An Industrial View on Enzymes for the Cleavage of Cephalosporin C

The enzymatic cleavage of cephalosporin C (CephC) into 7-aminocephalosporanic acid (7-ACA) and deacetyl-7-aminocephalosporanic acid (HACA), both key intermediates for cephalosporin antibiotics, has now been commercialized on an industrial scale. This article illustrates economic, technical, and regulatory aspects of the process, with special focus on the enzymes involved.Due to the compensation for low operational stability by low costs of preparation, cell immobilization of Trigonopsis variabilis seems an economically attractive and technically feasible way to prepare D-amino acid oxidase (EC 1.4.3.3). However, the application of immobilized cells is restricted to large-volume products, since it involves extensive development and characterization work. For glutaryl-7-ACA acylase (EC 3.5.1.3), expressed in Escherichia coli, isolation and immobilization of the enzyme on a commercial carrier seems more attractive from a regulatory point of view. The immobilized enzyme shows very high operational stability, which may compensate for the costs of the carrier. Despite its lower stability, cephalosporin G acetylesterase (EC 3.1.1.41), expressed in E. coli, was also immobilized on a commercial carrier for regulatory reasons. Moreover, extensive development of immobilized whole cells seemed economically not acceptable for this low-volume product. A mathematical model for the enzymatic cleavage showed limitations of a combined application of two biocatalysts in a stirred tank reactor, e.g., in terms of product yield

Large-scale purification of factor VIII by affinity chromatography: optimization of process parameters

The optimization of a new process for the extraction of human coagulation factor VIII (FVIII) from plasma with the tailor-made affinity matrix dimethylaminopropylcarbamylpentyl-Sepharose CL-4B (C3---C5 matrix) is described. First, plasma is applied to DEAE-Sephadex A-50 anion exchanger in order to separate a number of proteins, including coagulation factors II, IX and X (prothrombin complex), from FVIII. Subsequently, the unbound fraction of the ion exchanger, containing FVIII, is contacted with the C3---C5 affinity matrix. Optimization of the FVIII affinity chromatographic procedure is accomplished in terms of the ligand density of the matrix, adsorption mode (batch-wise versus column-wise adsorption and matrix to plasma ratio), and conditions of pH and conductivity to be applied on washing and desorption. In scale-up experiments, by processing 20 1 of plasma, the recovery (340 U VIII:C/kg plasma) and the specific activity (s.a.) (1.2 U VIII:C/mg protein) are better than those obtained by cryoprecipitation (recovery 300 U VIII:C/kg plasma, s.a. O.3 U VIII:C/mg protein). The newly developed process using the specially designed C3---C5 affinity matrix has potential application in the process-scale purification of FVIII

Exploring gastrointestinal variables affecting drug and formulation behavior: methodologies, challenges and opportunities

Various gastrointestinal (GI) factors affect drug and formulation behavior after oral administration, including GI transfer, motility, pH and GI fluid volume and composition. An in-depth understanding of these physiological and anatomical variables is critical for a continued progress in oral drug development. In this review, different methodologies (invasive versus non-invasive) to explore the impact of physiological variables on formulation behavior in the human GI tract are presented, revealing their strengths and limitations. The techniques mentioned allow for an improved understanding of the role of following GI variables: gastric emptying (magnetic resonance imaging (MRI), scintigraphy, acetaminophen absorption technique, ultrasonography, breath test, intraluminal sampling and telemetry), motility (MRI, small intestinal/colonic manometry and telemetry), GI volume changes (MRI and ultrasonography), temperature (telemetry) and intraluminal pH (intraluminal sampling and telemetry)

Impact of gastrointestinal tract variability on oral drug absorption and pharmacokinetics : an UNGAP review

The absorption of oral drugs is frequently plagued by significant variability with potentially serious therapeutic consequences. The source of variability can be traced back to interindividual variability in physiology, differences in special populations (age- and disease-dependent), drug and formulation properties, or food-drug interactions. Clinical evidence for the impact of some of these factors on drug pharmacokinetic variability is mounting: e.g. gastric pH and emptying time, small intestinal fluid properties, differences in pediatrics and the elderly, and surgical changes in gastrointestinal anatomy. However, the link of colonic factors variability (transit time, fluid composition, microbiome), sex differences (male vs. female) and gut-related diseases (chronic constipation, anorexia and cachexia) to drug absorption variability has not been firmly established yet. At the same time, a way to decrease oral drug pharmacokinetic variability is provided by the pharmaceutical industry: clinical evidence suggests that formulation approaches employed during drug development can decrease the variability in oral exposure. This review outlines the main drivers of oral drug exposure variability and potential approaches to overcome them, while highlighting existing knowledge gaps and guiding future studies in this area

Integratie van biorelevantie in de absorptie profilering van slecht in water oplosbare geneesmiddelen

status: publishe

Integration of biorelevance into absorption profiling of poorly water soluble drugs

nrpages: 17

Augmenting reality: An exploration of the intention to use commercial augmented reality comparing older and younger adults differing in technology innovativeness

The interactive technology augmented reality (AR) layers virtual elements upon the real world of its users, and it is becoming increasingly popular in various fields. Previous research has shown that it can be a valuable tool in the decision-making process of consumers since it enables them to virtually try-out products. However, these studies focused primarily on general persuasive effects, and young, techsavvy samples. Therefore, the study by Riethorst et al. focuses on the influence of both age and technology innovativeness on the intention to adopt commercial AR, using the Technology Acceptance Model as a theoretical base. Based on a field experiment (N = 71) at the home addresses of the participants, this study shows that younger and older adults do not differ in their intention to use commercial AR. However, when taking the level of technology innovativeness into account, the results show that for older adults, ease of use and consequently usefulness, enjoyment and use intention, increase (decrease) as the level of technology innovativeness increases (decreases). For younger adults, the level of technology innovativeness did not matter. These results can elevate the knowledge of marketers who are considering implementing commercial AR and furthermore help them to pinpoint their specific target groups

Relating mulltidrug resistance phenotypes in the kinetic properties of their drug efflux pumps.

The simplest model for pump-mediated multidrug resistance is elaborated quantitatively. The way in which toxicity data should be evaluated to characterize most effectively the drug-efflux pump is then examined. The isotoxic drug dose (