In vitro evaluation of a fast-disintegrating lyophilized dry emulsion tablet containing griseofulvin and comparison with its conventional dosage form

In vitro evaluation of a fast-disintegrating lyophilized dry emulsion tablet containing griseofulvin and comparison with its conventional dosage form

Rationale
Lyophilization or freeze drying is a process in which water is removed from a product after it is frozen and placed under a vacuum, allowing the ice to change directly from solid to vapor without passing through a liquid phase. The process consists of three separate, unique, and interdependent processes; freezing, primary drying (sublimation), and secondary drying (desorption). The dry emulsion can be formed from following possible ways:
• Freeze drying/ Lyophilization
• Spray Drying
• Solvent evaporation by vaccum drying

We choosed griseofulvin for our project. According to the biopharmaceutical classification system (BCS), to Class II of drugs with poor solubility and high permeability for doses of 125 and 250mg. Class II drugs usually suffer from low bioavailability following oral administration of traditional dosage forms. The purpose of this study was to investigate the in vitro dissolution of GF from lyophilized dry o/w emulsion (LDE) tablets. LDE tablets could be useful for the delivery of poorly soluble drugs for which fat co-administration results in improving bioavailability or for which an increased oral bioavailability is observed when incorporated in o/w emulsions. Freeze-dried emulsion tablets have the advantage of sharing the properties of freeze-dried dosage forms, such as rapid reconstitution, good preservation, and stability. The tablets also disintegrate rapidly in the mouth upon contact with saliva and therefore do not need to be swallowed, which usually results in improving patient’s compliance and acceptability.




Materials and Method.
All chemicals used will be of analytical grade.
Emulsion(%,w/w) Tablet theoretical composition (mg;w/w)
F1
Gelatin (2%, w/v) 78.3 Gelatin 18
HPMC 2.2 HPMC 25.3
Miglyol 8.7 Miglyol 100
GF 10.8 GF 125
F2
Gelatin (2%, w/v) 78.3 Gelatin 18
HPMC 2.2 HPMC 25.3
Sesame oil 8.7 Sesame oil 100
GF 10.8 GF 125
F3
Gelatin (2%, w/v) 76.6 Gelatin 18
Tween 80/ Span 80 4.25 Tween 80/ Span 80 50
Miglyol 8.5 Miglyol 100
GF 10.6 GF 125
F4
Gelatin (2%, w/v) 77.2 Gelatin 18
HPMC 2.1 HPMC 24.5
Sorbitol 0.7 Sorbitol 8.16
Glycine 0.7 Glycine 8.16
Miglyol 8.6 Miglyol 100.3
GF 10.72 GF 125
F5
Gelatin (2%, w/v) 75.6 Gelatin 18
HPMC 4.2 HPMC 50
Sorbitol 0.67 Sorbitol 7.9
Glycine 0.67 Glycine 7.9
Miglyol 8.4 Miglyol 100
GF 10.5 GF 125

Method
This technology includes physical trapping of the drug in the matrix composed of a saccharide and a polymer. Polymers generally employed are partially hydrolyzed gelatin, hydrolyzed dextran, dextrin, alginates, polyvinyl pyrrolidine, acacia, and these mixtures.
The methodology involves solution or dispersion of components is prepared and filled into blister cavities which are frozen below their eutectic point or below their glass trasition temperature. The frozen mixture is heated at low pressure called vaccum drying, above its collapse temperature causing water to sublimate and produce highly porous tablets. This idea come to first patented as zydis technology which was the first of its kind. This process is performed in Lyophilization equipment which consists of a drying chamber with temperature controlled shelves, a condenser to trap water removed from the product, a cooling system to supply refrigerant to the shelves and the condenser, and a vaccum system to reduce the pressure in the chamber and condenser to facilitate the drying process.

References

1. Iman Saad Ahmed, Mona Hassan Aboul-Einien, In vitro and in vivo evaluation of a fast-disintegrating lyophilized dry emulsion tablet containing griseofulvin, Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Kasr-El-Eini St., Cairo, Egypt
2. http://www.wikipedia/griseofulvin.org
3. Aulton.M.E., Dosage Form Design and Manufacture. Pharmaceutics: The Science of Dosage Form Design, 2nd Edition, 2002 :( 307-339)
4. www.elsevier.com/locate/ejps
5. www.hinary.org