In this PDF you'll be able to learn and understand the drug Menthol in a very subtle and easy way. If you have any doubts or any mistakes found , pls do contact me through my mail that is given below . jeevangowdalatha@gmail.com

1. 
MENTHOL
FROM ,
Jeevan Gowda
3 rd year
Sri Adichunchanchanagiri college of
pharmacy .
This Photo by Unknown Author is licensed
under CC BY-NC

2. 
OBJECTIVES
▪ To learn about the drug Menthol , it`s general introduction , isolation ,
identification , and analysis of Menthol drug .

3. 
General introduction
▪ DRUG – Mentha / Menthol .
▪ SYNONYM – Pudina , Brandy mint , Lamb mint , Peppermint oil .
▪ BIOLOGICAL SOURCE – Menthol is a monoterpene alcohol obtained
from different variety of Mint oils or Peppermint oils from the fresh
flowering tops of Mentha Piperita , Mentha Officinalis
▪ FAMILY – Labiatate .
▪ GEOGRAPHICAL SOURCE – Asia , Europe , North America
,cultivated in India , Japan , Germany , France , Italy .

4. 
CHEMICAL CONSTITUENTS
▪ Volatile oil ( 0.7 – 1.5 % ) contains free Menthol ( 78% ) Menthol easters (
20% ) .
▪ Other important constituents are mentho furan, menthone, menthyl acetate,
menthyl isovalerate, jasmone and other derivatives like cineole, l-limonene,
isopulegone, camphene, pinene, jasmine and esters (possess pleasant odour).
Mentho furan is responsible for bad odour due to resinification.
▪ Tannins ( 6 to 12% )
▪ Flavonoids
This Photo by Unknown Author is licensed under CC BY-SA

5. 
EXTRACTION AND ISOLATION
▪ HYDRO DISTILLATION METHOD
1. Take accurate weighed coarse powder of Mentha Piperita leaves .
2. Extract the oil by water/hydro distillation method using Clevenger
apparatus .
3. collect the oil ( present above the water layer ) from the collecting tube
or separate the oil from water by using separating funnel and allow cooling .
4. crystals of menthol will separate out .
5. collect the crystals by centrifugation .
6. recrystallize menthol from acetone or any other suitable solvent of low
boiling point .

6. 

7. 
▪ STEAM DISTILLATION METHOD
1. Required quantity of air dried mentha plant is charged in to stainless
steel having perforated bottom .
2. the steam under pressure is generated with the help of boiler and
steam is passed through the drug .
3. the mixture vapour ( water and volatile oil ) are passed through the
condenser where vapour is and back to liquid form .
4. the mentha oil is collected in separating can . Mentha oil is floated on
top of the water due to lighter than water .
5. the oil is then decanted and filtered .

8. This Photo by Unknown Author is licensed under CC BY-
SA-NC

9. 
Identification by chemical test
• Few drops of sample is mixed with 5ml of nitric acid and
heated on water bath. Blue color is developed within 5
minutes, after some time it becomes yellow which indicate the
presence of menthol.
• Small qty of menthol in TT + equal qty of thymol or
camphor →liquifaction of contents in TT→ presence of
Menthol.
• Crystals of Menthol in watch glass+ heat on water bath →
material evaporates.

10. 
Identification of menthol
▪ T.L.C Method
Sample preparation – dissolve 1 mg of menthol in 1 ml of menthol .
Stationary phase – silica gel 60 F 254
Standard sample – menthol .
Mobile phase – pure chloroform , hexane:ethyl acetate::8:2 .
Detecting agent – 1% vanillin – sulphuric acid reagent and heat the
plate at 110 c for 10 minutes .
Anisaldehyde – sulphuric acid reagent , heat at 115 c
for 10 minutes .
RF value – 0.34 , 0.48 – 0.62

11. 
Thin layer chromatography of menthol

12. 
▪ IR SPECTROSCOPY
Functional Groups:
IR spectroscopy helps identify functional groups present in menthol based on the absorption of infrared
radiation.
Characteristic Peaks:
A broad peak around 3300 cm^-1 indicates the presence of O-H stretching, typical of the hydroxyl group in
menthol . Peaks in the region 2900-2800 cm^-1 correspond to C-H stretching vibrations in methyl and
methylene groups . Peaks in the 1700-1600 cm^-1 range indicate C=O stretching vibrations, common in ketones.
Fingerprint Region:
The fingerprint region (below 1500 cm^-1) contains unique patterns for each compound, aiding in the
identification of menthol.
Hydroxyl Group Confirmation:
The presence of a broad peak around 3300 cm^-1 confirms the existence of the hydroxyl (OH) group in menthol
. Interpreting these characteristic peaks allows researchers to identify and analyze the functional groups within
menthol, contributing to its structural elucidation.

14. 
It runs on the principle of partitioning of volatile sample with gaseous mobile
phase and liquid stationary phase.
Velocity of the compound through the column depend on affinity for the
stationary phase.
Types: Based on stationary phase.
1)gas liquid chromatography
2)gas solid choromatography
Process :
Cylinder release controlled amount of Inert gas(mobile phase)
and sample is also injected,where they combine at the
column(made up of stain less steel).
Column contain stationary phase (LIQUID OR SOLID)
*When the sample passes through the column, if the sample have more
affinity Towards liquid phase then that separation is called liquid-liquid
separation,
*If sample have affinity towards mobile phase, then that separation is called
liquid -gas chromatography.
*Once the sample is separeted then the separated level is analysed and
displayed in detector.
GAS Chromatography

15. 
1)Carrier gas :Helium
2)Column oven temperature: Initial Final
90℃ 181℃
3) Detector temperature:180℃
4) Injector temperature:280℃
5) Flow rate:5.0ml/minute(constant)
6)split ratio:50
7)Injection volume:1μL
8) Gases flow rate: Makeup gas
He→30ml/minutes
H2→30ml/minute
Air→300ml/minute
GC Parameters.

16. 

18. 
Uses of Menthol
▪ Carminative, stimulant, aromatic, counter-irritant and also as
flavouring agent.
▪ Used in toothpaste, Shaving cream, Chewing Tobacco.
▪ Preparation of Chewing gums, Jellies, Perfumes and
essences .

19. 
ANY DOUBTS ??????????