Influence of vehicle

Many modern dermatological formulations are washable oil-in-water systems. Simple aqueous lotions are also used as they have a cooling effect on the skin. Ointments are used for the application of insoluble or oil-soluble medicaments and leave a greasy film on the skin, inhibiting loss of moisture and encouraging the hydration of the keratin layer. Aqueous creams combine the characteristics of the lotions and ointments. A classification of semisolid bases is given in Fig. 9.24. 

The descriptions ointment and cream have no universally accepted meaning and generally refer to the completed formulation. 

Rguie 9.24 Classification of topical semisolid bases into lipophilic and hydrophilic systems in either single-phase or two-phase forms. 

Ointments are generally composed of singlephase hydrophobic bases, such as pharmaceutical grades of soft paraffin or microcrystalline paraffin wax. 

The complexity of many of the topical bases means that a physicochemical explanation of their influence on the release of medicament is not always possible. It is not difficult, however, to ascertain this influence and to highlight the problem. The interactions between the physical properties of the base and the dmg are exemplified by the effect of propylene glycol in simple bases shown in Fig. 9.25, where the percentage of the glycol 

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Heylings, J.R., et al., Sensitization to 2,4-dinitrochlorobenzene influence of vehicle on absorption and lymph node activation. Toxicology, 109, 57, 1996. 

Watkinson, A. C. et al. The influence of vehicle on permeation from saturated solutions. International Journal of Pharmaceutics 121 21—26,1995. 

Figure 9.34 The influence of vehicle pH on the aqueous humour concentration of pilocarpine and glycerol. , 10" mol dm" pilocarpine solutions A, 0.14 mol dm glycerol solutions oil samples obtained at 20 min post-instillation and represent results from a minimum of six eyes.

Kaidbey, K. and Kligman, A., Topical photosensitizers influence of vehicles on penetration, Arch. Dermatol., 110, 868-870, 1974. 

Morris, W.E. and Dishart, K.T. (1971) Influence of vehicle emission control systems on the relationship between gasoline and vehicle exhaust hydrocarbon composition. Effect of automative emission requirements on gasoline characteristics. ASTM. STAND. 487, 63. 

Lehman, P. A, Slattery, J. T., Eranz, T. J. (1988). Percutaneous absorption of retinoids Influence of vehicle, light exposure, and dose, Dermatol.. 91, 56-61. 

Henary, B. Y., Crandall, J., Bhalla, K., Mock, C. N., Roudsari, B. S. (2003). Child and adult pedestrian impact The influence of vehicle type on injury severity. In 47th annual conference of the association for the advancement of automotive medicine. 

Longhitano, D., Henary, B., BhaUa, K., Ivarsson, J., Crandall, J. (2005). Influence of vehicle body type on pedestrian injury distribution. SAE Technical Paper, 2005-01-1876. 

Influence of the chemical composition of the fuel on pollutant emissions from vehicles in the US (auto/oil program). 

Alcohol. The number of driving under the influence of alcohol (DUl) cases reflects the enormity of the dmnken driving problem in the United States (9). Tests to measure blood alcohol concentration are conducted on blood, urine, or breath (10). In the case of urine and breath, the alcohol concentration measured is reported in terms of the equivalent blood alcohol concentration. Most states in the United States presume that a person is under the influence of alcohol with respect to driving a motor vehicle at a blood alcohol concentration of 0.10%, ie, an ethanol concentration >10 g/100 mL of blood. Some states maintain a lower necessary concentration of 0.08%. In some European countries levels are as low as 0.05%. A blood alcohol concentration of 0.10% in a 68-kg (150-lb) person is the equivalent of about four drinks of 80 proof alcohoHc beverage or four 340-g (12-oz) beers in the body at the time of the test (see Beer Beverage spirits, distilled Wine). Ethanol is metabolized at the equivalent rate of about one drink per hour. 

Molor Vehicle Corrosion and Influence of De-Icing Chemicals, OECD Report, Oct. (1969)... 

Warbrick, E.V., et al., Influence of application vehicle on skin sensitization to methylchlo-rothiazolinone/isothiazolinone An analysis using the local lymph node assay. Contact Dermatitis, 41, 325, 1999. 

Another instructive example of the relevance of ambient stimuli to the nature of the effect of serotonergic manipulations on locomotor activity is provided by Brody s (27) study of PCPA. He monitored the locomotion of vehicle- and PCPA-treated rats in an open field to which the animals had been previously familiarized. Animals were tested either with or without additional stimulation in the form of flashing lights and 90 dB(A) noise bursts. Without stimulation, PCPA-treated rats were less active than controls with stimulation, PCPA-treated rats were more active. The results of these and other such studies indicate that the central serotonergic systems may not directly modulate the level of locomotor activity per se, but they may profoundly influence locomotor activity by virtue of their effects on the sensory responsivity of the animal to a wide variety of environmental stimuli. 

Pyrethroid-induced neurobehavioral effects including clinical signs are known to be highly influenced by methodological changes in route, vehicle, dosing volume, species, and strain [19, 20]. The influence of the dose volume on the neurobehavioral effects after single oral administration was evaluated with... 

Ziegenmeyer, J. (1982). The influence of the vehicle on the absorption and permeation of drugs. In Dermal and Transdermal Absorption (Brandan, R. and Reisen, R, Eds.). Wissenschaf-tliche, Verlagsgesellschaft, Stuttgart, pp. 73-89. 

In a third report (very similar to the second), Hanhijarvi, Nevalainen and Mannisto (1985) clearly demonstrated that the type of vehicle can greatly influence irritation, in that dithranol was clearly more irritating when applied in paraffin that when applied in a gel. They were also able to demonstrate that although dithranol was less acutely irritating than butantrone, the cumulative irritations (mean scores at the end of six months of six times per week applications) were quite similar (Mannisto et al., 1984). There was no evidence of systemic toxicity nor of test article in plasma with either species. 

Fig. 35 Influence of the binder on the CPVC and of the binder and the CPVC on the viscosity of P.Y.13 in sheet offset vehicles of different composition at constant dispersion conditions in a three-roll mill.

Wenkers BP, Lippold BC (1999) Skin penetration of nonsteroidal antiinflammatory drugs out of a lipophilic vehicle influence of the viable epidermis. J Pharm Sci 88 1326-1331. 

The use of polyethers and quaternary salts as liquid-liquid and solid-liquid phase transfer catalysts has been well-documented in the literature. It has been shown that (1) the catalyst functions as a vehicle for transferring the anion of a metal salt from the aqueous or solid phase into the organic phase where reaction with an organic substrate ensues, (2) the rate of reaction is proportional to the concentration of the catalyst in the organic phase, and (3) small quantities of water have a significant effect on the catalytic process. This Communication specifically addresses the role of cyclic polyethers as phase transfer catalysts and the influence of water with regard to the location of the catalyst. 

Ng SS, Figg WD, Sparreboom A. Taxane-mediated antiangiogenesis in vitro influence of formulation vehicles and binding proteins. Cancer Res 2004 64 821. 

The major factor that has influenced the development of fuel cells over the last few years is the worldwide concern of the enviromnental consequences of the use of fossil fuels in the production of electricity and for the propulsion of vehicles. Fuel cells seem to be the best solution for clean, efficient and non-hazardous energy. 

The influence of a cream containing 20% glycerin and its vehicle on skin barrier properties has been investigated. Recent studies have shown that polymers offer several advantages and can be used in skin care products. Phase diagrams were determined for lactic and isohexanoic hydroxy acids as well as salicylic acid with water, a nonionic surfactant and a paraffinic oil, to outline the influence of hydroxy acids on the structure in a model for a skin lotion. The results showed the influence of the acid to be similar to that of the oil but that the difference in chain length between the two alpha acids had only insignificant influence. The results are discussed from two aspects the structures involved in the lotion as applied, and the action of the lotion residue on the skin after the evaporation of the water. 

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