Monophasic and Biphasic Liquid Dosage Forms

Flashcards covering monophasic liquids (mixtures, syrups, elixirs, linctuses, aromatic waters, liniments, lotions, gargles, mouthwashes, throat paints, douches, ear drops, nasal drops, sprays, inhalations) and biphasic liquids (suspensions and emulsions).

What is a monophasic liquid dosage form?

It refers to a liquid preparation consisting of only one phase, represented by a clear homogenous true solution prepared by dissolving a solid, liquid, or gas in a liquid solvent.

What is a single-dose bottle of a mixture called?

A draught.

What is the official concentration of sucrose in simple syrup according to the Indian Pharmacopoeia and British Pharmacopoeia?

Simple syrup contains $66.7\%\,\text{w/w}$ sucrose as per the Indian Pharmacopoeia and BP.

What are the concentration and specific gravity specifications for simple syrup according to the USP?

Simple syrup contains $85\%\,\text{w/v}$ ($65\%\,\text{w/w}$) sucrose and has a specific gravity of $1.313$ (USP).

To what temperature is purified water heated when preparing syrup using the solution with heat method?

Purified water is heated to $80\text{ to }85^\circ\text{C}$ before adding sucrose with vigorous agitation.

What is the standard alcohol concentration range in elixirs?

Elixirs contain $4\text{ to }40\%$ alcohol (ethanol).

Why are chemical preservatives not required in certain elixir formulations?

Preservatives are not needed when the alcohol content is $20\%$ or more, as that concentration is sufficient to act as a preservative.

How should linctuses be taken by a patient to ensure maximum therapeutic effect?

Linctuses should be taken in small doses, sipped and swallowed slowly without diluting with water.

How are aromatic waters prepared using the dilution method?

They are prepared by diluting one volume of concentrated water with thirty-nine volumes of purified water, as concentrated waters are $40$ times stronger than simple aromatic waters.

What is the key difference between liniments and lotions regarding their method of application?

Liniments are applied to unbroken skin with friction or rubbing, while lotions are applied to unbroken skin without friction.

Why is glycerin commonly used as a base in throat paint formulations?

Glycerin is viscous and adheres to the mucous membrane for a long period, which prolongs the action of medicaments and provides a sweet taste.

Why are aqueous vehicles generally avoided in the formulation of ear drops?

Because secretions in the ear are fatty in nature and do not easily mix with water.

Why are oily vehicles avoided in nasal drops?

Oily drops inhibit the movement of cilia in the nasal mucosa and may reach the lungs to cause lipoid pneumonia if used over long periods.

What are the pH and isotonicity requirements for nasal drops?

Nasal drops should be isotonic with $0.9\%\,\text{sodium chloride}$ and buffered to pH $6.5$ using a phosphate buffer.

What water temperature and duration are recommended for inhaling volatile medicaments from hot water?

Inhalations are added to hot water at about $65^\circ\text{C}$ and vapours are inhaled for about $10\,\text{minutes}$.

What is the typical solid particle size range in a pharmaceutical suspension?

Finely divided solid particles in a suspension range from $0.5\text{ to }5.0\,\mu\text{m}$ and should not exceed $10\,\mu\text{m}$.

How do flocculated and deflocculated suspensions compare in terms of sediment caking and redispersibility?

In flocculated suspensions, sediment does not form a hard cake and is easy to redisperse, whereas in deflocculated suspensions, sediment forms a closely packed hard cake that is difficult to redisperse.

What is the equation for calculating sedimentation volume in suspension stability evaluation?

Sedimentation volume is calculated as $F = \frac{H_u}{H_o}$, where $H_u$ is the ultimate height of sediment and $H_o$ is the initial height of the total suspension.

How is the degree of flocculation defined mathematically?

The degree of flocculation is calculated as $\frac{F}{F_\infty}$, where $F$ is the sedimentation volume of the flocculated suspension and $F_\infty$ is the sedimentation volume in the ultimate dispersed state.

What is the typical globule size range in a pharmaceutical emulsion?

Globule size in an emulsion ranges from $0.25\text{ to }25\,\mu\text{m}$ in diameter.

What are the particle size ranges for microemulsions and nanoemulsions?

Microemulsion particle sizes range from $10\text{ to }300\,\text{nm}$, whereas nanoemulsion particle sizes range from $10\text{ to }75\,\text{nm}$.

What are the standard Oil : Water : Gum primary emulsion ratios for fixed oils, mineral oils, volatile oils, and oleo resins?

The ratios are Fixed Oil = $4:2:1$, Mineral Oil = $3:2:1$, Volatile Oil = $2:2:1$, and Oleo Resin = $1:2:1$.

How is Scarlet Red dye used to identify the type of emulsion in a dye test?

If dispersed globules appear red in a colourless background under a microscope, it is an o/w emulsion; if colourless globules appear in a red background, it is a w/o emulsion.

What is the desired zeta potential value for electrically stabilized emulsions using a Zeta sizer?

The desired zeta potential value is $\pm 25\,\text{mV}$.

What causes cracking or breaking of an emulsion?

Cracking is caused by the complete, irreversible separation of oil and aqueous phases, often due to adding incompatible emulsifying agents such as mixing monovalent soap with divalent soap.