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Background

Counterfeit medicines have become an increasing issue worldwide, affecting both developing and developed countries. The presence of counterfeit medicines have a wide range of impacts including health, economic and social effects.[1-4] A major source of counterfeit medicines is sales via the Internet where it has been estimated that medicines purchased from Internet sites that conceal their actual physical address are counterfeit in over 50% of cases.[5]

Background

Solid dispersions are an intensively investigated enabling technology to formulate poorly soluble drugs. Many contributions already studied their higher solubility and resulting dissolution rate as well as the challenges at the level of physical stability due to their high intrinsic energy. Whereas the vast majority of these studies focus on the bulk characteristics of the samples, we are convinced that the (often distinct) properties of the sample surface should not be overlooked.

Background

The structural and physical stability of solid dispersions have not been adequately explored during post spray drying manufacturing processes. Solid dispersions are preferentially formulated as solid dosage forms such as tablets and capsules. Formulation parameters of spray drying may lead to differences in physical form and amorphous content of solids in single component systems [1]. However, there is limited understanding on the effect of spray drying processes and formulation variables on drug-polymer mixing in solid dispersions and this limitation also extends to the unit operations such as milling and tabletting. The drug-polymer mixing in solid dispersions was evaluated in two different laboratory spray dryers, the Buchi-mini spray dryer and Pro-C-epT Micro spray dryer (Figure 1). The effect of compression on the structural and the physical stability of the spray dried solid dispersions was investigated as a major scope of this study.

Non-linear Optical Imaging

Non-linear optical imaging is an emerging technique for imaging drugs and dosage forms [1]. Non-linear optical imaging may be used for non-destructive, non-contact imaging of solid drugs and dosage forms. It offers chemical and structural specificity with no requirement for labels, sub-micron spatial resolution (inherent confocal nature), rapid video-rate image acquisition, and the ability to image samples in aqueous environments in situ.

These combined features make non-linear optical imaging unique compared to existing imaging approaches in the pharmaceutical setting and make the technique well suited to a wide range of solid-state formulation and drug delivery analyses. These include imaging chemical and solid-state form distributions in dosage forms, drug release and dosage form digestion, and drug and micro/nanoparticle distribution in tissues and within live cells. While non-linear optical imaging is comparatively well established in the biomedical field, pharmaceutical applications of non-linear optical imaging are much less widely explored.

Introduction

The production and manufacturing of solid pharmaceutical products is in need of new technologies to ensure a safe and efficient medical therapy. Hot melt extrusion (HME) is a new and innovative technology in the field of pharmaceutics, which aids to overcome numerous limitations of traditional manufacturing techniques. The benefit of HME is three-fold: First, the bioavailability of poorly soluble drugs is significantly increased due to the conversion of the drug from the crystalline into its amorphous state [1]. Recent work showed that HME is even capable of converting a liquid nanosuspension into a solid formulation in a one-step process [2], thereby avoiding aggregation of nanocrystals. Second, drug release profiles can be specifically tailored (in most cases retarded release of water soluble drugs) via the application of a proper matrix carrier in combination with plasticisers [3]. Third, drug abuse can be prevented due to superior mechanical properties of the final product [4].

Introduction

Continuous processing is a promising approach for solid dosage manufacturing. High-shear wet granulation is performed in continuous mode using twin screw granulators (TSG), characterized by a modular screw profile including a sequence of different screw elements with various shapes, orientation and functions. For process engineers it is a challenge to come up with prediction models to establish the relationship between equipment and material attributes, process data and the end-product testing results. If a reliable model is available which is able to predict the quality of the product, it can be inverted to obtain the design space, corresponding to that set of operating conditions required for achieving the target product quality (Figure 1). Such a modelling framework combined with in-process measurements, can provide a good mechanistic insight into the important parameters of continuous

Tuesday, 02 April 2013 14:43

Film preparations for oral drug delivery

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Introduction

Oral films have gained interest in the last couple of years. Films for oral application offer an interesting new approach for drug administration. Active pharmaceutical ingredients (API) can be implemented in thin-sheeted polymer film matrices. These dosage forms are intended to be placed in mouth to dissolve in the saliva without the need of additional liquid and without swallowing of a solid dosage form.

Introduction

The inter-tablet coating uniformity is a critical quality attribute in active coating processes. In this project an active coating process is performed in order to produce a fixed dose combination of a sustained release formulation in the tablet core and an immediate release dose in the coating layer. The tablet cores consist of a push-pull osmotic system containing nifedipine as API (Adalat GITS). They are coated with Candesartan cilexetil as a second API. As the inter-tablet coating uniformity is a critical quality attribute to comply with regulatory requirements, the purpose of this work is to enhance the process understanding and to optimize the coating process with regard to the coating uniformity. Besides experimental investigations, PAT tools such as Raman spectroscopy [1] and terahertz pulsed imaging [2] have been applied to study this active coating process. In recent years, numerical simulations of coating processes have been gaining interest as analytical tool [3]. The discrete element method (DEM) in particular is suitable to simulate the tablet motion [4]. In this project, both experimental and numerical analysis of an active coating process is combined to investigate the influence of different process parameters with respect to the optimization of the coating uniformity.

Thursday, 28 February 2013 14:54

Investigating Drug Release During Dissolution With MRI

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Magnetic Resonance Imaging

The use of MRI as a powerful imaging and characterization modality in pharmaceutical dissolution research is now well established [1]. The non-invasive and non-destructive nature of MRI enables the investigation of structural, chemical and dynamical processes in many optically opaque systems at the microscopic level. Spatial maps of water penetration, tablet swelling and dissolution, as well as the mobilization and distribution of drug products can now be quantified and visualized [2,3]. In addition, the hydrodynamics within a USP recommended flow-through dissolution apparatus can also be visualized by MRI [4]. Such comprehensive information is essential in pharmaceutical research for: (i) the correct interpretation of conventional drug dissolution profiles and (ii) the optimal design (QbD) of controlled release formulations.

Thursday, 28 February 2013 14:25

Paradigm Shift in Lipid-Based Drug Delivery?

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Lipid-based drug delivery systems have become a popular approach for the delivery of poorly water-soluble drugs. The limitations associated with this formulation strategy have been the drug solubility in the delivery systems and the lack of characterization techniques predicting the in vivo performance. Solid state characterization of the in vitro digestion products has provided new insights that scrutinize current paradigms in the development of lipid-based drug delivery systems.

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