Chlorobutal is a preservative with sedative, hypnotic and weak anesthetic properties. It is prepared by combining acetone and chloroform in the presence of potassium hydroxide. Assays involve hydrolyzing a sample with sodium hydroxide, determining the chloride ions using Volhard's method with silver nitrate and ammonium thiocyanate, and expressing the results in terms of the hemihydrate form. Tests for purity include dissolving a sample in ethanol and sodium hydroxide followed by the addition of nitric acid and silver nitrate.

1. CHLOROBUTAL
Structure :
OTHER NAME : Chloretone
IUPAC NAME: 1,1,1-Trichloro 2-methyl 2- propanol
PREPARATION : It is prepared by direct combination of acetone
with chloroform in presence of solid KOH.
MEDICINAL USES :
Chlorobutal is an alcohol based preservative with
no surfacetant activity .
It is also elicits sedative –hyponotic and weak
anaesthetic action in addition to antibacterial and
antifungal properties .
PROPERTIES :
Crystalline compound of characteristics odour
Hyponotic properties on use as preservative for sea
sickness.

2. Due to the variable proportion of water of
crystallization the melting point is not lower than 77 0
c
ASSAY : A weighed quantity of substance is dissolved in alcohol
and hydrolysed by being boiled under reflex with Aq NaOH. The
chlorides ions are determined by Volhard’s method with N/10
AgNO3 an N/10 NH4SCN. Before the thiocynate titration the
mixture is shaken in presence of small quantity of nitro
benzene in order to coagulate the AgCl precipitate.The result is
expressed in terms of the hemi hydrate, so that 1000 ml of
N/10 AgNO3 are equivalent to 1/3 Of C4 H7Cl3O. 1/2 H2 O.
TEST FOR PURITY : Dissolve about 0.1g accurately weighed in
20ml of ethanol ( TS .Add 10ml of sodium hydroxide
TS .Heat in water bath for 5 minutes and cool .Add
20 ml of nitric acid (130g/l) TS . ,25.0 ml of silver nitrate
(0.1ml/l) vs and 2ml of dibutyl phthalate R,and shake
vigourously ..

3. DIMERCAPROL
FORMULA : C3H8OS2.
STRUCTURE :
IUPAC NAME : 2,3 dimercapto-1-propanol
PREPARATION:
𝑨𝒍𝒍𝒚𝒍𝒂𝒍𝒄𝒐𝒉𝒐𝒍 + 𝑩𝒓𝟐 → 𝑮𝒍𝒚𝒄𝒆𝒓𝒐𝒍 𝒅𝒊𝒕𝒓𝒐𝒎𝒊𝒏𝒆 𝒉𝒚𝒅𝒓𝒊𝒅𝒆 → Dimercaprol
MEDICINAL USES :
Dimercaprol is a chelating agent that is used to remove a
heavy metal ( such as lead or mercury ) from the blood
and also used to treat arsenic gold mercury poisoning .
It is used to together with another medicine called EDTA
to treat lead poisoning
It is used to Wilson diseases .
Antidote for arsenic,gold and mercury poisoning.
PROPERTIES:
 Melting point < 250
c
 Boiling point 140 o
c at 4.oo E TO 1 mmhg
ASSAY : Dissolve about 0.12 gm,accurately weighed in 20 ml of
HCl (0.1 mol/lt) Vs and titrate rapily with ioine Vs using starch is
an indicator. Report the experiment test without the test liquid

4. being examined, and make any necessary corrections. Each 1ml
of iodine Vs is equvivalent to 6.211mg of C3H8OS2.
TEST FOR PURITY :
Ignite 2.0 g with 1g of Anhydrous sodium carbonate ,cool
dissolve the residue in 15 ml of dil HCl and dilute to 45 ml
with water . The resulting olution complies with the limit test
for iron .
GLYCERYL TRINITRATE
FORMULA : C3H5O3(NO2)
STRUCTURE :
OTHER NAME : nitroglycerine
IUPAC NAME : 1,2,3 –trinitroxy propane
PREPARATION : It is prepared by slowly adding glycerol to an
ice cooled mixture of conc.H2SO4 and conc.HNO3. The solution is
cautiously run into ice cold water, the nitroglycerine then
separates as a heavy oil which is purified by repeated washing
with cold water.

5. MEDICINAL USES :
It is used to treat angina
It can help to stop chest pain if an angina has already
started
It can also help to prevent them from starting .
PROPERTIES :
 Boiling point 218 0
c ( Ex : plodes decomposition starting
at 50-600
c )
 Melting point 13.10
c
 At room temperature glyceryl trinitrate is an pale yellow
in colour and oily liquid with a sweet burning taste (ACG
99 )
ASSAY : Nitrate is determined calorimetrically in a weighed
quantity of the powdered tablets by interaction with
phenol-2,4-disulphonic acid and subsequent classification with
ammonia. The yellow colour is matched against that of solution

6. Containing known quantities of potassium nitrate which hav
been treated similarly. The assay depends on the formation of
coloured nitro compounds by the interaction of the glycerol
trinitrate with the phenol-2,4- disulphonic acid,and the sub
sequent conversion of these into intensely ammonium salts.
The method suffers from certain disadvantanges ,the most
important of which is the difficulty of correctly matching the
yellow colour.
TEST FOR PURITY :
High Performance Liquid Chromatography ( HPLC ) was used to
assay the active ingrediants and to assay the active release of
glyceryl trinitrate from the prepared ointment base after
establishing the formula , the prepared ointment was clinically
tested on selected patients under supervision of specialized
surgeons
UREA
STRUCTURE :
FORMULA : NH2CONH2.
IUPAC NAME : carbamide carbonyldiamide

7. PREPARATION : A laboratory method is to evaporate solution
of ammonium cynate to dryness (wohler) about 95% NH4CN
becomes converted into urea by reversible isomeric change.
NH4COCN CO(NH2)2
ammonium cynate UREA
It is also synthesised by interaction of ammonia with carbonyl
chloride.