Co-processed excipients

A relatively new class of co-processed excipients now exists. These excipients are essentially a preblend of two or more excipients that are commonly used in conjunction with each other. 

A number of different grades of lactose are commercially available that vary in their physical properties and many studies have been reported in the literature comparing the behavior of these various materials in different formulations. A number of co-processed excipients which contain lactose are available for direct-compression applications co-processed lactose and starch (Starlac, Meggle/Roquette Freres), lactose and microcrystalline cellulose Microcelac, Meggle) lactose and cellulose powder (Cellactose, Meggle), lactose, povidone, and crospovidone (Ludipress, BASF). 

Table 1.4 List of co-processed excipients created by combining plastic and fragmenting excipients.

S. Jacob, A. Shirwaikar, A. Joseph, K. Srinivasan, Novel co-processed excipients of mannitol and microcrystalline cellulose for preparing fast dissolving tablets of ghpizide, Indian... 

A.l. Arida, M.M. Al-Tabakha. Cellactose a co-processed excipient A comparison study. Pharm Dev Technol. 13 (2) 165-175,2008. 

Reimerdes D, Aufmuth KP. Tableting with co-processed lactose-cellulose excipient. Manuf Chemist 1992 63 21-24. 

Efforts have been made to engineer excipients which exhibit both good flow and compactability by co-processing materials. For example, combining excipients with... 

A. Goyanes, C. Souto, R. Martinez-Pacheco. Co-processed MCC-Eudragit E excipients for extrusion-spheronization. Eur J Pharm Biopharm. 79 (3) 658-663,2011. 

Calcium monohydrogen phosphate dihydrate Calcium phosphate, dibasic, dihydrate Dicalcium phosphate dihydrate Phosphoric xid, caicium salt (1 1), dihydrate. Dibasic calcium phosphate dihydrate USP/BP excipient tor production of pharmaceutical tablets by direct compression process. Penwest Pharmaceuticals Co. 

Microcalorimetry is an extremely sensitive technique that determines the heat emitted or adsorbed by a sample in a variety of processes. Microcalorimetry can be used to characterize pharmaceutical solids to obtain heats of solution, heats of crystallization, heats of reaction, heats of dilution, and heats of adsorption. Isothermal microcalorimetry has been used to investigate drug-excipient compatibility [82]. Pikal and co-workers have used isothermal microcalorimetry to investigate the enthalpy of relaxation in amorphous material [83]. Isothermal microcalorimetry is useful in determining even small amounts of amorphous content in a sample [84]. Solution calorimetry has also been used to quantitate the crystallinity of a sample [85]. Other aspects of isothermal microcalorimetry may be obtained from a review by Buckton [86]. 

---