Mumbai University, FY B pharm, General chemistry

1. Protective/ Topical agents
By
Dr. Taj Khan
Dept. of Pharmaceutical Chemistry, Oriental college of pharmacy
Sanpada, New Mumbai.

3. Definition: Topical means pertaining to a particular
locality or place or simply it means “local”.
Substances which are applied directly on the skin or
mucous membrane or any other surface.
Protective and adsorbents:
drugs which adsorb intestinal toxins, bacteria etc,
and give a protective coating to the inflamed mucus
memb.

4.  3MgO, 4SiO2, H2O
 Test for Purity
 Acidity or alkalinity
 Water-Soluble substances
 Acid-Soluble substances
 Iron
 Carbonates
 Loss on drying
 Organic compounds
 Chloride
Talc
talcum, french chalk, purified talc

5.  Storage:
 Talc is an inert substance not affected by acids or bases
or other chemicals. So store in a well closed container.
 Medicinal and pharmaceutical Uses:
 Pharmaceutical aid (dusting powder). Used as a
filtering and distributing medium in the preparation of
aromatic waters etc.
 Main ingredient in talcum powders and dusting
powders
Talc

6.  Preparation
 Zinc oxide is prepared on a large scale by burning
zinc metal in a current of air.
2Zn + O2 = 2ZnO
Insoluble Zn compounds:
Zinc oxide/ZnO

7.  Assay:
 The sample is dissolved in 2M acetic acid and diluted with water.
Xylenol orange titrurate and sufficient hexamine to produce violet
pink colour are added. A further quantity of hexamine is added
and titrated with 0.1M disodium edetate until the solution
becomes yellow.
 In this complexometric titration hexamine is added to raise the
pH to the alkaline side and the zinc oxide converted to zinc
acetate by dissolving in acetic acid and titrated with 0.1M
disodium edetate using xylenol orange as indicator. Zinc is
complexed by the disodium edetate and the indicator changes
colour from violet-pink to yellow at the end point.
ZnO

8.  Test for Purity
 Alkalinity
 Carbonates and substances insoluble in acids.
 As
 Fe
 Pb
 Loss or ignition
 Storage:
 Since it absorbs CO2 from the air, store it in a well closed
container.
 Medicinal Use:
 Astrigent and topical protective. ZnO is a mild antiseptic and
astringent. In the form of ZnO ointment or dusting powder, it is
used in the treatment of eczema, ringworm, pruritus and psoriasis.
It is also widely used in the mfg of plasters.
ZnO

9.  Zinc Oxide Paste
Zinc Oxide: 250 gm
Starch: 250 gm
White Soft Paraffin: 500 gm
 Zinc Oxide Ointment
 Zinc Gelatin
ZnO

10. Mixture of Zn salts obtained from commercial stearic acid which
itself is prepared from the hydrolysis of fats. It consists mainly of
variable proportions of Zinc stearate and Zinc palmitate.
Test for Purity
Acidity or alkalinity
Alkalis and alkaline earths
Chloride
Arsenic
Heavy metals
Sulphate
Storage:
Store in well closed containers.
Medicinal and Pharmaceutical Uses:
Dusting powder. Since zinc stearate is a mild antiseptic and
astringent, it is used in the form of dusting powder or ointment in
several skin conditions. Sometimes it is used as solid diluents.
Zinc stearate/(C17H35COO)2Zn

11. Calamine BP: Basic ZnCO3 suitably colored with ferric
oxide.
Calamine IP: ZnO colored with Ferric oxide. It is an
amorphous, reddish brown powder and the color
depends on the variety and amount of ferric oxide
present and the method by which it is incorporated. It is
practically insoluble in water and completely soluble in
mineral acids.
Since there is a possibility of adulteration with dyes,
there are tests for water soluble dyes and alcohol soluble
dyes.
Calamine

12.  Test for Purity
Acid-insoluble substances
Alkaline substances
Arsenic
Calcium
Lead
Water-soluble dyes
Alcohol-soluble dyes
Loss on ignition
 Storage:
Store in well closed containers.
 Medicinal and Pharmaceutical Uses:
Topical protective. Widely used in lotions, ointments and dusting powders
as soothing agent. It is used in sunburns, eczema and urticaria and some
other skin conditions. Calamine lotion (Lotio Calaminae) is very popular.
Calamine

13. Calamine Lotion
Calamine: 150 gm
Zinc Oxide: 50 gm
Bentonite: 30 gm
Sodium Citrate: 5 gm
Liquefied Phenol: 5 ml
Glycerin: 50 ml
Rose Water: qs 1000 ml
Other calamine preparations
Calamine Cream
Calamine Ointment
Calamine

14.  Occurs in nature in the mineral rutile, brookite and
ilmenite. Magnetic iron ores usually contain titanium.
 Preparation: prepared by heating ilmenite FeTiO3
with hydrogen chloride and chlorine.
 2FeTiO3 + 4HCl + Cl2 = 2FeCl3 + 2TiO2 +2H2O
 Test for Purity
 Clarity and color of solution
 Acidity or alkalinity
 Water-soluble substances
 Arsenic
 Barium
 Heavy metals
 Iron
Titanium Dioxide TiO2

15.  Storage:
 Well closed containers made of glass or any metal
other than Al.
 Medicinal and Pharmaceutical Uses:
Pharmaceutical Aid and Topical Protective. Since it
spreads well, it is used as a white pigment in paints.
Because of its high RI it is used in sun-tan
preparations.
Titanium Dioxide TiO2

16. Endof
chapter

17. These are the chemicals & their preparations used in
reducing or preventing infection due to
microorganisms.
Antiseptic: Inhibit the growth of MO (used for living
object)
Disinfectant: Destroy the Pathogenic MO (used for non
living object)
Germicides: Kill Bacteria, Fungi, Viruses, Spores
Bacteriostatic: Primarily inhibit the Bacteria – Only
arrest their growth not kill them.
Sanitizers: For maintaining the health for sanitization
purpose
Antimicrobial Agents and
Astringents

18. Uses of antimicrobial agents:
1% solution used for using into the eyes of
newborn babies, as prophylactic measure against
opthalmia neonaturum.
Effective against gonoccocal organisms.
0.5% aqs soln in the form of wet dressing applied
to third degree burn.

19.  Mechanism Of Action
1: Oxidation
2: Halogenation
3: Protein Precipitation
Antimicrobial Agents and Astringents

20. CLASSIFICATION OF DISINFECTANTS AND ANTISEPTICS
1. Halogens (chlorinated lime, chloramine B, chlorhexidine, iodovidone)
2. Oxidizing agents (hydrogen peroxide, potassium permanganate)
3. Acids (boric acid)
4. Phenol derivatives (phenol, cresol,)
5. Aldehydes and alcohols (formaldehyde, ethanol, isopropanol)
6. Metallic salts (silver nitrate, zinc sulfate, and copper sulfate)
7. Dyes or tints (brilliant green, methylene blue)
8. Detergents (decamethoxinum, soaps)
Antimicrobial Agents and Astringents

21.  Hydrogen peroxide, H2O2
Laboratory method:
BaO2.8H2O + H2SO4 → BaSO4 ↓+ H2O2 + 8H2O
 Industrial method:
2H2SO4 → H2S2O8 (aq.) + H2
H2S2O8 + 2H2O → 2H2SO4 + H2O2
Oxidative anti-microbial agents:

22. By redox process:
Industrially H2O2 is prepared by the auto-oxidation of 2-
alkylanthraquinols. The process involves a cycle of reactions.
The H2O2 formed (about 1%) is extracted with water and concentrated.

23.  Hydrogen peroxide, H2O2
 Test for purity:
Acidity
Organic stabilizers
Non-volatile matter
 Storage:
H2O2 is not stored in glass bottles since the alkali metal
oxides present in glass catalyzes its decomposition.
It is, therefore, stored in paraffin wax coated glass,
plastic or teflon bottles.
Small amounts of acid, glycerol, alcohol, acetanilide and
H3PO4 are often used as stabilizers to prevent its
decomposition.

24. Uses of H2O2:
(i) Antiseptic and germicide for washing wounds,
teeth and ears, under the name of perhydrol.
(ii) In the mfg of sodium perborate, sodium
percarbonate. These are used in high quality
detergents.
(iii) As an antichlor.
(iv) In the detection of Ti, V and Cr ions with which
it forms peroxides of characteristics colours.
(v) In the production of epoxides, propylene oxide
and polyurethanes.
(vi) In the synthesis of hydroquinone,
(cephalosoporin) and food products like tartaric acid.

25. Zinc peroxide, ZnO2
It is odourless white or yellowish solid.
It is produced by adding ZnO or zinc hydroxide to a solution of H2O2. It
can also be synthesized through the reaction of zinc chloride and hydrogen
peroxide.
It is stable, insoluble in water and dissolves in acid forming H2O2 . It
decomposes at 150 O
C to release O2
Storage: Oxidiser, store in cool, away from light
Away from incompatible materials (organic and reducing subs)
Use: Anti-microbial agent in topical preparation, additive for aseptic
products
It was historically used as a surgical antiseptic.

26. It enhance patient’s oral hygiene.
Safety, low cost, low abrasivity, water solubility, buffering ability,
compatibility with fluoride, and in high concentrations, antimicrobial
properties.
Incorporated into mouthrinses and dentrifices
It raise salivary pH that is lower than 8 (i.e. increase saliva alkalinity).
Additionally, sodium bicarbonate due to its slightly abrasive consistency
works as a mechanical cleanser of teeth and gingival tissues.
Sodium bicarbonate NaHCO3,
baking soda

27.  Salt consisting of K+
and MnO4−
ions. Formerly known as
permanganate of potash or Condy's crystals, it is a strong
oxidizing agent.
 Test for Purity:
Cl and SO4
Water-insoluble matter
Color of the solution
 Storage:
should be kept separated from oxidizable substances. Store in
well-
closed containers.
 Uses:
 As an oxidant, antiseptic
 Permanganate washes were once used to treat gonorrhea and are
still used to treat candidiasis.
 Antidote for strychnine
Potassium permanganate, KmnO4

28. Root canal irrigating solution is due mainly to its efficacy for pulpal
dissolution and antimicrobial activity.
1% sodium hypochlorite, acceptable biological compatibility.
It is the most used irrigating solution in endodontics, because its
mechanism of action causes biosynthetic alterations in cellular
metabolism and phospholipid destruction, formation of chloramines
that interfere in cellular metabolism, oxidative action with
irreversible enzymatic inactivation in bacteria, and lipid and fatty
acid degradation.
Sodium hypochlorite
NaOCl

29.  A dark violet (Greek, ioeides, violet) non-metallic
halogen element belonging to Group VIIb of the
periodic table.
 Preparation:
Prepared by heating KI or NaI with dil. H2SO4
and manganese dioxide.
2KI + MnO2 + 3H2SO4 → I2 + 2KHSO4 + MnSO4 +
2H2O
Iodine, I2

30.  Test for Purity:
Bromides and chlorides
Non-volatile matter
 Storage:
It is volatile in nature. Iodine topical solution should be
stored in
light-resistant containers at a temperature not exceeding 35
°C and iodine tincture should be stored in air-tight
containers.
 Uses:
solution in alcohol, called "tincture of iodine" is used as
antiseptic
In the manufacture of dyestuffs and drugs, and as a reagent
in analytical chemistry.
Iodine, I2

31.  Povidone-iodine (PVP-I) is a stable chemical complex of
polyvinylpyrrolidone (povidone, PVP) and elemental iodine. It
contains from 9.0% to 12.0% available iodine, calculated on a dry basis.
 Test for Purity:
Heavy metals
Nitrogen
iodide
sulphated ash
LOD
 Storage:
Since it slightly hygroscopic in nature, store in a well closed , light
resistant containers.
 Uses:
It is used as a disinfectant. Broad spectrum antiseptic for topical
application in the treatment and prevention of infection in wounds.
Povidone-I2

32. End of chapter

33. Are protein precipitant with Ltd penetration power
It coagulates the protein on the surface of the cell and brings out
hardening effect.
It constricts the tissue: Small Blood vessels
These are mild Antimicrobial Agents
USES:
Styptic to arrest minor bleeding by coagulation of blood
Anti-perspirant to reduce perspiration by constricting pores of skin
Anti-inflammatory action
At high concentration to remove unwanted tissue growth
Internally they can used in diarrhea
As cosmetic as skin tone and bring out the hardening effect
In dental products it can promotes hardening of the gums
It reduces the cell permeability
Astringents

34.  Aluminum Compound
 Alum:
 Potash Alum:[KAl(SO4)2, 12H2O]
 Ammonia Alum:[NH4Al(SO4)2,12H2O]
 Formula: AlK(SO4)2, 12H2O
 Synonyms:
 Aluminium Potassium Sulphate, Potash Alum, Potassium Alum
 Uses:
 Large dose gives irritation and gives Gum Necrosis, GI
Haemorrhage, adjuvant with vaccine (DTP)
 Alum precipitate proteins
 To apply on sores
 Used as mordant in dyeing industry. (a substance, that
combines with a dye or stain and thereby fixes it in a material.)
Astringents

35. Three forms are official - heptahydrate, hexahydrate, monohydrate
Formula: ZnSO4.7H2O
Preparation:
Zns + 2O2 → ZnSO4
Zn + H2SO4 → ZnSO4 + H2
Properties:
Colorless, transparent crystals, odorless
Very soluble in water; practically insoluble in ethanol
Uses:
In variety of Skin condition (keratosis), viral infection of genitals,
pityriasis (skin rash).
Water soluble Zn is used as supplements for Zn deficiency.
SE: When taken internally: Causes abdominal pain, dyspepsia,
nausea, vomiting, diarrhoea, gastric irritation
In high dose - anemia, neutropenia
Zinc Sulfate ZnSO4

37.  Inorganic compound with chemical formula AgNO3.
 Test for Purity:
clarity and color of the solution
acidity and alkalinity
foreign salts
 Al, Bi, Cu and Pb
 Storage:
Affected by light, store in tightly closed light resistant
containers.
 Uses:
Antiseptic properties. Until the development of antibiotics,
dilute solutions of AgNO3 used to be dropped into
newborn babies' eyes at birth to prevent contraction of
gonorrhea from the mother.
Silver Nitrate, AgNO3
Protein precipitant antimicrobial agents

38. Boric acid, H3BO3, B(OH)3
aka hydrogen borate, boracic acid, orthoboric acid &
acidum boricum. Colorless crystals or a white
powder that dissolves in water.
Antimicrobial Agents and Astringents

39. Preparation of boric acid:
Reacting borax (sodium tetraborate decahydrate)
with a mineral acid:
Na2B4O7·10H2O + 2HCl → 4 B(OH)3 [or H3BO3] +
2NaCl + 5H2O
It is also formed as a by product of hydrolysis of
boron trihalides and diborane:
B2H6 + 6H2O → 2B(OH)3 + 6H2
BX3 + 3H2O → B(OH)3 + 3HX (X=Cl, Br, I)
Antimicrobial Agents and Astringents
Boric acid

40.  Assay: Assayed by acid-base titration. Sample + water + glycerol titrate against
standard sodium hydroxide using phenolphthalein.
 Test for Purity:
clarity and color of the solution
SO4
solubility in ethanol
As
Heavy metals
LOD
 Storage: stable in air. store in well closed containers.
 Uses:
Antiseptic for minor burns or cuts and is sometimes used in dressings.
Very dilute solution as an eye wash. Dilute boric acid can be used as a
vaginal douche to treat bacterial vaginosis due to excessive alkalinity.
For acne treatment. For prevention of athlete's foot, by inserting
powder in the socks or stockings.
Antimicrobial Agents and Astringents
Boric acid