Formulation and characterization of ethylcellulose microparticles containing .L-alanyl- L-glutamine peptide

Kappa-carrageenan based hybrid hydrogel for soft tissue engineering applications

Biological materials such as cell-derived membrane vesicles have emerged as alternative sources for molecular delivery systems, owing to multicomponent features, the inherent functionalities and signaling networks, and easy-to-carry therapeutic agents with various properties. Herein, red blood cell membrane (RBCM) vesicle-laden methacrylate kappa-carrageenan (KaMA) composite hydrogel is introduced for soft tissue engineering. Results revealed that the characteristics of hybrid hydrogels were significantly modulated by changing the RBCM vesicle content. For instance, the incorporation of 20% (v/v) RBCM significantly enhanced compressive strength from 103 ± 26 kPa to 257 ± 18 kPa and improved toughness under the cyclic loading from 1.0 ± 0.4 kJ m-3to 4.0 ± 0.5 kJ m-3after the 5thcycle. RBCM vesicles were also used for the encapsulation of curcumin (CUR) as a hydrophobic drug molecule. Results showed a controlled release of CUR over three days of immersion in PBS solution. The RBCM vesicles laden KaMA hydrogels also supportedin vitrofibroblast cell growth and proliferation. In summary, this research sheds light on KaMA/RBCM hydrogels, that could reveal fine-tuned properties and hydrophobic drug release in a controlled manner.

Enhancement of Release and Solubility of Curcumin from Electrospun PEO-EC-PVP Tripolymer-Based Nanofibers: A Study on the Effect of Hydrogenated Castor Oil

This study reveals the state-of-the-art fabrication of a tripolymer-based electrospun nanofiber (NF) system to enhance the release, solubility, and transdermal penetration of curcumin (Cur) with the aid of in situ release of infused castor oil (Co). In this regard, Cur-loaded Co-infused polyethylene oxide (PEO), ethyl cellulose (EC), and polyvinyl pyrrolidone (PVP) tripolymer-based NF systems were developed to produce a hybridized transdermal skin patch. Weight percentages of 1-4% Cur and 3-10% of Co were blended with PEO-EC-PEO and PEO-EC-PVP polymer systems. The prepared NFs were characterized by SEM, TEM, FT-IR analysis, PXRD, differential scanning calorimetry (DSC), and XPS. Dialysis membranes and vertical Franz diffusion cells were used to study the in vitro drug release and transdermal penetration, respectively. The results indicated that maintaining a Cur concentration of 1-3 wt % with 3 wt % Co in both PEO-EC-Co-Cur@PEO and PEO-EC-Co-Cur@PVP gave rise to nanofibers with lowered diameters (144.83 ± 48.05-209.26 ± 41.80 nm and 190.20 ± 59.42-404.59 ± 45.31 nm). Lowered crystallinity observed from the PXRD patterns and the disappearance of exothermic peaks corresponding to the melting point of Cur suggested the formation of an amorphous NF structure. Furthermore, the XPS data revealed that the Cur loading will possibly take place at the inner interface of PEO-EC-Co-PEO and PEO-EC-Co-PVP NFs rather than on the surface. The beneficiary role of Co on the release and dermal penetration of Cur was further confirmed from the respective release data which indicated that PEO-EC-Co-Cur@PEO would lead to a rapid release (4-5 h), while PEO-EC-Co-Cur@PVP would lead to a sustained release over a period of 24 h in the presence of Co. Transdermal penetration of the released Cur was further evidenced with the development of color in the receiver compartment of the diffusion cell. DPPH results further corroborated that a sustained antioxidant activity is observed in the released Cur where the free-radical scavenging activity is intact even after subjecting to an electrospinning process and under extreme freeze-thaw conditions.

Thermosensitive gel based on cellulose derivative for topical delivery of propolis in acne treatment

Thermosensitive bioadhesive formulations can display increased retention time, skin permeation, and improve the topical therapy of many drugs. Acne is an inflammatory process triggered by several factors like the proliferation of the bacteria Propionibacterium acnes. Aiming a new alternative treatment with a natural source, propolis displays great potential due to its antibiotic, anti-inflammatory and healing properties. This study describes the development of bioadhesive thermoresponsive platform with cellulose derivatives and poloxamer 407 for propolis skin delivery. Propolis ethanolic extract (PES) was added to the formulations with sodium carboxymethylcellulose (CMC) or hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (Polox). The formulations were characterized as rheology, bioadhesion and mechanical analysis. The selected formulations were investigated as in vitro propolis release, cytotoxicity, ex vivo skin permeation by Fourier Transform Infrared Photoacoustic Spectroscopy, and the activity against P. acnes. Formulations showed suitable sol-gel transition temperature, shear-thinning behavior and texture profile. CMC presence decreased cohesiveness and adhesiveness of formulations. Polox/HPMC/PES system displayed less cytotoxicity, modified propolis release governed by anomalous transport, skin permeation and activity against P. acnes. These results indicate important advantages in the topical treatment of acne and suggest a potential formulation for clinical evaluation.

Drug Delivery Platforms Containing Thermoresponsive Polymers and Mucoadhesive Cellulose Derivatives: A Review of Patents

Nowadays, the development of mucoadhesive systems for drug delivery has gained keen interest, with enormous potential in applications through different routes. Mucoadhesion characterizes an attractive interaction between the pharmaceutical dosage form and the mucosal surface. Many polymers have shown the ability to interact with mucus, increasing the residence time of local and/or systemic administered preparations, such as tablets, patches, semi-solids, and micro and nanoparticles. Cellulose is the most abundant polymer on the earth. It is widely used in the pharmaceutical industry as an inert pharmaceutical ingredient, mainly in its covalently modified forms: methylcellulose, ethylcellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methylcellulose, and carboxymethylcellulose salts. Aiming to overcome the drawbacks of oral, ocular, nasal, vaginal, and rectal routes and thereby maintaining patient compliance, innovative polymer blends have gained the interest of the pharmaceutical industry. Combining mucoadhesive and thermoresponsive polymers allows for simultaneous in situ gelation and mucoadhesion, thus enhancing the retention of the system at the site of administration and drug availability. Thermoresponsive polymers have the ability to change physicochemical properties triggered by temperature, which is particularly interesting considering the physiological temperature. The present review provides an analysis of the main characteristics and applications of cellulose derivatives as mucoadhesive polymers and their use in blends together with thermoresponsive polymers, aiming at platforms for drug delivery. Patents were reviewed, categorized, and discussed, focusing on the applications and pharmaceutical dosage forms using this innovative strategy. This review manuscript also provides a detailed introduction to the topic and a perspective on further developments.

Design of Mucoadhesive Strips for Buccal Fast Release of Tramadol

Tramadol hydrochloride is a synthetic analogue of codeine and shows activity on the central nervous system as an opioid agonist and inhibitor of serotonin and norepinephrine reuptake. It has been used for controlling moderate to severe pain. Mucoadhesive fast-dissolving films can present greater drug availability and patient acceptance when compared to the systems of peroral administration. The films were prepared using the solvent casting method with ethylcellulose, polyvinylpyrrolidone and poly(vinyl alcohol). The effect of each polymer concentration was investigated using a 2³ factorial design with repetition at the central point. The formulations were subjected to physicochemical, mechanical, ex vivo mucoadhesive and in vitro drug release profile analysis. These properties were dependent on the polymeric composition (independent factors) of each system. The optimized formulations showed good macroscopic characteristics, improved resistance to bending, rigidity, rapid swelling up to 60 s, improved mechanical and mucoadhesive characteristics, and also fast dissolving and tramadol release. The optimized formulations constitute platforms and strategies to improve the therapy of tramadol with regard to availability at the site of application, considering the necessity of rapid pain relief, and show potential for in vivo evaluation.

Preparation and Characterization of Silver(I) Ethylcellulose Thin Films as Potential Food Packaging Materials

Ag(I)-containing ethylcellulose (EC) films suitable as antbacterial packaging materials have been prepared and fully characterized. Different preparation methods, including the use of green casting solvents, are proposed. The Ag(I) acylpyrazolonato complexes, [Ag(Q^py,CF3 )(L)], L=benzylimidazole (Bzim) and L=ethylimidazole (EtimH), used as active additives, display different modes of interactions with EC, depending on their structural features. A thorough investigation of the EC liquid-crystalline lyotropic phase and its changes with the introduction of silver additives, has been conducted, revealing either the inclusion of complex molecules into the inner structure of the EC matrix or their dispersion on its surface. Moreover, the bactericidal activity of the prepared Ag(I) films seems to be related to the interaction between silver additives and the polymeric EC matrix. Indeed, the EC-2b films show a particularly good performance even with a low silver content, with a relative bacterial killing of about 100 %. Tests for Ag(I) migration have been performed by using three food stimulants under two assay conditions. Low values of silver release are recorded, particularly at low concentration of silver content, in the case of all new prepared Ag(I) films.

Premium ethylcellulose polymer based architectures at work in drug delivery

Premium ethylcellulose polymers are hydrophobic cellulose ether based biomaterials widely employed as biocompatible templates for the design of novel drug delivery systems. They are classified as United States Food and Drug Administration Generally-Recognized-As-Safe chemical substances and have been extensively utilized within the biomedical and pharmaceutical industries for over half a century. They have so far demonstrated the potential to modulate and improve the physiological performance of bioactives leading to the desired enhanced prophylactic and therapeutic outcomes. This review therefore presents a scholarly survey of inter-disciplinary developments focused on the functionalities of ethylcellulose polymers as biomaterials useful for the design of smart delivery architectures for relevant pharmacotherapeutic biomedical applications. Emphasis was placed on evaluating scientific resources related to recent advancements and future directions associated with its applications as delivery systems for drugs and biologics within the past decade thus complementing other specialized reviews showcasing the theme.

Ethylcellulose-A Pharmaceutical Excipient with Multidirectional Application in Drug Dosage Forms Development

Polymers constitute the most important group of excipients utilized in modern pharmaceutical technology, playing an essential role in the development of drug dosage forms. Synthetic, semisynthetic, and natural polymeric materials offer opportunities to overcome different formulative challenges and to design novel dosage forms for controlled release or for site-specific drug delivery. They are extensively used to design therapeutic systems, modify drug release, or mask unpleasant drug taste. Cellulose derivatives are characterized by different physicochemical properties, such as swellability, viscosity, biodegradability, pH dependency, or mucoadhesion, which determine their use in industry. One cellulose derivative with widespread application is ethylcellulose. Ethylcellulose is used in pharmaceutical technology as a coating agent, flavoring fixative, binder, filler, film-former, drug carrier, or stabilizer. The aim of this article is to provide a broad overview of ethylcellulose utilization for pharmaceutical purposes, with particular emphasis on its multidirectional role in the development of oral and topical drug dosage forms.

Design and characterization of an organogel system containing ascorbic acid microparticles produced with propolis by-product

This study aimed to prepare and characterize organogels containing microparticles of ascorbic acid (AA) obtained from propolis by-product. The formulations F1 (5% of microparticles) and F2 (10% of microparticles) were evaluated regarding rheological and textural properties, antioxidant and radical scavenging activity, in vitro release and cellular studies. The organogels showed plastic flow behavior and rheopexy. The textural parameters were within acceptable values for semisolid formulations. The antioxidant capacity of organogels F1 and F2 by the DPPH assay demonstrated IC₅₀ ranging from 1523.59 to 1166.97 μg/mL, respectively. For the FRAP assay, the values found were 842.88 and 956.14 μmol of FSE/g formulation, respectively. Good scavenging activity against nitrogen species was observed. The concentration of 63 μg/mL did not present toxicity on HaCaT and HFF-1 cells. In vitro release profile of AA from organogels showed a slow pattern of drug release, mainly for F2. Therefore, the proposed organogel containing AA microparticles with propolis by-product matrix represents a promising platform for topical drug delivery with antioxidant effect.

Development of a microparticulate system containing Brazilian propolis by-product and gelatine for ascorbic acid delivery: evaluation of intestinal cell viability and radical scavenging activity

The use of propolis by-product (PBP) microparticles (MP) as delivery systems can be a promising tool to surpass drawbacks related to low stability of ascorbic acid (AA).

Evaluation of ethylcellulose and its pseudolatex (Surelease) in preparation of matrix pellets of theophylline using extrusion-spheronization

OBJECTIVES

This study evaluates the effect of substitution of microcrystalline cellulose (MCC) with ethylcellulose (EC) on mechanical and release characteristics of theophylline pellets.

MATERIALS AND METHODS

The effect of addition of EC was investigated on characteristics of pellets with varying drug content prepared by extrusion-spheronization. Also the effect of type of granulating liquid (water or Surelease) was investigated on characteristics of selected pellets. The pellets were characterized for particle size (sieve analysis), mechanical strength, morphology (microscopy), thermal (DSC) and dissolution behaviors.

RESULTS

The exrtudability of the wet mass was reduced upon inclusion of EC so that complete replacement of MCC was not possible. Increase in EC percentage led to lower production yield and formation of pellets with larger diameter and slightly rough surfaces. Inclusion of EC also affected the mechanical properties of pellets but had negligible effect on drug release profile. The surface of selected pellets became smoother and their production yield increased upon the use of Surelease as granulating liquid. In addition the rate of drug release decreased to some extent when Surelease was used.

CONCLUSION

Preparation of theophylline pellets with EC alone was not possible in process of extrusion-spheronization. Partial replacement of MCC with EC changed physicomechanical properties of pellets but hardly affected drug release. Although the use of Surelease as granulation liquid slightly decreased the rate of drug release, desirable matrix pellets with sustained drug release could not be produced. Despite this outcome however, these pellets could benefit from reduced coating thickness for drug release control.

Functional Polymeric Systems as Delivery Vehicles for Methylene Blue in Photodynamic Therapy

Antibiotic-resistant microorganisms have become a global concern, and the search for alternative therapies is very important. Photodynamic therapy (PDT) consists of the use of a nontoxic photosensitizer (PS), light, and oxygen. This combination produces reactive oxygen species and singlet oxygen, which can alter cellular structures. Methylene blue (MB) is a substance from the phenothiazine class often used as a PS. In this work, to facilitate the PS contact within the wounds, we have used Design of Experiments 2(3) plus central point to develop functional polymeric systems. The formulations were composed by poloxamer 407 [15.0, 17.5, or 20.0% (w/w)], Carbopol 934P [0.15, 0.20, or 0.25% (w/w)], and MB [0.25, 0.50, or 0.75% (w/w)]. The sol-gel transition temperature, flow rheometry, in vitro MB release, and ex vivo study of MB cutaneous permeation and retention were investigated. Moreover, the evaluation of photodynamic activity was also analyzed by in vitro degradation of tryptophan by singlet oxygen and using Artemia salina. The determination of the gelation temperature displayed values within the range of 25-37 °C, and the systems with better characteristics were subjected to rheological analysis and in vitro release profiling. The 20/0.15/0.25 formulation showed the best release profile (42.57% at 24 h). This system displayed no significant skin permeation (0.38% at 24 h), and the photooxidation of tryptophan test showed the production of reactive species of oxygen. The toxicity test using A. salina revealed that the MB associated with the light increased the mortality rate by 61.29%. Therefore, investigating the PDT efficacy of the functional polymeric system containing MB will be necessary in the future.

Pharmaceutical films made from the waste material from the preparation of propolis extracts: development and characterization

abstract This study investigated the development and characterized the physicochemical properties of films obtained from by-products (BP) from the preparation of propolis extracts. Films were produced in the presence and absence of a polymeric adjuvant (gelatin or ethylcellulose) and propylene glycol by a solvent casting method. Density, surface topography by scanning electron microscopy, mechanical properties (folding endurance, tensile strength and percentage elongation), water vapour permeability (WVP), moisture uptake capacity, thermogravimetry, differential scanning calorimetry and Fourier transform infrared spectroscopy (FTIR) were determined. The films were a transparent, light greenish-yellow colour, with a uniform surface, and were flexible and easy to handle. The thickness and density of the preparations indicated that the compounds were homogeneously dispersed throughout the film. Mechanical properties were influenced by the film composition; films containing gelatin were more resistant to stress, while those containing ethylcellulose were more flexible. Increasing the adjuvant concentration decreased the elasticity and the rupture resistance, but increased the moisture uptake capacity and WVP of the formulations. BP was thermally stable as were the films. FTIR tests suggested interactions between BP and the adjuvants. This work could contribute to the utilization of BP to prepare films for food and pharmaceutical uses

Surelease as granulating liquid in preparation of sustained release matrices of ethylcellulose and theophylline

OBJECTIVES

Use of Surelease as a granulation liquid in preparation of granules and matrices of theophylline and ethylcellulose was evaluated.

MATERIALS AND METHODS

Physical mixtures (at 1:1 or 1:1.5 drug:polymer) were granulated using water, Surelease or diluted Surelease as granulating liquid. The granule characteristics (shape, size, flow rate, mechanical properties, friability and release profile) were studied. Afterwards, matrices were manufactured and their crushing strengths, friability and release profiles were determined.

RESULTS

Granulation produced agglomerated particles with better flowability than physical mixtures. Change of granulation liquid from water to Surelease or diluted Surelease led to the marginal increase in size of granules at 1:1 drug:polymer, however, the flow rate and Carr's index were considerably improved. The hardness, elastic modulus, friability and rate of drug release were not affected by granulation liquid. Increase in polymer content resulted in reduction in size of granules, flow rate, elastic modulus and rate of drug release. However hardness of the granules was unaffected. Granulation process and granulation liquid did not affect the hardness, and dissolution rate of matrices at 1:1 drug:polymer, while the use of Surelease or diluted Surelease as a granulating liquid, increased the hardness and decreased drug release rate at 1:1.5 drug:polymer. Matrices prepared from Surelease or diluted Surelease showed similar characteristics.

CONCLUSIONS

Surelease is a suitable granulating liquid for preparation of ethylcellulose matrices especially when high amount of polymer is used and could not only improve the flow and compatibility of the granules, but also help in reducing the rate of drug release.