Chapter 13 Solutions Part 1 of 5: Introduction to

1. Presented by:
Asst. Prof. Ma. Lourdes L. Mojares, R. Ph.
CEU School of Pharmacy
Manila

2. SOLUTIONS: DEFINITION
 Liquid preparations that contain
one or more chemical substances
dissolved in a suitable solvent or
mixture of (mutually miscible)
solvents.
 It may be oral, otic, opthalmic or
topical.

3. SOLUBILITY
FACTORS AFFECTING SOLUBILITY
1. Temperature
2. Chemical and physical properties of the
solute and the solvent
3. Pressure
4. pH of the solution
5. State of subdivision of the solute
6. Physical agitation applied to the solution as it
dissolves

4. 1. Effect of Temperature
 Chemicals with Positive Heat of
Solution
The kind that absorbs heat when
dissolved.
It results to an increased solubility
with an increase in temperature.

5. 1. Effect of Temperature
 Chemicals with Negative Heat of
Solution
The kind that releases heat when
dissolved.
It results to an decreased solubility
with an increase in temperature.

6. 2. Effect of Physicochemical
Properties (pressure, temperature)
of the
solute and solvent
 The solubility of a “pure” chemical
substance at a given temperature
and pressure is constant.

7. 3. State of subdivision of the solute
(particle size)
 The “finer” the powder, the greater
the surface area that comes in
contact with the solvent.
 Therefore, the more rapid the
dissolving process.

8. 4. Physical Agitation Applied to
the Solution As It Dissolves
 The greater the agitation, the more
unsaturated solvent passes over the
drug.
 Therefore, the faster the formation
of a solution.

9. 5. Effect of pH of the Solution
 Many important organic medicinal
agents are either “weak acids” or
“weak bases.”
 Drugs as weak bases are not very
water-soluble, but are soluble in
dilute solutions of acids.

10. 5. Effect of pH of the Solution
 Drugs as weak acids form water-
soluble salts in basic solutions.
 These drugs may separate from the
solution by lowering the pH of the
solvent system.

11. Techniques to hasten dissolution
 Application of heat
 Reduction of particle size of the
solute
 Use a solubilizingagent
 Subject the ingredients to vigorous
agitation

12. Some solvents for liquid
preparations
 ALCOHOL, USP
 DILUTED ALCOHOL, NF
 RUBBING ALCOHOL
 GLYCERIN, USP
 ISOPROPYL RUBBING ALCOHOL
 PROPYLENE GLYCOL, USP
 PURIFIED WATER, USP

13. 1. ALCOHOL, USP
 The most useful solvent, next to
water.
 94.9% to 96% C2H5OH (v/v)
 Miscible with water and has the
ability to dissolve many water-
insoluble ingredients (flavorants,
preservatives).
 With preservative effect

14. 2. DILUTED ALCOHOL, NF
 Contains equal volumes of Alcohol,
USP and Purified Water, USP.
 49% concentration
 A useful hydroalcoholic solvent.

15. 3. RUBBING ALCOHOL
 Contains about 70% Ethanol v/v.
 Volatile and Flammable, should be
stored in tight containers, remote from
fire.
 Used externally as rubefacient, soothing
rub, germicide (for instruments), skin
cleanser (prior to injection), vehicle in
topical preparations.

16. 4. GLYCERIN, USP
 Glycerol , CH2-OH-CHOH-CH2OH
 Clear, viscous syrupy liquid with sweet
taste
 Miscible to both water and alcohol

17. 4. GLYCERIN, USP
 Comparable to alcohol, as solvent.
 Solutes are slowly soluble (requires
heating)
 Preservative, stabilizer, auxilliary
solvent with water and alcohol
 Used extensively in internal
preparations.

18. 5. ISOPROPYL RUBBING
ALCOHOL
 70% v/v isopropyl alcohol.
 Commercially available as 91%
 External Uses: rubefacient, soothing
rub, vehicle for topical products.

19. 5. ISOPROPYL RUBBING
ALCOHOL
 Commonly employed by diabetic
patients in preparing needles and
syringes for hypodermic injections of
insulin.
 Skin disinfection of diabetic patients.

20. 6. PROPYLENE GLYCOL, USP
CH3CH(OH)CH2OH
 Viscous liquid, miscible with water
and alcohol.
 Useful solvent with a wide range of
applications.
 Substitute for glycerin

21. 6. PURIFIED WATER, USP
 For preparation of aqueous dosage
forms, except those intended for
parenteral administration.
 Contains 1% as much dissolved solids
as tap water

22. TYPES OF SOLUTIONS
As to its use: As to composition
1. Oral solutions  Aromatic waters
2. Topical solutions  Syrups
3. Ophthalmic  Elixirs
solutions
 Spirits
4. Nasal and Otic
solutions  Tinctures and
fluidextracts
 Douches, Enemas and
* 3 and 4 are discussed gargles
in Chapter 17
 Liniments, collodions,
and others

23. 1. ORAL SOLUTIONS
COMPONENTS
 Medicinal agents
 Flavorants, Colorants and Sweetening
agents
 Stabilizers (glycerin or sorbitol) – used to
inhibit crystallization and to modify
solubility
 Preservatives (parabens)
 Vehicles

24. ORAL SOLUTIONS
ADVANTAGES DISADVANTAGES
1. Homogenous 1. Bulky
2. Easier to swallow than 2. Degrade more
the solid dosage forms rapidly
3. Onset of action and 3. More likely to
bioavailability of interact with other
drugs that have slow constituents
dissolution rate are
improved

25.  DRY POWDER FOR SOLUTION
Dry powder for reconstitution prior to use
Examples: Cloxacillin Na, Oxacillin Na and
Penicillin VK for oral solution (antibiotics)
 ORAL REHYDRATION SOLUTION
Available in liquid or packet of powder for
reconstitution
Examples: Pedialyte and Rehydrate solution,
Glucolyte, Oresol
 ORAL COLONIC LAVAGE SOLUTION
 OTHERS – Magnesium citrate solution

26. PEDIALYTE ORS

27. Glucolyte
Oral Rehydration Solution

28. Magnesium citrate Oral Solution

29. 2. TOPICAL SOLUTIONS
 Employed an aqueous vehicle
 Should be labeled “FOR EXTERNAL USE ONLY”
Examples:
1. Aluminum Acetate Solution
2. Calcium Hydroxide Topical Solution
3. Hydrogen Peroxide Topical Solution
4. ChlorhexidineGluconate Solution
5. Povidone Iodine Solution
6. Strong Iodine Solution

30. TOPICAL SOLUTIONS

31. 3. OTIC SOLUTIONS
 Ear or aural solutions
USES:
 For the removal of excessive cerumen
Examples: Cerumenex Ear drop, Debrox Drops
 For the treatment of ear infections, inflammation,
or pain
Examples: AuralganOtic Solution, AmericaineOtic,
ChloromycetinOtic, CorticosporinOtic, Otobiotic
solution, VoSolOtic Solution

32. CERUMENEX and DEBROX
OTIC SOLUTIONS

33. AURALGAN OTIC SOLUTION

34. VOSOL and
HYDROCORTISONE
OTIC SOLUTIONS

35. VoSoL OTIC SOLUTION
LABELLING

36. METHODS OF PREPARATION
of SOLUTIONS
 SIMPLE SOLUTION METHOD
Example: Strong Iodine (Lugol’s) Solution
 SOLUTION BY CHEMICAL REACTION
Example: Magnesium Citrate Solution
 SOLUTION BY EXTRACTION

37. PHARMACEUTICAL
SOLVENT WATERS
 PURIFIED WATER, USP
 WATER FOR INJECTION, USP
 STERILE WATER FOR INJECTION, USP
 BACTERIOSTATIC WATER FOR
INJECTION, USP
 STERILE WATER FOR INHALATION, USP
 STERILE WATER FOR IRRIGATION, USP
* WFI, SWFI and BWFI are discussed in Chapter 15

38. PURIFIED WATER, USP
 Obtained by: distillation, reverse osmosis or
by ion exchange treatment
 pH 5 to 7
 Contains NMT 10 ppm of total solids
 Used in preparations and in finished and
manufactured products, except for the
preparation of parenterals and ophthalmic
products

39. WATER FOR INJECTION, USP
 Conforms with the standards of Purified
Water, USP but is also pyrogen-free.
 Intended to be used in the manufacture of
injectable products which are to be
sterilized after their preparation.
 Intended to be used for 24-hours after its
collection.

40. STERILE WATER
FOR INJECTION, USP
 WFI that has been sterilized
 Packaged in single-dose containers of
type I or type II glass that do not exceed
the capacity of 1 liter
 Intended to be used as a solvent, vehicle
or diluent for already-sterilized and
packaged injectable medications

41. BACTERIOSTATIC WATER FOR
INJECTION, USP
 SWFI that contains one or more suitable
bacteriostatic agents
 Packaged in pre-filled syringes or in vials
containing NMT 30 mL
 Employed as a sterile vehicle in the
preparation of small volumes of injectable
preparations (in multiple-dose vials)
 To be labeled “NOT FOR USE IN
NEWBORNS”

42. STERILE WATER FOR
IRRIGATION, USP
 Same requirements as SWFI except in
container design, particulate matter and
labeling
 LabelingRequirements:
“ For Irrigation Only ”
“ Not for Injection ”

43. AROMATIC WATERS
 Are clear, saturated aqueous solutions of
volatile oils or other aromatic or volatile
substances
 A pleasantly flavored vehicle for water
soluble drugs or an aqueous phase in an
emulsion or suspension

44. AROMATIC WATERS
 Addition of electrolytes may result to
“salting-out” of the volatile ingredient
 Must be free from empyreumatic
(smoke-like) odors.
 Stored in a tightly closed, light-resistant
containers
 Protect from excessive heat

45. Methods of Preparation
of
Aromatic Waters
 DISTILLATION
COHOBATION – the process of redistillation two or more
times until the distillate becomes clear
 SOLUTION METHOD – the volatile, or aromatic substance
is admixed with water, with or without the use of a
dispersant (e.g. talc)
A. Simple Solution
B. Alternate Solution