this contains all about cathartics or laxativs....its a very good presentation for pharmacy student to decribe about the catharics drug type

4. Sodium Orthophosphate

5. I.P. limit: It contains not less than 99.0% and not more than
100.5% of magnesium sulphate calculated with reference to
dried substance.
Properties: It occurs as colorless crystals having a cool,
saline bitter taste. It effloresces in warm dry air. It is
soluble in water and sparingly soluble in alcohol.
when gently heated, it loses some of its water of hydration
and gets converted into the monohydrate
(white powder) which becomes anhydrous at 200 degree
Celsius.

6. 2) On commercial scale it is manufactured by reacting sulphuric with dolomite.
Magnesium sulphate so formed is dissolved in the solution and the sparingly soluble
calcium sulphate is deposited. The liquid is filtered the filtrate is concentrated and
crystallized
Test for Identification: It gives reaction which are characterstic of
magnesium and sulphate.
For magnesium: To solution of sample add dilute nitric acid solution a white
precipitate is produced that is redissolved by adding 1ml of 2M ammonium
chloride, add 0.25M disodium hydrogen phosphate a white crystalline precipitate is
produced.
For sulphate: To 5ml of sample solution add 1ml of dilute HCl and 1ml barium
chloride solution white precipitate. Add 1ml of iodine solution to the suspension,
the suspension remains yellow (distinction from sulphites and dithionites) but
decolorizes on adding stannous chloride (distinction from iodates).

8. (3) It is also produce in large quantities from magnesium salt occuring in brine which is used
for the extraction of bromine. The liquors after removal of bromine ate treated with milk of
lime, thus precipitating out magnesium salt as magnesium
Hydroxide. sulphur dioxide, and air are passed through the suspension of
Magnesium hydroxide.
2Mg(OH)2 + 2SO2 + O2  2MgSo4 + 2H2O
On crystallization, crystals of MgSO4 . 7H2O are obtained
Assay: -
Weigh accurately about 0.3gm of sample dissolve in 50ml of water,
add 10ml of strong ammonia ammonium chloride solution is added.
and titrate with 0.05M disodium EDTA using 0.1gm of moderate black 11 mixture as
indicator until blue color is obtained.
Each ml of 0.05M disodium EDTA≡ 0.00602 gm of MgSO4

9. Action & Uses:
Magnesium sulphate is given orally in dilute solutions. About 5g gives
rise to laxative effect. Due to bitter and nauseating taste it is given in fruit juices .
The mechanism of action is that magnesium sulphate does not get
absorbed from intestinal Tract and thus retains sufficient water within the lumen
.the hydrostalic pressor is able to promote motor activity or peristalsis of bowel.
Usual Dose is 10-15g. It is to be used with care in patients with impaired
renal function. It is used as osmotic laxative, in treatment of electrolyte deficiency,
in wet dressing in boils, in treatment of cholecystitis
, sea sickness, hypertension etc.

10. Sodium Orthosulphate
Properties
1. Dry Powder, PelletsLargeCrystals, Wet Solid
2. Colorless
3. Solubility-14.5 g/100 g water at 25 deg C
4. Density-2.54 g/cu cm
5. Decomposition-75°C
6. pH- 11
7. Molecular Weight-163.939 g/mol
White odourless crystals, granules or a crystalline powder; hydrated forms
available include hemi- and monohydrates, hexahydrate, octahydrate,
decahydrate and dodecahydrate; the dodecahydrate contains 1/4 mol of
sodium hydroxide.

11. Loss on ignition Anhydrous:-Not more than 2% (120o , 2 h, then 800o , 30 min)
Monohydrate:- Not more than 11% (120o , 2 h, then 800o , 30 min)
Dodecahydrate:- 45-58% (120o , 2 h, then 800o , 30 min)
Water insoluble substances :- Not more than 0.2%
Fluoride :- Not more than 50 mg/kg (Method I or III)
Arsenic:- Not more than 3 mg/kg (Method II)
Lead:- Not more than 4 mg/kg
PURITY

12. Test for sodium :-To 5 ml of a 1 in 20 solution of the sample add 1 ml of acetic acid
TS and 1 ml of uranyl zinc acetate TS. A yellow crystalline precipitate is formed within
a few min.
Test for phosphate :-To 5 ml of a 1 in 100 solution of the sample add 1 ml of
concentrated nitric acid and 5 ml of ammonium molybdate TS and warm. A bright
canary-yellow precipitate is obtained.
Test for orthophosphate:- Dissolve 0.1 g of the sample in 10 ml water, acidify
slightly with dilute acetic acid TS, and add 1 ml of silver nitrate TS. A yellow
precipitate is formed.
IDENTIFICATION

13. Assay Dissolve an accurately weighed quantity of the sample, equivalent to between
5.5 and 6 g of anhydrous Na3PO4, in 40 ml of water in a 400-ml beaker, and
add 100 ml of 1 N hydrochloric acid.
 Pass a stream of carbon dioxide-free air, in fine bubbles, through the solution
for 30 min to expel carbon dioxide, covering the beaker loosely to prevent loss
by spraying.
 Wash the cover and sides of the beaker with a few ml of water, and place the
electrodes of a suitable pH meter in the solution.
 Titrate the solution with 1 N sodium hydroxide to the inflection point
occurring at about pH 4,
 then calculate the volume (A) of 1 N hydrochloric acid consumed. Protect the
solution from absorbing carbon dioxide from the air, and continue the titration
with 1 N sodium hydroxide until the inflection point occurring at about pH 8.8
is reached.
 Calculate the volume (B) of 1 N sodium hydroxide consumed in the titration.
When (A) is equal to, greater than, 2(B), each ml of the volume (B) of 1 N
sodium hydroxide is equivalent to 163.9 mg of Na3PO4. When (A) is less than
2(B), each ml of the volume (A) - (B) of 1 N sodium hydroxide is equivalent to
163.9 mg of Na3PO4.

14. Light Kaolin, IP
Preparation: It differs from the heavy variety mainly in the degree of purity and in
particle size. It is prepared from heavy kaolin by elutriation,
Reducing gritty and coarse particles. It should not contain any dispersing agent.
Properties: It is a light white powder, unctuous (Ointment like, soft) to touch.
Standards: Besides identification test limits prescribed are: arsenic,
heavy metals, chloride, soluble matter, loss on drying and
on ignition. Furher it has to be tested for coarse particles and fine
particles.
Uses: Used IN cathartics.
Light kaolin is mainly used as adsorbent for toxic substances from the
gastro-intestinal tract and to provide bulk by swelling with water in
conditions of diarrhoea. It may also be used in poultices.
dusting powders, toilet powders and as filtering aid .
Storage: It should be stored in a well-closed container.

15. Heavy Kaolin IP
Occurrence: This is a purified form of a natural clay having an approximate
composition Al2O3. 2SiO2.2H2O. Natural kaolin is contaminated with carbonates of
calcium and magnesium and ferric oxide. These can be easily removed by
treatment with hydrochloric acid, followed by filtration, washing and drying
Properties: It is a soft whitish powder, odorless and almost tasteless. It is insoluble in
water, organic solvents, mineral acids and alkali solutions.
Standards: The pharmacopoeia prescribes identification and limits for: acidity or
alkalinity, arsenic, heavy metals, chloride, sulphate, substances soluble in mineral
acids, organic impurities and loss on ignition tests are also included for determining
adsorption power and swelling power.
Uses:- Heavy kaolin is used in the preparation of poultices. As it is liable to be
contaminated with spore bearing bacille and other bacteria.
Storage: It should be stored in a well-closed container.

16. The term bentonite is applied commercially to any plastic, colloidal, and swelling
clay regardless of its geological origin. Such clays are ordinarily composed
largely of minerals of the montmorillonite group.
Bentonite derived from ash falls tends to be in beds of uniform thickness (from a
few millimetres to 15 m) and extensive over large areas.
Bentonite from ash falls and other sources occurs worldwide in strata spanning a
broad range of ages, but is most abundant in Cretaceous or younger rocks.
Bentonite is a rock or a clay base industrial material. It is therefore a mixture of
minerals.

17. Bentonite feels greasy and soap-like to the touch (Bates & Jackson, 1987). Freshly
exposed bentonite is white to pale green or blue and, with exposure, darkens in time to
yellow, red, or brown (Parker, 1988). The special properties of bentonite are an ability to
form thixotrophic gels with water, an ability to absorb large quantities of water with an
accompanying increase in volume of as much as 12–15 times its dry bulk, and a high
cation exchange capacity.
Physical and chemical properties
Bentonite is used as filler in pharmaceuticals, and due to its absorption/adsorption
functions, it allows paste formation. Such applications include industrial protective
creams, calamine lotion, wet compresses, and antiirritants for eczema. In medicine,
bentonite is used as an antidote in heavy metal poisoning. Personal care products such
as mud packs, sunburn paint, baby and facepowders, and face creams may all contain
bentonite.
Use