Hans-Dieter Klimm

Bio: Hans-Dieter Klimm is an academic researcher from Heidelberg University. The author has contributed to research in topics: Swallowing & Ambulatory care. The author has an hindex of 3, co-authored 3 publications receiving 193 citations.

Difficulties swallowing solid oral dosage forms in a general practice population: prevalence, causes, and relationship to dosage forms

Abstract: We assessed the prevalence of difficulties in swallowing solid oral dosage forms in a general practice population. Reasons, nature, and characteristics of tablets and capsules causing such difficulties were investigated as well as general practitioners’ (GP) awareness of these difficulties. A questionnaire survey was conducted in 11 general practices and consecutive patients taking at least one solid oral dosage form for ≥4 weeks were invited to respond to a questionnaire at the practices and one at home. Physicians completed a short questionnaire for each included patient. Of all participants (N = 1,051), 37.4 % reported having had difficulties in swallowing tablets and capsules. The majority (70.4 %) of these patients was not identified by their GP. The occurrence of swallowing difficulties was related to gender (f>m), age (young>old), dysphagia [adjusted odds ratio (adOR): 7.9; p < 0.0001] and mental illness (adOR: 1.8; p < 0.05). By asking “Do you choke while eating or drinking?”, affected patients could be identified with a sensitivity of 62.6 % and a specificity of 78.1 %. Because of these difficulties, 58.8 % of the affected patients had already modified their drugs in a way that may alter safety and efficacy and 9.4 % indicated to be non-adherent. One in 11 primary care patients had frequent difficulties in swallowing tablets and capsules while GPs grossly underestimated these problems. Therefore, physicians should rule out swallowing difficulties regularly to avoid non-adherence and inappropriate drug modifications. Special attention should be paid to specific patient groups (e.g. women and patients with dysphagia, dysphagia indicators, or mental illness).

Do we prescribe what patients prefer? Pilot study to assess patient preferences for medication regimen characteristics.

Abstract: Background: The aim of this pilot study was to evaluate patients’ self-reported attitudes towards medication-related factors known to impair adherence and to assess their prevalence in ambulatory care as an essential prerequisite to improve patient adherence.

Plasma LDL cholesterol has no impact on P-glycoprotein (MDR1/ABCB1) activity in human peripheral blood mononuclear cells

Abstract: Several studies have demonstrated that the adenosine triphosphate-binding cassette transporter P-glycoprotein (P-gp) is at least partly located in cholesterol- and sphingolipid-enriched parts of the plasma membrane called “lipid rafts” and that modification of cellular cholesterol content has an impact on the activity of P-gp in vitro and ex vivo. Cholesterol modulation in vitro does not closely reflect the in vivo situation. The aim of our study was therefore to investigate whether differences in individual plasma low-density lipoprotein (LDL) cholesterol levels in humans have an impact on cholesterol content in peripheral blood mononuclear cells (PBMCs) and thereby on individual activity of P-gp. PBMCs of 20 ambulatory patients with elevated LDL cholesterol (173.9 ± 22.4 mg/dl; range 151.0–234.4 mg/dl) and 28 controls (125.2 ± 16.9 mg/dl; range 74.6–149.6 mg/dl) were isolated. Cellular cholesterol was measured by an enzymatic fluorimetric assay, efflux activity of P-gp in PBMCs was determined by a flow cytometric method (rhodamine123 efflux), and messenger ribonucleic acid expression was quantified by reverse transcriptase real-time polymerase chain reaction (RT-PCR). There was no difference in cellular cholesterol or P-gp activity between the two groups suggesting that high plasma LDL cholesterol concentration as observed in dyslipidemic patients does not correlate with cellular cholesterol content or P-gp activity in PBMCs. There was, however, a significant negative relationship between age and P-gp efflux activity indicating that P-gp activity in PBMCs decreases with advancing age. These results need further confirmation because investigation of age dependency of P-gp activity was not the primary aim of the study.

Emergence of 3D Printed Dosage Forms: Opportunities and Challenges

Abstract: The recent introduction of the first FDA approved 3D-printed drug has fuelled interest in 3D printing technology, which is set to revolutionize healthcare. Since its initial use, this rapid prototyping (RP) technology has evolved to such an extent that it is currently being used in a wide range of applications including in tissue engineering, dentistry, construction, automotive and aerospace. However, in the pharmaceutical industry this technology is still in its infancy and its potential yet to be fully explored. This paper presents various 3D printing technologies such as stereolithographic, powder based, selective laser sintering, fused deposition modelling and semi-solid extrusion 3D printing. It also provides a comprehensive review of previous attempts at using 3D printing technologies on the manufacturing dosage forms with a particular focus on oral tablets. Their advantages particularly with adaptability in the pharmaceutical field have been highlighted, which enables the preparation of dosage forms with complex designs and geometries, multiple actives and tailored release profiles. An insight into the technical challenges facing the different 3D printing technologies such as the formulation and processing parameters is provided. Light is also shed on the different regulatory challenges that need to be overcome for 3D printing to fulfil its real potential in the pharmaceutical industry.

Polymers for Extrusion-Based 3D Printing of Pharmaceuticals: A Holistic Materials-Process Perspective.

Abstract: Three dimensional (3D) printing as an advanced manufacturing technology is progressing to be established in the pharmaceutical industry to overcome the traditional manufacturing regime of 'one size fits for all'. Using 3D printing, it is possible to design and develop complex dosage forms that can be suitable for tuning drug release. Polymers are the key materials that are necessary for 3D printing. Among all 3D printing processes, extrusion-based (both fused deposition modeling (FDM) and pressure-assisted microsyringe (PAM)) 3D printing is well researched for pharmaceutical manufacturing. It is important to understand which polymers are suitable for extrusion-based 3D printing of pharmaceuticals and how their properties, as well as the behavior of polymer-active pharmaceutical ingredient (API) combinations, impact the printing process. Especially, understanding the rheology of the polymer and API-polymer mixtures is necessary for successful 3D printing of dosage forms or printed structures. This review has summarized a holistic materials-process perspective for polymers on extrusion-based 3D printing. The main focus herein will be both FDM and PAM 3D printing processes. It elaborates the discussion on the comparison of 3D printing with the traditional direct compression process, the necessity of rheology, and the characterization techniques required for the printed structure, drug, and excipients. The current technological challenges, regulatory aspects, and the direction toward which the technology is moving, especially for personalized pharmaceuticals and multi-drug printing, are also briefly discussed.