Ubiquitin Signaling and Degradation of Aggregate-Prone Proteins.

Mutant protein aggregation and misfolding is often correlated with toxicity in neurodegenerative diseases. Aggregate-prone proteins are tagged by ubiquitin that signals them for destruction by the proteasome or autophagy, two key pathways for protein degradation and proteostasis. Here, we review recent studies showing that the regulation of aggregate-prone proteins by ubiquitin signaling is more complex than initially postulated. We discuss how the ubiquitin code of aggregate-prone proteins is written by specific E3 ubiquitin ligases and edited by deubiquitylating enzymes (DUBs) in cells and in brain tissues, as well as how this affects protein degradation. These studies have advanced our understanding of the specificity of the ubiquitin system and provide new information about its relevance to neurodegenerative diseases and therapy.

Application of co-processed excipients for developing fast disintegrating tablets: A review.

The introduction of tablet dosage forms has brought a revolution in the pharmaceutical drug delivery system. Different forms of tablets have been developed based on the target site, the onset of action, and therapeutic drug delivery methods. Fast-disintegrating tablets (FDTs) are the most promising pharmaceutical dosage form, especially for pediatric and geriatric patients having difficulty swallowing. The key feature of FDTs is quick drug release soon after their administration through the oral cavity. With innovations in the formulation of FDTs, the demand for excipients with better functionalities, particularly in terms of flow and compression characteristics, has increased. Co-processed excipients are a mixture of 2 or more conventional excipients that provides significant benefits over the individual excipients while minimizing their shortcomings. Such multifunctional co-processed excipients minimize the number of excipients that are to be incorporated into tablets during the manufacturing process. The present review discusses FTDs formulated from co-processed excipients, their manufacturing techniques, and the latest research, patents and commercially available co-processed FDTs.

Co-processed tablet excipient composition, its preparation and use: US10071059 B2: patent spotlight.

Co-processing involves the incorporation of one excipients into the particle structure of other excipients to overcome the deficiencies of each excipients. The current patent describes the co-processing of microcrystalline cellulose and mannitol via fluid bed agglomeration with an aim to limit the use of lubricant in tablet composition. The co-processed excipients blend was compared with the physical blend of excipients and characterized for scanning electron microscopy, disintegration and hardness. The average particle size of co-processed excipients was less than 0.55 mm, characterized by large individual lactose-coated particles whereas, the physical blend particles are uncoated and irregular in shape. Tablets made from both physical blend and co-processed excipients were compared. As per the hardness and disintegration studies, with increase in mixing time of excipients both hardness and disintegration time decreases.

Multicomponent crystal compromising dasatinib and selected co-crystals formers: a patent evaluation of EP2861589B1.

Cocrystallization has gained significant prominence in pharmaceutical product development because of the enhancement of physical, chemical and pharmacological properties of active pharmaceutical ingredients, such as stability, solubility, dissolution rate, taste, hygroscopicity, mechanical property, bioavailability, permeability and therapeutic activity. Traditionally, co-crystals can be prepared by a grinding, solvent evaporation and slurry method. However, sophisticated methods such as spa drying, hot-melt extrusion, supercritical fluid and laser irradiation are also reported to be used for producing co-crystals. The selected patent describes the development of multicomponent crystals of dasatinib, with an aim to enhance the aqueous solubility of a selected drug. However issues surrounding the toxicity, stability, large scale manufacture, in vivo performance in human beings and regulations require adequate addressal prior to exploring the commercial viability of pharmaceutical co-crystals.

Oxaliplatin-flavone pharmaceutical co-crystal-CN111205332A: patent spotlight.

Co-crystallization is a technique for modifying physicochemical properties of pharmaceutical ingredients with an aim to enhance the therapeutic efficacy and subsequent reduction in toxicity. The patent describes the development of oxaliplatin co-crystals using flavonoids (baicalein and naringenin) via solvent volatilization technique with an objective to improve solubility and stability in GI tract and reduced side/toxic effects. The co-crystals were characterized via differential scanning calorimetry, thermogravimetric analysis, x-ray diffraction analysis. The co-crystals exhibited slow drug release, delayed hydrolysis, low cytotoxicity and enhanced therapeutic activity on human gastric adenocarcinoma cells. However, suitable solvent for co-crystal production, large scale production and regulatory challenges for continuous manufacturing of co-crystals must be addressed.

Advancements in Rectal Drug Delivery Systems: Clinical Trials, and Patents Perspective.

The rectal route is an effective route for the local and systemic delivery of active pharmaceutical ingredients. The environment of the rectum is relatively constant with low enzymatic activity and is favorable for drugs having poor oral absorption, extensive first-pass metabolism, gastric irritation, stability issues in the gastric environment, localized activity, and for drugs that cannot be administered by other routes. The present review addresses the rectal physiology, rectal diseases, and pharmaceutical factors influencing rectal delivery of drugs and discusses different rectal drug delivery systems including suppositories, suspensions, microspheres, nanoparticles, liposomes, tablets, and hydrogels. Clinical trials on various rectal drug delivery systems are presented in tabular form. Applications of different novel drug delivery carriers viz. nanoparticles, liposomes, solid lipid nanoparticles, microspheres, transferosomes, nano-niosomes, and nanomicelles have been discussed and demonstrated for their potential use in rectal administration. Various opportunities and challenges for rectal delivery including recent advancements and patented formulations for rectal drug delivery have also been included.

UGT1A1 gene polymorphisms in North Indian neonates presenting with unconjugated hyperbilirubinemia.

Genetic factors are implicated in pathogenesis of neonatal hyperbilirubinemia. In this nested case-control study, we determined 1) frequency of thymine-adenine (TA)n promoter polymorphism and Gly71Arg mutation in uridine diphosphoglucuronate-glucuronosyltransferase 1A1 (UGT1A1) gene in neonates > or =35-wk gestation presenting with bilirubin levels > or =18 mg/dL and controls, 2) interaction among (TA)n promoter polymorphism, glucose-6-phosphate dehydrogenase (G6PD) gene mutations, and peak bilirubin. The number of TA repeats was assessed by PCR-single-strand conformation polymorphism (SSCP) analysis and Gly71Arg mutation by PCR-RFLP. Fifty samples of both mutations were verified with DNA sequencing. One hundred twenty-seven neonates were enrolled (77 hyperbilirubinemics, 50 controls). The incidence of (TA)n polymorphism was higher in babies with hyperbilirubinemia [89.6% vs. 50%, OR 8.63 (95% CI, 3.2-24.1)]. Gly71Arg mutation was not found either in hyperbilirubinemics or controls. A novel polymorphism (Ala72Pro) at codon position 72 of exon 1 was detected in all 50 samples (21 hyperbilirubinemics, 29 controls), which were sequenced. Presence of variant (TA)n promoter (adjusted OR, 10.6; 95% CI, 3.3-34.2), G6PD deficiency (adjusted OR, 20.6; 95% CI, 3.6-117.3), and history of jaundice in sibling requiring phototherapy (adjusted OR, 12.6; 95% CI, 1.1-141.6) were independent risk factors for bilirubin levels > or =18 mg/dL.

E. coli-Based Selection and Expression Systems for Discovery, Characterization, and Purification of Ubiquitylated Proteins.

Ubiquitylation is an eukaryotic signal that regulates most cellular pathways. However, four major hurdles pose challenges to study ubiquitylation: (1) high redundancy between ubiquitin (Ub) cascades, (2) ubiquitylation is tightly regulated in the cell, (3) the transient nature of the Ub signal, and (4) difficulties to purify functional ubiquitylation apparatus for in vitro assay. Here, we present systems that express functional Ub cascades in E. coli, which lacks deubiquitylases, Ub-dependent degradations, and control mechanisms for ubiquitylation. Therefore, expression of an ubiquitylation cascade results in the accumulation of stable ubiquitylated protein that can be genetically selected or purified, thus circumventing the above challenges. Co-expression of split antibiotic resistance protein fragments tethered to Ub and ubiquitylation targets along with ubiquitylation enzymes (E1, E2, and E3) gives rise to bacterial growth on selective media. We show that ubiquitylation rate is highly correlated with growth efficiency. Hence, genetic libraries and simple manipulations in the selection system facilitate the identification and characterization of components and interfaces along Ub cascades. The bacterial expression system also facilitates the detection of ubiquitylated proteins. Furthermore, the expression system allows affinity chromatography-based purification of milligram quantities of ubiquitylated proteins for downstream biochemical, biophysical, and structural studies.

p53 codon 72 polymorphism and its overexpression in patients with laryngeal carcinoma: Prognostic implications.

Abnormalities in the p53 gene are the most common genetic alterations seen in laryngeal carcinoma. No data exist regarding the association between laryngeal carcinoma and a distinct codon 72 variant and its expression. We conducted a prospective study (1) to analyze the p53 codon 72 polymorphic variants in patients with laryngeal carcinoma, (2) to analyze the expression of p53 mRNA in tissues of patients with laryngeal carcinoma using the reverse transcriptase-polymerase chain reaction (RT-PCR) assay, and (3) to detect p53 antibodies in the plasma of patients with laryngeal carcinoma before and after treatment. Tissue and blood samples were taken from 40 patients with laryngeal carcinoma-36 men and 4 women, aged 40 to 65 years (mean: 56)-and 20 age-matched controls with laryngeal conditions other than carcinoma. RT-PCR was used to measure p53 mRNA expression, and PCR-restriction fragment length polymorphism was used to determine p53 polymorphism. In addition, p53 antibodies were detected in plasma by Western blot testing. The 40 patients were treated with either surgery (total laryngectomy or conservation surgery) or radiotherapy. Tissue and blood samples were analyzed before treatment and 4 weeks after treatment. The findings were compared with those of the 20 controls. The results revealed that (1) homozygosity of the Pro72 variant of p53 was present in 26 laryngeal carcinoma patients (65%), (2) heterozygosity for the Pro/Arg genotype was present in 13 patients (32.5%), and (3) the Arg72 variant of the p53 allele was present in 1 patient (2.5%) before treatment. Overexpression of p53 mRNA was found in all patients with laryngeal carcinoma and in none of the controls before treatment; the difference was approximately 3.3 folds higher in the carcinoma group. However, p53 expression was not related to the biologic aggressiveness of these tumors. It is interesting that 4 weeks after definitive therapy, the expression levels of p53 mRNA in the 40 patients were comparable to those of the controls. The p53 antibodies were detected in the plasma of all patients with laryngeal carcinoma prior to definitive therapy and in none of them afterward, indicating that these antibodies represent a prognostic marker in laryngeal carcinoma. Our findings suggest that there is a correlation between p53 overexpression and the development of laryngeal carcinoma. Anti-p53 antibodies can be used as a prognostic marker in laryngeal carcinoma, and they can be exploited in the future to control the response to therapy and to monitor for certain early recurrences before they become clinically detectable.