PHAN LEC (FINALS): Determination of Volatile Oil Content of Crude Drugs and Oleoresins

Ethereal Oils or

Essential Oils or

Essences.

Volatile Oils Also known as (3)

Volatile Oils

They are generally complex products composed of MIXTURES OF COMPOUNDS of widely variant chemical characteristics

Plant

Volatile oil are extracted from

Spirits

Preparation of volatile oil in a suitable solvent (containing solution)

Hydrocarbons

Important chemical components:

____ of the isocyclic series (double bond)

e.g. pinene, camphene, limonene, bornylene, fenchene, dipentene,

sylvestrene and phellandrene

Alcohols

Important chemical components:

both in the FREE STATE and in combination with acids as ESTERS.

linalool,

geraniol,

citroneol,

terpineol,

borneol,

menthol and

santalool.

Alcohols generally found in volatile oils (7)

Aldehydes

Important chemical components:

such as benzaldehyde, cinnamic aldehyde, salicylic aldehyde, citral and citronellal.

Ketones

Important chemical components:

the most important being camphor, carvone, fenchone, thujone and menthone.

Phenols

Important chemical components:

such as anethol, eugenol, carvacrol, saffrol and chavicol

Acids

Important chemical components:

sometimes in the free state in small quantities like

acetic, propionic, butyric, valeric, benzoic, cinnamic and hydrocyanic acids

but more often occurring in combination with alcohols as esters e.g. linalyl acetate, bornyl acetate and

methyl acetate.

Sulfur

Important chemical components:

compounds such as allyl isothiocyanate.

cuminaldehyde

Cumin oil

Carvone

Caraway oil

Cinnamaldehyde

cinnamon oil

Eugenol

Clove oil

Physical Constants

Determine for both fixed and volatile oil

Specific gravity

Physical Constants:

determined by the WESTPHAL BALANCE or pcynometer.

____ values ranges from 0.84 to 1.2. Oils

lighter than water are: orange, caraway, coriander, lemon, turpentine and rosemary oils.

Oils heavier than water include: anise, cinnamon, clove, sassafras oils

Rotatory Power/Optical Activity

Physical Constants:

measured by POLARIMETER.

Presence of adulterants such as alcohol or turpentine oil is determined by its influence in the rotatory power values.

Refractive index

Physical Constants:

most commonly used instrument is the

ABBE REFRACTOMETER.

___ values ranges from

1.46 to 1.61 at 20°C.

in some cases, the determination

may serve in the detection of extraneous matter

Distilling range

Physical Constants:

USP provides the official method for

determining the distilling range

Fractional distillation

Physical Constants:

fractionation of the oil determines possible presence of alcohol which distills or boils below 100°C.

A certain fraction of distilled oil may

be used to determine presence of adulterants by determining the rotary power

Solubility

Physical Constants:

generally, volatile oils are soluble in organic solvents. Purity may be well established based on the fact

that all volatile oils exhibit almost constant solubility with 90, 80 or 70% alcohol.

Presence of adulterants such

as turpentine oil, petroleum oils and fatty oils are slightly soluble thus producing turbidity.

❖ ester content

❖ alcohol content

❖ aldehyde content,

❖ ketone content

❖ phenol content

The purity of volatile oils are definitely established by the determination of chemical constants such (5)

Storage of Volatile oils

kept in a well-fitted tightly stoppered-amber-colored bottles in a cool place.

When mixed with a little alcohol the deterioration may be temporarily prevented.

Volatile oils from citrus plants may be preserved by the addition of five (5) to ten (10) percent of fixed oils.

steam distillation

ISOLATION/Distillation:

isolation of volatile oil is by ____ and measurement of the

volume of the oil obtained

Clavenger apparatus

ISOLATION/Distillation:

special distillation apparatus has been designed for the purpose whereby all the parts that will come in direct contact with the drug, volatile oil or steam are made of glass.

condenser

ISOLATION/Distillation:

is combined with the receiver to avoid as much as possible the loss of volatile oil vaporization and to provide direct reading of the volume of the oil

4 to 8 hours

ISOLATION/Distillation:

Complete extraction is effected by distillation for ____ hours.

oil lighter than water

its volume is directly measured in

the receiver which is provided with a lower portion graduated to tenths of a millimeter.

*long side arm used in____

oil is heavier than water

the oil is transferred to a

measuring cylinder and the water with whatever oil remains is placed in a separator. The rinsing together with the ethereal layer is allowed to stand so that the ether is evaporated and

any oil left is added to the oil in the measuring cylinder.

* short arm

acetates

Ester in volatile are in the form of _____ of alcohol

Esters

are refluxed with alc. KOH, saponified and yield the free alcohol and the potassium salt of the acid

Ester value

is the no. of mg of KOH required to saponify 1gm of the sample.

Menthol

Alcohol present in peppermint oil

Borneol

Alcohol present in rosemary oil

Free and combined as esters

Alcohol present in volatile oil may be

conversion of free alcohol to acetate ester

and

saponification sx

To determine total alc. content, the method requires

freshly produces acetate and original acetate with standard alcoholic potassium hydroxide

acetylization flask

acetic anhydride

Anhydrous acetate

Total menthol in peppermint oil- its used what kind of flask?

Acetylize alcohol-> ester using (2)

correction factor

should be done when the sample of volatile oil contains both ester and

alcohol

Correct menthol in ester form

Bisulfite Method

Aldehyde Content:

based on principle that aldehydes and ketones found in volatile oils form soluble addition products with sodium bisulfite and these products being soluble in water leave a certain volume of oil which do not contain aldehydes or ketones.

limited only for the assay of volatile oils which do not contain constituents other than aldehyde and ketones which react with sodium bisulfite. Likewise, this method is not applicable to volatile oils which contain aldehydes in very small amounts

Cassia flask

Bisulfite method use what flask

Hydroxylamine Method

Sodium hydroxide

What is titrimetric method of assay for aldehydes and ketone in volatile oil

It requires what titrant

*use erlenmeyer flask and indicator of bromophenol blue from to light green

They react with reagent to form soluble addition product leaveing non aldehyde, ketone, phenol compound in residual oily layer

Aldehyde, ketone, phenol have similarities in assay what it is

No phenolic portion

___ is found in unresolved liquid

Potassium hydroxide

Sodium bisulfite

Phenol content determination reacts with

While

Ketone and aldehyde reacts with?

Babcock bottle

Volatile oil in spirits use what bottle

*we add kerosine and solution calcium chloride

Babcock Bottle

is provided with a long neck calibrated into eight divisions of 0.2 mL each