Search

Biodegradable polyesters are widely employed in the development of controlled release systems for peptide drugs. However, one of the challenges in developing a polyester-based delivery system for peptides is the acylation reaction between peptides and polymers. Peptide acylation is an important factor that affects formulation stability and can occur during storage, in vitro release, and after drug administration. This review focuses on the mechanisms and parameters that influence the rate of peptide acylation within polyesters. Furthermore, it discusses reported strategies to minimize the acylation reaction. [ABSTRACT FROM AUTHOR]

Acylation of peptides is a well-known but unwanted phenomenon in polyester matrices such as poly( d , l -lactic- co -glycolic acid) (PLGA) microspheres used as controlled release formulations. Acylation normally occurs on lysine residues and the N-terminus of the peptide. The purpose of the present work was to assess other possible acylation sites on peptides. Goserelin was used as a model peptide that lacks lysine and a free N-terminus, but contains other nucleophilic residues, i.e. serine, tyrosine and arginine, which potentially can be acylated. Goserelin loaded PLGA microspheres were prepared by a double emulsion solvent evaporation technique. Liquid chromatography ion-trap mass spectrometry (LC-ITMS) was used for determining and monitoring acylation of released goserelin. It is demonstrated that arginine is subjected to acylation with glycolic acid and lactic acid units of PLGA, which was followed by loss of NH 3 from the guanidine group to obtain 2-oxazolin-4-one and 5-methyl-2-oxazolin-4-one residues with masses that are 41 and 55 Da higher, respectively, than the native goserelin. There was no evidence for acylation of serine and tyrosine in goserelin. Our results demonstrate that beside lysine also acylation of arginine can occur in peptides and proteins that are loaded and released from PLGA matrixes. [ABSTRACT FROM AUTHOR]

Purpose: Polyesters with hydrophilic domains, i.e., poly( d,l-lactic- co-glycolic- co-hydroxymethyl glycolic acid) (PLGHMGA) and a multiblock copolymer of poly(ε-caprolactone)-PEG-poly(ε-caprolactone) and poly( l-lactide) ((PC-PEG-PC)-(PL)) are expected to cause less acylation of encapsulated peptides than fully hydrophobic matrices. Our purpose is to assess the extent and sites of acylation of octreotide loaded in microspheres using tandem mass spectrometry analysis. Methods: Octreotide loaded microspheres were prepared by a double emulsion solvent evaporation technique. Release profiles of octreotide from hydrophilic microspheres were compared with that of PLGA microspheres. To scrutinize the structural information and localize the actual modification site(s) of octreotide, liquid chromatography ion-trap mass spectrometry (LC-ITMS) was performed on the acylated adducts. Results: Hydrophilic microspheres showed less acylated adducts in comparison with PLGA microspheres. LC-MS/MS showed that besides the N-terminus and primary amine of lysine, the primary hydroxyl of the end group of octreotide was also subjected to acylation. Nucleophilic attack of the peptide can also occur to the carbamate bond presented in (PC-PEG-PC)-(PL) since 1,4-butanediisocyanate was used as the chain extender. Conclusions: Hydrophilic polyesters are promising systems for controlled release of peptide because substantially less acylation occurs in microspheres based on these polymers. LC-ITMS provided detailed structural information of octreotide modifications via mass analysis of ion fragments. [ABSTRACT FROM AUTHOR]

The drug Liraglutide is an acylated analogue of glucagon-like peptide-1 (GLP-1) which is indicated for the treatment of type 2 diabetes mellitus and chronic obesity. Stability testing of biopharmaceuticals is an essential part of their quality control, aimed at revealing possible degradation pathways and identification of potential degradation products. Up to now, no information on the Liraglutide behaviour in formulation medium under stress conditions has been provided. In the present study, the original innovator and an analogue product of Liraglutide were subjected to stress by exposing to various temperature, pH and oxidation conditions to generate possible degradation products and aggregation. Liquid chromatography-mass spectrometry was used to determine impurity profiles and identify degradation products of stressed drug samples from different suppliers. Results showed that Liraglutide products exhibit high stability at room temperature. Exposure to high pH resulted in the formation of aggregates and chemical modifications, including oxidation, while exposure to low pH caused peptide precipitation. Liraglutide formulations showed slight susceptibility to oxidation on tryptophan residue. Overall, no significant differences were observed between the originator and the analogue of Liraglutide. Both exhibited similar behaviour in their impurity profiles during forced degradation. The approach used in this study offers potential benefits for industrial purposes in formulation development and product characterization. [ABSTRACT FROM AUTHOR]

[Display omitted] Due to the lack of pharmacopeia guidelines for injectable microspheres based on poly (D, L-lactide-co-glycolide) (PLGA), an internal method validation is a critical prerequisite for quality assurance. One of the essential issues of developing peptide-based drugs loaded PLGA microspheres is the precise determination of the amount of peptide drug entrapped in the microspheres. The aim of this study is the development and optimization of a method for measuring the drug content loading of PLGA microspheres using exenatide as a model peptide drug. Exenatide-loaded PLGA microspheres were prepared by a double emulsion solvent evaporation method. The extraction method to determine exenatide content in microspheres was optimized using Design of Experiments (DoE) approach. After the initial screening of six factors, using Fractional Factorial design (FFD), four of them, including type of organic solvent, buffer/organic solvent ratio (v/v), shaking time and pH, exhibited significant effects on the response, namely the exenatide loading, and a Box-Behnken design (BBD) was subsequently applied to obtain its optimum level. The optimum level for organic solvent volume, buffer/organic solvent ratio, shaking time, and pH were 4 ml, 1, 5.6 hrs, and pH 6, respectively. The exenatide content in microspheres under these conditions was 6.4 ± 0.0 (%w/w), whereas a value of 6.1% was predicted by the derived equation. This excellent agreement between the actual and the predicted value demonstrates that the fitted model can thus be used to determine the exenatide content. [ABSTRACT FROM AUTHOR]

There are many benefits to drug delivery from drug–carrier nanostructure systems. It might be developed to carefully control drug release rates or to deliver a precise amount of a therapeutic substance to particular body areas. Self-assembling is the process by which molecules and nanoparticles spontaneously organize into organized clusters. For instance, proteins and peptides can interact with one another to create highly organized supramolecular structures with various properties, such as helical ribbons and fibrous scaffolds. Another advantage of self-assembly is that it may be effective with a variety of materials, including metals, oxides, inorganic salts, polymers, semiconductors, and even organic semiconductors. Fullerene, graphene, and carbon nanotubes (CNTs), three of the most fundamental classes of three-dimensionally self-assembling nanostructured carbon-based materials, are essential for the development of modern nanotechnologies. Self-assembled nanomaterials are used in a variety of fields, including nanotechnology, imaging, and biosensors. This review study begins with a summary of various major 3D nanomaterials, including graphene oxide, CNTs, and nanodiamond, as well as 3D self-assembled polyfunctionalized nanostructures and adaptable nanocarriers for drug delivery. [ABSTRACT FROM AUTHOR]

[Display omitted] • BPL is a common chemical inactivating reagent used in vaccines. • Via BPL carcinogenicity, its residual should be hydrolyzed completely in vaccines to avoid cytotoxicity. • BPL residual determination in vaccines is challenging due to its low concentration, presence in a complex mixture of vaccine and lack of suitable chromophore. • BPL derivatization with RBH was used to enhance analytical sensitivity and stabilize the BPL molecule for measurement with HPLC-UV. β-propiolactone (BPL) is an alkylating agent used for inactivation of biological samples such as vaccines. Due to its known carcinogenic properties, complete hydrolysis of BPL is essential, and the detection of trace amounts is crucial. In this study a novel High-Performance Liquid Chromatography-Ultraviolet (HPLC-UV) method was developed. Rhodamine B hydrazide (RBH) was synthesized and utilized as a derivatizing reagent to react with BPL. The reaction was optimized in a weak acidic solution, resulting in a high yield. The separation of the RBH-derivatized BPL was achieved on a C8 column and detected by a UV detector at a wavelength of 560 nm. The method's validation demonstrated a high linearity (r2 > 0.99) over a concentration range of 0.5–50 µg/mL, with detection and quantification limits of 0.17 µg/mL and 0.5 µg/mL, respectively. The average recovery of samples was 85.20 % with a relative standard deviation (RSD) of 1.75 %. This method was successfully applied for BPL residue analysis in inactivated COVID-19 vaccines. This novel derivatization method offers a promising solution for monitoring BPL residues in the vaccine production process for quality control purposes and compliance with regulatory standards. [ABSTRACT FROM AUTHOR]

The current article is focused on introduction and validation of electro‐membrane extraction along with a high‐performance liquid chromatography combined with UV detector for the identification of the antiepileptic drugs phenytoin (PT) and phenobarbital (PB) in plasma, saliva, and urine. In addition, 3D‐printing was utilized to fabricate the designed caps required for fixing the electrodes in the prepared setup, giving us a high potential in device fabrication with various dimensions. To arrive at the highest extraction of PB and PT, the parameters impacting the extraction efficiency of electromembrane extraction for example, supported liquid membrane composition, sample solution pH, applied voltage, extraction time along with effect of graphene oxide are examined in detail. In optimized experimental conditions, the calibration plots were obtained to be linear on the concentration range of 25–500 ng/L with the detection limit and quantitation limit of 7.5 and 25 ng/L for both of PB and PT. Relative standard deviations of <9.9% and <9.1% were found for PB and PT, respectively and the enrichment factor for the presented method was computed to be 25.4 and 44.7 for PB and PT, respectively. The proposed method was satisfactorily employed in determination of PB and PT in plasma, urine and saliva. [ABSTRACT FROM AUTHOR]