Hydroxypropyl methylcellulose: Physicochemical properties and ocular drug delivery formulations

The synergistic effect of hydroxypropyl methylcellulose and κ-carrageenan or pectin on anti-freezing

Ten polysaccharides were mixed to select polysaccharides with the synergistic anti-freezing effect in this study. It was found that hydroxypropyl methylcellulose (HPMC) and pectin (PEC) or κ-carrageenan (κ-CAR) synergistically decreased the freezing temperature of water and enhanced the ice recrystallization inhibition activity. Moreover, HPMC/κ-CAR exhibited greater synergy than HPMC/PEC. Raman spectroscopy analysis demonstrated that these polysaccharides increased the disorder of water molecules and inhibited the transition from liquid water to solid ice, and HPMC and PEC or κ-CAR had a synergistic effect on increasing the disorder of water molecules. Particularly, dynamic ice-shaping measurements showed that the HPMC/κ-CAR mixture changed circular ice into hexagonal ice in 20.0 % sucrose solution, whereas the HPMC/PEC mixture did not. Moreover, κ-CAR was more compatible with HPMC than PEC. The above differences might explain why κ-CAR was more effective than PEC in improving the anti-freezing ability of HPMC.

Innovative Famciclovir Eye Drop Formulations for Herpes Zoster Infections

PURPOSE

Herpes zoster ophthalmicus, a manifestation of the varicella-zoster virus in the eye, presents significant clinical challenges. As there is no direct ocular treatment for this infection, new therapeutic options should be studied. Famciclovir, a widely used antiviral drug for herpes zoster, offers higher bioavailability than acyclovir (a common herpes zoster treatment). However, this drug is currently limited to oral dosage forms, which are associated with inherent limitations such as variable absorption or gastrointestinal side effects. This study aimed to formulate new famciclovir eye drops for controlled drug release and targeted delivery to the cornea and sclera.

METHOD

Eye drop formulations containing various polymers (polyvinyl alcohol, hydroxypropyl methyl cellulose and chitosan) were developed and evaluated for physicochemical properties, irritation index and stability. The best performing formulation was used in ex-vivo diffusion and retention studies with rabbit cornea and sclera. The results were analyzed with a new HPLC validation method.

RESULTS

The formulation with polyvinyl alcohol exhibited superior properties regarding transparency, turbidity and absence of bubbles. It maintained a physiological pH over time and had an appropriate viscosity of 19.97 ± 0.25 mPa.s. Non-irritancy was confirmed by the HET-CAM test, and the formulation was stable at room temperature (25 °C), fridge (4 °C) and freezer (-80 °C). Ex- vivo diffusion studies revealed higher diffusion through the sclera compared to the cornea, with greater drug accumulation in sclera.

CONCLUSIONS

These findings suggest that famciclovir eye drops may offer a viable treatment for ocular herpes zoster infections. Famciclovir also diffuses and retains in targeted membranes, possibly enhancing its therapeutic effects.

Formulation, in-vitro characterization and clinical evaluation of curcumin in-situ gel for treatment of oral submucosal fibrosis (OSF)

BACKGROUND

Oral submucosal fibrosis (OSF) is a chronic oral mucosal disease with a cancerization tendency, characterized by restricted mouth opening and dysphagia. Currently, the mainstay treatment is still the local corticosteroid injection. Curcumin can reconstruct the redox balance, inhibit epithelial-mesenchymal transition (EMT), and suppress the excessive deposition of extracellular matrix (ECM) collagen, making it a promising treatment for fibrotic diseases. However, curcumin has poor intestinal absorption and low bioavailability, which limits its efficacy in treating oral mucosa diseases.

MATERIALS AND METHODS

In this study, we investigated a new administration mode and dosage form for curcumin in the treatment of OSF, and evaluated its clinical efficacy as an adjuvant therapy for OSF (Registration number: ChiCTR2400092888). The gel formulations were characterized by phase-transition temperature, phase-transition time, pH, viscosity, corrosion rate, in-vitro release rate, and chemical stability. The selected formulation was clinically evaluated in terms of inter incisor distance, mucosal pain index, mucosal color score, and mucosal texture score.

RESULTS

The final gel formula contained 18% poloxamer 407 (PLX407), 2% poloxamer 188 (PLX188), and 0.5% hydroxypropyl methylcellulose (HPMC). Curcumin was released as the gel underwent degradation. Gel characterization confirmed that its physicochemical properties met clinical requirements. The clinical study showed significant improvements in clinical indicators in both groups after one course of treatment. Notably, the gel, when used in conjunction with triamcinolone acetonide injections, significantly alleviated oral mucosal pain in OSF patients.

CONCLUSION

This study demonstrates that curcumin thermosensitive in-situ gels, as a novel dosing regimen, can achieve painless management of OSF, which is also the novelty of this work.

Recent advances in versatile cellulose-based 3D-printed drug delivery systems: A review

Advancing effective drug therapies is crucial for improving human health. However, traditional drug delivery systems (DDSs) struggle to customize formulations for individual patient needs, prompting exploring innovative solutions. The emergence of 3D printing (3DP) technology allows for designing customized DDSs. Cellulose and its derivatives can positively lower blood cholesterol and stabilize blood glucose levels due to their excellent biocompatibility and safety. These cellulose-based materials are supposed to fulfill the necessary criteria for biocompatibility, printability, and biomanufacturing in DDSs. Despite their excellent potential and promising features, constructing 3D-printed DDSs utilizing nanocellulose (NC) and cellulose derivatives remains largely unexamined. Given this, this review highlights recent advances in cellulose-based inks for drug delivery, detailing the multifunctional roles of cellulose derivatives, such as adhesives, drug-loaded filaments, controlled-release materials, thickeners, and fillers. Their versatility impacts ink rheology, allowing for tailored mechanical properties and porous structures in DDSs, including tablets, capsules, dispersible films, or scaffolds. Furthermore, their in vitro and in vivo performances have been rigorously evaluated. Overall, this review emphasizes for the first time the unique advantages and various applications of 3D-printed cellulose-based DDSs in personalized medicine, which is significant in providing guidance for developing safe biomedical materials, triggering the growth of personalized medicine.

Lotilaner for Demodex Blepharitis: The Journey from Veterinary Use to Human Medicine

In 2023, Xdemvy® (0.25% lotilaner ophthalmic solution) was approved by the U.S. FDA for treating Demodex blepharitis in humans. This article reviews lotilaner's history, physicochemical properties, pharmacokinetics, pharmacology, clinical outcomes, and other indications for which it is being evaluated clinically. Furthermore, the article discusses Demodex blepharitis, alternative treatments used in the clinic to ameliorate its symptoms, and other drugs in development. Prior to its approval in humans, lotilaner found extensive application in treating parasitic infections in cats and dogs. Lotilaner was previously approved in 2017 as an oral veterinary medicine (Credelio®) for canines to treat demodicosis, other mite infections, and tick infections. Lotilaner belongs to the isoxazoline class of drugs and is a potent arthropod-selective gamma-aminobutyric acid-gated chloride ion channel inhibitor. Like several other drugs in the isoxazoline class, lotilaner has a long plasma half-life and high plasma protein binding of about 99.9%. When used as indicated, lotilaner treats infested Demodex blepharitis in 42 days, with its antiparasitic action starting within 24 h. Furthermore, lotilaner is also being evaluated for its efficacy in other conditions such as Lyme disease and dry eye disease. Other products evaluated for treating Demodex blepharitis include ivermectin eye ointment, ivermectin-metronidazole gel, permethrin cream, terpinen-4-ol wipes, and hypochlorous acid spray. Along with these, azithromycin eye drop, azithromycin/loteprednol eye drop, and other treatments are being evaluated for treating blepharitis. Other drugs from the isoxazoline drug class including afoxolaner, sarolaner, and fluralaner, could also be potentially explored for human use.

Pediatric blepharokeratoconjunctivitis: A challenging ocular surface disease

Pediatric blepharokeratoconjunctivitis (PBKC) is a chronic and recurrent ocular surface inflammatory disorder affecting children in early life. It is frequently under- or late- diagnosed, representing a potential cause of severe visual morbidity worldwide. An expert panel consensus recently agreed on its definition and proposed diagnostic criteria for suspected and definitive PBKC to reduce confusion and avoid varied terminology previously used in the literature, improving early and precise diagnosis. Previous evidence has pointed to the role of the adaptive immune system in recognizing and handling antigenic eyelid bacterial products, particularly from the cell wall, and the direct toxic and inflammatory effects of their cytolytic exotoxins on the ocular surface. PBKC is a frequent referral in pediatric and cornea clinics characterized by a history of recurrent chalazia, blepharitis, meibomian gland dysfunction, conjunctival hyperemia, phlyctenules formation, and corneal infiltrates with vascularization and scarring. The latter is a major cause of significant visual loss and amblyopia. Current treatment strategies aim to control inflammation on the ocular surface, halt disease progression, and avoid corneal involvement. Further research on pathogenic mechanisms will shed light on novel potential therapeutic strategies. Awareness of PBKC should enhance early diagnosis, prompt adequate treatment, and improve outcomes. We compile current evidence on epidemiology, pathophysiology, clinical spectrum of disease, diagnostic criteria, and management strategies for PBKC.

Moxifloxacin in HPMC-nanocellulose composite film for the management of ocular inflammation: Effect of carboxymethylated gum on permeation and antimicrobial activity

Moxifloxacin (MFX) is known to decrease inflammation in lung infection by inhibiting interleukin-8 secretion and tumor necrosis factor-alpha production. Carboxymethylated gum combined with hydroxypropyl methylcellulose (HPMC)-nanocellulose (NCC) composite films were developed for the management of ocular inflammation and improved antimicrobial activity of MFX. Carboxymethyl starch (CMS), carboxymethyl tamarind (CMT), or carboxymethyl cellulose (CMC) gum in HPMC-nanocellulose composite film formulation was prepared using solvent casting method for studying ocular anti-inflammatory effect of MFX after ocular application using carrageenan-induced rabbit eye model. Presence of NCC and methylated gum sustained the corneal drug permeation. Improved antimicrobial activity has also been observed due to the combined effect of NCC and methylated gum. Highest zone of inhibition against gram-positive and gram-negative bacteria has been resulted owing to CMT in the film. MTT assay exhibited biocompatibility with human epithelial corneal cells (>84 % and above). A favourable docking score was found with MFX (-6.1 and -6.2 kcal/mol for interleukin and Tumor Necrosis Factor-α, respectively). Ocular inflammation was also diminished within 2 h of using film (CMT), whereas inflammation continued for >3 h of the induced rabbit without film. CMT incorporated film could be used for better management of inflammation associated with bacterial conjunctivitis.

Cellulose-based biodegradable superabsorbent hydrogel: A sustainable approach for water conservation and plant growth in agriculture

Innovative deficit irrigation technologies are imperative to overcome challenges posed to crop growth/yield and agriculture sustainability due to water scarcity in arid and semiarid regions. In the current study, superabsorbent biodegradable hydrogel based on carboxymethylcellulose sodium salt (NaCMC) and hydroxy ethyl cellulose (HEC) has been developed using citric acid (CA) as a crosslinker. The hydrogel has demonstrated excellent water absorption, retention, and release properties. Moreover, hydrogel (2 %) modified soil (HMS) has depicted increased porosity (57 %) and reduced soil density (1.06 g/cm3), compared to unmodified soil (UMS) with porosity of 53 % and density of 1.16 g/cm3, as well as, the water use efficiency of the plants (25.25 %-45.52 % over UMS) grown in HMS, which is vital for comprehending soil properties and their impact on water retention and aeration. The plant growth study in HMS concerning critical growth parameters such as germination rate, Seedling Vigour Index (SVI), Root Shoot Ratio (RSR), crop growth ratio (CGR), and chlorophyll content of three plants, i.e., one summer-grown plant-cucumber and two winter-grown plants- tomato and mung bean, has manifested promising results. Decisive parameters such as seedling viability (4.51 %), plant growth rate (3.77 %), and photosynthetic ability (16.74 %) were increased for chosen plants grown in HMS as compared to UMS. Improved growth parameters and photosynthetic ability of plants in HMS have suggested ameliorated nutrient and water absorption rates, increased resource utilization, and improved response to extrinsic resource allotment caused by hydrogel modification. Statistical analyses supported the trends in plant growth. Thus, hydrogel modification of the soil can effectively mitigate water use by retaining moisture efficiently and positively facilitating growth.

Potential of vB_Pa_ZCPS1 phage embedded in situ gelling formulations as an ocular delivery system to attenuate Pseudomonas aeruginosa keratitis in a rabbit model

Pseudomonas aeruginosa keratitis (or pink eye) is a challenging ocular infection that causes serious complications due to the deficiency of effective antibiotic treatment. Thus, in this study we isolated and characterized a specific bacteriophage, phage vB_Pa_ZCPS1, to be used to formulate an in situ- gel loaded bacteriophage for an in vivo rabbit infection treatment model. Phage vB_Pa_ZCPS1 is a double-stranded DNA bacterial virus, of 46,135 bp encoding 75 open reading frames (ORFs) with no antibiotic resistance genes detected. Moreover, it has a podoviral morphotype from the Caudoviricetes class with a 62.4 nm capsid and a short inflexible tail of around 18.8 nm, as indicated by the transmission electron microscope (TEM). Phage vB_Pa_ZCPS1 presented good stability to the UV exposure and a wide range of pH values from 3.0 to 11.0. In addition, the phage-bacteria dynamics study showed that phage vB_Pa_ZCPS1 was effective against P. aeruginosa, especially at low multiplicities of infections (MOIs), including 0.001, 0.01, and 0.1. Respectively, it was loaded to the characterized in situ gel composed of 14 % Pluronic F-127 and 1.5 % HPMC K4M polymer. The in situ-gel has a gelling time of 30 s ± 1, and a temperature of 33 °C ± 1, where the viscosity of the gel increases 10-fold. For the in vivo trial, the infected group treated with phage presented improved clinical outcomes, where the histopathological analysis revealed normal corneal thickness and intact corneal stratified squamous epithelium. Thus, the in situ-gel loaded phage vB_Pa_ZCPS1 could be a potential candidate approach to treat P. aeruginosa keratitis.

Research Progress of the Preparation of Cellulose Ethers and Their Applications: A Short Review

Cellulose ethers (CEs), synthesized through the etherification of cellulose, have emerged as indispensable "green additives" in our modern industries, earning the moniker of industrial "monosodium glutamate" due to their unparalleled multifunctionality. Unlike traditional petroleum-based modifiers, CEs offer a unique combination of renewability, low toxicity, and tunable properties (e.g., water retention, thickening, and stimuli-responsiveness), making them pivotal for advancing sustainable construction practices. This review presents an overview of the preparation methods of various CEs and the applications of CEs especially in concrete and mortars as well as corresponding mechanisms. We systematically analyze the preparation methodologies (homogeneous vs. heterogeneous processes) and highlight the effect of molecular determinants (degree of substitution, molecular weight, functional groups) on the performances of CEs. CEs can enhance the workability and other properties of concrete and mortars primarily by acting as water-retaining and thickening agents to mitigate rapid water loss, improve hydration efficiency and cohesion. The effects of CEs on the delay of hydration and microstructure of concrete and mortars are also analyzed and highlighted. Beyond construction, we reviewed the current and emerging CE applications in biomedicine, tissue-engineering, petroleum industry and food engineering, highlighting their cross-disciplinary potential. This review provides some insights into the structure-property-application relationships of CEs and their brief historical developments, offering guidance for optimizing their utilizations especially in sustainable construction practices.

Physicochemical Properties and Biocompatibility of Injectable Hydroxyapatite Cement and Its Application in Compressive Tibial Plateau Fractures

Injectable carbonated hydroxyapatite (ICHA) cement was developed by adding 2% Hydroxypropyl methylcellulose (HPMC) to carbonated hydroxyapatite (CHA) cement, improving its rheological properties and injectability for minimally invasive orthopedic use. The cement's physical and chemical properties, including curing time, strength, porosity, and consistency, were tested in vitro. Scanning electron microscopy, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) were used to analyze the cured cement. Bone marrow stromal cells were cultured with ICHA cement extracts and specimens to test cell growth (MTT assay) and cytotoxicity. In vivo, the cement was implanted into rabbit muscles to assess inflammation and capsule formation, along with other biocompatibility tests, including hemolysis and pyrogen testing. ICHA cement sets without heat generation, with a 9-min initial setting time and a 15-min final setting time, similar to CHA cement. The strength reaches 20 MPa after 1 day and peaks at 35 MPa after 7 days. Its porosity is slightly higher than CHA cement, and it resists dilution well, preventing disintegration in water. The consistency of ICHA cement is lower than CHA cement at different time points (p < 0.001), showing a logarithmic change pattern. With adjustable setting time, good resistance to dilution, and compressive strength similar to cancellous bone, ICHA cement is well suited for clinical use. Its composition closely resembles natural bone, offering strong fixation and stability for tibial plateau healing, which supports early movement and reduces the risk of joint stiffness and post-traumatic arthritis.

In Vitro Evaluation of Gelatin-Based Hydrogels as Potential Fillers for Corneal Wounds

Corneal persistent epithelial defects are common ophthalmic injuries that can cause significant visual and structural damage. While diagnosis is straightforward, treatment remains challenging. Noninvasive therapies like eye drops are preferred, but severe neurotrophic keratopathy may require surgical interventions. This study explores gelatin-based hydrogels as noninvasive alternatives for corneal repair. Four photo-cross-linkable hydrogels with gelatin and riboflavin phosphate (RFP) were evaluated: a control and variants incorporating 2.5% dextran (D), 0.4% hyaluronic acid (HA), or 1% methylcellulose (MC). In vitro assessments included physicochemical properties, biocompatibility, and release kinetics alongside ex vivo wound healing assays. The gelatin-RFP hydrogel maintained corneal transparency, while additives reduced it. Dextran slowed compound release, and HA and MC reduced the release rate of larger molecules. All hydrogels showed excellent biocompatibility, and ex vivo models confirmed re-epithelialization, though slower than controls. The unmodified gelatin-RFP hydrogel demonstrated the best potential for corneal tissue engineering, supporting its future clinical translation.

The new bilastine eye drop formulation protects against conjunctival dehydration and promotes corneal wound healing in a comparative in vitro study

Bilastine is a non-sedating, highly selective H1-antihistamine with proven efficacy and safety in treating allergic rhinoconjunctivitis and urticaria in adults and children. Allergic conjunctivitis, a common ocular condition, negatively impacts quality of life. Topical eye drops are the standard treatment, though ocular bioavailability is often low. Incorporating biopolymers such as hyaluronic acid (HA) into topical formulations enhances adhesive properties, prolongs retention on the ocular surface, and ultimately improves drug bioavailability. This study evaluated the new multidose preservative-free bilastine 0.6% solution with sodium HA against eight commercially available antiallergic eye drops. Using an ex vivo bovine cornea model, bilastine 0.6% demonstrated the highest bioadhesion strength (0.025 mJ), indicating superior retention on the ocular surface. It also showed strong protective effects against in vitro dehydration, mainly due to the presence of HA, and did not exhibit cytotoxicity in human primary conjunctival cells. In wound healing assays, preservative-free ketotifen 0.025%, bilastine 0.6%, and azelastine 0.05% promoted corneal wound repair at 72 h, outperforming preserved formulations. Overall, preservative-free bilastine 0.6% with HA enhances corneal hydration, retention, and re-epithelialization in vitro, suggesting potential benefits for the management of allergic conjunctivitis and offering promising advancements in treating this widespread condition.

Spectroscopic Characterization Using 1H and 13C Nuclear Magnetic Resonance and Computational Analysis of the Complex of Donepezil with 2,6-Methyl-β-Cyclodextrin and Hydroxy Propyl Methyl Cellulose

Donepezil (DH), a selective acetylcholinesterase inhibitor, is widely used to manage symptoms of mild to moderate Alzheimer's disease by enhancing cholinergic neurotransmission and preventing acetylcholine breakdown. Despite the effectiveness of oral formulations, extensive hepatic metabolism and low systemic bioavailability have driven the search for alternative delivery systems. This study focuses on nasal delivery as a non-parenteral substitute, utilizing hydroxypropyl methylcellulose (HPMC) for its mucoadhesive properties and methyl-β-cyclodextrin (Me-β-CD) for its ability to enhance permeability and form inclusion complexes with drugs. Prior studies demonstrated the potential of HPMC-based nasal films for nose-to-brain delivery of donepezil and highlighted Me-β-CD's role in improving drug solubility. Building on this, transparent gel formulations containing DH, HPMC, and 2,6 Me-β-CD were developed to investigate molecular interactions within two- and three-component systems. This study utilized a combination of nuclear magnetic resonance (NMR) spectroscopy and density functional theory (DFT) to provide detailed insights into the interactions between DH, 2,6-Me-β-CD, and HPMC. The findings provide critical insights into drug-excipient interactions, aiding the optimization of stability, solubility, and controlled release. This advances the rational design of nanotechnology-based drug delivery systems for enhanced therapeutic efficacy.

Stability enhancement of Amphotericin B using 3D printed biomimetic polymeric corneal patch to treat fungal infections

Amphotericin B eye drops (reconstituted from lyophilized Amphotericin B formulation indicated for intravenous use) is used off-label for fungal keratitis. However, the reconstituted formulation is stable only for a week, even after refrigeration. Moreover, a high dosing frequency makes it an inconvenient treatment practice. The current study aims to develop a stable Amphotericin B-loaded biomimetic polymeric corneal patch (Ampat) using 3D printing. Hydroxypropyl methylcellulose and chitosan were used to formulate Ampat, which was then characterized for its physical and mechanical properties. The stability studies were performed at different conditions, protected from light. Further, the therapeutic efficacy of Ampat was evaluated against Candida albicans-induced fungal keratitis using ex vivo and in vivo efficacy models. Amphotericin B in Ampat was found to be stable at room temperature (25 °C) and refrigerated conditions for at least two months. Computer simulations showed that the hydrolysis was a major degradation mechanism of Amphotericin B and was reduced when loaded in the polymeric corneal patch. The ex vivo and in vivo studies show that Ampat was as efficacious as the marketed Amphotericin B formulation but with a reduced administration frequency (1 vs 12 times per day). The present study demonstrated Ampat as a potential alternative to reconstituted lipid-bound eye drops to treat fungal keratitis.

In vivo bone regeneration performance of hydroxypropyl methylcellulose hydrogel-based composite bone cements in ovariectomized and ovary-intact rats: a preliminary investigation

The objective of this study is to fabricate and develop hydroxypropyl methylcellulose (HPMC) hydrogel (HG)-based composite bone cements with incorporation of hydroxyapatite (HA), beta-tricalcium phosphate (β-TCP), and with/without polymethylmethacrylate (PMMA) for vertebroplasty. For animal study, twenty female Wister rats (250-300 g, 12 weeks of age) were divided into four groups including a two non-ovariectomy (NOVX) groups and two ovariectomy (OVX)-induced osteoporosis groups. Two prepared biocomposites including HG/β-TCP/HA and HG/β-TCP/HA/PMMA were injected into the tibial defects of both OVX and NOVX rats for evaluating in vivo osteogenesis after 12 weeks. Micro-computed tomography and histological analysis using hematoxylin and eosin (H&E) and Masson's trichrome stains of the two composite cements implanted into the tibial defects of OVX and NOVX rats revealed enhanced bone regeneration potential. However, no statistically significant differences were noted among the groups based on new bone formation, demonstrating that the injected composite cements showed similar osteogenesis effects in both OVX and NOVX rats. These findings suggest that the newly developed composite bone cement composed of HG, β-TCP, HA and/or PMMA may be a promising and professional tool for treating osteoporotic and non-osteoporotic vertebral fractures.

The effect of mucoadhesive polymers on ocular permeation of thermoresponsive in situ gel containing dexamethasone-cyclodextrin complex

Dexamethasone (DXM) is a commonly used corticosteroid in the treatment of ocular inflammatory conditions that affect more and more people. The aim of this study was to evaluate the effect of the combination of hydroxypropyl-β-cyclodextrin (HPBCD), in situ gelling formulations, and other mucoadhesive polymers, i.e., hydroxypropyl methylcellulose (HPMC) and zinc-hyaluronate (ZnHA), on permeation by applying in vitro and ex vivo ophthalmic permeation models. Additionally, gelling properties, in vitro drug release, and mucoadhesion were measured to determine the impact of these factors on permeation and ultimately on bioavailability. The results showed that GEL1 and GEL2 had an optimal gelling temperature, 36.3 ℃ and 34.6 ℃, respectively. Moreover, the combination of Poloxamer 407 (P407) with other polymers improved the mucoadhesion (GEL1: 1333.7 mN) compared with formulations containing only P407 (P12: 721.8 mN). Both HPBCD and the gel matrix had a considerable influence on the drug release and permeability of DXM, and the combination could facilitate the permeation into the aqueous humor. After 30 min of treatment, the DXM concentration in the aqueous humor was 1.16-1.37 µg∕mL in case of the gels, whereas DXM could not be detected when treated with the DXM suspension. The results of the experiments using an in vitro cell line indicated that the formulations could be considered safe for topical treatment of the eye. In conclusion, with application of a small amount of HPMC (0.2 % w∕w), the concentration of P407 could be reduced to 12 % w/w while maintaining the ideal gelling properties and gel structure without negatively affecting permeability compared with the formulation containing a higher amount of P407. Furthermore, the gel matrix may also provide programmed and elongated drug release.

Influence of physico-chemical properties of hydroxypropyl methylcellulose on quetiapine fumarate release from sustained release matrix tablets

Quetiapine fumarateis a typical antipsychotic with a short half-life of 6 h and is administered multiple times daily. In this study, a copolymer for controlled delivery of quetiapine fumarate will be developed. In order to prevent side effects and improve patient compliance, hydroxypropyl methylcellulose K15M (HPMC K15M) was included in the formulation of the quetiapine fumarate oral sustained-release tablets at a concentration of 10-30%. A series of analytical methods were used to determine the characteristics of the prepared hydrogels, including Fourier transform-infrared spectroscopy, Differential scanning calorimetry, X-ray diffraction, and Scanning electron microscope. At two different pH values (1.2 and 6.8), swelling and release studies were conducted. A variety of release kinetic models was used to study drug release mechanisms. A non-Fickian diffusion mechanism released hydrogels prepared from quetiapine fumarate. It was found that swelling was increased by increasing the amount of HPMC K15M. Compared to the other batches (10-20%), the produced tablets with 30% HPMC K15M content had a better release profile after 20 h of dissolution. Because of the effective matrix complex's limited solubility in water, the drug diffuses through the gel layer at a steady rate rather than dissolving quickly.

Essential Oil Components Incorporated Emulsion Hydrogels for Eradicating Dermatophytosis Caused by Pathogenic Fungi Trichophyton mentagrophytes and Microsporum canis

Dermatophytosis is a prevalent fungal infection and public health burden, majorly caused by the attack of zoophilic fungi genera of Trichophyton and Microsporum. Among them, T. mentagrophytes and M. canis are the dominating pathogens that cause dermatophytosis in humans. Though anti-fungal treatments are available, the widespread drug resistance and minimal efficacy of conventional therapies cause recurring infections. In addition, prolonged anti-fungal medications induce several systemic side effects, including hepatotoxicity and leucopenia. The anti-dermatophytic formulation of biocompatible essential oil components (EOCs) is attractive due to their highly potent anti-dermatophytic action. Herein, two EOCs, Eugenol (EU) and Isoeugenol (IU), incorporated emulsion hydrogel (EOCs-EHG) synthesized from hydroxypropylmethyl cellulose and poly(ethylene glycol) methyl ether methacrylate. The cytocompatibility of the hydrogels is confirmed by treating them with fibroblast and keratinocyte cell lines. The EOCs-EHG demonstrated pH and temperature-responsive sustained release of entrapped EOCs and inhibited fungal spore germination. T. mentagrophytes and M. canis biofilms are eradicated at a minimal inhibitory concentration of 2 µg mL-1 each of EU and IU. The in vivo anti-dermatophytic activity of EOCs-EHG is confirmed in dermatophyte-infected Wistar albino rat models. The topical application of EOCs-EHG demonstrated complete infection eradication and facilitated skin regeneration, emphasizing the therapeutic potential of EOCs-EHG against dermatophytosis.

Small Molecule Topical Ophthalmic Formulation Development-Data Driven Trends & Perspectives from Commercially Available Products in the US

Topical ophthalmic drug product development is a niche research domain as the drug formulations need to be designed to perform in the unique ocular physiological conditions. The most common array of small molecule drug formulations intended for topical ophthalmic administration include solutions, suspensions, emulsions, gels, and ointments. The formulation components such as excipients and container closure are unique to serve the needs of topical ophthalmic delivery compared to other parenteral products. The selection of appropriate formulation platform, excipients, and container closure for delivery of drugs by topical ophthalmic route is influenced by a combination of factors like physicochemical properties of the drug molecule, intended dose, pharmacological indication as well as the market trends influenced by the patient population. In this review, data from literature and packaging inserts of 118 reference listed topical ophthalmic medications marketed in the US are collected and analyzed to identify trends that would serve as a guidance for topical ophthalmic formulation development for small molecule drugs. Specifically, the topics reviewed include current landscape of the available small molecule topical ophthalmic drug products in the US, physicochemical properties of the active pharmaceutical ingredients (APIs), formulation platforms, excipients, and container closure systems.

Binary and Ternary Inclusion Complexes of Niflumic Acid: Synthesis, Characterization, and Dissolution Profile

Although niflumic acid (NA) is one of the most used non-steroidal anti-inflammatory drugs, it suffers from poor solubility, low bioavailability, and significant adverse effects. To address these limitations, the complexation of NA with cyclodextrins (CDs) is a promising strategy. However, complexing CDs with low molecular weight drugs like NA can lead to low CE. This study explores the development of inclusion complexes of NA with 2-hydroxypropyl-β-cyclodextrin (2HP-β-CD), including the effect of converting NA to its sodium salt (NAs) and adding hydroxypropyl methylcellulose (HPMC) on complex formation. Inclusion complexes were prepared using co-evaporation solvent and freeze-drying methods, and their CE and Ks were determined through a phase solubility study. The complexes were characterized using physicochemical analyses, including FT-IR, DSC, SEM, XRD, DLS, UV-Vis, 1H-NMR, and 1H-ROESY. The dissolution profiles of the complexes were also evaluated. The analyses confirmed complex formation for all systems, demonstrating drug-cyclodextrin interactions, amorphous drug states, morphological changes, and improved solubility and dissolution profiles. The NAs-2HP-β-CD-HPMC complex exhibited the highest CE and Ks values, a 1:1 host-guest molar ratio, and the best dissolution profile. The results indicate that the NAs-2HP-β-CD-HPMC complex has potential for delivering NA, which might enhance its therapeutic effectiveness and minimize side effects.

Low-viscosity hydroxypropyl methylcellulose obtained by electron beam irradiation and its performance in spray drying

Low-viscosity hydroxypropyl methylcellulose (HPMC) was obtained by electron beam irradiation, and its use as an excipient for improving the properties of spray dried pharmaceutical powders was investigated. The minimum molecular weight of HPMC which could maintain the capacity of encapsulation and powder modification was explored. As the irradiation dose was increased from 10 to 200 kGy, the molecular weight and viscosity of HPMC decreased linearly. However, its main structure and degrees of methoxy and hydroxypropyl substitution were not significantly affected. The irradiated HPMC could encapsulate particles during spray drying and, thus, modify powder properties. Furthermore, the water content of spray-dried powders with irradiated HPMC was lower than that with parent HPMC. After the spray-dried powder with irradiated HPMC was prepared into granules, their dissolution rate was also faster. However, in order to achieve high encapsulation, the molecular weight of HPMC should be ensured to be above 7.5 kDa. The designated low-viscosity HPMC obtained by electron beam irradiation is a suitable powder-modification material for use in spray drying, and it shows promise as a superior excipient in medicine, food, paint industries, among others.

Enhancing the Biodegradability, Water Solubility, and Thermal Properties of Polyvinyl Alcohol through Natural Polymer Blending: An Approach toward Sustainable Polymer Applications

The escalating environmental crisis posed by single-use plastics underscores the urgent need for sustainable alternatives. This study provides an approach to introduce biodegradable polymer blends by blending synthetic polyvinyl alcohol (PVA) with natural polymers-corn starch (CS) and hydroxypropyl methylcellulose (HPMC)-to address this challenge. Through a comprehensive analysis, including of the structure, mechanical strength, water solubility, biodegradability, and thermal properties, we investigated the enhanced performance of PVA-CS and PVA-HPMC blends over conventional polymers. Scanning electron microscopy (SEM) findings of pure PVA and its blends were studied, and we found a complete homogeneity between the PVA and both types of natural polymers in the case of a high concentration of PVA, whereas at lower concentration of PVA, some granules of CS and HMPC appear in the SEM. Blending corn starch (CS) with PVA significantly boosts its biodegradability in soil environments, since adding starch of 50 w/w duplicates the rate of PVA biodegradation. Incorporating hydroxypropyl methylcellulose (HPMC) with PVA not only improves water solubility but also enhances biodegradation rates, as the addition of HPMC increases the biodegradation of pure PVA from 10 to 100% and raises the water solubility from 80 to 100%, highlighting the significant acceleration of the biodegradation process and water solubility caused by HPMC addition, making these blends suitable for a wide range of applications, from packaging and agricultural films to biomedical engineering. The thermal properties of pure PVA and its blends with natural were studied using diffraction scanning calorimetry (DSC). It is found that the glass transition temperature (Tg) increases after adding natural polymers to PVA, referring to an improvement in the molecular weight and intermolecular interactions between blend molecules. Moreover, the amorphous structure of natural polymers makes the melting temperature ™ lessen after adding natural polymer, so the blends require lower temperature to remelt and be recycled again. For the mechanical properties, both types of natural polymer decrease the tensile strength and elongation at break, which overall weakens the mechanical properties of PVA. Our findings offer a promising pathway for the development of environmentally friendly polymers that do not compromise on performance, marking a significant step forward in polymer science's contribution to sustainability. This work presents detailed experimental and theoretical insights into novel polymerization methods and the utilization of biological strategies for advanced material design.

Acceleration of wound healing using adipose mesenchymal stem cell secretome hydrogel on partial-thickness cutaneous thermal burn wounds: An in vivo study in rats

BACKGROUND AND AIM

The intricate healing process involves distinct sequential and overlapping phases in thermal injury. To maintain the zone of stasis in Jackson's burn wound model, proper wound intervention is essential. The extent of research on the histoarchitecture of thermal wound healing and the application of mesenchymal stem cell (MSC)-free-based therapy is limited. This study aimed to assess the efficacy of MSC-secretome-based hydrogel for treating partial-thickness cutaneous thermal burn wounds.

MATERIALS AND METHODS

Eighteen male Wistar rats were divided into three groups, namely the hydrogel base (10 mg), hydrogel secretome (10 mg) and Bioplacenton™ (10 mg) treatment groups. All groups were treated twice a day (morning and evening) for 7 days. Skin tissue samples from the animals were processed for histological evaluation using the formalin-fixed paraffin-embedded method on days 3 and 7.

RESULTS

This study's findings showed that secretome hydrogel expedited thermal burn wound healing, decreasing residual burn area, boosting collagen deposition and angiogenesis, guiding scar formation, and influencing the inflammation response facilitated by polymorphonuclear leukocytes and macrophages.

CONCLUSION

The secretome hydrogel significantly improves healing outcomes in partial-thickness cutaneous thermal burn wounds. The administration of secretome hydrogel accelerates the reduction of the residual burn area and promotes fibroblast proliferation and collagen density. The repairment of histo-architecture of the damaged tissue was also observed such as the reduction of burn depth, increased angiogenesis and epidermal scar index while the decreased dermal scar index. Furthermore, the secretome hydrogel can modulate the immunocompetent cells by decreasing the polymorphonuclear and increasing the mononuclear cells. Thus, it effectively and safely substitutes for thermal injury stem cell-free therapeutic approaches. The study focuses on the microscopical evaluation of secretome hydrogel; further research to investigate at the molecular level may be useful in predicting the beneficial effect of secretome hydrogel in accelerating wound healing.

Hard Gelatin Capsules with Alginate-Hypromellose Microparticles as a Multicompartment Drug Delivery System for Sustained Posaconazole Release

Microparticles as a multicompartment drug delivery system are beneficial for poorly soluble drugs. Mucoadhesive polymers applied in microparticle technology prolong the contact of the drug with the mucosa surface enhancing drug bioavailability and extending drug activity. Sodium alginate (ALG) and hydroxypropyl methylcellulose (hypromellose, HPMC) are polymers of a natural or semi-synthetic origin, respectively. They are characterized by mucoadhesive properties and are applied in microparticle technology. Spray drying is a technology employed in microparticle preparation, consisting of the atomization of liquid in a stream of gas. In this study, the pharmaceutical properties of spray-dried ALG/HPMC microparticles with posaconazole were compared with the properties of physical mixtures of powders with equal qualitative and quantitative compositions. Posaconazole (POS) as a relatively novel antifungal was utilized as a model poorly water-soluble drug, and hard gelatin capsules were applied as a reservoir for designed formulations. A release study in 0.1 M HCl showed significantly prolonged POS release from microparticles compared to a mixture of powders. Such a relationship was not followed in simulated vaginal fluid (SVF). Microparticles were also characterized by stronger mucoadhesive properties, an increased swelling ratio, and prolonged residence time compared to physical mixtures of powders. The obtained results indicated that the pharmaceutical properties of hard gelatin capsules filled with microparticles were significantly different from hard gelatin capsules with mixtures of powders.

Biopolymeric Innovations in Ophthalmic Surgery: Enhancing Devices and Drug Delivery Systems

The interface between material science and ophthalmic medicine is witnessing significant advances with the introduction of biopolymers in medical device fabrication. This review discusses the impact of biopolymers on the development of ophthalmic devices, such as intraocular lenses, stents, and various prosthetics. Biopolymers are emerging as superior alternatives due to their biocompatibility, mechanical robustness, and biodegradability, presenting an advance over traditional materials with respect to patient comfort and environmental considerations. We explore the spectrum of biopolymers used in ophthalmic devices and evaluate their physical properties, compatibility with biological tissues, and clinical performances. Specific applications in oculoplastic and orbital surgeries, hydrogel applications in ocular therapeutics, and polymeric drug delivery systems for a range of ophthalmic conditions were reviewed. We also anticipate future directions and identify challenges in the field, advocating for a collaborative approach between material science and ophthalmic practice to foster innovative, patient-focused treatments. This synthesis aims to reinforce the potential of biopolymers to improve ophthalmic device technology and enhance clinical outcomes.

Progress in the Application of Microneedles in Eye Disorders and the Proposal of the Upgraded Microneedle with Spinule

PURPOSE

In the local administration methods for treating eye diseases, the application of microneedles has great potential due to the shortcomings of low efficacy and significant side effects of local administration preparations. This article provides ideas for the research on the application of ophthalmic microneedle in the treatment of eye diseases.

RESULTS

This article analyzes the physiological structures of the eyes, ocular diseases and its existing ocular preparations in sequence. Finally, this article reviews the development and trends of ocular microneedles in recent years, and summarizes and discusses the drugs of ocular microneedles as well as the future directions of development. At the same time, according to the inspiration of previous work, the concept of "microneedle with spinule" is proposed for the first time, and its advantages and limitations are discussed in the article.

CONCLUSIONS

At present, the application of ocular microneedles still faces multiple challenges. The aspects of auxiliary devices, appearance, the properties of the matrix materials, and preparation technology of ophthalmic microneedle are crucial for their application in the treatment of eye diseases.

Formulation and Preparation of Losartan-Potassium-Loaded Controlled-Release Matrices Using Ethocel Grade 10 to Establish a Correlation between In Vitro and In Vivo Results

In the current study, matrices of losartan potassium were formulated with two different polymers (Ethocel 10 premium and Ethocel 10FP premium), along with a filler and a lubricant, at different drug-to-polymer w/w ratios (10:3, 10:4, and 10:5). The matrices were tested by the direct compression method, and their hardness, diameter, thickness, friability, weight variation, content uniformity, and in vitro dissolution tests were assessed to determine 24-h drug release rates. The matrices with Ethocel 10 FP at a 10:4 ratio exhibited pseudo-zero-order kinetics (n-value of 0.986), while the dissolution data of the test matrices and reference tablets did not match. The new test-optimized matrices were also tested in rabbits, and their pharmacokinetic parameters were investigated: half-life (11.78 ± 0.018 h), Tmax (2.105 ± 1.131 h), Cmax (205.98 ± 0.321 μg/mL), AUCo (5931.10 ± 1.232 μg·h/mL), AUCo-inf (7348.46 ± 0.234 μg·h/mL), MRTo-48h (17.34 ± 0.184 h), and Cl (0.002 ± 0.134 mL/min). A correlation value of 0.985 between the in vitro and in vivo results observed for the test-optimized matrices was observed, indicating a level-A correlation between the percentage of the drug released in vitro and the percentage of the drug absorbed in vivo. The matrices might improve patient compliance with once-a-day dosing and therapeutic outcomes.

Overview of processed excipients in ocular drug delivery: Opportunities so far and bottlenecks

Ocular drug delivery presents a unique set of challenges owing to the complex anatomy and physiology of the eye. Processed excipients have emerged as crucial components in overcoming these challenges and improving the efficacy and safety of ocular drug delivery systems. This comprehensive overview examines the opportunities that processed excipients offer in enhancing drug delivery to the eye. By analyzing the current landscape, this review highlights the successful applications of processed excipients, such as micro- and nano-formulations, sustained-release systems, and targeted delivery strategies. Furthermore, this article delves into the bottlenecks that have impeded the widespread adoption of these excipients, including formulation stability, biocompatibility, regulatory constraints, and cost-effectiveness. Through a critical evaluation of existing research and industry practices, this review aims to provide insights into the potential avenues for innovation and development in ocular drug delivery, with a focus on addressing the existing challenges associated with processed excipients. This synthesis contributes to a deeper understanding of the promising role of processed excipients in improving ocular drug delivery systems and encourages further research and development in this rapidly evolving field.

CD-MOFs: From preparation to drug delivery and therapeutic application

Cyclodextrin metal-organic frameworks (CD-MOFs) show considerable advantages of edibility, degradability, low toxicity, and high drug loading, which have attracted enormous interest, especially in drug delivery. This review summarizes the typical synthesis approaches of CD-MOFs, the drug loading methods, and the mechanism of encapsulation and release. The influence of the structure of CD-MOFs on their drug encapsulation and release is highlighted. Finally, the challenges CD-MOFs face are discussed regarding biosafety assessment systems, stability in aqueous solution, and metal ion effect.

Poloxamer sols endowed with in-situ gelability and mucoadhesion by adding hypromellose and hyaluronan for prolonging corneal retention and drug delivery

The purpose of this study was to develop poloxamer (P407)-based in-situ thermogellable hydrogels with reducing concentration of P407 by adding hypromellose (HPMC) and with enhancing mucoadhesion of resulting hydrogels by adding hyaluronic acid (HA) for prolonging ocular delivery of hydroxypropyl-β-cyclodextrin (HPβCD)-solubilized testosterone (TES). Results demonstrated that 0.5% TES solution was successfully solubilized with adding 10% HPβCD. Non-gellable 13% P407 sol became in-situ gellable with adding 2.0-2.5% HPMC and mucoadhesibility was further imporved with adding 0.3% HA-L (low MW) or HA-H (high MW). Optimized 0.5% HPβCD-solubilized TES P407-based thermogellable hydrogels with enhancement of mucoadhesion for prolonging ocular delivery comprised 13% P407, 2.5% HPMC, and 0.3% HA-L or HA-H. Furthermore, rheological measurements under simulated eye blinking confirmed that non-thixotropic properties of optimized hydrogels could be spreaded evenly and retain a greater amount of drug-loaded hydrogels on the ocular surface for a longer period to prolong drug delivery. Compared with conventional eye drops, the prolonged residence time of optimized hydrogels from ex vivo and in vivo studies were observed, indicating relationships between rheological properties and in vivo performances. It was concluded that P407-based thermosensitive hydrogels with reducing concentration of P407 and enhancing mucoadhesion was successfully formulated by adding 2.5% HPMC and 0.3% HA in 13% P407 for potentially accomplishing effective clinical treatment of DED.

In vitro and in silico methods to investigate the effect of moderately increasing medium viscosity and density on ibuprofen dissolution rate

Medium viscosity can affect drug dissolution rate, however, it is not usually considered in routine dissolution testing or less complex biorelevant media. The effects of moderately increasing medium viscosity on the in vitro and in silico dissolution of ibuprofen were investigated with two viscosity enhancing agents (VEA) (hydroxypropyl methylcellulose (HPMC) and sucrose), three viscosity levels (range 0.7-5.5 mPa.s), two solubilities and two fluid velocities in the paddle, flow-through and intrinsic dissolution apparatuses. A factorial design analysis highlighted which factors significantly affected key dissolution metrics. Experimental results in the flow-through apparatus (FTA) were compared with in silico dissolution profiles generated by an in-house simulation code (SIMDISSOTM). Increasing viscosity reduced the intrinsic dissolution rate of ibuprofen for both VEAs. The dissolution rate reduction was also observed in the FTA with sucrose, but less so with HPMC, suggesting particle wetting, motion and surface area effects. Particle motion simulations suggested reduced particle lifting times as viscosity increased, indicating an effect of viscosity on particle dispersal. The viscosity- and fluid density-mediated reduction in the dissolution rate observed with sucrose was accurately simulated by SIMDISSOTM, in particular at higher velocities. Velocity had a significant impact on dissolution rates in the paddle apparatus, with a significant viscosity-related reduction in dissolution observed in the low solubility-low velocity scenario. Even small increases in medium viscosity can reduce the dissolution rate of a BCS class II drug, and in silico particle motion and dissolution data can assist interpretation of particulate dissolution behaviour.

The Potential of Films as Transmucosal Drug Delivery Systems

Pharmaceutical films are polymeric formulations used as a delivery platform for administration of small and macromolecular drugs for local or systemic action. They can be produced by using synthetic, semi-synthetic, or natural polymers through solvent casting, electrospinning, hot-melt extrusion, and 3D printing methods, and depending on the components and the manufacturing methods used, the films allow the modulation of drug release. Moreover, they have advantages that have drawn interest in the development and evaluation of film application on the buccal, nasal, vaginal, and ocular mucosa. This review aims to provide an overview of and critically discuss the use of films as transmucosal drug delivery systems. For this, aspects such as the composition of these formulations, the theories of mucoadhesion, and the methods of production were deeply considered, and an analysis of the main transmucosal pathways for which there are examples of developed films was conducted. All of this allowed us to point out the most relevant characteristics and opportunities that deserve to be taken into account in the use of films as transmucosal drug delivery systems.

Trends in Formulation Approaches for Sustained Drug Delivery to the Posterior Segment of the Eye

The eye, an intricate organ comprising physical and physiological barriers, poses a significant challenge for ophthalmic physicians seeking to treat serious ocular diseases affecting the posterior segment, such as age-related macular degeneration (AMD) and diabetic retinopathy (DR). Despite extensive efforts, the delivery of therapeutic drugs to the rear part of the eye remains an unresolved issue. This comprehensive review delves into conventional and innovative formulation strategies for drug delivery to the posterior segment of the eye. By utilizing alternative nanoformulation approaches such as liposomes, nanoparticles, and microneedle patches, researchers and clinicians can overcome the limitations of conventional eye drops and achieve more effective drug delivery to the posterior segment of the eye. These innovative strategies offer improved drug penetration, prolonged residence time, and controlled release, enhancing therapeutic outcomes for ocular diseases. Moreover, this article explores recently approved delivery systems that leverage diverse polymer technologies, such as chitosan and hyaluronic acid, to regulate drug-controlled release over an extended period. By offering a comprehensive understanding of the available formulation strategies, this review aims to empower researchers and clinicians in their pursuit of developing highly effective treatments for posterior-segment ocular diseases.

Polysaccharides in contact lenses: From additives to bulk materials

As the number of applications has increased, so has the demand for contact lenses comfort. Adding polysaccharides to lenses is a popular way to enhance comfort for wearers. However, this may also compromise some lens properties. It is still unclear how to balance the variation of individual lens parameters in the design of contact lenses containing polysaccharides. This review provides a comprehensive overview of how polysaccharide addition impacts lens wear parameters, such as water content, oxygen permeability, surface wettability, protein deposition, and light transmittance. It also examines how various factors, such as polysaccharide type, molecular weight, amount, and mode of incorporation into lenses modulate these effects. Polysaccharide addition can improve some wear parameters while reducing others depending on the specific conditions. The optimal method, type, and amount of added polysaccharides depend on the trade-off between various lens parameters and wear requirements. Simultaneously, polysaccharide-based contact lenses may be a promising option for biodegradable contact lenses as concerns regarding environmental risks associated with contact lens degradation continue to increase. It is hoped that this review will shed light on the rational use of polysaccharides in contact lenses to make personalized lenses more accessible.

The effect of the molecular structure of hydroxypropyl methylcellulose on the states of water, wettability, and swelling properties of cryogels prepared with and without CaO2

Hydroxypropyl methylcellulose (HPMC) belongs to the cellulose ether family that has hydroxyl groups substituted by hydrophobic methyl groups (DS) and hydrophilic hydroxypropyl groups (MS). Herein, the interactions between water molecules and cryogels prepared with HPMC in the presence and absence of a linear nonionic surfactant, as well as CaO₂ microparticles, which react with water producing O₂, were systematically investigated by sorption experiments and Time-Domain Nuclear Magnetic Resonance. Regardless of the DS and MS, most water molecules presented transverse relaxation time t2 typical of intermediate water and a small population of more tightly bound water. HPMC cryogels with the highest DS of 1.9 presented the slowest swelling rate of 0.519 ± 0.053 g_water/(g.s) and the highest contact angle values 85.250^o ± 0.004^o, providing the best conditions for a slow reaction between CaO₂ and water. The presence of surfactant favored hydrophobic interactions that allowed the polar head of the surfactant to be exposed to the medium, resulting in a higher swelling rate and lower contact angle values. The HPMC with the highest MS presented the fastest swelling rate and the lowest contact angle. These findings are relevant for the formulations and reactions, where tuning the swelling kinetics is crucial for the final application.

Polymeric micelles loaded in situ gel with prednisolone acetate for ocular inflammation: development and evaluation

Aim: Our study developed a prednisolone acetate polymeric micelles (PM) system for ocular inflammation related to allergic uveitis. Methods: For PM development, a thin-film hydration procedure was used. Irritation, in vitro, ex vivo transcorneal permeation, micelle size, entrapment efficiency and histology within the eye were all calculated for PM. Results: The optimized in situ gel (A4) showed superior ex vivo transcorneal permeation with zero-order kinetics. Conclusion: The developed formulation could be a promising candidate for treating anterior uveitis via topical application to the anterior segment of the eye.

Rheological and mechanical properties of hydroxypropyl methylcellulose-based hydrogels and cryogels controlled by AOT and SDS micelles

HYPOTHESIS

The type and concentration of surfactants affect the rheological behavior of hydroxypropyl methylcellulose (HPMC) chains in hydrogels, influencing the microstructure and mechanical properties of HPMC cryogels.

EXPERIMENTS

Hydrogels and cryogels containing HPMC, AOT (bis (2-ethylhexyl) sodium sulfosuccinate or dioctyl sulfosuccinate salt sodium, two C8 chains and sulfosuccinate head group), SDS (sodium dodecyl sulfate, one C12 chain and sulfate head group), and sodium sulfate (salt, no hydrophobic chain) at different concentrations were investigated using small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), rheological measurements, and compressive tests.

FINDINGS

SDS micelles bound to the HPMC chains building "bead necklaces", increasing considerably the storage modulus G' values of the hydrogels and the compressive modulus E values of the corresponding cryogels. The dangling SDS micelles promoted multiple junction points among the HPMC chains. AOT micelles and HPMC chains did not form "bead necklaces". Although AOT increased the G' values of the hydrogels, the resulting cryogels were softer than pure HPMC cryogels. The AOT micelles are probably embedded between HPMC chains. The AOT short double chains rendered softness and low friction to the cryogel cell walls. Therefore, this work demonstrated that the structure of the surfactant tail can tune the rheological behavior of HPMC hydrogels and hence the microstructure of the resulting cryogels.

Biopolymeric Coatings for Local Release of Therapeutics from Biomedical Implants

The deployment of structures that enable localized release of bioactive molecules can result in more efficacious treatment of disease and better integration of implantable bionic devices. The strategic design of a biopolymeric coating can be used to engineer the optimal release profile depending on the task at hand. As illustrative examples, here advances in delivery of drugs from bone, brain, ocular, and cardiovascular implants are reviewed. These areas are focused to highlight that both hard and soft tissue implants can benefit from controlled localized delivery. The composition of biopolymers used to achieve appropriate delivery to the selected tissue types, and their corresponding outcomes are brought to the fore. To conclude, key factors in designing drug-loaded biopolymeric coatings for biomedical implants are highlighted.

Innovation in the Development of Synthetic and Natural Ocular Drug Delivery Systems for Eye Diseases Treatment: Focusing on Drug-Loaded Ocular Inserts, Contacts, and Intraocular Lenses

Nowadays, ocular drug delivery still remains a challenge, since the conventional dosage forms used for anterior and posterior ocular disease treatments, such as topical, systemic, and intraocular administration methods, present important limitations mainly related to the anatomical complexity of the eye. In particular, the blood-ocular barrier along with the corneal barrier, ocular surface, and lacrimal fluid secretion reduce the availability of the administered active compounds and their efficacy. These limitations have increased the need to develop safe and effective ocular delivery systems able to sustain the drug release in the interested ocular segment over time. In the last few years, thanks to the innovations in the materials and technologies employed, different ocular drug delivery systems have been developed. Therefore, this review aims to summarize the synthetic and natural drug-loaded ocular inserts, contacts, and intraocular lenses that have been recently developed, emphasizing the characteristics that make them promising for future ocular clinical applications.

Recent Advances in Cellulose-Based Hydrogels: Food Applications

In the past couple of years, cellulose has attracted a significant amount of attention and research interest due to the fact that it is the most abundant and renewable source of hydrogels. With increasing environmental issues and an emerging demand, researchers around the world are focusing on naturally produced hydrogels in particular due to their biocompatibility, biodegradability, and abundance. Hydrogels are three-dimensional (3D) networks created by chemically or physically crosslinking linear (or branching) hydrophilic polymer molecules. Hydrogels have a high capacity to absorb water and biological fluids. Although hydrogels have been widely used in food applications, the majority of them are not biodegradable. Because of their functional characteristics, cellulose-based hydrogels (CBHs) are currently utilized as an important factor for different aspects in the food industry. Cellulose-based hydrogels have been extensively studied in the fields of food packaging, functional food, food safety, and drug delivery due to their structural interchangeability and stimuli-responsive properties. This article addresses the sources of CBHs, types of cellulose, and preparation methods of the hydrogel as well as the most recent developments and uses of cellulose-based hydrogels in the food processing sector. In addition, information regarding the improvement of edible and functional CBHs was discussed, along with potential research opportunities and possibilities. Finally, CBHs could be effectively used in the industry of food processing for the aforementioned reasons.

Thermostability and in vivo performance of AAV9 in a film matrix

BACKGROUND

Adeno-associated virus (AAV) vectors are stored and shipped frozen which poses logistic and economic barriers for global access to these therapeutics. To address this issue, we developed a method to stabilize AAV serotype 9 (AAV9) in a film matrix that can be stored at ambient temperature and administered by systemic injection.

METHODS

AAV9 expressing the luciferase transgene was mixed with formulations, poured into molds and films dried under aseptic conditions. Films were packaged in individual particle-free bags with foil overlays and stored at various temperatures under controlled humidity. Recovery of AAV9 from films was determined by serial dilution of rehydrated film in media and infection of HeLa RC32 cells. Luciferase expression was compared to that of films rehydrated immediately after drying. Biodistribution of vector was determined by in vivo imaging and quantitative real-time PCR. Residual moisture in films was determined by Karl Fischer titration.

RESULTS

AAV9 embedded within a film matrix and stored at 4 °C for 5 months retained 100% of initial titer. High and low viscosity formulations maintained 90 and 85% of initial titer after 6 months at 25 °C respectively. AAV was not detected after 4 months in a Standard Control Formulation under the same conditions. Biodistribution and transgene expression of AAV stored in film at 25 or 4 °C were as robust as vector stored at -80 °C in a Standard Control Formulation.

CONCLUSIONS

These results suggest that storage of AAV in a film matrix facilitates easy transport of vector to remote sites without compromising in vivo performance.

Novel Features of Cellulose-Based Films as Sustainable Alternatives for Food Packaging

Packaging plays an important role in food quality and safety, especially regarding waste and spoilage reduction. The main drawback is that the packaging industry is among the ones that is highly dependent on plastic usage. New alternatives to conventional plastic packaging such as biopolymers-based type are mandatory. Examples are cellulose films and its derivatives. These are among the most used options in the food packaging due to their unique characteristics, such as biocompatibility, environmental sustainability, low price, mechanical properties, and biodegradability. Emerging concepts such as active and intelligent packaging provides new solutions for an extending shelf-life, and it fights some limitations of cellulose films and improves the properties of the packaging. This article reviews the available cellulose polymers and derivatives that are used as sustainable alternatives for food packaging regarding their properties, characteristics, and functionalization towards active properties enhancement. In this way, several types of films that are prepared with cellulose and their derivatives, incorporating antimicrobial and antioxidant compounds, are herein described, and discussed.

Surface Modifiers on Composite Particles for Direct Compaction

Direct compaction (DC) is considered to be the most effective method of tablet production. However, only a small number of the active pharmaceutical ingredients (APIs) can be successfully manufactured into tablets using DC since most APIs lack adequate functional properties to meet DC requirements. The use of suitable modifiers and appropriate co-processing technologies can provide a promising approach for the preparation of composite particles with high functional properties. The purpose of this review is to provide an overview and classification of different modifiers and their multiple combinations that may improve API tableting properties or prepare composite excipients with appropriate co-processed technology, as well as discuss the corresponding modification mechanism. Moreover, it provides solutions for selecting appropriate modifiers and co-processing technologies to prepare composite particles with improved properties.

Balsam Poplar Buds: Extraction of Potential Phenolic Compounds with Polyethylene Glycol Aqueous Solution, Thermal Sterilization of Extracts and Challenges to Their Application in Topical Ocular Formulations

Phenolic compounds of natural origin have been valued for their beneficial effects on health since ancient times. During our study, we performed the extraction of phenolic compounds from balsam poplar buds using different concentrations of aqueous polyethylene glycol 400 solvents (10-30% PEG400). The aqueous 30% PEG400 extract showed the best phenolic yield. The stability of the extract during autoclave sterilization was evaluated. The extract remained stable under heat sterilization. Ophthalmic formulations are formed using different concentrations (8-15%) of poloxamer 407 (P407) together with hydroxypropyl methylcellulose (0.3%), sodium carboxymethyl cellulose (0.3%) or hyaluronic acid (0.1%). Physicochemical parameters of the formulations remained significantly unchanged after sterilization. Formulations based on 12% P407 exhibited properties characteristic of in situ gels, the gelation point of the formulations was close to the temperature of the cornea. After evaluating the amount of released compounds, it was found that, as the concentration of polymers increases, the amount of released compounds decreases. Formulations based on 15% P407 released the least biologically active compounds. Sterilized formulations remained stable for 30 days.

Design and Optimization of In Situ Gelling Mucoadhesive Eye Drops Containing Dexamethasone

Poor bioavailability of eye drops is a well-known issue, which can be improved by increasing the residence time on the eye surface and the penetration of the active pharmaceutical ingredient (API). This study aims to formulate in situ gelling mucoadhesive ophthalmic preparations. To increase the residence time, the formulations were based on a thermosensitive polymer (Poloxamer 407 (P407)) and were combined with two types of mucoadhesive polymers. Dexamethasone (DXM) was solubilized by complexation with cyclodextrins (CD). The effect of the composition on the gel structure, mucoadhesion, dissolution, and permeability was investigated with 3³ full factorial design. These parameters of the gels were measured by rheological studies, tensile test, dialysis membrane diffusion, and in vitro permeability assay. The dissolution and permeability of the gels were also compared with DXM suspension and CD-DXM solution. The gelation is strongly determined by P407; however, the mucoadhesive polymers also influenced it. Mucoadhesion increased with the polymer concentration. The first phase of drug release was similar to that of the CD-DXM solution, then it became prolonged. The permeability of DXM was significantly improved. The factorial design helped to identify the most important factors, thereby facilitating the formulation of a suitable carrier for the CD-DXM complex.

Hydroxypropyl methylcellulose-sugarcane bagasse adsorbents for removal of 17α-ethinylestradiol from aqueous solution and freshwater

Adsorbents made of hydroxypropyl methylcellulose (HPMC) and sugarcane bagasse (BG) microparticles were applied for the separation of 17α-ethinylestradiol (EE2) from aqueous solution in batch, and from aqueous solution and freshwater in fixed-bed columns. HPMC chains and BG microparticles were crosslinked by the esterification with citric acid. The adsorbents presented compression modulus values that increased from 208 ± 20 kPa (pure HPMC) to 917 ± 90 kPa, when the content of BG particles added to HPMC was 50 wt% (HPMC50BG). The porosity (~ 97%), specific surface area (1.16 ± 0.10 m²/g) and swelling degree (20 ± 1 g water/g) values were not affected by the addition of BG particles. The adsorption isotherms determined for EE2 on HPMC and on HPMC50BG fitted to the Langmuir and Freundlich models; the adsorption capacity of HPMC was slightly higher than that of composite HPMC50BG. Nevertheless, the addition of BG particles rendered outstanding mechanical reinforcement and dimensional stability to the adsorbents. The adsorption was driven by (i) hydrophobic interactions between EE2 methylene and aromatic groups and HPMC methyl groups, as evidenced by FTIR spectroscopy, and (ii) H bonds between HPMC and EE2 hydroxyl groups, as revealed by the adsorption enthalpy change (ΔH_ads) of - 45 kJ/mol. Column adsorption experiments of EE2 from aqueous solution on HPMC and HPMC50BG indicated adsorptive capacity (q₀) values of 8.06 mg/g and 4.07 mg/g, respectively. These values decreased considerably for the adsorption of EE2 from river water, probably due to the competition of EE2 with humic substances dissolved in natural water. The HPMC adsorbents could be recycled retaining up to 83% of the original efficiency.

Development and In Vitro-Ex Vivo Evaluation of Novel Polymeric Nasal Donepezil Films for Potential Use in Alzheimer's Disease Using Experimental Design

The objective and novelty of the present study is the development and optimization of innovative nasal film of Donepezil hydrochloride (DH) for potential use in Alzheimer’s disease. Hydroxypropyl-methyl-cellulose E50 (factor A) nasal films, with Polyethylene glycol 400 as plasticizer (factor B), and Methyl-β-Cyclodextrin, as permeation enhancer (factor C), were prepared and characterized in vitro and ex vivo. An experimental design was used to determine the effects of the selected factors on permeation profile of DH through rabbit nasal mucosa (response 1), and on film flexibility/foldability (response 2). A face centered central composite design with three levels was applied and 17 experiments were performed in triplicate. The prepared films exhibited good uniformity of DH content (90.0 ± 1.6%−99.8 ± 4.9%) and thickness (19.6 ± 1.9−170.8 ± 11.5 μm), storage stability characteristics, and % residual humidity (<3%), as well as favourable swelling and mucoadhesive properties. Response surface methodology determined the optimum composition for flexible nasal film with maximized DH permeation. All selected factors interacted with each other and the effect of these interactions on responses is strongly related to the factor’s concentration ratios. Based on these encouraging results, in vivo serum and brain pharmacokinetic study of the optimized nasal film, in comparison to DH oral administration, is ongoing in an animal model.