In pharmaceutical technology, the properties of gelatine such as film formation, thermoreversibility and adhesion are particularly important. The most important application areas for pharmaceutical gelatine are the manufacture of capsules and the embedding of vitamins.
Gelatine capsules are an elegant and widespread pharmaceutical dosage form; they enable drugs to be easily and safely administered whether in liquid, paste or solid form. At the same time, pharmaceuticals in capsule form have a high degree of bioavailability. Pharmaceutical capsules enable active ingredients to be formulated with long shelf lives, protected from light and oxygen. Depending on the nature of the substance to be encapsulated, either hard- or soft capsules can be used. Soft capsules are the more suitable for liquid or paste fillings based on oil whilst hard capsules are used in general for powdered substances.
Hard capsules are made of pure gelatine and have a water content of about 10-15 %. They are generally produced with added dye. They are produced using an immersion process and subsequently supplied to the pharmaceutical industry as closed empty capsules. In a separate process, they are then opened, filled with substance (e.g. powder or granulate) and closed off.
Soft capsules on the other hand are formed, filled and closed off in the one process. The designation soft capsule implies that the outer wall contains, apart from gelatine, a plasticiser, the degree of softness and elasticity of which depends on the quantity and type of plasticiser used, the residual moisture and the thickness of the capsule wall. Soft capsules tend to have thicker walls than hard capsules. Glycerine and sorbitol, or a mixture of both, are normally used as plasticisers.
Soft capsules are generally produced using the rotary die method, a process invented by Robert Pauli Scherer towards the end of the 1920s: in this process, two dyed and highly elastic bands of gelatine are passed through rollers. Whilst the capsules are being formed, they are filled with the required active ingredients. Gelatine-coated tablets (caplets) represent a new technical development in this area: using an immersion process, tablets are covered with a gelatine film and subsequently dried. This particular technology enables the economical advantages of tablet manufacture to be combined with the advantages of gelatine capsules for patients. The GELITA Group is the leading company world-wide in the supply of gelatine for all types of capsules.
Gelatine also plays an important part in the preparation of oil-based vitamin (A+E) preparations of long shelf life and easy applicability, both for human and animal consumption. Finely distributed vitamin A- or E oil drops in aqueous gelatine solution can be converted, by means of appropriate solidification and drying procedures, into a free-flowing powder; this can then be dissolved in aqueous solution but remains highly dispersed. The coating of vitamins with such special gelatines enables them to be protected from light and oxygen during long-term storage. In addition, the coatings can be prepared in such a way that they dissolve in both warm and cold solutions, as e.g. in the case of effervescent vitamin tablets.
Gelatine sponges play an important role in dental and surgical applications. These are prepared by foaming a gelatine solution and subsequently drying and hardening. Such blood-staunching gelatine sponges are completely resorbed in the course of wound healing. GELITA is one of the leading manufacturers of such gelatine sponges and supplies numerous domestic and foreign companies who then sterilize, pack and market the finished product.
In emergency medicine, blood replacement solutions based on gelatine are frequently used in cases where substantial blood losses have been incurred. Special gelatine quality is used for such plasma expanders; the pharmaceutical companies involved then subject it to heat or enzyme treatment and possibly modify it chemically before sterile-packaging it.
Gelatine is also used for a number of other medical and technological applications: in the manufacture of skin-compatible zinc-treated bandages, as a granulate-, tabletting- or sugar-coated tablet excipient or as a thickener for a number of drug dosage forms.
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