For 75 years, Niro has supplied drying plants for powders and particulates to the pharmaceutical industry. This includes small capacity spray dryers designed for R & D as well as industrial size plants for continuous production of pharmaceutical compounds under cGMP conditions.
Primary Pharmaceuticals
Active Pharmaceutical Ingredients (API) as well as excipients are typically produced by extraction or chemical syntheses. In most cases, the material is subsequently crystallised, mechanically separated, and dried. These steps can often be replaced by spray drying. Spray drying does not only offer control of the moisture or residual solvent content in the powder, but also enables the creation of powders with a tailor-made particle size distribution, morphology, and nature.
Increased Bioavailability
Many modern molecules have a poor solubility in water or body fluids. It takes an extremely long time for the API crystals to dissolve and for the drug concentration to reach the required level. If the drug is given orally, the dissolution rate may be increased effectively by keeping the spray dried API in amorphous form supported by an excipient polymer.
Modified Release
One way to achieve a therapeutic drug concentration in blood plasma is to encapsulate the API
in a biodegradable excipient. Controlled by slowly dissolution of the spray dried particles, the drug is released at a constant rate over a prolonged period of time. To prepare such particles by spray drying, excipients are brought into solution, mixed with API and subsequently spray dried. Alternatively, spray congealing techniques can be used.
As an alternative to “classic” spray drying, it is for some products possible to melt the API together with a meltable excipient encapsulate. As an alternative only the excipient is molten and the API is added just before atomization. The mix is then sprayed into cold process gas. Spray drying as well as spray cooling can be used to modify the release pattern eg. taste masking.
Secondary Pharmaceuticals
Final drug forms have traditionally been manufactured by routes other than spray drying, but in the last decades many leading companies enjoy the advantages that spray drying technology offers, including unique possibilities of powder engineering and process optimisation.
Aseptic Production
Production of dry sterile dosage forms often involves mixing of the API with one or more excipients. To achieve a homogeneous mixture, the particle size distribution of the excipient(s) must match that of the API. In a one-step-operation, spray drying can turn a sterile solution into sterile particles of the required size with no risk of introducing impurities – a well-known problem if milling is used.
Powders for Inhalation
Spray drying has become the method of choice for the preparation of fine particles for inhalation. The spray dryer must be equipped with a dedicated atomisation device to produce the very fine droplets and a system for collection of the resulting fine particles.
Directly Compressible
Until now, a separate granulation step has often been required in the production of solid dosage forms. The granulate is needed to avoid segregation and to assure good flow properties so the dies of a high-speed tablet press can be filled accurately. With the Fluidized Spray Dryer - FSD™ or IFD™ - concept the granulation step can be an integrated part of the continuous drying process. The FSD™ technology can also be used to achieve a low residual volatiles content in the final spray dried powder.
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