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Monophasic liquid dosage forms

A monophonic liquid contains only one phase i.e., solutes which is completely soluble in solvents. Monophasic liquids are homogenous systems of dosage forms containing either miscible liquids or solids which are completely soluble in water, intended for internal use or external use.

Classification/type of Monophasic liquid dosage forms:

1. Monophasic liquid meant for internal use:

Ex: solutions, mixtures, syrups, elixirs, linctus etc.

1. Mixtures:

A mixture is a liquid preparation containing medicaments meant for internal use. It contains several doses.

I. Mixture containing soluble substances:

Ex: Carminative mixture

Formula:
NaHCo₃ Compound tincture of cardamom

Aromatic spirit of ammonia Weak tincture of ginger

Spirit of chloroform Peppermint water

Procedure:

1. Dissolve the solid substances in little quantity of vehicle. Ex – NaHCO3 in Peppermint oil.

2. If any foreign particle appears filter it.

3. Add any liquid ingredient.

4. Volatile liquids are added at the end just before adjusting the final volume with vehicle.

5. Final volume is adjusted with remaining vehicle.

Storage: It is stored in a well-closed greenish-tinted graduated bottle.

Uses: It is used as carminative, NaHCo3 act as antacid.

II. Mixture containing in-diffusible solids

In-diffusible solids are insoluble in water. So a suitable suspending agent should be included in the formula to increase the dispersion of insoluble solids. Ex: CaCo3 mixture

Formula:

CaCo3

Compound powder of tragacanth

Tincture catechu

Purified water

Procedure:

1. Finely powder the indiffusible solids with diffusible or soluble solids and compound tragacanth powder in a motor. Measure three quarters of vehicle and add a portion of it with trituration to form smooth cream.

2. The content in the motor is examined for the presence of foreign particle if any that can be removed with the help of glass rod or passing through muslin cloth in a measuring cylinder.

3. Add the liquid ingredient if any and volume is made up by adding vehicle.

4. The mixture is transferred into a bottle. Corked, polished to remove finger marks and labelled.

5. The label should be mention “shake well before use”

Storage: It is stored in a well closed greenish tinted graduated bottle.

Uses: It is used in the treatment of diarrhoeal, CaCo3 and tincture catechu acts as anti-diarrhoeal agent. Compound powder of tragacanth acts as suspending agent.

III. Mixtures containing diffusible solids:

Diffusible substances are slightly or partially soluble but diffuse uniformly on shaking for enough time to measure the dose so suspending agent is not necessary in the formulation.

Formula:

MgSo4

Light magnesium water carbonate

Peppermint water

MgCo3 is a diffusible solid while MgSo4 is soluble in water.

1. Finley powder diffusible solid in a motor with soluble solid if any measure three quarter of the vehicle and pour a portion of it with trituration to form smooth cream. Then gradually add the remainder of the vehicle.

Stage II III and IV are similar to mixture containing in-diffusible solids.

Storage: It is stored in a well closed greenish tinted graduated bottle. Whole thing is to be taken at a time should be written on the label.

Use: It is used in the treatment of constipation MgCo3 acts as a saline purgative, light MgCo3 acts as an antacid and laxative peppermint water acts as flavoured vehicles.

IV. Mixture containing ppt. forming liquids:

Certain liquid preparations contain resinous matter, when mixed with water, the resin is precipitated which may adhere to the sides of the bottle or form a clotted precipitate which will not re-diffuse upon shaking. To prevent this compound tragacanth powder or tragacanth mucilage are used.

Formula: Potassium iodide 2.0g

Tincture lobelia ether 4.0ml

Tincture stramonium 16.0ml

Chloroform water add up to 90.0ml

Procedure:

1. Mix 20.0ml of mucilage of tragacanth with equal volume of water.

2. Measure tincture lobelia ether and tincture stramonium separately in a dry measure and pour slowly into the centre of the mucilage with constant stirring.

3. Dissolve potassium iodide in water and mix it with above mixture.

4. Strain the mixture through muslin piece if foreign particles are present

5. Add more of chloroform water to produce the required volume.

6. Transfer the mixture into the bottle, cork, label and dispense.

V. Mixture containing slightly soluble liquids:

Ex: Paraldehyde mixture: On shaking the slights soluble liquids with the solutions of other ingredients and liquids. It readily mixes with them and distributed throughout the liquid for sufficient time to ensure uniform distribution in each dose.

Formula: Paraldehyde Syrup

Liquid extract of liquorice Water

Procedure:

Triturate the paraldehyde, liquid extract of liquorice, syrup and water in a motor. Transfer to a bottle and shake well.

Storage: It is stored in a well closed container.

Uses: Paraldehyde mixture is used to control convulsions in infants.

Paraldehyde is used as sedative.

Liquid extract of liquorice and syrup act as sweetening agent.

Water acts as vehicle.

Formulation of mixtures:

The following are the additives or excipients which included in the preparation of mixtures.

1. Vehicles: Ex: Water, aromatic water, syrup vehicle.

2. Medicament: Ex: CaCo3, MgSo4

3. Anti oxidants: Ex: Sodium Meta bi-sulphate

4. Flavours: Ex: Lemon spirit, Orange syrup.

5. Preservatives: Ex: CHCl3, benzoic acid

2. Linctus:

Linctus is sweet viscous liquid preparations containing medicament meant for internal use. Linctus are commonly used in the treatment of cough. To obtain the maximum effect, they should be taken in small doses, sipped and swallowed slowly without addition of water.

Uses: These used in the treatment of cough. These have sedative or expectorant and demulcent property.

Ex: Codeine linctus B.P.C

3. Draught:

It is a liquid medicament intended for internal use which consists of one dose only.

Container: Narrow mouthed, screw capped, colourless plain bottle.

Use: Used in emergency treatment as emetics in poisoning.

Ex: Ipecac emetic draught, Paraldehyde draught

4. Elixirs:

Elixirs are clear, flavoured sweetened hydro-alcoholic liquid preparations for oral administration. Elixirs contain medicament, syrup, glycerol, water, flavouring agent and preservatives. Elixirs are commonly used as flavoured vehicle. Elixirs may be simple elixirs without medicament and medicated elixirs.

Ex: Elixir of vitrol

Piperazine citrate

Elixir simple

Terpin hydrate Elixir

Auxiliary label: Store in dark place

Uses: Used as flavoured vehicle.

5. Syrup:

Syrup are sweet, viscous concentrated solution of sucrose. The concentration of sucrose in syrup is 66.7%. If purified water is used alone for preparing syrup, is known as simple syrup, when the syrup contains some medicinal substance it is known as medicated syrup. Syrups are used as sweetening agent, flavoured vehicle as demulcent and as a preservative.

Storage: Syrups should be freshly prepared unless special precautions have been taken to prevent contamination.

Uses: 1. Act as sweetening agent.

2. Act as preservative.

3. They increase the viscosity of the solution.

2. Monophasic liquid dosage forms meant for external use:

Ex: Gargles, mouth washes, throat paints, eye drops, eye lotion, ear drops etc.

1. Mouth washes:

Mouth washes are simple aqueous intended to clean & deodorize the buccal cavity. Mouth washes used for its deodorants, rinsing, refreshing & antiseptic action. The vehicle may be water or combination of water & alcohol. Mouth washes generally contain astringent & antibacterial. Medicated mouth washes containing astringent anti-bacterial agents, Protein precipitants or other agents are also used but they must be used under the supervision of the dentist. A very simple preparation like compound Nacl mouth wash containing Nacl & NaHCo3 in peppermint water is commonly used by a normal person. The continuous use may prove harmful.

Container: Narrow mouthed, coloured fluted bottle closed with plastic screw cap.

Label:

1. Dilute it with an equal volume of warm water before use.

2. Rinse the mouth 3-4 times daily as required.

Storage: Preserve in a well closed container store in a cool place.

2. Gargles:

Gargles are aqueous clear solutions used for the treatment of an infection of the throat. Gargles are generally dispensed in concentrated form. They must be diluted with warm water before use. Gargles are highly medicated than the mouth washes. Gargles are pleasantly flavoured & having PH of 5-9.5.

Gargles are used by forcing the air from the lungs through the gargles which is in held in the throat. The gargles are brought into intimate contact with the mucous membrane of the throat & allowed to remain there for a few moments after which they are thrown out of the mouth.

Container: Narrow mouthed, colourless fluted bottles & screw capped.

Label: Must be diluted with warm water before use.

Storage: Preserve in a well closed container.

Use: To treat throat infections.

3. Throat paint:

Throat paints are liquid preparations applied to the mucous membrane of buccal cavity. These are used to treat mouth & throat infections, throat paints contains antiseptic astringent & analgesic property.

They may contain volatile solvent that evaporates quickly to leave a dry resinous film of medicaments. Throat paints are more viscous due to high content of glycerin. These are sticky & adheres to the affected site & prolong the action of the medicaments.

Container: – Wide mouthed screw capped coloured bottles with brush.

Labeling: – For external use only.

Storage: – It should be stored in air tight containers & placed in a cool.

4. EAR DROPS:

Ear drops are liquid preparations that are installed in to the ear. These are usually solutions or suspension. It contains one or more medicaments that are dissolved or suspended in a suitable vehicle. 15ml of ear drops should be dispensed.

Vehicle: – Water, alcohol, glycerine, propylene glycol, hexylene glycol.

Medicaments: – The following medicaments are used in the ear drops, depending on the purpose. They are

1. Boric acid

2. H2O2

3. Phenol

4. Chloromphenicol

Container: – Coloured fluted glass bottle with dropper.

Label: – Not to be taken

Not to be diluted

For external use only

Storage: – Store in a cool place

Dose:- 3-5 Drops

Uses:

1. Cleaning the ear

2. Drying weeping surfaces

3. Softening in the wax

4. Treating mild infections

5. Nasal drops:

Nasal drops are usually aqueous solutions intended for installation into the nostrils by means of dropper. They are commonly used for their antiseptic, anti-inflammatory, anti-histamine & local anaesthetic properties.

At one time, oily preparations containing liquid paraffin or vegetable oils as vehicles were used to prolong the action of the drug but now the use of oily vehicles in the preparation of nasal drops is discouraged because on prolong use the oil retards the capillary action of the nasal mucous or drops of oil may enter the trachea & cause lipoid pneumonia. Therefore the aqueous vehicle is advisable for nasal drops.

Container: Fluted coloured glass bottle with plastic screw cap & dropper.

Label: For external use only.

Storage: Store in a cool place.

6. Liniments:

Liniments are solutions or suspensions or emulsions applied for external application. They are generally applied with massage. They posses analgesic, rubifacient, counter irritant & stimulating properties. These are not applied to broken skin. Liniment contain volatile ingredients so cool storage necessary & keep away from flame 50 ml of liniment be dispensed. Two types of vehicles are used for preparation of liniments. They are alcohol and oils.

Container: Narrow mouthed, coloured fluted bottle with screw capped.

Label: For external use only

Shake well before use

Not to be applied to wounds or broken skin inflammable.

Storage: Stored in well – filled well closed, air tight containers & place in a place.

Use: Counter – irritant, Rubifacient & analgesic.

7. Lotions:

Lotions are liquids suspensions or dispersion used for external application to the skin. They are applied to the skin without rubbing. This is applied with the help of cotton wool. Cotton wool is soaked in the lotion and applied on the affected part. These lotions are applied on broken skin. Lotion may be employed for local cooling, soothing, protecting and moisturizing purpose. Dermatologists frequently prescribe lotion for antiseptic, anti-inflammatory, local anaesthetics & anti fungal action.

Container: Fluted bottle, closed with plastic screw cap

Label: For external use only

Shake well before use

Storage: Preserve in a well in a well-close container.

Use: protective.

Difference between elixirs and syrups:

Elixirs	Syrups
Elixirs are clear sweetened aromatic hydro-alcoholic liquid.	Syrups are concentrated or nearly saturated solution of Sucrose in purified water.
In elixirs the main ingredient Used as ethyl alcohol and it is Concentrated is 5.40%w/w.	In syrup the main ingredient used as sugar and its conc. is 66.7%.

Difference between lotion and liniments:

Liniments	Lotion
1. Applied with friction	Applied without friction
2. It is not applied to broken skin	It is applied to broken skin
3. It is applied with brush	It applied with absorbent material
4. It make contain camphor	It don’t contain camphor
5. It act as counter – irritant and rubefacient	It act as anti – septic, anti – inflammatory and cooling effect

FAQs

1. Are monophasic liquid dosage forms suitable for pediatric patients?

Yes, they are often preferred for pediatric patients due to their ease of administration and precise dosing.

2. Can monophasic solutions be used for both over-the-counter and prescription medications?

Absolutely. They are versatile and can be employed for a wide range of medications, from simple cough syrups to complex injectables.

3. How do monophasic liquid dosage forms compare to multiparticulate dosage forms?

Monophasic solutions are typically faster acting due to their rapid absorption, while multiparticulate forms may offer extended release profiles.

4. Do these formulations require refrigeration for storage?

Storage requirements may vary by the specific medication, but most monophasic solutions are stable at room temperature, which makes them convenient for patients.

5. Are there any potential side effects associated with monophasic liquid dosage forms?

Side effects, if present, are usually related to the active ingredient rather than the formulation itself. Patients should consult their healthcare providers for information specific to their medications.