Propylene Glycol Water Research Articles

Thermodynamics of self-ionization of propylene glycol-water mixtures at different temperatures

The autoprotolysls constants (K,) of propylene glycol (PH)-water mlxtures wlth composltlons of 20, 40, 75, and 90 wt % propylene glycol have been determlned In the temperature range 15-45 O C by uslng the cell Pt, H, (9, 1 atm)lNaS, MBr, propylene glycol-waterlAgBr-Ag where NaS Is the sodlum lyate of the solvent and M Is Na or K. The experimental results have been expressed as a function of temperature In the form pK, = A / T D + CT proposed by Harned and Roblnson and the coefflclents A , D , and C have been obtalned by the method of least squares. The varlatlon of pK, wlth solvent composltlon has been dlscussed In terms of the propertles of the mixed solvents. Thermodynamic quantltles such as AGO, AH, and AS for the self-lonlratlon process have been evaluated at 25 OC and dlscussed In terms of the structural aspects of the mlxed solvents.

Excess Free Energy Approach to the Estimation of Solubility in Mixed Solvent Systems III: Ethanol–Propylene Glycol–Water Mixtures

□ The reduced three-suffix solubility equation derived from the Wohl excess free energy expression is used to describe the solubility of phenobarbital in propylene glycol-water, ethanol-propylene glycol, and ethanol-water-propylene glycol mixtures and the solubility of hydrocortisone in propylene glycol-water mixtures. Solvent-solvent interaction constants were obtained by fitting total vapor pressure versus composition data, obtained at 25±0.1°C, to the Wohl excess free energy model for the solvents. The equation describes solubility in these systems satisfactorily except for phenobarbital in ethanol-propylene glycol, where the solubility is fairly high and the assumptions involved in the derivation of the equation do not hold.

Dermatophyte infections in hereditary palmo-plantar keratoderma. Frequency and therapy.

The frequency of dermatophyte infections in hereditary palmo-plantar keratoderma ( HPPK ) of the Unna - Thost variety was investigated in 280 patients admitted to the Department of Dermatology, Central Hospital, Boden , during 1977-1981, and was found to be 35.0%. The distribution of fungi did not differ from that found for the total number of dermatophytes. An almost complete therapeutical resistance was found especially in Trichophyton rubrum infections, when patients were treated with micronized griseofulvin and topical econazole cream. Treatment of dermatophyte infections in HPPK with 50% propylene glycol in distilled water gave poor results but when 1% econazole nitrate was added negative cultures were found in 86.4% of the patients treated for 3 weeks.

Aspirin Degradation in Mixed Polar Solvents

Degradation studies were conducted on 0.2% w/v aspirin liquid formulation in a wide range of water-propylene glycol mixtures and water-triethylene glycol diacetate mixtures at four temperatures. The effect of a surfactant, polyoxyethylene (20) sorbitan monolaurate, on aspirin stability was also investigated. There was a linear relationship between water content and degradation rate constants. The surfactant increased aspirin degradation in all formulations. Formulations containing the higher concentration of the surfactant showed the greater aspirin decomposition.

The acute toxicity of perfluorooctanoic and perfluorodecanoic acids in male rats and effects on tissue fatty acids

The acute toxicities of single ip injections of perfluorooctanoic (PFOA) and perfluorodecanoic (NDFDA) acids were evaluated in male Fischer rats. The LD50 30 day for PFOA was 189 (208-175) mg/kg and for NDFDA was 41 (47-34) mg/kg. All rats treated with lethal doses of PFOA died within the first 5 days; with NDFDA there was delayed lethality, with deaths in the second and third weeks after dosing. Four groups of rats were used for a more detailed study of toxicity and for analysis of fatty acids from liver, testes, and whole blood. One group received a single dose of 100 mg PFOA/kg; a second, a single dose of 2 ml of propylene glycolwater (1:1)/kg (vehicle control); a third, a single dose of 50 mg NDFDA/kg; the fourth was given 2 ml vehicle/kg and pair-fed with the NDFDA group. The first three groups were fed ad libitum. Rats from each group were killed at 2, 4, 8, and 16 days after dosing for fatty acid analysis. Rats dosed with NDFDA lost half their body weight in 16 days and ate virtually no food from Day 7 to Day 14 after dosing. Weight loss was less rapid in pair-fed controls. With PFOA there were transient decreases in food intake and body weight which were reversed by Day 7. Liver weights of PFOA rats were slightly greater than those from vehicle controls. With NDFDA, liver weights were much greater than those from pair-fed controls. In the livers of PFOA rats there were transient increases in oleic and palmitic acids and a decrease in stearic and docosahexaenoic acids. These changes were maximum by Day 2 and nearly resolved by Day 8. With NDFDA, similar changes were observed and arachidonic acid was also greatly decreased. These changes were quantitatively much larger and more persistent. NDFDA has unusually high toxic potency for a perfluorinated hydrocarbon, and some of the toxic effects caused by this acid are remarkably similar to those seen with 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD). The acute toxicity of NDFDA may be due to an ability to interfere with fatty acid metabolism, and studies of its toxicity may be valuable in helping to understand mechanisms of action of TCDD.

Thermodynamics of hydrogen chloride in propylene glycol-water mixtures from electromotive force measurements

Thermodynamics of hydrogen chloride in propylene glycol-water mixtures from electromotive force measurements

Phenobarbital solubility in propylene glycol-glycerol-water systems

Phenobarbital solubility in various binary and ternary propylene glycol-glycerol-water solvent systems was determined. Phenobarbital concentrations several times those of the ethanol-containing USP and BPC elixirs were obtained. From log solubility-solvent composition plots, a general equation was developed for phenobarbital solubility prediction in propylene glycol-water, glycerol-water, and propylene glycol-glycerol-water solvent systems. Solubility predictions using another equation, based on linear log solubility-dielectric constant relationships, were limited by the need to use different constants for different solvent blends. Heats of solution for phenobarbital determined in selected solvent blends as well as in USP and BPC elixirs varied within a very narrow range, suggesting similar solute-solvent interactions.

What's new: a review of advances in therapy.

INFECTIONS Recurrent furunculosis often affects several members of the same family. Even if all are treated with appropriate antistaphylococcal an- tibiotics, recurrences are frequent. Steele 1 first treated a number of families with oral oxacillin or dicloxacillin, twice-daily showers with hexachlo- rophene-containing soap, and bacitracin cream intranasally for 2 weeks. Then, in randomly se- lected families, all members were inoculated in- tranasally with nonpathogenic Staphylococcus au- reus 502A or with a placebo. No recurrences of furunculosis occurred if colonization of the nares was successful. With a placebo inoculation recur- rences were frequent. Since cultures of S. aureus 502A can apparently be kept frozen indefinitely and still retain viability, this approach lends itself to office use. Gonococcal septicemia often presents with a few necrotic pustules on acral areas. The usual practice is to hospitalize patients with this disease, although they are not particularly ill, and treat them intensively with antibiotics. According to Thompson et al, z this may be unnecessary. They found that penicillin G, one million units intrave- nously every 3 hours for 3 days, was no more effective than oral erythromycin, 500 mg every 6 hours for 5 days. Thus, it seems that gonococcal septicemia can be readily and safely treated on an outpatient basis. Ketoconazole, a new, oral antifungal agent, has been shown to be effective in most cases of tinea versicolor. 3 The 4 weeks of therapy was associ- ated with minimal systemic side effects in a few patients. Even more effective, less costly, and safer is the topical application of 50% propylene glycol in water. Faergemann and Fredriksson '~ re- ported complete clearing in twenty patients after 2 weeks of twice daily use. Perhaps even a lower concentration of propylene glycol would be effec- tive and would reduce the risk of excessive drying and irritation. In a well-conducted, double-blind study, unde- cylenic acid powder was shown to be more effec- tive than a placebo in the treatment of tinea pedis. Chretien et al '~ reported that after only 2 weeks of therapy negative cultures were obtained in 88% of those treated with the active preparation and in only 14% of the control group. In striking con- trast, a negative potassium hydroxide (KOH) preparation was present in about 60% of patients treated with either the active or the placebo prep- aration. This disparity between the results of fun- gal cultures and KOH preparations shows up fairly

The loss of creatine phosphokinase (CK) from intramuscular injection sites in rabbits. A predictive tool for local toxicity.

The CK activity was measured in muscle tissue taken from the injected area (dorsal longissimus muscle) and the contralateral side of the injection site 72 hours after intramuscular injection into rabbits of 1 ml of different dilutions of propylene glycol or glycerol formal in distilled water or 0.9% saline. The total loss of CK activity from the injection site was calculated as the difference between the CK concentration in the normal muscle tissue and that of the injection site from the same animal. From the results the arbitrary amount of muscle tissue depleted of CK activity was further calculated and compared with the severity of the gross pathological findings. A large necrotic area at the injection site was present in all samples with more than 1 g of muscle tissue depleted of CK activity. Minor and probably acceptable pathological changes were found in samples with less than 1 g of muscle tissue depleted of CK activity. The local damaging effect of drug preparations for intramuscular use can thus be evaluated from the calculated amount of muscle tissue depleted of CK activity.

Physico-chemical studies on aerosol solutions for drug delivery III. The effect of relative humidity on the particle size of inhalation aerosols

The change in size of aerosol solution particles has been investigated for various humidity conditions at 37°C. The systems studied were water, 20% v/v and 50% v/v propylene glycol in water. Particle size, as determined by cascade impactor, was dependent on relative humidity; the greater the humidity the larger the measured size. The implications of the results for quality control procedures and drug formulation are discussed.

Physico-chemical studies on aerosol solutions for drug delivery I. Water-propylene glycol systems

The aerosolization characteristics of two commercial nebulizers have been examined using propylene glycol-water systems. The output of aerosol solution droplets passed through a maximum at 30% v/v propylene glycol; however, an increased output was parallelled by an increased particle size. The quantity of aerosol solution in particles below an arbitrary therapeutic limit of 5 μm was calculated. Viscosity and surface tension were considered to be the two important physico-chemical variables that determine aerosol characteristics. The use of propylene glycol-water vehicles to deliver a dose of a test steroid is considered.

Proton Medium Effects Utilising Ferrocene Redox Couple as Reference in Propylene Glycol- Water, Methanol-Propylene Glycol and Methanol-Water Mixtures

Abstract Utilising the ferrocene reference method, proton medium effects (log mγ H+) were determined in methanol-water, pro­ pylene glycol-water and methanol-propylene glycol mixtures of varying composition. On the basis of the ferrocene meth od, it was shown that all methanol-water, propylene glycol-water and methanol-propylene glycol mixtures including the pure solvents are more basic than water and these results were explained in terms of the structural theory of ion sol­ vation proposed by Feakins and coworkers. Further, it was shown that methanol is slightly more basic than propylene glycol which is in agreement with the conclusions arrived from earlier EMF measurements.

Solubility of Nonelectrolytes in Polar Solvents IV: Nonpolar Drugs in Mixed Solvents

The molecular and group surface area approach to solubility is shown to be applicable to mixed aqueous solvent systems. An equation is derived which is consistent with the exponential increase in the aqueous solubility of nonpolar drugs that frequently accompanies the addition of a cosolvent. This equation predicts that: (a) the ability of a drug to be solubilized by a cosolvent is proportional to its hydrophobic surface area per molecule, and (b) the ability of a cosolvent to solubilize any drug is inversely proportional to its interfacial tension against a reference liquid hydrocarbon. These predictions are experimentally verified with solubility studies of several alkyl p-aminobenzoates in propylene glycol-water mixtures and of hexyl p-aminobenzoate in mixtures of water the ethanol, methanol, ethylene glycol, propylene glycol, glycerin, and formamide.

A Keratolytic Gel Containing Salicylic Acid in Propylene Glycol

Mixtures of propylene glycol and water have been shown to be effective in several types of ichthyosis. A new formulation has been developed which contains a gelling agent, propylene glycol, ethanol, and salicylic acid in distilled water. This gel has been shown to be very effective in removal of thickened stratum corneum in a variety of disorders associated with hyperkeratosis.

Block-face application of a 7:3 propylene glycol-water mixture to facilitate cutting of large frozen sections.

Block-face application of a 7:3 propylene glycol-water mixture to facilitate cutting of large frozen sections.

THE MEASUREMENT OF FLUID DEPOSITION IN HUMANS FOLLOWING MIST TENT THERAPY

Mist tent therapy is used in the treatment of cystic fibrosis to deposit fluid droplets in the terminal airways of the lung. It is assumed that water deposited in the peripheral airways thins the secretions and facilitates their clearance from the lung. The distribution of inhaled mist was assessed by labelling aerosol from an ultrasonic nebulizer with technetium 99m and measuring the distribution of radioactivity in a subject who breathed the aerosol in the mist tent. Subjects breathed from the tent for 1 hour after which the total uptake of fluid was measured by a scintillation probe and its distribution with a rectilinear scanner. Three different ultrasonic nebulizers were used. In some studies 10% propylene glycol in water was used as the nebulizing fluid. In six healthy adults and eight patients with cystic fibrosis, less than 5% of the activity nebulized and distributed in the tent entered the body. Of this, 90% of the inhaled radioactivity initially lodged in the nasopharynx and rapidly appeared in the stomach. Very little activity was detected over the lungs. These results indicate that very little aerosol fluid from a mist tent is directly deposited in the terminal airways of the lung.

Flumethasone pivalate (Locorten); Anti‐inflammatory, antipruritic

Locorten is a new topical coricosteroid. Locorten Cream is 0.03% flumethasone pivalate in a water‐washable base, containing cetyl alcohol, sodium lauryl sulfate, propylene glycol, methyl and propyl parabens and water.

Étude par luminescence des interactions dans les acides oligo et polyadényliques

Luminescence study of interactions in oligo- and polyadenylic acids Interactions between the bases of oligoadenylic acids (A n) lead to a red shift of both the fluorescence and the phosphorescence spectra at 77° K in a water-propylene glycol mixture (1:1, v v ). These shifts depend on the number n of adenine residues in the oligomer as well as on the nature of the phosphodiester linkage (2′–5′ or 3′–5′). The luminescence of copolymers containing adenosine and cytidine and of complexes of poly A with oligo U or poly U has also been studied. The fluorescence of poly A nC, where n is the ratio of the number of A and C residues in the copolymer is of the excimer type for n = 1 (as observed in the dinucleotides ApC or CpA) and similar to that of poly A for n = 6.5. Oligomers containing m adenosine residues and one terminal cytidine have been obtained from pancreatic ribonuclease digestion of copoly A nC with n = 6.5. The fluorescence of these oligomers is like that of the corresponding oligo A m even for the smallest value of m (m = 5). Oligo U 10 quenches the fluorescence of poly A as does poly U. The quenching is linearly related to the amount of oligo U 10 linked by hydrogen bonds to the poly A. No evidence of energy transfer at the singlet level in poly A could be obtained. The luminescent properties and results obtained from other physical methods are discussed in relation with the possible existence of a weak transition on the long wavelength side of the main ultraviolet absorption band of adenosine.

Studies on corticosteroid ointments. VII. Percutaneous absorption of hydrocortisone-4-14C (3). Accumulation into the skin of hydrocortisone acetate

Accumulation of hydrocortisone [4-14C] acetate into the epidermis and its release from the corium into saline were examined by the in vitro method described previously. The skin used was epidermis separated from a full-thickness of the skin excised from human or guinea pig abdomen. The results of examination showed that the rate of release of hydrocortisone [4-14C] acetate from the liquid vehicles to the epidermis was equal to the rate of its release to the full-thickness skin, and radioactivity was not detected in the saline, as reported ealier. However, when the corium, removed of epidermis, was used, release of labeled hydrocortisone acetate from liquid paraffin into saline through the corium was remarkably increased, and the amount of labeled hydrocortisone acetate in saline increased with lapse of time. When other vehicles were used, such as propylene glycol-water (30 : 70) or HS-12-P (Iauricdiethanolamide) -water (10 : 90), the release of labeled hydrocortisone acetate into saline was not detected. Therefore, release of hydrocortisone [4-14C] acetate from liquid vehicle into saline through the corium dose not always increased with removal of the epidermis.

Evaluation of Propylene Glycol as an Energy Source in Broiler Diets

WITHIN the past few years nutritionists have become interested in obtaining synthetic sources of nutrients such as protein from organisms grown on petroleum. Propylene glycol, a compound which results from the cracking of propane, may be a possible synthetic energy source in animal diets. Propylene glycol (1-2-dihydroxy propane) is unique among the glycols because its low toxicity permits it to be taken internally.Hanzlik et al. (1931) compared the intramuscular irritant properties of propylene glycol and found that it caused a temporary burning sensation when placed on the tongue of human subjects. However, there was no apparent injury to this organ or to the oral mucosa. The irritant action was fleeting, lasting 5 to 10 minutes, and there were no after effects locally or systemically.Seidenfeld and Hanzlik (1932) fed up to 10% solutions of propylene glycol in water to rats during about one-eighth of their normal span of life .