Unequal Behaviour between Hydrolysable Functions of Nirmatrelvir under Stress Conditions: Structural and Theoretical Approaches in Support of Preformulation Studies.

Nirmatrelvir is an antiviral drug approved for the treatment of COVID-19. The available dosage form consists of tablets marketed under the brand name PAXLOVID®. Although knowledge of nirmatrelvir's intrinsic stability may be useful for any potential development of other pharmaceutical forms, no data regarding this matter is available to date. Preliminary forced degradation studies have shown that the molecule is stable under oxidative and photolytic conditions, while hydrolytic conditions, both acidic and basic, have proven deleterious. Indeed, the molecule presents a priori several functions that can undergo hydrolysis, i.e., three amide moieties and a nitrile function. However, considering the degradation products formed under forced conditions and which were detected and identified by LC-UV-HRMSn, the hydrolysis process leading to their formation is selective since it involved only 2 of the 4 hydrolysable functions of the molecule. Ab initio studies based on density functional theory (DFT) have helped better understand these reactivity differences in aqueous media. Some hydrolyzable functions of nirmatrelvir differ from others in terms of electrostatic potential and Fukui functions, and this seems to correlate with the forced degradation outcomes.

Therapeutic Treatment Plan Optimization during the COVID-19 Pandemic: A Comprehensive Physicochemical Compatibility Study of Intensive Care Units Selected Drugs.

BACKGROUND: The SARS-CoV-2 pandemic has resulted in a dramatic rise of the demand for medical devices and drugs. In this context, an important shortage of programmable syringe pumps, used to administrate different drugs in intensive care units, was seen. The opportunity of administrating combinations of five intensive care units selected drugs (Sufentanil, Clonidine, Loxapine, Midazolam, and Ketamine) was considered. METHODS: The drug mixtures were studied in a pure form or diluted in NaCl 0.9% or G5%. Twenty-six possible combinations of the five drugs were produced in glass vials or polypropylene syringes and stored at 25 °C for 14 days. The LC method was implemented to study drugs combinations in the presence of the degradation products. The clearness and pH were also monitored. RESULTS: All the 26 possible combinations displayed adequate physicochemical stability at 25 °C: at least 3 days and 7 days, respectively, for the dilution in 0.9% NaCl or glucose 5%, and the pure drug products mixtures. CONCLUSIONS: The study provided sufficient stability results, covering the medication administration period of at least three days. The combination of more than two drugs offers the advantage of minimizing the individual doses and reduces unwanted side-effects. Hence, this study opens up the possibility of combining the five drugs in one single syringe, which is useful especially under the current circumstances associated with an important shortage of programmable syringe pumps and pharmaceuticals.

Simple Approach to Enhance Green Tea Epigallocatechin Gallate Stability in Aqueous Solutions and Bioavailability: Experimental and Theoretical Characterizations.

Because of its antioxidant, antimutagenic, and anti-infectious properties, epigallocatechin gallate (EGCG) is the most interesting compound among the green tea catechins polyphenols. However, its health effects are inconclusive due to its very low bioavailability, largely due to a particular instability that does not allow EGCG to reach the potency required for clinical developments. Over the last decade, many efforts have been made to improve the stability and bioavailability of EGCG using complex delivery systems such as nanotechnology, but these efforts have not been successful and easy to translate to industrial use. To meet the needs of a large-scale clinical trial requiring EGCG in a concentrated solution to anticipate swallowing impairments, we developed an EGCG-based aqueous solution in the simplest way while trying to circumvent EGCG instability. The solution was thoroughly characterized to sort out the unexpected stability outcome by combining experimental (HPLC-UV-mass spectrometry and infrared spectroscopy) and computational (density functional theory) studies. Against all odds, the EGCG-sucrose complex under certain conditions may have prevented EGCG from degradation in aqueous media. Indeed, in agreement with the ICH guidelines, the formulated solution was shown to be stable up to at least 24 months under 2-8 °C and at ambient temperature. Furthermore, considerable improvement in bioavailability in rats, against EGCG powder formulated in hard-gel capsules, was shown after gavage. Thus, the proposed formulation may provide an easily implementable platform to administer EGCG in the context of clinical development.

Ruxolitinib photodegradation mechanisms by theoretical and experimental chemistry.

Ruxolitinib is a Janus Kinase inhibitor currently approved for the treatment of myelofibrosis. It is also a promising drug for the treatment of skin and infectious diseases. In terms of pharmaceutical stability, although ruxolitinib has been established as being sensitive to light, no data on photodegradation processes are available to date, while these may be useful for quality risk management and any potential development of other pharmaceutical forms for other routes of administration. One way to partially fill this gap was to carry out a study that combines a consistent determination of the most sensitive sites of the molecule to photolysis through theoretical calculations based on functional density, with the identification of the main photodegradation products obtained after forced degradation. This integrated approach has shown converging results describing the mechanisms based on photo-oxidation that can lead to the opening of the pyrrole ring. Having access to the structure of the degradation products and intermediates then made it possible to carry out an in silico evaluation of their potential mutagenicity and it appears that some of them feature alert structures.

Intrinsic stability of the antiviral drug umifenovir by stress testing and DFT studies.

Umifenovir is an antiviral drug approved in China and Russia for the treatment of influenza. The available dosage form consists of capsules marketed under the brand name Arbidol®. Due to its broad spectrum, umifenovir may also be used in other viral contexts, alone or combined with other antiviral drugs. Although knowledge of umifenovir intrinsic stability may be useful for any potential development of other pharmaceutical forms for other routes of administration and for quality risk management, no data regarding this matter is available to date. In this study, the exploration of the molecule's behaviour under hydrolytic, oxidative and photolytic conditions was carried out experimentally and supported by density functional theory (DFT) studies. It comes out that umifenovir is sensitive to these stress conditions giving rise to 6 structurally characterized degradation products. The one-electron oxidation process produced on the sulphur atom is probably the main cause of umifenovir degradation with reference to the structures of the degradation products formed and the DFT data.

Management of diabetic foot ulcers: a 25% lidocaine topical cream formulation design, physicochemical and microbiological assessments.

Background: Given the importance of surgical debridement in healing of diabetic foot ulcers, effective local anaesthesia is required to manage the related extreme pain. The pharmaceutical proprietary products currently available have low concentrations and do not exceed 5% w/w local anaesthetic. Objective: Formulation design of a lidocaine cream of 25% and assessment of the intrinsic stability. Methods: A cream pharmaceutical form was chosen for its ability to cross the skin barrier and effectively anaesthetise the skin. The choice of cream formula is based on changes in the size of the emulsions and resistance to physical stress. Stability tests were assessed over a 6-month period in terms of physical (evaluation of oil droplets), microbiological (germ count and identification, and preservative antimicrobial efficacy) and chemical parameters (content and pH). Results: Under the study conditions, the drug product displayed good physicochemical and microbiological stability for 6 months at 20°C and 40°C, and no degradation product was detected. Due to the systemic adverse effects of lidocaine, the pH stability guarantee the drug product tolerance along with very weak systemic passage. Conclusions: Given the good physicochemical and microbiological stability of the drug product over 6-month period, it has been made available to the clinical unit. An average of 250 patients per year benefit from the treatment with an excellent efficacy/tolerability ratio.

Physical and chemical stability of a generic etoposide formulation as an alternative to etoposide phosphate.

The generic Mylan® etoposide (ETP) has been investigated as an alternative for Etopophos®, in part due to a global shortage of the latter. The generic alternative is different both in its formulation and in its very limited stability (6 h at 25 °C against 4 days for Etopophos®) once reconstituted in ready-to-use chloride or glucose solutions. Its intrinsic stability has been thoroughly studied under various conditions. Two degradation products resulting from hydrolysis were characterized by LC-HR-MSn and supported by density functional theory calculations of the frontier molecular orbitals energies, molecular electrostatic potential mapping, and Mulliken charge analysis. Chemical degradation increases with temperature and can be fitted to a zero order kinetic model with a half-life of 119 days and a kinetic constant of 0.0028 mM day-1. Precipitation was only observed in solutions at 5 °C and -20 °C indicating that at these temperatures the reconstituted solutions are thermodynamically metastable. In conclusion, ETP at concentrations of 0.68 and 1 mM prepared and stored at 25 °C under good manufacturing practices remained unchanged over a period of 21 days irrespective of the nature of the solvents or the type of container.

Pemetrexed degradation by photocatalytic process: Kinetics, identification of transformation products and estimation of toxicity.

This study employed a UV-A/visible/TiO2 system to investigate the degradation of pemetrexed, an antifolate agent used in chemotherapy. The laboratory-scale method employed a photostability chamber that could be used to study multiple samples. Reversed-phase HPLC coupled with high-resolution ESI-LTQ-Orbitrap mass spectrometry was used to determine the transformation products (TPs) of PEME. Based on the identified TPs and existing chemical knowledge, the mechanism of degradation of the target compound was proposed. Concentrations were monitored as a function of time, and the degradation kinetics were compared. The structures of seven TPs, four of which have not been described to date, were proposed. Most of the TPs stemmed from OH radical additions to the dihydropyrrole moiety and oxidative decarboxylation of the glutamate residue. Based on the elucidated structures, a computational toxicity assessment was performed, showing that the TPs with higher log D values than the parent compound are more toxic than the PEME itself. To support these findings, the toxicities of irradiated samples on Vibrio fischeri were monitored over time. The experimental results corresponded well with the results of previous computational studies.

Investigating therapeutic usage of combined Ticagrelor and Aspirin through solid-state and analytical studies.

The mainstay treatment for patients with acute coronary syndrome is an oral route dual antiplatelet therapy with a P2Y12-receptor antagonist and Aspirin (ASA). To improve patient adherence to such treatments, combination therapies (polypill) are envisioned. Physicochemical solid-state studies have been carried out to develop a preformulation strategy of ASA with the P2Y12-receptor antagonist Ticagrelor (TIC). The investigations were carried out using differential scanning calorimetry, liquid chromatography-high resolution-multistage mass spectrometry (LC-HR-MSn) and as complementary techniques Fourier transform infrared measurements and thermogravimetric analysis. A simple eutectic transition at 98°C with a mole fraction for the eutectic liquid of 0.457 has been observed and the mixing of ASA and TIC molecules in each other's crystal structures appears to be limited. No cocrystals of TIC and ASA have been found. The appearance of the eutectic liquid was linked with a clear onset of chemical instability of the two pharmaceuticals. The decomposition mechanism in the liquid phase involves prior decomposition of ASA, whose residues react with well-identified TIC interaction sites. Seven interaction products were observed by LC-HR-MSn linked to corresponding degradation products. The most important degradation pathway is N-dealkylation. In conclusion, polypills of ASA and TIC are a viable approach, but the decomposition of ASA should be avoided by eliminating high temperatures and high humidity.

Identification of the major degradation pathways of ticagrelor.

Ticagrelor is a direct-acting and reversible P2Y12-adenosine diphosphate (ADP) receptor blocker used as antiplatelet drug. Forced degradation under various stress conditions was carried out. The degradation products have been detected and identified by high-pressure liquid chromatography multistage mass spectrometry (LC-MS(n)) along with high-resolution mass spectrometry. C18 XTerra MS column combined with a linear gradient mobile phase composed of a mixture of 10 mM acetate ammonium/acetonitrile was shown suitable for drug and impurity determinations and validated as a stability indicating method. Structural elucidation of the degradation products relied on MS(n) studies and accurate mass measurements giving access to elemental compositions. Up to nine degradation products resulting from oxidation/auto-oxidation, S-dealkylation and N-dealkylation have been identified, covering a range of possible degradation pathways for derivatives with such functional groups. Kinetics was also studied in order to assess the molecule's shelf-life and to identify the most important degradation factors.

Effectiveness of cleaning of workplace cytotoxic surface.

PURPOSE: To minimize the risk of chronic occupational exposure of antineoplastic drugs, cleaning procedures must be evaluated. This study was conducted to compare the detergent efficiency of cleaning solutions (two hydro-alcoholic solutions, three disinfectants and two detergents) used in different cleaning protocols. METHODS: The central surface of a stainless steel plate (30 × 50 cm) was exposed to a carboplatin solution equivalent to 105,100 ng of platinum. After cleaning according to a standardized protocol, residual platinum contaminations were assayed on 10 × 10 cm sections. RESULTS: After standardized cleaning, the residual quantity of platinum on the surface of the deposit accounted for between 1.0 and >15 % of the initial deposit. Spread of contamination on the plate depended on the cleaning movement and was between 2.1 and 53.9 % of the total quantity on the plate. The two detergents were more efficient (2,793-4,780 ng/plate) than hydro-alcoholic solutions (>20,000 ng/plate). The efficacy of the disinfectant was intermediate (5,891-6,122 ng/plate for solutions and 15,360 ng/plate for pre-soaked gauze). The cleaning protocol was also important with better efficiency of 8 mL of cleaning solution for 1,500 cm(2) (versus 4 mL), sprayed directly on the plate (versus wiping) with no contact time (versus 5 min). CONCLUSION: The efficacy of chemical decontamination of cytotoxic work surfaces depends not only on the cleaning solution used, but also on the cleaning protocol. It is necessary to adapt the protocol to the surface to clean and it must be standardized and validated. This work is an example of an experimental procedure to evaluate the efficacy of cleaning solutions and protocols used at a workstation after exposure to antineoplastic drugs.

Identification of roles for peptide: N-glycanase and endo-beta-N-acetylglucosaminidase (Engase1p) during protein N-glycosylation in human HepG2 cells.

BACKGROUND: During mammalian protein N-glycosylation, 20% of all dolichol-linked oligosaccharides (LLO) appear as free oligosaccharides (fOS) bearing the di-N-acetylchitobiose (fOSGN2), or a single N-acetylglucosamine (fOSGN), moiety at their reducing termini. After sequential trimming by cytosolic endo beta-N-acetylglucosaminidase (ENGase) and Man2c1 mannosidase, cytosolic fOS are transported into lysosomes. Why mammalian cells generate such large quantities of fOS remains unexplored, but fOSGN2 could be liberated from LLO by oligosaccharyltransferase, or from glycoproteins by NGLY1-encoded Peptide-N-Glycanase (PNGase). Also, in addition to converting fOSGN2 to fOSGN, the ENGASE-encoded cytosolic ENGase of poorly defined function could potentially deglycosylate glycoproteins. Here, the roles of Ngly1p and Engase1p during fOS metabolism were investigated in HepG2 cells. METHODS/PRINCIPAL FINDINGS: During metabolic radiolabeling and chase incubations, RNAi-mediated Engase1p down regulation delays fOSGN2-to-fOSGN conversion, and it is shown that Engase1p and Man2c1p are necessary for efficient clearance of cytosolic fOS into lysosomes. Saccharomyces cerevisiae does not possess ENGase activity and expression of human Engase1p in the png1Delta deletion mutant, in which fOS are reduced by over 98%, partially restored fOS generation. In metabolically radiolabeled HepG2 cells evidence was obtained for a small but significant Engase1p-mediated generation of fOS in 1 h chase but not 30 min pulse incubations. Ngly1p down regulation revealed an Ngly1p-independent fOSGN2 pool comprising mainly Man(8)GlcNAc(2), corresponding to approximately 70% of total fOS, and an Ngly1p-dependent fOSGN2 pool enriched in Glc(1)Man(9)GlcNAc(2) and Man(9)GlcNAc(2) that corresponds to approximately 30% of total fOS. CONCLUSIONS/SIGNIFICANCE: As the generation of the bulk of fOS is unaffected by co-down regulation of Ngly1p and Engase1p, alternative quantitatively important mechanisms must underlie the liberation of these fOS from either LLO or glycoproteins during protein N-glycosylation. The fully mannosylated structures that occur in the Ngly1p-dependent fOSGN2 pool indicate an ERAD process that does not require N-glycan trimming.