Poloxamer 407
Also known as: Poloxamer 407, Pluronic F127, Poly(ethylene oxide)-poly(propylene oxide) block copolymer
Overview
Poloxamer 407 is a synthetic block copolymer, not derived from natural sources, widely utilized in pharmaceutical and biomedical formulations. It is chemically known as Pluronic F127 and classified as a nonionic surfactant and thermoresponsive polymer. Its primary application is as a versatile pharmaceutical excipient and drug delivery vehicle, particularly in topical and injectable formulations. A key characteristic of Poloxamer 407 is its thermoresponsive behavior, meaning it transitions from a liquid state at lower temperatures to a gel at physiological temperatures (around 25-37°C). This property, along with its ability to form micelles and hydrogels, makes it highly effective for enhancing drug solubility, controlling drug release, and providing a base for thermosensitive gels. It is also employed in wound care gels and as a thickening agent. While extensively studied in pharmaceutical sciences for its physicochemical properties and drug delivery applications, direct clinical trials evaluating Poloxamer 407 as a standalone supplement ingredient are limited.
Benefits
Poloxamer 407 primarily functions as a pharmaceutical excipient, offering significant benefits in drug delivery rather than direct therapeutic effects. Its main advantage is its ability to serve as an effective vehicle for topical and localized drug delivery, improving drug stability and controlling release profiles. For instance, in vitro studies have shown that gels containing over 20% Poloxamer 407, when combined with polyhexanide, exhibit significant antimicrobial and antibiofilm activity against pathogens like *Staphylococcus aureus* and *Pseudomonas aeruginosa* [1]. This suggests its utility in formulations for wound care. Preclinical animal studies have also demonstrated its capacity to facilitate brain targeting of drugs, such as agomelatine, leading to enhanced pharmacokinetics and improved behavioral outcomes in rats [2]. Furthermore, Poloxamer 407 hydrogels can be engineered to modulate gelation temperature and mechanical properties, allowing for tailored drug release and improved skin permeation of active pharmaceutical ingredients like diclofenac [3]. When combined with other agents, such as hyaluronic acid and ginsenoside Rg3, it shows potential in supporting tissue repair and localized drug delivery in skin disease models [4]. While these benefits are well-supported by preclinical and in vitro evidence, direct human clinical data on Poloxamer 407's efficacy as a standalone supplement ingredient are limited, as its role is primarily as a delivery system.
How it works
Poloxamer 407 functions primarily as a carrier system rather than possessing direct pharmacological activity. Its mechanism of action revolves around its amphiphilic nature and thermoresponsive properties. At lower temperatures, it exists as a liquid, but as the temperature increases to physiological levels (e.g., body temperature), it undergoes a phase transition to form a gel. This gelation is due to the self-assembly of poloxamer molecules into micelles and then into a three-dimensional hydrogel network. This network can encapsulate drugs, enhancing their solubility, protecting them from degradation, and controlling their release rate over time. By forming a physical barrier, it enables sustained local drug delivery at the site of application or injection. Poloxamer 407 interacts physically with tissues by forming these gels, allowing for prolonged contact and localized therapeutic effects of the incorporated active ingredients. It is not absorbed systemically in significant amounts, ensuring its action is localized.
Side effects
Poloxamer 407 is generally recognized as safe (GRAS) as a pharmaceutical excipient and is widely used in various topical and injectable formulations. Common side effects are minimal, with some individuals potentially experiencing mild local irritation depending on the specific formulation and site of application. Uncommon side effects, occurring in 1-5% of users, are rare, but hypersensitivity or allergic reactions are theoretically possible, though infrequently reported. Rare side effects, occurring in less than 1% of users, are not well-documented, and no significant systemic toxicity has been reported at typical usage levels. Poloxamer 407 itself does not have intrinsic drug interactions; any interactions would depend on the active drugs delivered within the poloxamer matrix. There are no specific contraindications for Poloxamer 407 itself. However, caution is advised for special populations such as pregnant or lactating individuals, as safety in these groups has not been extensively studied. Overall, its safety profile is considered favorable for its intended use as a pharmaceutical excipient.
Dosage
Poloxamer 407 is not a supplement with a typical 'dose' for ingestion, but rather an excipient used in formulations. Its 'dosage' refers to its concentration within a pharmaceutical product. For effective gelation and drug delivery, Poloxamer 407 is typically used at concentrations ranging from 15% to 26% w/w in hydrogels and topical formulations. The optimal dosage range commonly falls between 20% and 26% concentration, as this range effectively balances gel strength with desired drug release kinetics. There is no established maximum safe dose for Poloxamer 407, as its safety depends on the specific route of administration (e.g., topical, injectable) and the overall formulation. Gelation occurs rapidly upon reaching body temperature, and formulations are designed for sustained release of the incorporated drug over periods ranging from hours to days. It is primarily used in hydrogels, topical gels, and injectable formulations. Since Poloxamer 407 is not absorbed systemically, its 'absorption factors' relate to the release kinetics of the active drug it carries. It is often combined with active drugs, antimicrobials (e.g., polyhexanide), or other polymers (e.g., hyaluronic acid) to achieve specific therapeutic outcomes.
FAQs
Is Poloxamer 407 active as a supplement?
No, Poloxamer 407 is primarily a pharmaceutical excipient and drug delivery vehicle, not a bioactive supplement. It helps deliver other active ingredients.
Is it safe for topical use?
Yes, Poloxamer 407 is widely used in topical formulations and is generally considered safe with minimal irritation reported.
Can it deliver drugs effectively?
Yes, it is highly effective in enhancing the solubility and controlling the release of various drugs, making it a valuable drug delivery system.
Does it have antimicrobial properties?
Poloxamer 407 itself does not inherently possess antimicrobial properties, but formulations containing it along with antimicrobials can show significant activity.
Is it absorbed systemically?
No, Poloxamer 407 is not significantly absorbed into the bloodstream; it primarily acts locally at the site of application or injection.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11596435/ – This in vitro experimental study investigated wound gels with varying Poloxamer 407 concentrations and pH levels containing polyhexanide. It found that higher pH improved antimicrobial activity, while Poloxamer 407 concentrations above 20% reduced it, demonstrating significant antibiofilm activity against six pathogens. The study highlights the formulation's potential but notes the need for clinical validation.
- https://pubmed.ncbi.nlm.nih.gov/31176115/ – This animal study in Wistar rats evaluated a Poloxamer 407-thickened lipid colloidal system for brain targeting of agomelatine. The research demonstrated improved brain pharmacokinetics and behavioral outcomes, suggesting Poloxamer 407's utility in enhancing drug delivery to the brain. Limitations include its preclinical nature, as human data are not available.
- https://iro.uiowa.edu/view/pdfCoverPage?instCode=01IOWA_INST&filePid=13851253000002771&download=true – This rheological study focused on Poloxamer 407 hydrogels containing diclofenac sodium. It showed that increasing Poloxamer 407 concentration lowers the gelation temperature, which in turn affects drug release and skin permeation. The study provides valuable mechanistic insights for designing effective topical formulations.
- https://pubmed.ncbi.nlm.nih.gov/35866029/ – This research describes the development of Poloxamer 407 and hyaluronic acid hydrogels for treating skin diseases with ginsenoside Rg3. The study indicates the potential of these formulations for tissue repair and localized drug delivery, though it remains in the preclinical stage.
