Allergic hypersensitivity to neomycin. Relationship between patch test reactions and 'use' tests

The prevalence of neomycin patch test sensitivity in the general population is approximately 1%. We describe the relationship between positive neomycin patch tests and clinical "use tests" with two antibiotic combinations (Neosporin G cream and Neosporin ointment). The neomycin use test was positive in seven of eight subjects with a strongly positive patch test, and in two of four subjects with a weakly positive patch test. A positive use test usually occurred earlier and was always more intense with the cream base. The use test reactions were usually mild even with continued application of the antigen. Use tests with commercial products may be helpful in evaluating the clinical relevance of positive patch tests.

The stability of betamethasone-17-valerate in semi-solid bases

The stability of betamethasone-17-valerate in semi-solid bases has been investigated. Emphasis has been placed on the stability problems which could arise upon dilution of proprietary preparations by the use of model systems. Betamethasone-17-valerate has been shown to decompose to betamethasone-21-valerate and betamethasone alcohol. Quantitation of the decomposition was by direct densitometry on thin layer chromatographic plates. The decomposition was found to be an apparent first order process and to depend on the diluent used and its concentration. Attempts were also made to relate the rate of decomposition to the pH of the base used, and to stabilize the products.

[The role of ointment bases in the formulation of 2 antifungal drugs. II. Liberation studies on 5-fluorocytosine and tolnaftate ointment bases by the microbiological agar plate method]

In this study a microbiological in vitro agar plate method was developed to measure the liberation of two antifungal agents; 5-Fluorocytosine and Tolnaftate; comparatively from six different type ointment bases. The effect of dimethylformamide to the liberation of these two antifungals was also studied. Cetyl alcohol ointment and Emulsion ointment (B.P. 1968) bases gave the best results for the two active agents. Dimethylformamide accelerated the release of these antifungals from the emulsion type bases (Emulsion Ointment and Simple Ointment).

Effect of liquid additives on release of chloramphenicol from ointment bases

1, 3 and 5% water, ethyl alcohol, glycerol and propylene glycol were incorporated into oleaginous, absorption, emulsion (O/W and W/O) and water-soluble ointment bases (resp.) containing 5% of chloramphenicol and diffusion rate via the dialysis method was measured for 2 h. The rate of release was found to be greater from water-soluble bases than from the other bases, since rates from oleaginous, absorption and W/O emulsion bases were found to be the least in this respect. The effect of liquids added to these bases on drug release was found to be less pronounced than that obtained with water-soluble and O/W emulsion bases. For O/W emulsion bases the addition of ethyl alcohol increased the release of chloramphenicol as its concentration was increased. Propylene glycol increased the release at a concentration of 3%, but higher concentration produced opposite results. Glycerol was found to have a little effect in 5% concentration, but it increased the release as the concentration dropped to 3% concentration.

Antibiotics in surgery of the colon

In a randomized prospective study of patients undergoing elective colonic surgery the postoperative wound infection rate was 13% (early, 10%) in patients receiving systemic cephaloridine perioperatively and 12% (early, 7.3%) in those given oral neomycin and erythromycin base preoperatively. Wound infections were more frequent in patients with severe lymphopenia or hypoalbuminemia preoperatively, but the potential degree of wound contamination was the main determinant of postoperative infection.

Route of absorption of drug and ointment after application to the eye

Chloramphenicol, tetracycline hydrochloride, sodium sulfacetamide, and fluorescein sodium prepared in both aqueous solutions and ointments were placed in the conjunctival sac of humans. Each drug soon was tasted in the back of the mouth with no difference being noticed with the use of aqueous solution or ointment. Tetracycline and fluorescein studies showed that systemic absorption were similar regardless of whether solution or ointment were used. Furthermore, it was found that the ointment passed through the lacrimal drainage system and into the nose and throat. The ocular contact time of ointment with the eye is greater than that of water, and ointment is much more slowly absorbed via the lacrimal drainage system. Both the drugs and the ointment base applied topically to the eye travel through the nasolacrimal system as the way of elimination when given in the small volumes that are held by the conjunctival sac.

Physical parameters of chlorphenamine maleate suppositories and its release as a function of particle size, concentration and nature of the base

Suppositories of chlorphenamine maleate were formulated. The influence of particle size and percentage concentration of chlorphenamine maleate on the physical standards of its suppositories as well as the release of the drug from oily base (cacao butter), water-soluble base (carbowax) and emulsifying base (Witepsol) has been investigated.

Release of drugs from ointment bases II: In vitro release of benzocaine from suspension-type aqueous gels

The in vitro release of benzocaine, suspended in an aqueous gel, through silicone rubber membranes was studied to test an extension of existing mathematical models. The theoretical treatment proposed is intended for experimental systems involving release, through a non-porous membrane, of a drug whose concentration is a few times (larger than or equal to 3) greater than its solubility in the vehicle. For either micronized (2micrometer) or macrosize (125 micrometer) drug, the Q (amount released) versus t1/2 (time1/2) plots were not linear until substantial time had elapsed. Excellent agreement was found between the experimental points and theoretical plots, generated by a computer fit to experimental data of an equation derived from a reported vehicle-boundary diffusion layer model. The values of the solubility and of the diffusion layer model. The values of the solubility and of the diffusion coefficient of benzocaine in the gel, calculated by the present mathematical treatment from release data, were in agreement with literature data. The particle size of released benzocaine did not influence the release pattern, thus confirming release in the present conditions to be diffusion rather than dissolution controlled. The present method is applicable for determining the solubility and diffusion coefficient of drugs in vehicles in cases not contemplated in current release theories.

Contact sensitivity to emulsifiers

Common emulsifiers were tested in over 1,200 patients with eczema. Triethanolamine stearate tested at 5% in petrolatum caused irritant reactions in 9.5% of the patients. On the other hand, non-ionic emulsifying agents tested at 10-20% produced irritation in only a few cases. Allergic reactions were found in 2.1% of those tested. Lanette, sorbitan sesquioleate, the Spans, polyoxyethylene oxypropylene stearate, polyoxyethylene sorbitol lanolin derivative, and triethanolamine stearate each elicited allergic reactions in 0.3-0.7% of the cases. The Tweens caused an allergy in only two cases, but glycerol monostearate caused no reaction at all. Five out of six patients sensitive to sorbitan sesquioleate reacted positively to the Spans as well. The patients allergic to one or more emulsifiers were also sensitive to several other substances included in our routine test series with the exception of four patients who reacted only to the emulsifying agents.

[Penetrations kinetics and distribution of topically applied estrogens (author's transl)]

The penetration into the single layers of human skin in vitro of 17 alpha-estradiol, 17 beta-estradiol and estriol was investigated. The radiolabeled substances were incorporated into 4 standard ointments and into an alcoholic solution mixture. After application to the skin and after different penetration periods, the horny layer was taken off by adhesive tape stripping. The epidermis and the dermis were separated by slicing them down parallel to the skin surface in a freeze microtome. In each single layer, the amount of substance was determined and calculated relative to the applied quantity and in absolute concentrations (mug per tissue weight and molarity). Besides the expected dependence of the penetration on the type of ointment, there is a distinct dependence on the chemical structure: estriol penetrates considerably slower and in less concentrations into the living layers of the human skin than the estradiols. Furthermore, estriol reaches the dermis only in low concentrations so that this substance may be termed epidermotropic. 17 alpha-estriol which has only weak sexhormone properties in humans penetrates as well as the sexhormone 17 beta-estradiol.

Simplification of local therapy of psoriasis with 8-methoxypsoralen. Methods and initial results

Local 8-methoxypsoralen black-light treatment was carried out on sixty-two patients. For the first time, oil was employed as a preparation base in order to increase the transparency and so the effectiveness of irradiation. Also the need for a descaling pretreatment was avoided. In investigations still being carried out, 27.5% patients showed very good improvement, 48-4% good and 24-2% unsatisfactory results of treatment. In many cases, less than fifteen irradiation sessions were necessary for clinical healing. However, to obtain a uniform pigmentation, additional irradiation proved necessary.

Penetration, permeation, and resorption of 8-methoxypsoralen. Comperative in vitro and in vivo studies after topical application of four standard preparations

The penetration, permeation, and resorption of radioactively labelled 8-Methoxypsoralen was investigated in human skin. Siultaneously, the effects to time and ointment carrier on the penetration kinetics were ascertained. The carriers tested were: vaseline, aqueous wool-wax alcohol ointment, aqueous hydrophilic ointment and polyethylene glycol ointment. The absolute concentrations of 8-Methoxypsoralen were estimated in the horny layer, epidermis and dermis. With the most advantageous carrier, aqueous wool-wax alcohol ointment, 4-6X10(-5) M and 10(-5) M were attained in the epidermis and dermis, respectively. Moreover, it was shown that the substance penetrates rapidly (10 min) into the epidermis and dermis and the high concentrations reached constant over a period of 16 h. Only with a formulation of aqueous wool-wax alcohols is any accumulation at all achieved in the deeper areas of the horny layer. A uniform decrease in drug concentration with increasing depth of the horny layer is found with the other 3 vehicles, whereby slight variations in concentrations pertain from carrier to carrier. 4 h after local application, 8-Methoxypsoralen can be detected in the urine. Regardless of the ointment base employed, 8-Methoxypsoralen is no longer detectable in the urine 40 h after application. In comparison to the oral therapy, the same magnitude of percutaneous resorption into the central compartment is to be derived from the data, if half the body surface is treated locally.

Studies of the pain produced by mafenide acetate preparations in burns

In a double-blind triple cross-over clinical study, 37 patients were exposed to several formulations of mafenide acetate (Sulfamylon Cream) and their pain responses were recorded and converted to a semiquantitative pain index. The 11.2% concentration in cream was two to three times more painful than the 5% concentration. Hypertonicity and not the pH level appears to be the cause of the pain produced by the high (11.2%) concentration. The tonicity of the cream carrier and 11.2% mafenide acetate are 1,080 mOsm/kg and 1,100 mOsm/kg, respectively, for a total of 2,180 mOsm/kg. The carrier cream without glycerol and a 5% concentration of mafenide cream were much less painful than the 11.2% concentration of mafenide. Both afforded a great deal of relief to the patients who received the medications.

An improved method of assessing topical corticosteroid activity

Topical application of ointment bases causes varying degrees of epidermal thickening in guinea-pigs. This is reproducible and can be accurately measured. Suppression of these changes was produced by addition of beta-methasone 17-valerate, fluocinolone acetonide, fluocinonide and hydrocortisone acetate. The inhibitory effect of these steroids was related to the type of corticosteriod, its concentration and the ointment base. The effect was still evident at extremely high dilutions of the steroids and could be measured at concentrations as low as 5 X 10(-5) % of fluocinonide in FAPG. This technique has the merits of being reproducible, sensitive and accurate. It should find a place among existing methods in assaying the efficacy of topical corticosteroids and in aiding in the selection of bases most suitable for formulation of these preparations.

[Studies on the skin surface dosage of dermatopharmaceutical preparations]

In human volunteers presenting with normal skin an investigation has been carried out to determine the specific skin surface dose, the actual application volume, and the theoretical surface film thickness resulting from thin and thick layer inunction of 4 common corticosteroid topicals. The findings obtained indicate that the skin surface dose provides the most suitable criterion for the terrain saturation behaviour exhibited by different formulation types of semi-solid topical preparations (inunguenda). Various aspects of the surface dosage concept are discussed with regard to the active agents and forms of application of external skin remedies. Predicative clinical determinations of the skin surface doses of topicals relating to special therapeutic and assessment procedures are believed to be a valuable complement to experimental (predictive) determinations of this parameter; some problems involved are pointed out by reference to a clinical trial example. Data on the application dosage of topicals--either by skin surface dose or by volume or layer thickness quantification--have been extracted from the dermatological literature and are reviewed with the aim of furnishing a basis for comparative estimation of our experimental results.

Simplified dithranol treatment for psoriasis

Progressive simplification of dithranol therapy has made treatment at home more acceptable. This has included ommitting ultra-violet light, talc and dressings, and substituting an ordinary bath instead of one containing tar. A stiffened dithranol 0.5% ointment was found to be slightly more effective than the best paste hitherto employed. It was also very much easier to use.