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Four substances were evaluated for their potential usefulness as dry binders for direct compression techniques in tablet making. The flow properties of these substances including angle of repose, timed delivery through an orifice and compressibility were determined. The effect of particle size of the binder on its flow properties was investigated. Comparative rates of water sorption demonstrated by the various substances evaluated as dry binders were also determined.

The effect of talc, magnesium stearate, stearic acid, and Acrawax C, which are commonly used as lubricants, on the dry-binding efficiency of tragacanth, polyethylene glycol 4000, polyvinylpyrrolidone, and mannitol were investigated. The effect of Aerosil which is sometimes utilized as a flow conditioner for directly compressible powder blends was also studied. The type and concentration of lubricant or flow conditioner appeared to influence the binding efficiency of the binders investigated to various degrees. The results showed that the bonding characteristics of all the binders tested except mannitol were reduced by the addition of the lubricants and the flow conditioner.

The effect of addition of ascorbic acid, which is a drug known to be difficult to compress directly, on the self-binding efficiency of tragacanth, Carbowax 4000, Plasdone, and mannitol were investigated. The flow properties of ascorbic acid of different particle sizes were determined since they would affect the flowability of the binders investigated and would help to determine the optimum particle size of the drug required for maximum binding efficiency.

Comparative self-binding qualities of four substances studied as potential dry binders for direct compression applications in tablet making were investigated. The effect of particle size of these materials on hardness, friability and hardness-friability ratio of disks made with mere binders was studied. The results showed that for comparable particle sizes, values of hardness-friability ratio of the various disks were in the following descending order: Plasdone, tragacanth, Carbowax 4000 and then mannitol.

The effects of starch and Veegum as disintegrants on the dry-binding qualities of tragacanth, polyethylene glycol 4000, polyvinylpyrrolidone and mannitol were investigated. The type of diluent and its concentration in the powder blends appeared to influence the binding efficiency of the binders investigated.

Directly compressible powder blends containing either ascorbic acid or phenobarbitone, and utilizing tragacanth, Carbowax 4000, Plasdone, and mannitol as dry binders, were formulated. The flowability of the powder mixes prior to compression was determined. Furthermore, the tablets prepared according to the suggested formulae were tested for hardness, friability, uniformity of weight, distribution of active ingredient, disintegration, and dissolution. The effect of aging on the qualities of the tablets was also studied.

The effects of lactose and dibasic calcium phosphate as diluents on the dry-binding qualities of tragacanth, polyethylene glycol 4000, polyvinylpyrrolidone and mannitol were investigated. The type, concentration and particle size of the diluent appeared to influence the flowability and the binding properties of the binders investigated.