Dispersing Dosage forms

MD Donovan, DR Flanagan. Bioavailability of disperse dosage form. In HA Lieberman, MM Rieger, GS Banker, eds. Pharmaceutical Dosage Forms Disperse Systems, Vol. 1. 2nd ed. New York Marcel Dekker, 1996, pp 315-376. 

R Bodmeier, O Paeratakul. Suspensions and dispersible dosage forms of multiparticulates. In I Ghebre-Sell-assie, ed. Multiparticulate Oral Drug Delivery. New York Marcel Dekker, 1994, pp 143-157. 

Solid dispersions. SCF techniques can be applied to the preparation of solvent-free soUd dispersion dosage forms to enhance the solubility of poorly soluble compounds. Traditional methods suffer from the use of mechanical forces and excess organic solvents. A soUd dispersion of carbamazepine in polyethyleneglycol 4000 (PEG4000) increased the rate and extent of dissolution of carbamazepine ]. In this method, a precipitation vessel was loaded with a solution of carbamazepine and PEG4000 in acetone, which was expanded with supercritical CO2 from the bottom of the vessel to obtain solvent-free particles. 

RD Schocnwald. DR Flanagan. Bioavailabiliiy of disperse dosage forms. In HA... 

B. Idson, in H. A. Lieberman and co-eds.. Pharmaceutical Dosage Forms, Disperse Systems, Vol. 1, Marcel Dekker, New York, 1988, Chapt. 6. 

This chapter describes the basic principles involved in the development of disperse systems. Emphasis is laid on systems that are of particular pharmaceutical interest, namely, suspensions, emulsions, and colloids. Theoretical concepts, preparation techniques, and methods used to characterize and stabilize disperse systems are presented. The term particle is used in its broadest sense, including gases, liquids, solids, molecules, and aggregates. The reader may find it useful to read this chapter in conjuction with Chapters 8, 12, and 14, since they include some of the most important applications of disperse systems as pharmaceutical dosage forms [1]. 

The number of the constituent phases of a disperse system can be higher than two. Many commercial multiphase pharmaceutical products cannot be categorized easily and should be classified as complex disperse systems. Examples include various types of multiple emulsions and suspensions in which solid particles are dispersed within an emulsion base. These complexities influence the physicochemical properties of the system, which, in turn, determine the overall characteristics of the dosage forms with which the formulators are concerned. 

Table 6 Relationship Between the Use of Surfactants in the Preparation of Pharmaceutical Dosage Forms, Their Dispersibility in Water and Their HLB Values...

---