ORAL SOLUTIONS

Solutions
• In pharmaceutical terms, solutions are “liquid preparations that contain one or more
chemical substances dissolved in a suitable solvent or mixture of mutually miscible
solvents”

• Solubility: The solubility may then be expressed as grams of solute dissolving in milliliters
of solvent.

• When a solute dissolves, the substance’s inter molecular forces of attraction(ion–dipole

forces and hydrogen bonding )must be overcome by forces of attraction between the
solute and the solvent molecules. This entails breaking the solute–solute forces and the
solvent–solvent forces to achieve the solute–solvent attraction.
• When the exact solubility has not been determined, general expressions of relative solubility may
be used. These terms are defined in the USP and presented
GENERAL METHODS OF PREPARATION OF SOLUTIONS
1. SIMPLE MIXING: Solutions of this type are prepared by dissolving the solute in a
suitable solvent (by stirring or heating). The solvent may contain other ingredients
which stabilize or solubilize the active ingredient.
2. SOLUTION BY CHEMICAL REACTION : These solutions are prepared by reacting
two or more solutes with each other in a suitable solvent e.g. Calcium carbonate
and lactic acid used to prepare Calcium lactate mixture.

Some chemical agents in a given solvent require an extended time to dissolve. To

hasten dissolution, a pharmacist may employ one of several techniques, such as
applying
• heat,
• reducing the particle size of the solute,
• using a solubilizing agent, and/or
• subjecting the ingredients to vigorous agitation
.
ADVANTAGES OF SOLUTIONS
1. Easier to swallow.
2. More quickly effective than tablets and capsules.
3. Homogenous therefore give uniform dose than suspension or emulsion which need shaking.
4. Dilute irritant action of some drugs (aspirin, Kl, KBr) minimize adverse effects in the GIT like
KCl.
DISADVANTAGES OF SOLUTIONS
1. Bulky therefore difficult to transport and store.
2. Unpleasant taste or odours are difficult to mask.
3. Needs an accurate spoon to measure the dose.
4. Less stable than solid dosage forms. major signs of instability are : colour change, precipitation
microbial growth chemical gas formation
 ORAL SOLUTIONS AND PREPARATIONS FOR ORAL SOLUTION
Components :
Most solutions intended for oral administration in addition to vehicle contains:
• Flavorants and Colorants to make the medication more attractive and palatable.
• Stabilizers to maintain the chemical and physical stability of the medicinal agents
• Preservatives to prevent the growth of microorganisms in the solution.

The formulation pharmacist must be wary of chemical interactions between the

various components of a solution that may alter the preparation’s stability
and/or potency.
• Liquid pharmaceuticals for oral administration are usually formulated such that
the patient receives the usual dose of the medication in a conveniently
administered volume, as 5 (one tea spoonful), 10, or 15 mL (one tablespoonful).
• A few solutions have unusually large doses, for example, Magnesium Citrate Oral
Solution, USP, with a usual adult dose of 200 mL.
• On the other hand, many solutions for children are given by drop with a
calibrated dropper usually furnished by the manufacturer in the product package
Examples of Oral Solution
• Dry mixtures for solution
• Oral rehydration solutions
• Oral colonic lavage solution
• Magnesium citrate oral solution
• Sodium citrate and citric acid oral solution
 DRY MIXTURES FOR SOLUTION
• A number of medicinal agents, particularly certain antibiotics, e.g., penicillin V, have
insufficient stability in aqueous solution to meet extended shelf-life periods. Thus,
commercial manufacturers of these products provide them to the pharmacist in dry
powder or granule form for reconstitution with a prescribed amount of purified water
immediately before dispensing to the patient.
Components : The dry powder mixture contains all of the formulative components,
including drug, flavorant, colorant, buffers, and others, except for the solvent.
Storage : Once reconstituted by the pharmacist, the solution remains stable when stored
in the refrigerator for the labeled period, usually 7 to 14 days, depending on the
preparation. This is a sufficient period for the patient to complete the regimen usually
prescribed. However, in case the medication remains after the patient completes the
course of therapy; the patient should be instructed to discard the remaining portion, which
would be unfit for use at a later time.
Examples
• Cloxacillin Sodium for Oral Solution, an anti-infective antibiotic
• Penicillin V Potassium for Oral Solution, an anti-infective antibiotic
• Potassium Chloride for Oral Solution, a potassium supplement
 ORAL SOLUTIONS(Pharmacist Role)
The pharmacist may be called on to
• dispense a commercially prepared oral solution;
• dilute the concentration of a solution, as in the preparation of a pediatric form of an
adult product;
• prepare a solution by reconstituting a dry powder mixture; or
• extemporaneously compound an oral solution from bulk components.
• In each instance, the pharmacist should be sufficiently knowledgeable about the
dispensed product to expertly advise the patient of the proper use, dosage, method of
administration, and storage of the product.
• Knowledge of the solubility and stability characteristics of the medicinal agents and the
solvents employed in the commercial products is useful to the pharmacist for informing
the patient of the advisability of mixing the solution with juice, milk, or other beverage
upon administration.
• Information regarding the solvents used in each commercial product appears on the
product label and in the accompanying package insert.
 ORAL REHYDRATION SOLUTIONS
• Diarrhea is characterized by an increased frequency of loose, watery stools, and because
of the rapid fluid loss, dehydration can be an outcome. More than 5 million children
younger than 4 years of age die of diarrhea each year worldwide.
• Oral rehydration solutions are usually effective in treatment of patients with mild volume
depletion, 5% to 10% of body weight.
• These are available OTC and are relatively inexpensive, and their use has diminished the
incidence of complications associated with parenterally administered electrolyte
solutions.
Composition :A liter of typical oral rehydration solution contains 45 mEq Na+, 20 mEq K+,
35 mEq Cl−, 30 mEq citrate, and 25 g dextrose.

• These formulations are available in liquid or powder packet form for reconstitution.
Precautions:These products should not be mixed with or given with other electrolyte-
containing liquids, such as milk or fruit juices. Otherwise, there is no method to calculate
how much electrolyte the patient actually received.
Commercial ready-to-use oral electrolyte solutions to prevent dehydration or
achieve rehydration include
• Pedialyte Solution (Ross) and Rehydralyte Solution (Ross). These products also
contain dextrose or glucose.
• Infalyte Oral Solution (Bristol-Myers Squibb) contains electrolytes in a syrup of
rice solids. The rice-based formula produces a lower osmotic effect than the
dextrose-or glucose-based formulas and is thought to be more effective in
reducing stool output and shortening the duration of diarrhea.
 ORAL COLONIC LAVAGE SOLUTION
• Traditionally, preparation of the bowel for procedures such as a colonoscopy
consisted of administration of a clear liquid diet for 24 to 48 hours preceding the
procedure, administration of an oral laxative such as magnesium citrate or
bisacodyl the night before, and a cleansing enema administered 2 to 4 hours prior
to the procedure
• Consequently, an alternative method to prepare the gastrointestinal tract has
been devised. This procedure requires less time and dietary restriction and
obviates the cleansing enemas.
• This method entails oral administration of a balanced solution of electrolytes with
polyethylene glycol (PEG-3350-Electrolyte Solution), i.e, PEG-ES.
• Before dispensing it to the patient, the pharmacist reconstitutes this powder
with water, creating an iso-osmotic solution having a mildly salty taste. The PEG
acts as an osmotic agent in the gastrointestinal tract, and the balanced electrolyte
concentration results in virtually no net absorption or secretion of ions.
• Thus, a large volume of this solution can be administered without a significant
change in water or electrolyte balance.
Formulation of this oral colonic lavage
The formulation of this oral colonic lavage solution is as follows:
• PEG-3350….. 236.00 g
• Sodium sulfate …. 22.74 g
• Sodium bicarbonate …. 6.74 g
• Sodium chloride…. 5.86 g
• Potassium chloride g 2.97 g
In 4,800 mL disposable container
Adult dose
The recommended adult dose of this product is 4 L of solution before the gastrointestinal
procedure. The patient is instructed to drink 240 mL of solution every 10 minutes until
about 4 L is consumed.
• The patient is advised to drink each portion quickly rather than sipping it continuously.
• Ideally, the patient should not have taken any food 3 to 4 hours before beginning to take
the solution. In no case should solid foods be taken by the patient for at least 2 hours
before the solution is administered.
• No foods except clear liquids are permitted after this product is administered and prior
to the examination.
Storage The product must be stored in the refrigerator after reconstitution, and this aids
somewhat in decreasing the salty taste of the product.