Anhydrous a-lactose

Fig. 7 Relation of tablet crushing strength and surface area of selected size fractions of anhydrous a-lactose, which had been compressed at 37.5 mPa. Data are shown for initial size fractions of (A) 24-32 /am, (B) 32-63 /am, (C) 63-100 /am, (D) 100-160 /am, (E) 160-200 /am, and (F) 250-315 /am. (Data adapted from Ref. 51.)...

Forms of Anhydrous a-Lactose. The water of crystallization may be removed from a-hydrate crystals under various conditions to produce different types of anhydrous lactose. 

Ethanol and methanol (preferred with less than 3% moisture) have been used to extract lactose from skim milk or whey powders (Kyle and Henderson 1970). The dried lactose powder that crystallized from the alcoholic extract was believed to be anhydrous a-lactose, but other work indicates that the product is a mixture of anhydrous a- and /3-lactose (Lim and Nickerson 1973). 

It has been demonstrated in the laboratory that by careful manipulation of alcohol concentration, amorphous lactose high in the /3 anomeric form could be precipitated (Majd and Nickerson 1976 Ross 1978A Olano and Rios 1978). Parrish et al. (1980B) have formed /3-lactose from stable forms of anhydrous a-lactose and have prepared /3-lactose from a-lactose monohydrate with potassium methoxide (1979B). None of these processes have been commercialized. 

Parrish, F. W., Ross, K. D. and Valentine, K. M. 1980B. Formation of /3-lactose from the stable forms of anhydrous a-lactose. J. Dairy Sci. 45, 68-70. 

Sharp, R F. 1943. Stable crystalline anhydrous a-lactose. U.S. Patent 2,319,562. 

Anhydrous a-maltose decomposes at about 100-120°C, and anhydrous a-lactose at 200-220 C. Note that in the case of an unknown a temperature of decomposition in one range or the other is valid as an index of identity only if the substance has been characterized as a reducing sugar. Before applying the test to an unknown, perform a comparable evaporation of a 0.1 M solution of glucose, fructose, galactose, or mannose. 

Anhydrous lactose is primarily anhydrous p-lactose with up to about 25% anhydrous a-lactose. It consists of agglomerates of fine crystals produced by roller drying a solution of a-lactose monohydrate. Flow properties are... 

Lactose occurs as white to off-white crystalline particles or powder. Several different brands of anhydrous lactose are commercially available which contain anhydrous P-lactose and anhydrous a-lactose. Anhydrous lactose typically contains 70-80% anhydrous P-lactose and 20-30% anhydrous a-lactose. 

X3 a-lactose monohydrate (%) potato starch (%) anhydrous a-lactose (%) Crushing strength (N) Disintegration time (s)... 

The meaning of the coefficients in these equations may be illustrated using the previously discussed data for the tableting of placebo mixtures (2), a-lactose monohydrate, potato starch and anhydrous a-lactose. We again consider the crushing strength of the tablets. 

Compressive deformation studies were conducted on single crystals of a-lactose, using mechanical strength and acoustic emission analyses to deduce any possible differences in the deformation behavior of a-lactose monohydrate and anhydrous a-lactose [56]. The a-lactose monohydrate crystals were found to exhibit greater mechanical strength... 

Dlsaccharldes and Derivatives Thereof.- a,a-Trehalose anhydrous, a-lactose monohydrate (a redetermination),2-acetamldo-l,3,6-tri-... 

Figure 22 Influence of the amount of lactose or dicalcium phosphate dehydrate (% total weight) on the extrusion forces (N) for mixtures of lactose or dicalcium phosphate dehydrate-Avicel PH 101-water after granulation with a planetary mixer. Each end point is the mean of six values. The SD is lower than 3% for each point. Six different types of lactose were used , a-lactose monohydrate 80 mesh o, a-lactose monohydrate 200 mesh , a-lactose monohydrate 325 mesh , spray dried lactose DCL 11 x, anhydrous P-lactose DCL 21 , anhydrous a-lactose DCL 30. One type of dicalcium phosphate dehydrate was used, a. (From Ref 33.)...

The solubilities of D-xylose and D-mannose in aqueous ethanol (0-100%) at 25 C have been measured by use of refractometry and h.p.l.c., and some physical properties (m.p., solubilities) of crystalline anhydrous a-lactose, , e-lactose, and 8-lactose have been reported. The excess Gibbs free energies of aqueous solutions of carbohydrates and other polyols at 25°C have been determined and correlated with the sugar configurations. The standard enthalpy of formation (1263.4 1.2 kJmol"" ) of o-D-mannose at 298.15 K has been calculated from the corresponding standard energy of combustion (-15.6123 0.0065 kJg ) which was... 

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