Gels In Pharmaceuticals are Homogeneous, Semisolid preparations usually consisting of solutions or dispersion of one or more medicaments in suitable hydrophobic and hydrophilic bases. Suitable gelling agents are used for the preparation of gels. Antioxidants, Preservatives, and Stabilizers may be added to the gels. Gels applied for large open wounds, and severely injured skin shall be sterile.
Types of Gels In Pharmaceuticals:
- Classification of Gels is Following:
- Controlled release gels
- Extended-release gels
- Amphiphilic gels
- Hydrophilic gels
- Non-aqueous gels
- Bioadhesive gels
- Thermosensitive sol-gel reversible hydrogels
- Complexation gels
Polymers used for the preparation of pharmaceutical gels
The Polymers such as natural gum, Pectin, Tragacanth, Agar, Alginic acid, Carrageen, and synthetic, semi-synthetic material, MethylCellulose, Hydroxy methylcellulose, Carboxymethylcellulose, and the carbopols is used to prepare pharmaceutical gels. Gels are prepared by either a fusion process or a unique process required for a specific gellant.
The difference among Gels, Jellies, and Pastes:
Gels: Gels are usually clear transparent semisolids containing solubilized active substances.
Jellies: Jellies are water-soluble bases prepared from natural gums or synthetic gums.
Pastes: Pastes are dispersions of high concentrations of insoluble powdered substances (20 to 50%) in a fatty or aqueous base.
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Standard Test for Gels:
1. Uniformity of Weight: The average net weight of the content of the ten containers is not less than the labeled amount, and the net weight of the content of any single container is not less than 91 % and not more than 109% of the labeled amount.
Where the labeled amount is 50 g or less or Not less than 95.5 % and not more than 104.5 % of the labeled amount where the labeled amount is more than 50 g but not more than 100 g, for more than 100 g contents limits given in the Standards of Weights and Measures (Packaged Commodities) Rules, 1977 may be followed.
2. Sterility Test: Shall comply with the specification if labeled as sterile.
3. pH: It should be within the specified Limit.
4. Viscosity: Shall comply with the specification.
5. Appearance: Shall comply with the specification
6. Homogeneity: Shall comply with the specification
7. Assay content: Shall comply with the specification
8. Any other in-house Tests.