Sodium starch glycollate

Titanium dioxide Sodium starch glycolate Talc... 

Although untreated starches do not swell sufficiently, certain modified forms, such as sodium starch glycolate, do swell in cold water and are better as disintegrants. Various cellulose derivatives, including methylcellulose and carboxymethylcellulose, have been used in this role, but with limited success due to the marked increase in viscosity they produce around the dispersing tablet mass. 

Note Colloidal silica (glidant) and sodium starch glycolate (disin-tegrant) were fixed at 0.1% and 5%, respectively, in all batches. Source. Ref. 100. 

Fig. 4 Sodium starch glycolate viewed (a) using ordinary illumination and (b) between crossed polarizers.

It is a yellow solid with a solubility in water of 0.007 mg/mL. The Tykerb tablet contains 405 mg of the active ingredient, and the inactives are magnesium stearate, microcrystalline cellulose, povidone, and sodium starch glycolate. 

Sodium starch glycolates are generally spherical, a characteristic which accounts for their good flowability [4]. Figure 1 shows the scanning electron photomicrographs (SEMs) of some the commercial sodium starch glycolates. 

FIG. 1. Scanning electron photomicrographs of sodium starch glycolates (A) Explotab, (B) Primojel, and (C) Tablo 600 X Magnification. 

Rudnic, E.M., Kanig, J., and Rhodes, C.T., The effect of molecular structure on the function of sodium starch glycolate in wet granulated systems. Drug Dev. Ind Pharm., 9 303-320 (1983). 

Tablets were prepared either with an insoluble (dicalcium phosphate dihydrate), a soluble (6-lactose) or a moderately soluble filler-binder (a-lactose monohydrate). As a disintegrant four different starches (com, rice, potato and tapioca) were used. As a comparison the effect of two super-disintegrants (crospovidone and sodium starch glycolate) was studied. The disintegrants were added at two concentration levels. The compression load was adjusted in order to obtain tablets with comparable initial cmshing strengths.

The four starches used in this study have been proven to be suitable tablet ingredients [19]. Both used super-disintegrants, Primojel (sodium starch glycolate) and Polyplasdone XL (crospovidone), are commonly used as a disintegrant in tablets prepared by direct compression. 

The initial disintegration times of the tablets prepared with a-lactose were excellent all tablets disintegrated within 2 minutes. The 6-lactose tablets showed longer, but still adequate disintegration times. The difference between the effectiveness of sodium starch glycolate and crospovidone in 6-lactose tablets was previously studied by Van Kamp et al. [24] and ascribed to the higher capillary action of crospovidone. 

Of the tablets prepared with sodium starch glycolate, only the 6-lactose/sodium starch glycolate combination was influenced by all three adjustable factors (Table 8.8). Moreover, the effect of the relative humidity depended on the level of the temperature as well as the level of the disintegrant concentration and vice versa. 

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