Gels are also called as Jellies some times. Gels are semisolid, transparent and non-greasy drug dosage forms mainly aimed for topical application. The Gels can be applied to the skin, used nasally, vaginally, or rectally. Gels are semisolid materials consisting of dispersion’s of small or large molecules in an aqueous base and the formulation of Gels involves the addition of several natural gums and Gelling agents (Gelling agents are used synthetic macro-molecules Gels (Jellies).
TYPES OF GELS
There are mainly two types of Gels, Single-Phase Gels and Two-Phase Gels. A brief description of them is given below,
1. SINGLE – PHASE GELS are gels in which the macro-molecules are uniformly distributed throughout a liquid with no apparent boundaries between the dispersed macro-molecules and the liquid.
2. TW0 – PHASE GELS (magma “Milk magnesia”) consisting of floccules of small distinct particles.
HOW GELS ARE PREPARED
The preparation of Gels or Jellies is mainly done through 4 types of processes, as follows.
• By changing the pH (as for carbomers)
• Formed by dispersing the molecule in the continuous phase (e.g., by heating starch)
• By cross-linking the dispersed molecules
• By reducing the continuous phase (as for jellies formed with sucrose). Preparation of Gels
Ointment are Semi-solid preparations of hydrocarbons (paraffins, petrolatum, mineral oil, synthetic hydrocarbons, etc,). Ointments have a yellow paraffin base. Ointments are greasy, absorbtive and highly macerating. The Simple definition is Ointments are semisolid preparations intended for external application to the skin or mucous membranes.
TYPES OF OINTMENTS
Ointments are mainly categorized into 2 types based on the drug content in it. they are as follows,
1. UNMEDICATED OINTMENTS
These ointments do not contain any drugs. They are useful as emollients, protectants or lubricants. Example: Petroleum jelly.
2. MEDICATED OINTMENTS
These ointments contain drugs which shows systemic effects. Some of the types of Medicated Ointments are Dermatologic ointments, Rectal ointments, Vaginal ointments, Ophthalmic ointments, Nasal ointments, etc.
Ointment bases are of Four groups:
1. Oleaginous bases
2. Absorption bases
3. Water-removable bases
4. Water-soluble bases Ointment Bases
|Gels are transparent and Translucent semi-solid preparations in a suitable ointment base.||Ointments are semi-solid preparations in which the drug is dispersed or dissolved.|
|Gels are non-porous due to the presence of binding agents. Gels are non-greasy preparations.||Ointments are non-porous and highly greasy and absorptive preparations.|
|Gels are used for medicating, lubricating and miscellaneous purposes.||Ointments are used for emollient medicative purposes and for protection of lesions.|
|Gels are stored in well closed containers in order to prevent evaporation of water.||Ointments are stored in wide mouthed containers or tubes in a cool and dry place, away from sunlight.|
|Formulation of Gels involves the usage of several natural gums and gelling agents.||Formulation of ointments involves hydrocarbon, absorption, emulsifying and water soluble bases.|
|Gels become liquid when came into contact with the skin, dry and leave a thin film of active medication.||Strong emollient effect in Ointment makes it useful in dry skin conditions.|
|Gels are mainly made to be applied to mucous membranes of the skin.||Ointments which are more greasy are made for hairy regions like scalp, etc.|
|Gels are good to be used on the face because ointments are mostly greasy. gels can dry things up very fast, so applying them onto the moist area would be helpful.||Ointments usually stay longer on the skin than creams and gels. If a drug is applied to a place that can be easily rubbed off, then ointment is a good choice.|
|Gels are cosmetically acceptable and is widely used for non-medicinal activities.||Ointment provides a protective film on the skin (e.g., useful in housewife’s hands, irritant dermatitis)|
|Gels are stiff in nature when compared to pastes.||Ointments are very stiff in nature.|