Evaluation of Extractables in Processed and Unprocessed Polymer Materials Used for Pharmaceutical Applications

Polymeric materials are often used in pharmaceutical packaging, delivery systems, and manufacturing components. There is continued concern that chemical entities from polymeric components may leach into various dosage forms, particularly those that are comprised of liquids such as parenterals, injectables, ophthalmics, and inhalation products. In some cases, polymeric components are subjected to routine extractables testing as a control measure. To reduce the risk of discovering leachables during stability studies late in the development process, or components that may fail extractables release criteria, it is proposed that extractables testing on polymer resins may be useful as a screening tool. Two studies have been performed to evaluate whether the extractables profile generated from a polymer resin is representative of the extractables profile of components made from that same resin. The ELSIE Consortium pilot program examined polyvinyl chloride and polyethylene, and another study evaluated polypropylene and a copolymer of polycarbonate and acrylonitrile butadiene styrene. The test materials were comprised of polymer resin and processed resin or molded components. Volatile, semi-volatile, and nonvolatile chemical profiles were evaluated after headspace sampling and extraction with solvents of varying polarity and pH. The findings from these studies indicate that there may or may not be differences between extractables profiles obtained from resins and processed forms of the resin depending on the type of material, the compounds of interest, and extraction conditions used. Extractables testing of polymer resins is useful for material screening and in certain situations may replace routine component testing.KEY WORDS: extractables, PC/ABS, polyethylene, polypropylene, polyvinylchloride     

Polycaprolactone-poly(ethylene glycol) multiblock copolymers as potential substitutes for di(ethylhexyl) phthalate in flexible poly(vinyl chloride) formulations

New high-molecular-weight hydrophobic/hydrophilic segmented copolymers of poly(ester ether carbonate) structure, containing poly(epsilon-caprolactone) (PCL) and poly(ethylene glycol) (PEG) segments in their main chain, were synthesized and characterized. These copolymers were obtained by a two-step chain-extension reaction carried out in the presence of alpha,omega-dihydroxy-oligoPCL of molecular weight 1250 and PEG samples of molecular weight 150, 400, 600, 1000, and 2000. The molecular structures of all synthesized materials were characterized by means of (1)H NMR and (13)C NMR spectroscopy, their molecular weights were determined by means of size exclusion chromatography, and their thermal properties were obtained by means of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The poly(ester ether carbonate)s of this study are partly or totally miscible at least up to 50 wt % with poly(vinyl chloride) (PVC) and could be used to produce flexible PVC formulations. The miscibility between PVC and the poly(ester ether carbonate)s reported in this paper was investigated by means of DSC and DMA analysis. PVC blends were also analyzed by determining their swellability and the amount of extractables in aqueous media. By comparison purposes, the chain-extension product of PCL1250, that is, PCL polycarbonate, was also synthesized and characterized. The results obtained demonstrated that the copolymers with shortest PEG segment length, i.e. PEG150, 400, and 600, give the best results in terms of miscibility with PVC and lead to blends with maximum resistance to extraction by water. Therefore, they represent, in principle, good substitutes for low-molecular-weight, leachable PVC plasticizers, such as di(ethylhexyl) phthalate.     

X-ray sterilization of biopharmaceutical manufacturing equipment—Extractables profile of a film material and copolyester Tritan™ compared to gamma irradiation

The biopharmaceutical industry gains enormous flexibility in production processes by using sterilized preassembled single-use devices. Gamma irradiation is an established sterilization technology that may be restricted in the future by the availability of ⁶⁰Co as irradiation source and irradiation capacities. X-ray technology is considered an alternative type of radiation for sterilizing SU equipment. In the context of extractables and leachables—one concern connected with the use of single-use process equipment—the effect of X-ray irradiation on the extractables profile of the materials needs to be compared to established gamma irradiation to qualify this alternative technology. An approach is presented to obtain robust and comprehensive extractables data for materials used in SU devices after sterilization either using X-ray or gamma irradiation. A careful selection of the test items and the test design allows a one-to-one comparison of data obtained from a combination of orthogonal analytical techniques. The extractables of a modern SU film material and the copolyester Tritan™ are evaluated. The data presented allow a risk evaluation on the safety of this new sterilization modality for biopharmaceutical applications. It is demonstrated that the extractables profile of a polymer is not affected by the type of irradiation used for sterilization.     

Fabrication of a Dipole-assisted Solid Phase Extraction Microchip for Trace Metal Analysis in Water Samples

This paper describes a fabrication protocol for a dipole-assisted solid phase extraction (SPE) microchip available for trace metal analysis in water samples. A brief overview of the evolution of chip-based SPE techniques is provided. This is followed by an introduction to specific polymeric materials and their role in SPE. To develop an innovative dipole-assisted SPE technique, a chlorine (Cl)-containing SPE functionality was implanted into a poly(methyl methacrylate) (PMMA) microchip. Herein, diverse analytical techniques including contact angle analysis, Raman spectroscopic analysis, and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis were employed to validate the utility of the implantation protocol of the C-Cl moieties on the PMMA. The analytical results of the X-ray absorption near-edge structure (XANES) analysis also demonstrated the feasibility of the Cl-containing PMMA used as an extraction medium by virtue of the dipole-ion interactions between the highly electronegative C-Cl moieties and the positively charged metal ions.     

Microwave-Assisted Process (MAPTM) for the Extraction of Contaminants from Soil

Laboratory-scale tests were performed to evaluate the use of Environment Canada's patented Microwave-Assisted Process (MAP_TM) for the extraction of petroleum hydrocarbons from contaminated soil. The purpose of these tests was to determine the potential for using the process for large-scale processing of contaminated soil. Tests were performed using three soil types: a certified sediment and certified soil, both contaminated with polycyclic aromatic hydrocarbons (PAHs), and spiked peat soil contaminated with long-chain petroleum hydrocarbons. The test methods used were based on existing MAP techniques that have been proven for the sample preparation of contaminated soils for analytical purposes. The parameters evaluated concentrated on those that are amenable to a continuous large-scale process running at atmospheric pressures. This meant using solvents that are inexpensive and readily available in large volumes, low solvent to material ratios, and optimized energy inputs. In general, it was found that microwaves could be used to enhance the solvent extraction of the contaminants from the soil and that the properties of the soil greatly affected the extent to which the contaminants were removed.     

Identification of Particles in Raw Materials

Raw materials need to be of a certain quality with respect to physical and chemical composition. They also need to have no contaminants in the form of particles because these could get into the product or indicate the raw materials are not pure enough to make a good quality product. When particles are found, it is important to identify their chemical and elemental composition to correct any process errors that can cause them and to have acceptable quality of the final product. Sources of materials can be the environment, process equipment and processing, and packaging. Microscope versions of Raman spectroscopy, laser-induced breakdown spectroscopy (LIBS), and IR spectroscopy are excellent tools for identifying particles in materials because they are fast and accurate techniques needing minimal sample preparation that can provide chemical composition as well as images that can be used for identification. The micro analysis capabilities allow for easy analysis of different portions of samples so that multiple components can be identified and sample preparation can be reduced or eliminated. The complementarity of the techniques provides the advantage of identifying various chemical components, as well as elemental and image analyses. The sources of materials were seen to be the environment, process equipment and processing, and packaging.     

微波萃取苦荞壳中总黄酮工艺研究

本文在提取苦荞壳中总黄酮的工艺实验中,优化了提取溶剂的种类,水和乙醇,同时还使用了超声波和微波辅助提取,并分别将不同因素,如溶剂种类及浓度,提取时间,温度,pH,液固比等,对提取结果的影响作了比较,结果表明,当介质为乙醇时的微波萃取效果明显优于其他提取方法。     

Supercritical carbon dioxide extraction of marigold at high pressures: comparison of analytical and pilot-scale extraction

The effects of pressure and co-solvent on the extraction of anti-inflammatory faradiol esters in marigold (Calendula officinalis L.) were investigated by supercritical fluid extraction at laboratory and pilot scales. Pressures higher than 300 bar and modifier (ethanol) concentrations ranging from 0 to 20% (v/v) were used at an extraction temperature of 50 degrees C. With an analytical extractor, exhaustive extraction of the drug and highest concentrations in the extracts were achieved with 0.5% ethanol at the maximum pressure of 689 bar. Increased modifier concentrations improved the extractability at lower pressure, but the higher amount of total extractables led to a lower concentration of faradiol esters in the extracts. The HPLC fingerprints of the extracts, the yields of total extract and the concentration of faradiol esters obtained with analytical and pilot scale extractors under the same conditions were comparable.     

Methods for Assessment of Biodegradability of Plastic Films in Soil

Traditional and novel techniques were tested and compared for their usefulness in evaluating biodegrad-ability claims made for newly formulated “degradable” plastic film products. Photosensitized polyethylene (PE), starch-PE, extensively plasticized polyvinyl chloride (PVC), and polypropylene (PP) films were incorporated into aerobic soil. Biodegradation was measured for 3 months under generally favorable conditions. Carbon dioxide evolution, residual weight recovery, and loss of tensile strength measurements were supplemented, for some films, by gas chromatographic measurements of plasticizer loss and gel permeation chromatographic (GPC) measurement of polymer molecular size distribution. Six- and 12-week sunlight exposures of photosensitized PE films resulted in extensive photochemical damage that failed to promote subsequent mineralization in soil. An 8% starch-PE film and the plasticized PVC film evolved significant amounts of CO₂ in biodegradation tests and lost residual weight and tensile strength, but GPC measurements demonstrated that all these changes were confined to the additives and the PE and PVC polymers were not degraded. Carbon dioxide evolution was found to be a useful screening tool for plastic film biodegradation, but for films with additives, polymer biodegradation needs to be confirmed by GPC. Photochemical cross-linking of polymer strands reduces solubility and may interfere with GPC measurements of polymer degradation.     

桦褐孔菌三萜类物质的提取与含量测定

以桦褐孔菌发酵菌丝体为材料,通过对溶剂乙醇(95%)、甲醇、乙酸乙酯、丙酮、异丙醇、正己烷和氯仿的提取效果比较表明,提取三萜类化合物的最佳溶剂为异丙醇,提取时间为24h,每个样品所需溶剂量(6mL)和菌丝体样品量(100mg)较少,并可同时对大量样品进行有效提取。以白桦脂醇为标准品,对香草醛-冰醋酸-高氯酸分光光度法进行评价,证明该方法简单快速、准确度高、试验误差小、重复性好。利用此方法对桦褐孔菌的野生菌核和发酵菌丝体内三萜类化合物含量进行测定,结果表明野生菌核(59.86mg/g)和发酵菌丝体(94.92mg/g)中都含有很高的三萜类化合物,且发酵菌丝体中三萜类化合物含量高于野生菌核。因此在桦褐孔菌产品开发中,发酵菌丝体可代替野生菌核进行大工业化生产。     

Molecular modelling of phthalates - PPARs interactions

Di(2-ethylhexyl) phthalate (DEHP) is the most widely plasticizer for polyvinyl chloride (PVC) that is used in plastic tubes, in medical and paramedical devices as well as in food storage packaging. The toxicological profile of DEHP has been evaluated in a number of experimental animal models and has been extensively documented. Its toxicity is in part linked to the activation of the peroxisome proliferator-activated receptor alpha (PPAR(alpha)). As a response, an intensive research for a new, biologically inert plasticizer has been initiated. Among the alternative studied, tri(2-ethylhexyl) trimellitate (TEHTM) or trioctyl trimellitate (TOTM) has attracted increasing interest. However, very little information is available on their biological effects. We proceeded to dock TOTM, DEHP and its metabolites in order to identify compounds that are likely to interact with PPAR(alpha) and PPAR(gamma) binding sites. The results obtained hint that TOTM is not able to bind to PPARs and should therefore be safer than DEHP.     

Recent Advances of Using Ionic Liquids for Biopolymer Extraction and Processing

The evolution of petroleum‐derived polymers is one of the crowning accomplishments of the past century. Although the significant economic gains from this industrial model of resource utilization are achieved, the environmental impacts are fatal. One of the principles of sustainable development is to replace such polymers with potential alternatives derived from renewable materials. Biopolymers derived from natural resources afford a new, versatile, environmentally benign feedstock that could exhibit closed‐loop life cycles as part of a future material's industrial ecology. However, the solubility and processability of biopolymer materials provoke a serious bottleneck owing to their dense networks of inter ‐ and intramolecular bondings and structural heterogeneity. Recently, ionic liquids (ILs) have emerged as promising green solvents and acquired augmented appreciation for their peerless power of biopolymer processing. Among the fourteen principle of green chemistry, the two key elements encourage the exploitation of renewable raw materials by using environmentally benign solvents that cover in dissolution of biopolymers using ILs. This mini review represents a brief overview of the comprehensive ILs assisted extraction and processing of various biopolymeric materials for value‐added applications.     

桦褐孔菌三萜类物质的提取与含量测定

以桦褐孔菌发酵菌丝体为材料,通过对溶剂乙醇（95%）、甲醇、乙酸乙酯、丙酮、异丙醇、正己烷和氯仿的提取效果比较表明,提取三萜类化合物的最佳溶剂为异丙醇,提取时间为24h,每个样品所需溶剂量（6mL）和菌丝体样品量（100mg）较少,并可同时对大量样品进行有效提取。以白桦脂醇为标准品,对香草醛-冰醋酸-高氯酸分光光度法进行评价,证明该方法简单快速、准确度高、试验误差小、重复性好。利用此方法对桦褐孔菌的野生菌核和发酵菌丝体内三萜类化合物含量进行测定,结果表明野生菌核（59.86mg/g）和发酵菌丝体（94.92mg/g）中都含有很高的三萜类化合物,且发酵菌丝体中三萜类化合物含量高于野生菌核。因此在桦褐孔菌产品开发中,发酵菌丝体可代替野生菌核进行大工业化生产。     

用于SCAR检测的基因组DNA简易提取法

用一种简单的方法,无需接触有毒的有机试剂,无需离心,即可从小麦叶片中提取完整的基因组DNA,质量满足SCAR检测的要求,该方法可在短时间内制备大量样品,适于进行遗传连锁性分析时对F2分离群体的单株检测和分子标记辅助选择时筛选育种材料,操作简单,实用性强,值得推广。     

Effects of diverse water pipe materials on bacterial communities and water quality in the annular reactor

To investigate the effects of pipe materials on biofilm accumulation and water quality, an annular reactor with the sample coupons of four pipe materials (steel, copper, stainless steel, and polyvinyl chloride) was operated under hydraulic conditions similar to a real plumbing system for 15 months. The bacterial concentrations were substantially increased in the steel and copper reactors with progression of corrosion, whereas those in stainless steel (STS) and polyvinyl chloride (PVC) reactors were affected mainly by water temperature. The heterotrophic plate count (HPC) of biofilms was about 100 times higher on steel pipe than other pipes throughout the experiment, with the STS pipe showing the lowest bacterial number at the end of the operation. Analysis of the 16S rDNA sequences of 176 cultivated isolates revealed that 66.5% was Proteobacteria and the others included unclassified bacteria, Actinobacteria, and Bacilli. Regardless of the pipe materials, Sphingomonas was the predominant species in all biofilms. PCR-DGGE analysis showed that steel pipe exhibited the highest bacterial diversity among the metallic pipes, and the DGGE profile of biofilm on PVC showed three additional bands not detected from the profiles of the metallic materials. Environmental scanning electron microscopy showed that corrosion level and biofilm accumulation were the least in the STS coupon. These results suggest that the STS pipe is the best material for plumbing systems in terms of the microbiological aspects of water quality.     

Investigation of a failed DNA assay leads to identification of an unexpected contaminant in a commonly used chromatography buffer

For mammalian cell-derived recombinant biotherapeutics, controlling host cell DNA levels below a threshold is a regulatory requirement to ensure patient safety. DNA removal during drug substance manufacture is accomplished by a series of chromatography-based purification steps and a qPCR-based analytical method is most used to measure DNA content in the purified drug substance to enable material disposition. While the qPCR approach is mature and its application to DNA measurement is widespread in the industry, it is susceptible to trace levels of process-related contaminants that are carried forward. In this study, we observed failures in spike recovery studies that are an integral component of the qPCR-based DNA testing, suggesting the presence of an inhibitory compound in the sample matrix. We generated hypotheses around the origin of the inhibitory compound and generated multiple sample matrices and deployed a suite of analytical techniques including Raman and NMR spectroscopy to determine the origin and identity of the inhibitory compound. The caustic wash step and depth filter extractables were ruled out as root causes after extensive experimentation and DNA testing. Subsequently, 2-(N-morpholino)ethanesulfonic acid (MES), a buffer used in the chromatography unit operations, was identified as the source of the contaminant. A 500-fold concentration followed by Raman and NMR spectroscopy analysis revealed the identity of the inhibitory compound as polyvinyl sulfone (PVS), an impurity that originates in the MES manufacturing process. We have implemented PVS concentration controls for incoming MES raw material, and our work highlights the need for rigor in raw material qualification and control.     

Developments in multiple headspace extraction

This paper reviews new developments in multiple headspace extraction (MHE), especially its combination with two miniaturized extraction techniques, solid-phase microextraction (SPME) and single-drop microextraction (SDME). The combination of the techniques broadens the applicability of SPME and SDME to quantitative determination of analytes in complex liquid and solid matrixes. These new methods offer several advantages over traditional liquid-solid, liquid-liquid and headspace extraction techniques. The potential applications include extraction of volatiles and semivolatiles from environmental and physiological samples and from different polymer products such as medical and biomedical materials, food packaging and building materials. The theoretical principals of the techniques are also briefly reviewed.     

Novel reactive perstraction system applied to the hydrolysis of penicillin G

The activity of penicillin acylase has been studied in aqueous and organic solvents, as free enzyme as well as immobilized within the membrane of liquid-core capsules. The activity of the enzyme is inhibited by the accumulation of the products of the hydrolysis reaction, namely phenyl acetic acid (PAA). In order to overcome this inhibition a range of organic solvents were tested for use in in situ product recovery. Of these solvents dibutyl sebacate (DBS) was chosen due to the rapid extraction rate, the high logP and to facilitate capsule production. The extraction efficiency at pH 3.5 for PAA was >80% for phase ratios of >50% free solvent with partition coefficients of 8 and 0.7 for PAA and penicillin G (PenG), respectively, thereby showing that PAA could be selectively extracted at pH 3.5 and 25 degrees C. Liquid-core capsules containing DBS were shown to efficiently remove PAA selectively and the PAA could be effectively back-extracted and the capsules re-used in a three-stage process resulting in high product separation. Immobilization of penicillin acylase onto the capsule membranes resulted in increased operational stability of the enzyme and a very high enzyme activity. Over 53.3% of the PAA formed could be recovered in the capsule core with a concentration over sevenfold higher than in the aqueous phase. Higher extraction efficiencies could be obtained by varying the substrate concentration and number of capsules. The enzyme immobilized on capsules could be stored for over 4 months at pH 8 and 4 degrees C with no loss of activity. Over 80% of the initial activity could be recovered over five repeated batch cycles of the bioconversion process. The importance of capsular perstraction and reactive capsular perstraction has been clearly demonstrated.     

Molecular modelling of phthalates – PPARs interactions

Di(2-ethylhexyl) phthalate (DEHP) is the most widely plasticizer for polyvinyl chloride (PVC) that is used in plastic tubes, in medical and paramedical devices as well as in food storage packaging. The toxicological profile of DEHP has been evaluated in a number of experimental animal models and has been extensively documented. Its toxicity is in part linked to the activation of the peroxisome proliferator-activated receptor α (PPAR_α). As a response, an intensive research for a new, biologically inert plasticizer has been initiated. Among the alternative studied, tri(2-ethylhexyl) trimellitate (TEHTM) or trioctyl trimellitate (TOTM) has attracted increasing interest. However, very little information is available on their biological effects. We proceeded to dock TOTM, DEHP and its metabolites in order to identify compounds that are likely to interact with PPAR_α and PPAR_γ binding sites. The results obtained hint that TOTM is not able to bind to PPARs and should therefore be safer than DEHP.     

Developments in multiple headspace extraction

This paper reviews new developments in multiple headspace extraction (MHE), especially its combination with two miniaturized extraction techniques, solid-phase microextraction (SPME) and single-drop microextraction (SDME). The combination of the techniques broadens the applicability of SPME and SDME to quantitative determination of analytes in complex liquid and solid matrixes. These new methods offer several advantages over traditional liquid–solid, liquid–liquid and headspace extraction techniques. The potential applications include extraction of volatiles and semivolatiles from environmental and physiological samples and from different polymer products such as medical and biomedical materials, food packaging and building materials. The theoretical principals of the techniques are also briefly reviewed.