Self-Controlled Coating Process for Drugs

Römbach, Eric; Ulrich, Joachim

doi:10.1021/cg070071a

Cited by 12 publications

(10 citation statements)

References 14 publications

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“…Forward thinking, the hollow needle-like crystals could be used as a container for pharmaceuticals that is able to extend the shelf life of the enclosed drug, through to the facilitation of a retarded drug release by a slow dissolution rate of the surrounding material [57]. Furthermore, a selfcontrolled coating process (in situ) was introduced by Roembach et al [59] that allows the formation of a solid material and the coating, simultaneously.…”

Section: Product Designmentioning

confidence: 99%

Problems, potentials and future of industrial crystallization

Ulrich

Frohberg

2013

Front. Chem. Sci. Eng.

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This review discusses important research developments and arising challenges in the field of industrial crystallization with an emphasis on recent problems. The most relevant areas of research have been identified. These are the prediction of phase diagrams; the prediction of effects of impurities and additives; the design of fluid dynamics; the process control with process analytical technologies (PAT) tools; the polymorph and solvate screening; the stabilization of non-stable phases; and the product design. The potential of industrial crystallization in various areas is outlined and discussed with particular reference to the product quality, process design, and control. On this basis, possible future directions for research and development have been pointed out to highlight the importance of crystallization as an outstanding technique for separation, purification as well as for product design.

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Section: Product Designmentioning

confidence: 99%

Problems, potentials and future of industrial crystallization

Ulrich

Frohberg

2013

Front. Chem. Sci. Eng.

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“…Without this microstructural element, the system cannot be accurately classified as a eutectic solid. This particular concept is often neglected in the pharmaceutical literature, where accounts of eutectic formation are reported without considering thermal and structural characterization details [24][25][26][27].…”

Section: Eutecticsmentioning

confidence: 99%

Aqueous Solubility Enhancement Through Engineering of Binary Solid Composites: Pharmaceutical Applications

Moore

Wildfong

2009

J Pharm Innov

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Limits to the aqueous solubility of emerging new chemical entities, as well as older drug molecules, represent a barrier to solid oral dosage form development. Numerous techniques are conventionally employed in aqueous solubility enhancement, although a universal strategy has proven elusive. Formation of binary solid composites, such as eutectics or amorphous solid dispersions, offers an alternative to traditional solubility enhancement techniques. The reality of these systems, however, is that very few examples have been made commercially available, ultimately stemming from a lack of understanding regarding structural and thermodynamic stability-indicating phenomena associated with higher-energy solid materials. In the present work, a comprehensive structurally based review of the fundamental solid-state properties of binary composite materials is presented. Specific emphasis is placed on current topics of research in the area of binary composite formation and the relationship to the underutilization of this technology with the pharmaceutical industry.

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“…An in situ coating process [1][2][3] has the following prerequisites. The multi-component system from which the pastilles are formed must behave as a eutectic.…”

Section: Example 1: Forming and Coating The Solid Drug Simultaneouslymentioning

confidence: 99%

Design of Crystalline Solids

2009

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Product design is an active area of research. In a top-down approach to product design, the required product properties dictate product development from the very basic choice of the functional material to use for a defined task up to the processing required to render the material in a suitable form. This article focuses on processing crystalline solids with a particular field of application in mind and shows how process conditions can be used both to generate a material with particular properties and to tailor these properties. The examples selected are biased towards novel pharmaceutical applications; the principles of the processes and the resulting product properties discussed can, however, be transferred to other areas where materials with similar functions are required. The case studies presented pertain to in situ coating of solid particles (cases 1 and 2) with a crystalline coating of a different chemical nature, to freeze casting for generating porous particles and, finally, to the potential for exploiting phase transformations to generate tubular crystalline solids that can function as micro-delivery devices for other materials. Potential advantages of all four processing techniques are the delivery of well-defined products with tailored properties that can be controlled by judicious choice of the process conditions. Example 1: Forming and Coating the Solid Drug Simultaneously by Drop SolidificationAn in situ coating process [1][2][3] has the following prerequisites. The multi-component system from which the pastilles are formed must behave as a eutectic. For eutectic systems, one component can be isolated with a high degree of purity [4,5]. If a drop of this multi-component system is brought into contact with a colder environment, crystallization (nucleation and crystal growth) will commence on its surface [6]. If this drop is allowed to solidify in its entirety, the eutectic behavior ensures that the components are spatially separated. From this it follows that the higher-melting component, i.e., the component that crystallizes first, will preferentially accumulate on and near the surface of the pastille. As a consequence, the lower-melting components accumulate in the interior of the pastille. It is then conceivable that a eutectic mixture of an active pharmaceutical ingredient (drug substance) and a suitable coating material can be found that fulfils the above requirements. It then becomes possible to design and control the solidification in such a manner that a pastille is formed (see Fig. 1a) the exterior of which is predominantly composed of the coating material whereas the drug substance accumulates in the center of the pastille.In the following, the solidification of a drop of a binary melt will be described in detail. Matsuoka [7] summarized the binary solid-liquid equilibrium phase diagram types found in the International Critical Tables [8]. According to Matsuoka, it is

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Self-Controlled Coating Process for Drugs

Cited by 12 publications

References 14 publications

Problems, potentials and future of industrial crystallization

Problems, potentials and future of industrial crystallization

Aqueous Solubility Enhancement Through Engineering of Binary Solid Composites: Pharmaceutical Applications

Design of Crystalline Solids

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