Structural, Rheological and Textural Properties of Soft Paraffins

Barry, Brian W.; Grace, A.J.

doi:10.1111/j.1745-4603.1971.tb01004.x

Cited by 35 publications

(20 citation statements)

References 51 publications

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“…It is known that petroleum jelly consists of both solid and liquid hydrocarbons (normal, iso and ring paraffins) in the form of a gel structure, thus maintaining a solid-like state at room temperature (Birdwell and Jessen, 1966;Barry and Grace, 1971). This gel structure is composed of a three-dimensional crystalline network which encloses and immobilizes the liquid hydrocarbons.…”

Section: Methodsmentioning

confidence: 99%

“…Petroleum jelly has a two-phase colloidal gel-type structure containing liquid, microcrystalline and crystalline hydrocarbons (Barry and Grace, 1971). During a preparation of petroleum jelly when a molten material is cooled, the stiffening wax phase is developed into an amorphous three-dimensional network or matrix which forms a compact structure with voids of molecular dimensions, while the liquid phase is bound to the network or matrix by a sorption mechanism.…”

Section: Yield Stressmentioning

confidence: 99%

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Rheological evaluation of petroleum jelly as a base material in ointment and cream formulations: Steady shear flow behavior

Park

Song

2010

Arch. Pharm. Res.

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The objective of the present study is to systematically characterize a nonlinear rheological behavior of petroleum jelly (petrolatum) in steady shear flow fields correspondent to the spreading condition onto the human body. With this aim, using a strain-controlled rheometer, the steady shear flow properties of commercially available petroleum jelly have been measured at 37 degrees C (body temperature) over a wide range of shear rates. In this article, the shear rate dependence of steady shear flow behavior was reported from the experimentally obtained data. In particular, the existence of a yield stress and a non-Newtonian flow behavior were discussed in depth with a special emphasis on their importance in actual application onto the human body. In addition, several inelastic-viscoplastic flow models including a yield stress parameter were employed to make a quantitative description of the steady shear flow behavior, and then the applicability of these models was examined in detail. Main findings obtained from this study can be summarized as follows: (1) Petroleum jelly exhibits a finite magnitude of yield stress. The appearance of a yield stress is attributed to its three-dimensional network structure that can show a resistance to flow and plays an important role in determining a storage stability and sensory feature of the product. (2) Petroleum jelly demonstrates a pronounced non-Newtonian shear-thinning flow behavior which is well described by a power-law equation and may be interpreted by the disruption of a crystalline network under the influence of mechanical shear deformation. This rheological feature enhances sensory qualities of pharmaceutical and cosmetic products in which petroleum jelly is used as a base material during their actual usage. (3) The Casson, Mizrahi-Berk, Heinz-Casson and Herschel-Bulkley models are all applicable and have almost an equivalent ability to quantitatively describe the steady shear flow behavior of petroleum jelly whereas the Bingham model does not give a good validity. Among these flow models, the Herschel-Bulkley model provides the best applicability.

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Section: Methodsmentioning

confidence: 99%

Section: Yield Stressmentioning

confidence: 99%

Rheological evaluation of petroleum jelly as a base material in ointment and cream formulations: Steady shear flow behavior

Park

Song

2010

Arch. Pharm. Res.

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“…priate function derived by direct oscillatory measurements at frequencies ranging from to 25 Hz. [5][6][7][8][9]. [5][6][7][8][9].…”

Section: Resultsmentioning

confidence: 99%

Correlation of Viscoelastic Functions for Pharmaceutical Semisolids: Comparison of Creep and Oscillatory Tests for Oil-in-Water Creams Stabilized by Mixed Emulsifiers

Eccleston

Barry

Davis

1973

Journal of Pharmaceutical Sciences

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“…The validity of continuous shear methods for examining semisolids will not be discussed in detail in this paper. The problems involved for mechanically similar materials, the soft paraffins, were considered by Barry & Grace (1971a). It was concluded that the rheological behaviour in continuous shear was essentially that illustrated in Fig.…”

Section: Spreadabilitymentioning

confidence: 99%

Continuous shear, viscoelastic and spreading properties of a new topical vehicle, FAPG base

1973

Journal of Pharmacy and Pharmacology

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The rheology of a new topical vehicle FAPG base was investigated over the temperature ranges of 25-37'. Continuous shear rheograms obtained with a Ferranti-Shirley cone and plate viscometer were hysteresis loops with spur points; loop areas, yield values and apparent viscosities decreased with increase in temperature and an activation energy for viscous flow of 10.4 kcal mol-l (43.5 kJ mol-l) was derived. In creep (concentric cylinder geometry) the base was viscoelastic with a low limit of linearity with respect to strain. Creep compliance curves showed an initial elastic response, a region of retarded elasticity and a viscous region ; compliances increased and viscosities decreased with temperature rise. Patient acceptance of skin spreadability of the base was assessed using a master curve concept; the spreading properties were close to the preferred values for maximum patient acceptance. It is concluded that FAPG base deserves further study as a vehicle for dermatological use.For skin therapy, the vehicle used should have optimum physicochemical properties for assuring drug stability and release besides inhibiting microbial growth and being aesthetically satisfactory. Recently, a new topical vehicle 'FAPG base was reported to have possible significant advantages over traditional ointments and creams (British Patent No. 1,259,858 and other Patents pending; Garnier, 1971a,b;Rhodes, 1971). We have examined the rheological properties of the material in continuous shear and in creep and have attempted to assess patient acceptance of its spreadability. METHODS A N D RESULTS Material.A production sample of FAPG base was provided by Syntex Pharmaceuticals Ltd., St. Ives House, Maidenhead, Berks. It is a mixture of propylene glycol, stearyl alcohol, polyethylene glycol and glycerol combined to form a gel-like structure with a crystalline network. The product is a smooth, white, soft, non-aqueous, hydrophilic semisolid with a slight pearly sheen (Garnier, 1971b).Microscopy. The base was examined with a Kofler Micro Hot Stage attached to a polarizing microscope. At room temperature the material was anisotropic (Fig. 1A) and slight melting occurred between 32-34'. Between 47-49' the preparation melted to form an isotropic solution which recrystallized in a different form on cooling. The flocculated suspension appearance was replaced by a mosaic of thin, flat, anisotropic, polyhedral crystals (Fig. IB). This implies that FAPG base may change its crystalline form on storage to yield a product with different mechanical properties.A Ferranti-Shirley cone and plate viscometer with automatic flow curve recorder unit was used with a large cone (diameter 7 cm, Continuous shear rheology.

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Structural, Rheological and Textural Properties of Soft Paraffins

Cited by 35 publications

References 51 publications

Rheological evaluation of petroleum jelly as a base material in ointment and cream formulations: Steady shear flow behavior

Rheological evaluation of petroleum jelly as a base material in ointment and cream formulations: Steady shear flow behavior

Correlation of Viscoelastic Functions for Pharmaceutical Semisolids: Comparison of Creep and Oscillatory Tests for Oil-in-Water Creams Stabilized by Mixed Emulsifiers

Continuous shear, viscoelastic and spreading properties of a new topical vehicle, FAPG base

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