Coating processes – Medical or dental purpose product; parts; subcombinations;... – Particulate or unit-dosage-article base
Patent
1986-12-02
1987-12-22
Lusignan, Michael R.
Coating processes
Medical or dental purpose product; parts; subcombinations;...
Particulate or unit-dosage-article base
128743, 427327, A01N 102, B05D 312, A61B 1500
Patent
active
047146214
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD OF THE INVENTION
The invention relates to a method for applying a coating of allergen on the tip of an instrument, which is to be employed for in vivo allergy diagnosis, so-called prick tests on skin.
In the present specification and claim, the term "allergen" refers to a substance capable of causing an allergic reaction, unless stated otherwise.
STATE OF THE ART
In vivo allergy diagnosis is a means of identifying the specific allergen(s) to which a patient is allergic, the technique of this diagnostication involving the following procedure: A drop of allergen extract or of allergen in some other suitable form is deposited on the skin. Thereafter, the skin is punctured by means of the tip of a cannula, or with a needle, lancet or other pointed tool, to thus cause the allergen to penetrate into the skin where the allergen then may give rise to an allergic reaction; for instance, the allergen may react with IgE antibodies bound to mast cells which release inflammatory mediators. The technique as such is well known and is described in numerous textbooks and review articles (see for example Allergy and Clinical Immunology, Grune & Stratton Inc., 1976, p. 164-170).
The instruments employed for puncturing may take various forms and shapes. Thus, for instance, special needles have been employed, which are made of steel and have a tip configuration optimized for skin testing (Malling, J-J et al., Allergy 37 (1982), p. 563-67). When such a needle is to be employed, an excess of allergenic material is deposited on the skin, whereupon puncturing is effected by means of the needle, and the residual excess of allergen is then wiped off. Needles that have been coated with allergenic substances prior to their use in prick testing have also been proposed as suitable tools. For instance in No. DE-A-2,940,342, a lancet is described, onto the tip of which a drop of an allergenic preparation is deposited, freezed and lacquered prior to use. Neither pickling in general nor acid pickling as a pretreatment step is discussed.
The techniques employed at present for carrying out this type of tests have several disadvantages among which may be mentioned, for example, operators working with these tests run the risk of becoming sensitized and that difficulties arise in comparing results from tests of different dates, these latter disadvantages being i.a. due to the difficulty of causing a standardized amount of allergen to reproducibly penetrate the skin. Moreover, it may turn out to be difficult to compare results obtained with different species of allergens. Also, in accordance with methods commonly employed at present, an excess of allergen is applied and then afterwards wiped off. This means that on each occasion comparatively large amount of expensive material is being used up.
The object of this invention is to minimize these disadvantages, i.e. to increase the reproducibility of test results obtained variously at different times and with different allergen preparations of either the same or different allergens. The invention, moreover, is aimed at reducing sensitization hazards for patients and for personnel carrying out the tests.
As far as we know, earlier attempts at reproducibly coating the metal tip of the puncturing instruments have failed, mainly because no insight had been gained into the nature of the factors governing the adherence of allergenic substances to metal objects. An important point to be noted is that the allergenicity of the allergenic substance must not be destroyed. From the instrument the substance must be transferrable in a potent form to the skin of the patient to be tested. In addition, it is a requirement that the substance remains in place on the tip of the needle until the instrument is actually applied in the desired manner. If the substance becomes disengaged from the tip too soon this will involve a great risk that the result obtained turns out to be nonreproducible, plus the risk that the person performing the test is exposed to an increased sensitization hazard. A factor a
Lusignan Michael R.
Pharmacia AB
Philpitt Fred
LandOfFree
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