Potential application of Metolose in a thermoresponsive transdermal therapeutic system

In Situ Gelling Hydroxypropyl Cellulose Formulation Comprising Cannabidiol-Loaded Block Copolymer Micelles for Sustained Drug Delivery

Cannabidiol (CBD) is a natural terpenophenolic compound with known pharmacological activities, but the poor solubility of CBD in water limits its widespread use in medicine and pharmacy. Polymeric (nano)carriers demonstrated high potential for enhancing the solubility and therapeutic activity of lipophilic drugs such as CBD. Here, we report the elaboration of a novel hydroxypropyl cellulose (HPC)-based in situ gelling formulation for controlled delivery of CBD. In the first stage, nanosized polymeric micelles from poly(ethylene oxide)-block-poly(α-cinnamyl-ε-caprolactone-co-ε-caprolactone) (PEO-b-P(CyCL-co-CL) diblock copolymers) were used to increase the solubility of CBD in water. Different copolymers were assessed, and the carrier with the highest encapsulation efficiency (EE) and drug loading capacity (DLC) was selected for further elaboration of nanocomposite in situ gel formulations. Next, the sol-to-gel transition behavior of HPC as a function of K2SO4 concentration in the aqueous solution was investigated by microcalorimetry and dynamic oscillatory rheology, and the optimal formulation capable of forming a physical gel under physiological conditions was determined. Finally, injectable nanocomposite hydrogels comprising cannabidiol were fabricated, and their drug release profile and cytotoxicity against human tumor cell lines were evaluated. The in situ gels exhibited prolonged drug release over 12 h, controlled by gel erosion, and the cytotoxicity of formulated cannabidiol was comparable with that of a free drug.

Review of Applications and Future Prospects of Stimuli-Responsive Hydrogel Based on Thermo-Responsive Biopolymers in Drug Delivery Systems

Some of thermo-responsive polysaccharides, namely, cellulose, xyloglucan, and chitosan, and protein-like gelatin or elastin-like polypeptides can exhibit temperature dependent sol–gel transitions. Due to their biodegradability, biocompatibility, and non-toxicity, such biomaterials are becoming popular for drug delivery and tissue engineering applications. This paper aims to review the properties of sol–gel transition, mechanical strength, drug release (bioavailability of drugs), and cytotoxicity of stimuli-responsive hydrogel made of thermo-responsive biopolymers in drug delivery systems. One of the major applications of such thermos-responsive biopolymers is on textile-based transdermal therapy where the formulation, mechanical, and drug release properties and the cytotoxicity of thermo-responsive hydrogel in drug delivery systems of traditional Chinese medicine have been fully reviewed. Textile-based transdermal therapy, a non-invasive method to treat skin-related disease, can overcome the poor bioavailability of drugs from conventional non-invasive administration. This study also discusses the future prospects of stimuli-responsive hydrogels made of thermo-responsive biopolymers for non-invasive treatment of skin-related disease via textile-based transdermal therapy.

Poloxamer-based in situ gelling thermoresponsive systems for ocular drug delivery applications

In situ gels have recently received interest as ocular drug delivery vehicles because they combine the merits of easy instillation and sustained drug release. In this review, we focus on the use of poloxamers as in situ gelling systems in ocular drug delivery because of their thermoresponsive gelling behaviour, biocompatibility, and ease of sterilisation. Furthermore, the sol-gel transition temperature, mucoadhesive properties, and drug release profiles of poloxamer-based in situ gels can be finely tuned, enabling them to be used as vehicles for the delivery of small and large drug molecules to treat diseases of the anterior and posterior segments of the eye. Poloxamer-based ocular products have already found their way to the pharmaceutical market, but remain a potential arena for further investigation and commercial exploitation.

Biopolymer-based strategies in the design of smart medical devices and artificial organs

Advances in regenerative medicine and in modern biomedical therapies are fast evolving and set goals causing an upheaval in the field of materials science. This review discusses recent developments involving the use of biopolymers as smart materials, in terms of material properties and stimulus-responsive behavior, in the presence of environmental physico-chemical changes. An overview on the transformations that can be triggered in natural-based polymeric systems (sol-gel transition, polymer relaxation, cross-linking, and swelling) is presented, with specific focus on the benefits these materials can provide in biomedical applications.

Effects of Cyclodextrins (β and γ) and l-Arginine on Stability and Functional Properties of Mucoadhesive Buccal Films Loaded with Omeprazole for Pediatric Patients

Omeprazole (OME) is employed for treating ulcer in children, but is unstable and exhibits first pass metabolism via the oral route. This study aimed to stabilize OME within mucoadhesive metolose (MET) films by combining cyclodextrins (CD) and l-arginine (l-arg) as stabilizing excipients and functionally characterizing for potential delivery via the buccal mucosa of paediatric patients. Polymeric solutions at a concentration of 1% w/w were obtained by dispersing the required weight of metolose in 20% v/v ethanol as solvent at a temperature of 40 °C using polyethylene glycol (PEG 400) (0.5% w/w) as plasticizer. The films were obtained by drying the resulting polymer solutions at in an oven at 40 °C. Textural (tensile and mucoadhesion) properties, physical form (differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy), residual moisture content (thermogravimetric analysis (TGA)) and surface morphology (scanning electron microscopy (SEM)) were investigated. Optimized formulations containing OME, CDs (β or γ) and l-arg (1:1:1) were selected to investigate the stabilization of the drug. The DSC, XRD, and FTIR showed possible molecular dispersion of OME in metolose film matrix. Plasticized MET films containing OME:βCD:l-arg 1:1:1 were optimum in terms of transparency and ease of handling and therefore further functionally characterized (hydration, mucoadhesion, in vitro drug dissolution and long term stability studies). The optimized formulation showed sustained drug release that was modelled by Korsmeyer⁻Peppas equation, while the OME showed stability under ambient temperature conditions for 28 days. The optimized OME loaded MET films stabilized with βCD and l-arg have potential for use as paediatric mucoadhesive buccal delivery system, which avoids degradation in the stomach acid as well as first pass metabolism in the liver.

Cold Chain-Free Storable Hydrogel for Infant-Friendly Oral Delivery of Amoxicillin for the Treatment of Pneumococcal Pneumonia

Pneumonia is the major cause of death in children under five, particularly in developing countries. Antibiotics such as amoxicillin greatly help in mitigating this problem. However, there is a lack of an infant/toddler-friendly formulation for countries with limited clean water orr electricity. Here, we report the development of a shear-thinning hydrogel system for the oral delivery of amoxicillin to infant/toddler patients, without the need of clean water and refrigeration. The hydrogel formulation consists of metolose (hydroxypropyl methylcellulose) and amoxicillin. It preserves the structural integrity of antibiotics and their antibacterial activity over 12 weeks at room temperature. Pharmacokinetic profiling of mice reveals that the hydrogel formulation increases the bioavailability of drugs by ∼18% compared to that with aqueous amoxicillin formulation. More importantly, oral gavage of this formulation in a mouse model of secondary pneumococcal pneumonia significantly ameliorates inflammatory infiltration and tissue damage in lungs, with a 10-fold reduction in bacterial counts compared to those in untreated ones. Given the remarkable antibacterial efficacy as well as the use of FDA-regulated ingredients (metolose and amoxicillin), the hydrogel formulation holds great promise for rapid clinical translation.

A review of polymers as multifunctional excipients in drug dosage form technology

In the article, groups of multifunctional polymers used in drug dosage form technology were classified and evaluated. These compounds, in addition to their basic function as excipients, may have additional properties, e.g. stimuli sensitivity, enzyme inhibition, intestinal epithelium penetration enhancement, efflux pump inhibition, taste-masking, pharmacological activity and the ability to interact with enzymes responsible for drug metabolism. While classifying specific groups of multifunctional polymers, special emphasis was placed on the advantages of using them when designing new drug. Such advantages include, i.a., increasing substance bioavailability, improving substance stability during formulation and the possibility of obtaining forms of controlled or localized release to a specific site in the organism.

New formulation of in situ gelling Metolose-based liquid suppository

CONTEXT

An in situ gelling liquid suppository is liquid at room temperature but forms a gel at body temperature. In our work, Metolose® SM-4000 (methylcellulose) is studied that basically shows thermal gelation at 68°C (2%, w/w).

OBJECTIVE

The objective was to study the potency of different factors (concentration, pH, additives) to change the value of thermal gelation temperature (T (t)) for Metolose® to form an in situ gelling liquid suppository.

MATERIALS AND METHODS

We studied the effect of Metolose® concentration, pH, and salts (sodium chloride, potassium chloride, sodium hydrogen carbonate, and sodium monohydrogen phosphate) on T (t) by viscosimetry. To choose the appropriate compound, in vitro drug release was examined. Rectal safety test was performed on rats in vivo after 12-hour application.

RESULTS

Increasing the Metolose® concentrations (0.5-4%, w/w), T (t) can be decreased, but it also altered the consistency of gel. pH does not affect the T (t). The water-soluble salts allowed reducing the gelation temperature to 37°C. Sodium monohydrogen phosphate in 4.5% concentration was found to be the most appropriate. The impact of examined factors on in vitro drug release of piroxicam from the in situ-formed gel was characterized according to Fickian diffusion. Metolose® and the chosen salt did not cause any morphological damage on the rectal tissues.

DISCUSSION

According to our study, Metolose® has the physical and chemical potential to be used as base for liquid suppositories.

Design and formulation of mebeverine HCl semisolid formulations for intraorally administration

Gel formulations of mebeverine hydrochloride (MbHCl) containing hydroxypropylmethylcellulose (HPMC), metolose (MTL), and poloxamer 407 (PLX) were prepared to be used in the treatment of different oral painful conditions. HPMC was used as a mucoadhesive gel base while MTL and PLX were used to prepare sol-gel thermosensitive gels. MTL and PLX formulations showed proper sol-gel transition temperature for intraoral application. Formulations were evaluated in terms of their viscosity, mechanical properties, mucoadhesivity, stability, and in vitro drug release. The formulation prepared with 2% of HPMC K100M provided the highest viscosity at room temperature. However, the viscosity of HPMC-PLX mixture showed a significant increase at body temperature. The greatest mucoadhesion was also noted in HPMC-PLX combinations. Texture profile analysis exhibited the differences of the adhesion, hardness, elasticity, cohesiveness, and compressibility of the formulations. The release profiles of MbHCl were obtained, and non-Fickian release was observed from all the formulations. The formulations were stored at different temperature and relative humidity. No significant changes were observed at the end of the 3 months. HPMC-PLX formulation of MbHCl was chosen for in vivo studies, and it remained longer than dye solution on the rabbit's intraoral mucosal tissue. It was found worthy of further clinical evaluation.

A review of multi-responsive membranous systems for rate-modulated drug delivery

Membrane technology is broadly applied in the medical field. The ability of membranous systems to effectively control the movement of chemical entities is pivotal to their significant potential for use in both drug delivery and surgical/medical applications. An alteration in the physical properties of a polymer in response to a change in environmental conditions is a behavior that can be utilized to prepare 'smart' drug delivery systems. Stimuli-responsive or 'smart' polymers are polymers that upon exposure to small changes in the environment undergo rapid changes in their microstructure. A stimulus, such as a change in pH or temperature, thus serves as a trigger for the release of drug from membranous drug delivery systems that are formulated from stimuli-responsive polymers. This article has sought to review the use of stimuli-responsive polymers that have found application in membranous drug delivery systems. Polymers responsive to pH and temperature have been extensively addressed in this review since they are considered the most important stimuli that may be exploited for use in drug delivery, and biomedical applications such as in tissue engineering. In addition, dual-responsive and glucose-responsive membranes have been also addressed as membranes responsive to diverse stimuli.

Formulation of thermoresponsive and bioadhesive gel for treatment of oesophageal pain and inflammation

The aim of this study was the formulation and examination of a novel thermoresponsive and bioadhesive, in situ gelling drug delivery system, which can be used in the treatment of oesophageal pain and inflammation. A bioadhesive cellulose derivative (Metolose) 60SH) was used as a thermoresponsive material, because Metolose has thermal gelation properties at certain temperature. The thermal gelation temperature (T(2)) of Metolose 60SH 2 w/w% solution is above body temperature (65-66 degrees C), but by using different methods (Metolose 60SH concentration, auxiliary materials), it can be shifted near to body temperature. The pH alteration between pH=2-10 and the application of different alcohols did not influence the gelation temperature, but using water-soluble salts and changing the concentration of Metolose 60SH solution between 2 and 3 w/w% the thermal gelation point could be decreased. Different NSAIDs were used as model drugs and which had not influence on thermal gelation temperature, but difference in in vitro liberation and penetration can be observed. In vitro adhesion test pointed out that the condition of investigated membrane can change the adhesion. Morphological test of oesophageal tissue showed that investigated materials had no irritative or tissue-damaging effect on the oesophageal mucosa even after 12h.