Effect of cytochrome P-450 inhibition and stimulation on intensity of polyethylene degradation in microsomal fraction of mouse and rat livers

Polyethylene glycol (PEG): The nature, immunogenicity, and role in the hypersensitivity of PEGylated products

Polyethylene glycol (PEG) is a versatile polymer that is widely used as an additive in foods and cosmetics, and as a carrier in PEGylated therapeutics. Even though PEG is thought to be less immunogenic, or perhaps even non-immunogenic, with a variety of physicochemical properties, there is mounting evidence that PEG causes immunogenic responses when conjugated with other materials such as proteins and nanocarriers. Under these conditions, PEG with other materials can result in the production of anti-PEG antibodies after administration. The antibodies that are induced seem to have a deleterious impact on the therapeutic efficacy of subsequently administered PEGylated formulations. In addition, hypersensitivity to PEGylated formulations could be a significant barrier to the utility of PEGylated products. Several reports have linked the presence of anti-PEG antibodies to incidences of complement activation-related pseudoallergy (CARPA) following the administration of PEGylated formulations. The use of COVID-19 mRNA vaccines, which are composed mainly of PEGylated lipid nanoparticles (LNPs), has recently gained wide acceptance, although many cases of post-vaccination hypersensitivity have been documented. Therefore, our review focuses not only on the importance of PEGs and its great role in improving the therapeutic efficacy of various medications, but also on the hypersensitivity reactions attributed to the use of PEGylated products that include PEG-based mRNA COVID-19 vaccines.

Understanding the Role and Impact of Poly (Ethylene Glycol) (PEG) on Nanoparticle Formulation: Implications for COVID-19 Vaccines

Poly (ethylene glycol) (PEG) is a widely used polymer in a variety of consumer products and in medicine. PEGylation refers to the conjugation of PEG to drugs or nanoparticles to increase circulation time and reduce unwanted host responses. PEG is viewed as being well-tolerated, but previous studies have identified anti-PEG antibodies and so-called pseudoallergic reactions in certain individuals. The increased use of nanoparticles as contrast agents or in drug delivery, along with the introduction of mRNA vaccines encapsulated in PEGylated lipid nanoparticles has brought this issue to the fore. Thus, while these vaccines have proven to be remarkably effective, rare cases of anaphylaxis have been reported, and this has been tentatively ascribed to the PEGylated carriers, which may trigger complement activation in susceptible individuals. Here, we provide a general overview of the use of PEGylated nanoparticles for pharmaceutical applications, and we discuss the activation of the complement cascade that might be caused by PEGylated nanomedicines for a better understanding of these immunological adverse reactions.

Biofilm Growth Causes Damage to Silicone Voice Prostheses in Patients after Surgical Treatment of Locally Advanced Laryngeal Cancer

Voice prosthesis implantation with the creation of a tracheoesophageal fistula is the gold standard procedure for voice rehabilitation in patients after a total laryngectomy. All patients implanted with a voice prosthesis (VP) have biofilms of fungi and bacteria grow on their surface. Biofilm colonization is one of the main reasons for VP degradation that can lead to VP dysfunction, which increases the high risk of pneumonia. In a 20-month evaluation period, 129 cases of prostheses after replacement procedures were investigated. Microbiological examination of the biofilms revealed that there were four of the most common fungi species (Candida spp.) and a large variety of bacterial species present. We studied the relationship between the time of proper function of Provox VP, the microorganism composition of the biofilm present on it, and the degradation level of the silicone material. Evaluation of the surface of the removed VP using an atomic force microscope (AFM) has demonstrated that biofilm growth might drastically change the silicone's mechanical properties. Changes in silicone stiffness and thermal properties might contribute to the failure of VP function. Our data can serve in future studies for the development of methods to prevent or inhibit biofilm formation on the VP surface that would translate to an increase in their durability and safety.

Designing PEGylated therapeutic molecules: advantages in ADMET properties

BACKGROUND

PEGylation, association of poly(ethylene glycol) (PEG) to drug molecules or drug-bearing particles, is one of the most promising techniques on the way to improve the pharmacokinetic features of a drug which, in turn, leads to pharmacodynamic improvements.

OBJECTIVE

The aim of this review is to describe PEGylation as a procedure for alteration of drug molecular structure with the main emphasis on its pharmacokinetic consequences.

METHODS

After a brief but concise overview of the history and chemistry of PEGylation, the boundary of this literature survey is confined to the findings and reports on the impact of PEGylation on biodistribution and bioelimination of therapeutic molecules.

CONCLUSION

It is concluded, based on the whole body of the data in literature, that the main results of PEGylation on pharmacokinetic properties of the drug include prolongation of lifespan in circulation, alterations in drug elimination pathway(s) and changes in drug biodistribution profile, among others, which all are derived from the structural changes that occur in the drug molecule, mainly reversible attachment of a large polymeric moiety to parent drug.

The impact of PEGylation on biological therapies

The term PEGylation describes the modification of biological molecules by covalent conjugation with polyethylene glycol (PEG), a non-toxic, non-immunogenic polymer, and is used as a strategy to overcome disadvantages associated with some biopharmaceuticals. PEGylation changes the physical and chemical properties of the biomedical molecule, such as its conformation, electrostatic binding, and hydrophobicity, and results in an improvement in the pharmacokinetic behavior of the drug. In general, PEGylation improves drug solubility and decreases immunogenicity. PEGylation also increases drug stability and the retention time of the conjugates in blood, and reduces proteolysis and renal excretion, thereby allowing a reduced dosing frequency. In order to benefit from these favorable pharmacokinetic consequences, a variety of therapeutic proteins, peptides, and antibody fragments, as well as small molecule drugs, have been PEGylated. This paper reviews the chemical procedures and the conditions that have been used thus far to achieve PEGylation of biomedical molecules. It also discusses the importance of structure and size of PEGs, as well as the behavior of linear and branched PEGs. A number of properties of the PEG polymer--e.g. mass, number of linking chains, the molecular site of PEG attachment--have been shown to affect the biological activity and bioavailability of the PEGylated product. Releasable PEGs have been designed to slowly release the native protein from the conjugates into the blood, aiming at avoiding any loss of efficacy that may occur with stable covalent PEGylation. Since the first PEGylated drug was developed in the 1970s, PEGylation of therapeutic proteins has significantly improved the treatment of several chronic diseases, including hepatitis C, leukemia, severe combined immunodeficiency disease, rheumatoid arthritis, and Crohn disease. The most important PEGylated drugs, including pegademase bovine, pegaspargase, pegfilgrastim, interferons, pegvisomant, pegaptanib, certolizumab pegol, and some of the PEGylated products presently in an advanced stage of development, such as PEG-uricase and PEGylated hemoglobin, are reviewed. The adaptations and applications of PEGylation will undoubtedly prove useful for the treatment of many previously difficult-to-treat conditions.

Modulation of antibody pharmacokinetics by chemical polysialylation

Chemical coupling of a variety of polymers to therapeutic proteins has been studied as a way of improving their pharmacokinetics and pharmacodynamics in vivo. Conjugates have been shown to possess greater stability, lower immunogenicity, and a longer blood circulation time due to the chemicophysical properties of these hydrophilic long chain molecules. Naturally occurring colominic acid (polysialic acid, PSA) has been investigated as an alternative to synthetic polymers such as poly(ethylene glycol) (PEG) due to its lower toxicity and natural metabolism. Antibodies and their fragments are a good example of the types of proteins which benefit from pharmacokinetic engineering. Here, we chemically attached differing amounts and differing lengths of short (11 kDa) and longer (22 kDa) chain colominic acid molecules to the antitumor monoclonal antibody H17E2 Fab fragment. Different coupling ratios and lengths were seen to alter the electrophoretic mobility of the Fab fragment but have a minor effect on the antibody immunoreactivity toward the placental alkaline phosphatase (PLAP) antigen. Polysialylation generally increased Fab fragment blood half-life resulting in higher tumor uptake in a KB human tumor xenograft mouse model. One H17E2 Fab-PSA conjugate had over a 5-fold increase in blood exposure and over a 3-fold higher tumor uptake with only a marginal decrease in tumor/blood selectivity ratio compared to the unconjugated Fab. This conjugate also had a blood bioavailability approaching that of a whole immunoglobulin.

PEGylation: Posttranslational bioengineering of protein biotherapeutics

Polymer conjugation, especially by poly(ethylene glycol), has become a leading technology for the delivery of proteins. Nowadays, biotech drugs represent an increasing share of the new approved drugs, but their use is often prevented by drawbacks and safety concern. In particular, short in vivo half-life and immunogenicity are significant problems faced by the researchers dealing with the development of protein and peptide drugs. The chemical linking of a polymer to the protein surface has proved effective in prolonging protein blood circulation and reducing the immunogenicity by decreasing renal clearance and shielding immunogenic epitopes, respectively. So far, PEGylation has already led to nine marketed conjugates with great therapeutic success.:

Polyurethane elastomer biostability

Polyurethanes have unique mechanical and biologic properties that make them ideal for many implantable devices. They are subject to some in vivo degradation mechanisms, however. Polyester polyurethanes are subject to hydrolytic degradation and are no longer used in long-term implanted devices. Polyether polyurethanes, while hydrolytically stable, are subject to oxidative degradation in several forms, including environmental stress cracking and metal ion oxidation. Mineralization is also known to occur. A new polycarbonate polyurethane has superior biostability in early in vivo qualification tests compared to the polyether polyurethanes, including no evidence of hydrolysis, ESC or MIO.