Us-based Vanderbilt manufactures VEEGUM R, VEEGUM F, VEEGUM HV and VEEGUM K in compliance with the (USP)/National Formulary (NF) monograph for magnesium aluminum silicate. In addition, Vanderbilt also produces similar grades which comply with the European Pharmacopoeia (EP) monograph for aluminum magnesium silicate.
VEEGUM magnesium aluminum silicate products are naturally occurring water-washed smectite clays used worldwide to stabilise emulsions and suspensions and to thicken a wide range of products. Smectite clay (also known as bentonite) is valued for its ability to swell in water and to impart useful rheological properties to aqueous compositions. VEEGUM and VAN GEL clays have consistently been the preferred choice among formulator’s in India and across the world to stabilise suspensions, perfect emulsions and optimise flow properties .
VEEGUM products are used extensively in India primarily for pharma and personal care applications, although they are widely used in other industrial and household care areas as well. Pharma and cosmetic grades of VEEGUM clay are also controlled for arsenic, lead and bacteria content. Formulators find that the value of VEEGUM and VAN GEL clays as stabilising and rheological agents is due to their colloidal structure in water.
When clay and water are mixed, water penetrates between the platelets, forcing them further apart. For most VEEGUM and VAN GEL grades, the speed with which platelet separation occurs is directly related to the amount of energy introduced during hydration.
Once the clay is hydrated (i.e., the platelets are separated) a three dimensional colloidal structure commonly called the “house of cards”is formed . This colloidal structure accounts for the characteristic rheology imparted by these clays. Dispersions of VEEGUM and VAN GEL clays are thixotropic and pseudoplastic, in addition to contributing useful yield value. Formulators highly value this colloidal structure for its ability to trap and segregate solids in suspensions, oils in emulsions, and gases in foams or mousses. Once the clay is hydrated, the colloidal structure builds rapidly at first, providing a quick increase in viscosity. As time passes, the remaining free platelets take a longer time to find an available site in the structure, so viscosity increases at a progressively slower rate. Formulators find that Smectite dispersions are also pseudoplastic as an increase in the rate of shear results in decreasing viscosities.
The colloidal structure also provides the smectite’s most useful property – yield value. This is a measure of the resistance of the structure to breakdown. From the point of view of formulators, a unique and valuable feature of VEEGUM and VAN GEL clays is their ability to impart yield value at low viscosity.With VEEGUM and VAN GEL, stabilisation of the dispersed phase is possible even in thin, fluid systems where flowability is important.
Formulators are impressed with the behavior of VEEGUM and VAN GEL clays in the presence of other ingredients, not just in water alone. Most water-soluble components will modify the rheological properties of smectite clay, usually beneficially. Salts, surfactants and water-miscible solvents will increase the smectite’s viscosity and yield value contribution and decrease thixotropy, but still provide a shear-thinning composition.
From the formulators point of view , one of the most useful features of VEEGUM and VAN GEL clays is their ability to stabilise oil-in-water (O/W) emulsions at low concentrations. VEEGUM and VAN GEL clays reduce the tendency of emulsions to thin out and break at elevated temperatures.
Small amounts (typically 1-2 per cent) will stabilise emulsions containing anionic or nonionic surfactants that include a wide variety of oils, fats, and waxes. In case of water-in-oil (W/O) emulsions , most formulators have found VEEGUM clay to be an effective W/O emulsion stabiliser, increasing internal phase viscosity to inhibit coalescence in their formulations. Besides , formulators also use VEEGUM clay in the production of fluid W/O emulsions that are otherwise difficult to stabilise.
Apart from its emulsion stabilising property, the colloidal structure of VEEGUM and VAN GEL clays provides excellent suspension of fine particles in aqueous systems. Its high yield value enables the successful suspension of even high density particulates which is a huge advantage to formulators looking for long-term stability of their emulsions.
From the formulators point of view , VEEGUM and VAN GEL products have many advantages as suspending agents. They prevent hard packing of the suspended material; control bleeding, suspensions that tend to settle are easily redispersed; ensure products of uniform dosage in pharmaceutical suspensions and pesticide concentrates; achieve maximum suspension without losing pourability; do not form gelatinous, irreversible gels, as is the case with many organic gums and offer better suspension efficiency than organic gums; especially at low viscosities.
In the personal care and cosmetics segment, formulators have found that VEEGUM clay contributes spreadability and cosmetic elegance to topical products. Owing to the insoluble, platy nature of its aqueous dispersions, formulators used it to produce tackfree topical products. It is also used to reduce or eliminate the tacky, gummy or stringy nature of organic gums and polymers.
In addition to their tactile and organoleptic benefits, formulators often use VEEGUM and VAN GEL clays with organic thickeners to enhance the best characteristics of each. The smectites contribute to synergistic viscosity and yield value, while the gums’ and polymers’ protective colloidal action improves the clay’s stability in the presence of electrolytes, surfactants, and other water solubles.
Formulators in the cosmetics and home care segment routinely use VEEGUM and VAN GEL clays in products spanning the pH 2 to pH 13 range. These include AHA emulsions, anti-perspirant, internal analgesic suspensions, chlorine bleach scrubs and caustic oven cleaners.
Being anionic , VEEGUM and VAN GEL clays are compatible with most anionics and non-ionic; they are incompatible with most cationics. Their dispersions can be combined with water-miscible solvents: up to 20 per cent alcohol, 50 per cent glycerin and 30 per cent propylene glycol and polyethylene glycols.
A unique benefit to cosmetic, industrial and home care formulators stems from the fact that by virtue of being minerals, VEEGUM and VAN GEL clays are not decomposed by bacteria, heat or excess mechanical shear. They are insoluble in solvents and water, and can be used at pH values encompassing nearly all household and industrial cleaners. This feature is very convenient in addressing the shelf life issues around finished formulations using VEEGUM and VAN GEL.
Formulators use VEEGUM and VAN GEL clays as non-migratory binders in tablets, sticks, and pressed cakes. They do not migrate to the product surface during drying, thereby ensuring uniformity and the desired level of hardness, rub-off, and colour value. They also function as low-bulk disintegrants in pharma and industrial tablets.
Formulators in the industrial and household care segments report that industrial grades of VEEGUM and VAN GEL products offer clay purity and uniformity equal to that of the cosmetic and pharma grade VEEGUM products. For this reason, they use them in household and industrial cleaners, agricultural pesticide concentrates, abrasive suspensions, ceramic glazes and bodies, coatings, polishes, and industrial specialties. The industrial grades are used to provide suspension, emulsion stabilization, and tailored rheology even at extreme pH ranges.
VEEGUM and VAN GEL products are often used synergistically with organic thickeners. The viscosity or stability of formulations containing these mixtures will be greater than that of the same formulation made with either component. These combinations allow the formulator to fine-tune viscosity, yield value, and flow properties beyond what is possible with either the clay or organic thickener alone. In the agrochemical segment in India, VAN GEL B clay and xanthan gum combinations are widely used by formulators to stabilise flowable, concentrated (up to 70 per cent solids) agricultural pesticide suspensions. On the personal care front , formulators often use VEEGUM clay with nonionic cellulosic thickeners to improve suspension stability and flow properties in anti-dandruff shampoos.
VEEGUM and VAN GEL have found wide acceptance in India and are a preferred choice for most formulators in the personal care, pharma, household care segments and are here to stay.
