Properties of bioadhesive ketoprofen liquid suppositories: preparation, determination of gelation temperature, viscosity studies and evaluation of mechanical properties using texture analyzer by 4 × 4 factorial design

Citric acid crosslinked hydroxyethyl tamarind gum-based hydrogel films: A promising biomaterial for drug delivery

This investigation explored citric acid crosslinked hydroxyethyl tamarind gum hydrogel films as a potential biomaterial for drug delivery. Hydroxyethylation of tamarind gum aimed to improve its solubility, swelling, and crosslinking potential. The synthesized hydroxyethylated tamarind gum (HETG) was comprehensively characterized, revealing the presence of hydroxyethyl groups and increased viscosity in comparison to unmodified tamarind gum. The citric acid crosslinked HETG hydrogel films were developed by esterification-crosslinking mechanism. The films were characterized using instrumental techniques and evaluated for total carboxyl content, mechanical properties, swelling behavior, drug loading, drug release, antibacterial activity, hemocompatibility and in vitro wound healing activity. The presence of ester crosslinks and extent of crosslinking was confirmed through total carboxyl content and instrumental analysis. Varying HETG (2-2.5%w/v) and citric acid (1-1.4 %w/v) concentrations resulted in films with tunable mechanical strength, swelling, and drug loading. The films effectively controlled the release of a water-soluble drug (80.87-99.70 % in 24 h) through a non-Fickian diffusion mechanism. The optimized HETG hydrogel film showed antimicrobial activity, hemocompatibility, and support for cell growth, confirming its biocompatibility and potential for wound healing. Citric acid-crosslinked HETG films appear promising for drug delivery to wounds, meriting further in vivo study.

Enhancing anti-inflammatory effect of brucine nanohydrogel using rosemary oil: a promising strategy for dermal delivery in arthritic inflammation

Brucine (BRU), an active constituent of Strychnos nux-vomica L., is one of the potential agents to control subside swelling in arthritis. However, its hydrophobic nature, poor permeation, shorter half-life, narrow therapeutic window, and higher toxicity impede its clinical applications. Hence, this investigation was aimed to develop and evaluate novel BRU loaded β-cyclodextrin (β-CD) nanosponges (BRUNs) hydrogel consisting rosemary essential oil (RO), which have been tailored for delayed release, enhanced skin permeation, and reduced irritation, while retaining anti-oxidant and anti-inflammatory activities of this bioactive. Firstly, BRUNs were fabricated by melt technique and characterized appropriately. BRUNs6 demonstrated two fold enhancement in BRU solubility (441.692 ± 38.674) with minimum particle size (322.966 ± 54.456) having good PDI (0.571 ± 0.091) and zeta potential (-14.633 ± 6.357). In vitro release results demonstrated delayed release of BRU from BRUNs6 (67 ± 4.25%) over 24 h through molecular diffusion mechanism. Further, preserved anti-inflammatory (53.343 ± 0.191%) and antioxidant potential (60.269 ± 0.073%) of bioactive was observed in BRUNs6. Hence, this Ns batch was engrossed with Carbopol®934 hydrogel with RO and characterized. In vitro (release and anti-inflammatory activity), ex-vivo (skin permeability) and in vivo (carrageenan-induced inflammation) assays along with irritation study were conducted for fabricated hydrogels. Results revealed that in vitro release of BRU was further delayed from Ns hydrogel with RO (56.45 ± 3.01%) following Fickian mechanism. Considerable enhancement in skin permeability (60.221 ± 0.322 µg/cm2/h) and preservation of anti-inflammatory activity (94.736 ± 2.002%) was also observed in BRUNs6 hydrogel containing RO. The irritation of BRU was found reduced (half) after its entrapped in Ns. Further, as a proof of concept, BRUNs6 hydrogel with RO effectively reduced (75.757 ± 0.944%) carrageenan-induced inflammation in rat model in comparison to pure BRU (54.914 ± 1.081%). Hence, BRUNs hydrogel with RO can be considered as a promising alternative for dermal delivery of BRU in arthritis.

Development and Characterization of Thermosensitive and Bioadhesive Ophthalmic Formulations Containing Flurbiprofen Solid Dispersions

In this study, we aimed to develop thermosensitive and bioadhesive in situ gelling systems containing solid dispersions of flurbiprofen (FB-SDs) using poloxamer 407 (P407) and 188 (P188) for ophthalmic delivery. FB-SDs were prepared with the melt method using P407, characterized by solubility, stability, SEM, DSC, TGA, and XRD analyses. Various formulations of poloxamer mixtures and FB-SDs were prepared using the cold method and P407/P188 (15/26.5%), which gels between 32 and 35 °C, was selected to develop an ophthalmic in situ gelling system. Bioadhesive polymers Carbopol 934P (CP) or carboxymethyl cellulose (CMC) were added in three concentrations (0.2, 0.4, and 0.6% (w/w)). Gelation temperature and time, mechanical properties, flow properties, and viscosity values were determined. The in vitro release rate, release kinetics, and the release mechanism of flurbiprofen (FB) from the ophthalmic formulations were analyzed. The results showed that FB-SDs' solubility in water increased 332-fold compared with FB. The oscillation study results indicated that increasing bioadhesive polymer concentrations decreased gelation temperature and time, and formulations containing CP gel at lower temperatures and in a shorter time. All formulations except F3 and F4 showed Newtonion flow under non-physiological conditions, while all formulations exhibited non-Newtonion pseudoplastic flow under physiological conditions. Viscosity values increased with an increase in bioadhesive polymer concertation at physiological conditions. Texture profile analysis (TPA) showed that CP-containing formulations had higher hardness, compressibility, and adhesiveness, and the gel structure of formulation F4, containing 0.6% CP, exhibited the greatest hardness, compressibility, and adhesiveness. In vitro drug release studies indicated that CP and CMC had no effect below 0.6% concentration. Kinetic evaluation favored first-order and Hixson-Crowell kinetic models. Release mechanism analysis showed that the n values of the formulations were greater than 1 except for formulation F5, suggesting that FB might be released from the ophthalmic formulations by super case II type diffusion. When all the results of this study are evaluated, the in situ gelling formulations prepared with FB-SDs that contained P407/P188 (15/26.5%) and 0.2% CP or 0.2% CMC or 0.4 CMC% (F2, F5, and F6, respectively) could be promising formulations to prolong precorneal residence time and improve ocular bioavailability of FB.

Preparation and In Vitro and In Vivo Evaluation of Rectal In Situ Gel of Meloxicam Hydroxypropyl-β-cyclodextrin Inclusion Complex

Meloxicam (MLX) is one of the most effective NSAIDs, but its poor water solubility and low bioavailability limit its clinical application. In this study, we designed a thermosensitive in situ gel of the hydroxypropyl-β-cyclodextrin inclusion complex (MLX/HP-β-CD-ISG) for rectal delivery to improve bioavailability. The best method for preparing MLX/HP-β-CD was the saturated aqueous solution method. The optimal inclusion prescription was optimized using an orthogonal test, and the inclusion complex was evaluated via PXRD, SEM, FTIR and DSC. Then, MLX/HP-β-CD-ISG was characterized regarding the gel properties, release in vitro, and pharmacokinetics in vivo. The inclusion rate of the inclusion complex obtained via the optimal preparation process was 90.32 ± 3.81%. The above four detection methods show that MLX is completely embedded in the HP-β-CD cavity. The developed MLX/HP-β-CD-ISG formulation has a suitable gelation temperature of 33.40 ± 0.17 °C, a gelation time of 57.33 ± 5.13 s, pH of 7.12 ± 0.05, good gelling ability and meets the requirements of rectal preparations. More importantly, MLX/HP-β-CD-ISG significantly improved the absorption and bioavailability of MLX in rats, prolonging the rectal residence time without causing rectal irritation. This study suggests that the MLX/HP-β-CD-ISG can have a wide application prospect with superior therapeutic benefits.

Advances and future perspectives in epithelial drug delivery

Epithelial surfaces protect exposed tissues in the body against intrusion of foreign materials, including xenobiotics, pollen and microbiota. The relative permeability of the various epithelia reflects their extent of exposure to the external environment and is in the ranking: intestinal≈ nasal ≥ bronchial ≥ tracheal > vaginal ≥ rectal > blood-perilymph barrier (otic), corneal > buccal > skin. Each epithelium also varies in their morphology, biochemistry, physiology, immunology and external fluid in line with their function. Each epithelium is also used as drug delivery sites to treat local conditions and, in some cases, for systemic delivery. The associated delivery systems have had to evolve to enable the delivery of larger drugs and biologicals, such as peptides, proteins, antibodies and biologicals and now include a range of physical, chemical, electrical, light, sound and other enhancement technologies. In addition, the quality-by-design approach to product regulation and the growth of generic products have also fostered advancement in epithelial drug delivery systems.

Achievements in Thermosensitive Gelling Systems for Rectal Administration

Rectal drug delivery is an effective alternative to oral and parenteral treatments. This route allows for both local and systemic drug therapy. Traditional rectal dosage formulations have historically been used for localised treatments, including laxatives, hemorrhoid therapy and antipyretics. However, this form of drug dosage often feels alien and uncomfortable to a patient, encouraging refusal. The limitations of conventional solid suppositories can be overcome by creating a thermosensitive liquid suppository. Unfortunately, there are currently only a few studies describing their use in therapy. However, recent trends indicate an increase in the development of this modern therapeutic system. This review introduces a novel rectal drug delivery system with the goal of summarising recent developments in thermosensitive liquid suppositories for analgesic, anticancer, antiemetic, antihypertensive, psychiatric, antiallergic, anaesthetic, antimalarial drugs and insulin. The report also presents the impact of various types of components and their concentration on the properties of this rectal dosage form. Further research into such formulations is certainly needed in order to meet the high demand for modern, efficient rectal gelling systems. Continued research and development in this field would undoubtedly further reveal the hidden potential of rectal drug delivery systems.

Nanostructured DPA-MPC-DPA triblock copolymer gel for controlled drug release of ketoprofen and spironolactone

OBJECTIVE

Uncontrolled rapid release of drugs can reduce their therapeutic efficacy and cause undesirable toxicity; however, controlled release from reservoir materials helps overcome this issue. The aims of this study were to determine the release profiles of ketoprofen and spironolactone from a pH-responsive self-assembling DPA-MPC-DPA triblock copolymer gel and elucidate underlying physiochemical properties.

METHODS

Drug release profiles from DPA₅₀ -MPC₂₅₀ -DPA₅₀ gel (pH 7.5), over 32 h (37 °C), were determined using UV-Vis spectroscopy. Nanoparticle size was measured by dynamic light scattering (DLS) and critical micelle concentration (CMC) by pyrene fluorescence. Polymer gel viscosity was examined via rheology, nanoparticle morphology investigated using scanning transmission electron microscopy (STEM) and the gel matrix observed using cryo-scanning electron microscopy (Cryo-SEM).

KEY FINDINGS

DPA₅₀ -MPC₂₅₀ -DPA₅₀ copolymer (15% w/v) formed a free-standing gel (pH 7.5) that controlled drug release relative to free drugs. The copolymer possessed a low CMC, nanoparticle size increased with copolymer concentration, and DLS data were consistent with STEM. The gel displayed thermostable viscosity at physiological temperatures, and the gel matrix was a nanostructured aggregation of smaller nanoparticles.

CONCLUSIONS

The DPA₅₀ -MPC₂₅₀ -DPA₅₀ copolymer gel could be used as a drug delivery system to provide the controlled drug release of ketoprofen and spironolactone.