Alimta ® (pemetrexed for injection)

This information is intended for UK registered healthcare professionals only as a scientific exchange in response to your search for information. Please refer to the link for full prescribing information: Alimta Summary of Product Characteristics (SmPC)

Compatibility of Alimta® (pemetrexed) with other diluents, in-line filters and olephin resins

Relevant information on the compatibility of pemetrexed with other diluents, in-line filters and olephin resins is provided.

Compatibility with other diluents

Pemetrexed should only be reconstituted with 0.9% sodium chloride (NaCl) injection (preservative free). Pemetrexed is physically incompatible with diluents containing calcium, including lactated Ringer's injection and Ringer's injection. In the absence of other compatibility studies this medicinal product must not be mixed with other medicinal products.1

After the initial reconstitution, the pemetrexed solution should appear clear, it may range in colour from colourless to light yellow to green-yellow without adversely affecting product quality. Refer to section 6.6 of the Alimta Summary of Product Characteristics (SmPC) for instructions on reconstitution.1

Compatibility with in-line filters

The administration of pemetrexed does not require the use of an infusion set with an in-line filter. However, the use of an in-line filter should not have any adverse impact on the drug product. Pemetrexed solutions are compatible with a 0.22-micron polyethersulfone (PES) membrane with a polytetrafluoroethylene (PTFE) or Teflon® hydrophobic vent filter.2

Early internal study of pemetrexed solutions with in-line filter using high performance liquid chromatography (HPLC) analysis

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration. As administration of oncolytics through an infusion set with an in-line filter is a common practice in hospitals, a study was undertaken to evaluate the compatibility of commercially available pemetrexed solutions with a simulated intravenous (IV) administration set containing an in-line filter.2

Solutions of commercially available lyophilized pemetrexed were prepared at an approximate final concentration of 0.1 mg/mL to represent the lowest and worst-case concentration during in-use conditions with an in-line filter. The prepared solutions were then pumped through a polyvinyl chloride (PVC) administration set with and without an in-line 0.22-micron PES microporous membrane with a PTFE or Teflon® hydrophobic vent filter.2

Results of the analyzed solutions by HPLC showed

  • no difference in potency for solutions filtered with or without an in-line filter, and

  • no product loss due to adsorption or absorption of pemetrexed to the filter.2

This study demonstrated that commercially available pemetrexed solutions are compatible with a 0.22-micron PES membrane with a PTFE or Teflon® hydrophobic vent filter.2

Additional study on microprecipitates using flow injection analysis (FIA)

A recent study investigated the formation of microprecipitates in pemetrexed infusions and provided information on the use of administration lines with a 0.22-micron microfilter. In this study, pemetrexed 500 mg vials were reconstituted with 20 mL 0.9% NaCl and then diluted to a final concentration of 5 mg/mL in 0.9% NaCl or D5% polyolefin bags.3

After preparation, 1 mL samples were analyzed without dilution using a FIA/HPLC method. Bags were then stored at 2°C to 8°C (36°F-46°F), and samples were analyzed at day 7, 14, 21, and 28 following filtration of the solution through an infusion line with a 0.22-micron in-line microfilter.3

Results of the analyzed samples at different timepoints demonstrated

  • no decrease in pemetrexed concentration

  • no presence of microprecipitates, and

  • no adsorption of pemetrexed on the filter material.3

Note: per pemetrexed labeling, if not used immediately, the reconstituted and infusion solutions of pemetrexed should be stored under refrigeration at 2°C to 8°C (36°F-46°F) for up to 24 hours only, since the recommended diluent contains no antimicrobial preservatives.1

The authors of this study concluded that the formation of microprecipitates in pemetrexed solutions stored at 2°C to 8°C (36°F-46°F) and their removal using a 0.22-micron in-line filter would not appear to cause a negative impact for patients.3

Compatibility with olephin resins

Incompatibilities have not been observed between pemetrexed and olephin resins (e.g. polyethylene and/or polypropylene) as found in infusion bottles or PVC bags and administration sets.2


1. Alimta [summary of product characteristics]. Eli Lilly Nederland B.V., The Netherlands

2. Data on file, Eli Lilly and Company and/or one of its subsidiaries.

3. D'Huart E, Vigneron J, Morice S, et al. Pemetrexed stability: additional information about microparticles. Eur J Hosp Pharm. 2019;26(1):56.

Date of Last Review: February 11, 2020

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