 10 to 20 spores when viewed under 4 mm objective, when a drop of the mixture is mounted under a cover glass.
Slowly oscillate the glass tube between the two palms without any air bubbles, until the suspension is uniform. Take a glass tube with internal diameter of about 2-3 mm and place one drop each on two sides, spread the suspension on the slide less than the area of the cover slip. Apply a cover slip and leave the slide on an even surface to settle.
Select 25 fields and count the spores and particles in these fields using 10×40 magnification.
Make a similar suspension as above and count particles in 25 fields on two sides.
Take average of 4 readings.
Calculate the percentage of foreign organic matter from the formula given below:
Percentage of foreign organic matter = 94000 x 100 x n x w / s x m x p
m= weight in mg of the sample, calculated on sample dried at 1050C
w= weight in mg of the lycopodium spores
n= number of particles in 25 fields
p= number of particles in per mg of the pure foreign matter dried at 1050C
94,000= number of spores in one mg of lycopodium
Calculations
1 mg of lycopodium powder contains spores = 94000
W mg of lycopodium powder powder contains 94000 x w number of spores.
s number of spores in ten fields mix with n number of starch grains in ten fields.
94000 x w number of spores mix with = 94000 x n x w / s (number of starch grain)
1 mg of pure sample of foreign organic matter (F.O.M) contains p number of starch grains
Weight of ginger in the mixture= 94000 x n x w/ s x p (mg of ginger)
m (mg) of mixture contain = 94000 x n x w/ s x p
1 mg of mixture contains = 94000 x n x w/ s x p x m
Percentage of F.O.M = 94000 x n x w x 100/ s x p x m
[ps2id id=’conclusion’ target=”/]
CONCLUSION
Number of starch grains in the given sample is ________
[ps2id id=’references’ target=”/][ps2id id=’1′ target=”/]
REFERENCES
- Joshi S, Aeri V, Practical Pharmacognosy. 1st edition, Frank Bros. & Co. New Delhi; 2009: 211-212.
