Design of cellulose ether-based macromolecular prodrugs of ciprofloxacin for extended release and enhanced bioavailability

Recent trends in bioresponsive linker technologies of Prodrug-Based Self-Assembling nanomaterials

Prodrugs are designed to improve pharmaceutical properties of potent compounds and represent a central approach in drug development. The success of the prodrug strategy relies on incorporation of a reversible linkage facilitating controlled release of the parent drug. While prodrug approaches enhance pharmacokinetic properties over their parent drug, they still face challenges in absorption, distribution, metabolism, elimination, and toxicity (ADMET). Conjugating a drug to a carrier molecule such as a polymer can create an amphiphile that self-assembles into nanoparticles. These nanoparticles display prolonged blood circulation and passive targeting ability. Furthermore, the drug release can be tailored using a variety of linkers between the parent drug and the carrier molecule. In this review, we introduce the concept of self-assembling prodrugs and summarize different approaches for controlling the drug release with a focus on the linker technology. We also summarize recent clinical trials, discuss the emerging challenges, and provide our perspective on the utility and future potential of this technology.

Selective Oxidation of 2-Hydroxypropyl Ethers of Cellulose and Dextran: Simple and Efficient Introduction of Versatile Ketone Groups to Polysaccharides

Oxidation of polysaccharides has been a useful approach to new materials. However, selectivity in oxidation of polysaccharide macromolecular polyols remains a significant challenge with few methods for the synthesis of ketone-substituted polysaccharides. We report here a selective, practical, and efficient process, beginning with 2-hydroxypropyl ethers of polysaccharides that are simple and economical to prepare. We demonstrate this approach herein using commercial 2-hydroxypropyl cellulose (HPC) and 2-hydroxypropyl dextran (HPD) that we prepared. We oxidize the terminal, secondary alcohols of the oligo(2-hydroxypropyl) substituents with sodium hypochlorite so that the product has an oligo(2-hydroxypropyl) side chains terminated by a ketone. We demonstrate the high chemo- and regioselectivity of this oxidation by analytical methods including hydrolysis to monosaccharides and mass spectrometry of the resulting mixture. We provide an initial demonstration of the potential utility of these keto-polysaccharides by reacting Ox-HPC with primary amines to form Schiff base imines, providing proactive polymers.

Biodegradable Poly(ester- co-acrylate) with Antifoulant Pendant Groups for Marine Anti-Biofouling

Polymer resins are critical for marine anti-biofouling coatings. In this study, degradable poly(ester- co-acrylate) with antifoulant pendant groups has been prepared by the radical ring-opening polymerization of 2-methylene-1,3-dioxepane, methyl methacrylate, and N-methacryloyloxy methyl benzoisothiazolinone. Such a polymer containing main-chain esters can hydrolytically and enzymatically degrade. Both degradation rates increase with main-chain ester content. Moreover, since the antifoulant groups are chemically grafted to the degradable main chain, their release can be controlled by the degradation besides the hydrolysis of side groups. Our study shows that the copolymer coating is efficient in inhibiting the accumulation of marine bacterial biofilm of Pseudomonas sp. and diatom Navicular incerta. Marine field test reveals that the copolymer has excellent efficiency in preventing biofouling for more than 6 months.

Amorphisation of Free Acid Ibuprofen and Other Profens in Mixtures with Nanocellulose: Dry Powder Formulation Strategy for Enhanced Solubility

The formulation of arylpropionic acid derivatives (profens), which are poorly soluble Biopharmaceutical Classification System (BCS) Type II drugs, has a strong impact on their therapeutic action. This article shows that heat-treated powder mixtures of free acid profens with high surface area Cladophora cellulose induces drug amorphization and results in enhanced solubility and bioavailability. Similar mixtures produced using conventional low surface area cellulose, i.e., microcrystalline cellulose, does not produce the same effect. The concept is thoroughly described and links the solid-state characterization data, such as differential scanning calorimetry, X-ray powder diffraction, and Fourier-transform infra-red spectroscopy, with in vitro dissolution in biorelevant media and in vivo pharmacokinetic analysis in rats. The concept is demonstrated for several substances from the profens group, including ibuprofen (main model drug), ketoprofen, flurbiprofen, and naproxen. The presented approach opens new ways to produce solid dosage forms of profen drugs in their free acidic form as alternatives to existing analogues, e.g., drug-salt conjugates or soft gel liquid capsules.