Emerging role of polyethylene glycol on doxycycline hyclate-incorporated Eudragit RS in situ forming gel for periodontitis treatment

Levofloxacin HCl-Loaded Eudragit L-Based Solvent Exchange-Induced In Situ Forming Gel Using Monopropylene Glycol as a Solvent for Periodontitis Treatment

Solvent exchange-induced in situ forming gel (ISG) is currently an appealing dosage form for periodontitis treatment via localized injection into the periodontal pocket. This study aims to apply Eudragit L and Eudragit S as matrix components of ISG by using monopropylene glycol as a solvent for loading levofloxacin HCl for periodontitis treatment. The influence of Eudragit concentration was investigated in terms of apparent viscosity, rheological behavior, injectability, gel-forming behavior, and mechanical properties. Eudragit L-based formulation presented less viscosity, was easier to inject, and could form more gel than Eudragit S-based ISG. Levofloxacin HCl-loading diminished the viscosity of Eudragit L-based formulation but did not significantly change the gel formation ability. Higher polymer loading increased viscosity, force-work of injectability, and hardness. SEM photographs and µCT images revealed their scaffold formation, which had a denser topographic structure and less porosity attained owing to higher polymer loading and less in vitro degradation. By tracking with fluorescence dyes, the interface interaction study revealed crucial information such as solvent movement ability and matrix formation of ISG. They prolonged the drug release for 14 days with fickian drug diffusion kinetics and increased the release amount above the MIC against test microbes. The 1% levofloxacin HCl and 15% Eudragit L dissolved in monopropylene glycol (LLM15) was a promising ISG because of its appropriate viscosity (3674.54 ± 188.03 cP) with Newtonian flow, acceptable gel formation and injectability (21.08 ± 1.38 N), hardness (33.81 ± 2.3 N) and prolonged drug release with efficient antimicrobial activities against S. aureus (ATCC 6538, 6532, and 25923), methicillin-resistant S. aureus (MRSA) (S. aureus ATCC 4430), E. coli ATCC 8739, C. albicans ATCC 10231, P. gingivalis ATCC 33277, and A. actinomycetemcomitans ATCC 29522; thus, it is the potential ISG formulation for periodontitis treatment by localized periodontal pocket injection.

Moxifloxacin HCl-Incorporated Aqueous-Induced Nitrocellulose-Based In Situ Gel for Periodontal Pocket Delivery

A drug delivery system based on an aqueous-induced in situ forming gel (ISG) consists of solubilizing the drug within an organic solution of a polymer using a biocompatible organic solvent. Upon contact with an aqueous medium, the solvent diffuses out and the polymer, designed to be insoluble in water, solidifies and transforms into gel. Nitrocellulose (Nc), an aqueous insoluble nitrated ester of cellulose, should be a promising polymer for an ISG using water induction of its solution to gel state via phase inversion. The aim of this investigation was to develop and evaluate a moxifloxacin HCl (Mx)-incorporated aqueous-induced Nc-based ISG for periodontitis treatment. The effects of different solvents (N-methyl pyrrolidone (NMP), DMSO, 2-pyrrolidone (Py), and glycerol formal (Gf)) on the physicochemical and bioactivity properties of the ISGs were investigated. The viscosity and injection force of the ISGs varied depending on the solvent used, with Gf resulting in higher values of 4631.41 ± 52.81 cPs and 4.34 ± 0.42 N, respectively. All ISGs exhibited Newtonian flow and transformed into a gel state upon exposure to the aqueous phase. The Nc formulations in DMSO showed lower water tolerance (12.50 ± 0.72%). The developed ISGs were easily injectable and demonstrated water sensitivity of less than 15.44 ± 0.89%, forming a gel upon contact with aqueous phase. The transformed Nc gel effectively prolonged Mx release over two weeks via Fickian diffusion, with reduced initial burst release. Different solvent types influenced the sponge-like 3D structure of the dried Nc ISGs and affected mass loss during drug release. Incorporating Nc reduced both solvent and drug diffusion, resulting in a significantly narrower zone of bacterial growth inhibition (p < 0.05). The Mx-incorporated Nc-based ISGs exhibited efficient antibacterial activity against four strains of Staphylococcus aureu and against periodontitis pathogens including Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. This study suggests that the developed Mx-incorporated Nc-based ISGs using DMSO and NMP as the solvents are the most promising formulations. They exhibited a low viscosity, ease of injection, and rapid transformation into a gel upon aqueous induction, and they enabled localized and prolonged drug release with effective antibacterial properties. Additionally, this study represents the first reported instance of utilizing Nc as the polymer for ISG. Further clinical experiments are necessary to evaluate the safety of this ISG formulation.

Lime Peel Oil–Incorporated Rosin-Based Antimicrobial In Situ Forming Gel

Localized intra-periodontal pocket drug delivery using an injectable in situ forming gel is an effective periodontitis treatment. The aqueous insoluble property of rosin is suitable for preparing a solvent exchange-induced in situ forming gel. This study aims to investigate the role of incorporating lime peel oil (LO) on the physicochemical properties of injectable in situ forming gels based on rosin loaded with 5% w/w doxycycline hyclate (DH) in dimethyl sulfoxide (DMSO) and N-methyl pyrrolidone (NMP). Their gel formation, viscosity, injectability, mechanical properties, wettability, drug release, and antimicrobial activities were evaluated. The presence of LO slowed gel formation due to the loose precipitate formation of gel with a high LO content. The viscosity and injectability were slightly increased with higher LO content for the DH-loaded rosin-based in situ forming gel. The addition of 10% LO lowered gel hardness with higher adhesion. LO incorporation promoted a higher drug release pattern than the no oil-added formulation over 10 days and the gel formation rate related to burst drug release. The drug release kinetics followed the non-Fickian diffusion mechanism for oil-added formulations. LO exhibited high antimicrobial activity against Porphyromonas gingivalis and Staphylococcus aureus. The DH-loaded rosin in situ forming gel with an addition of LO (0, 2.5, 5, and 10% w/w) inhibited all tested microorganisms. Adding 10% LO to rosin-based in situ forming gel improved the antimicrobial activities, especially for the P. gingivalis and S. aureus. As a result, the study demonstrates the possibility of using an LO amount of less than 10% loading into a rosin-based in situ forming gel for efficient periodontitis treatment.

Release kinetics of hydroxypropyl methylcellulose governing drug release and hydrodynamic changes of matrix tablet

BACKGROUND

Hydrophilic hydroxypropyl methylcellulose (HPMC) matrix tablets are the standard role model of the oral controlled-release formulation. Nevertheless, the HPMC kinetics for the mechanistic understanding of drug release and hydrodynamic behaviors are rarely investigated. This study aims to investigate the release behaviors of both HPMC and paracetamol (model drug) from the hydrophilic matrix tablet.

METHODS

Two different viscosity grades of HPMC were used (Low viscosity: 6 cps, High viscosity: 4,000 cps). Three different ratios of drug/HPMC (H:38.08%, M:22.85%, and L:15.23% (w/w) of HPMC amounts in total weight) matrix tablets were prepared by wet granulation technique. The release profiles of the drug and HPMC in a matrix tablet were quantitatively analyzed by HPLC and 1H-nuclear magnetic resonance (NMR) spectroscopy. The hydrodynamic changes of HPMC were determined by the gravimetric behaviors such as swelling and erosion rates, gel layer thickness, front movement data,and distributive near-infrared (NIR) chemical imaging of HPMC in a matrix tablet during the dissolution process.

RESULTS

High viscosity HPMC tablets showed slower release of HPMC than the release rate of drug, suggesting that drug release preceded polymer release.Different hydration phenomenon was qualitatively identified and corresponded to the release profiles. The release behaviors of HPMC and drug in the tablet could be distinguished with the significant difference with fitted dissolution kinetics model (Low viscosity HPMC 6cps; Korsmeyer-Peppas model, High viscosity HPMC 4000cps; Hopfenberg model, Paracetamol; Weibull model) according to the weight of ingredients and types of HPMC.

CONCLUSION

The determination of HPMC polymer release correlating with drug release, hydrodynamic behavior, and NIR chemical imaging of HPMC can provide new insights into the drug release-modulating mechanism in the hydrophilic matrix system.

Effect of pH adjustment and ratio of oppositely charged polymers on the mechanistic performance and sustained release of volatile perfume in interpolyelectrolyte complex microcapsules

In this study, volatile perfume was encapsulated in microcapsules (MCs) via interpolyelectrolyte complexes (IPECs) of oppositely charged polymers, with high encapsulation efficiency, to be delivered in a sustained manner. Positively charged chitosan (CTS) and negatively charged Eudragit® S100 (ES100) were used as eco-friendly biopolymers. Limonene (LMN) was selected as the model perfume. First, the solution of LMN in ethyl acetate and poloxamer 407 (POX407) in acidic solution was emulsified using ultrasonication. CTS and ES100 were added in that particular order to form o/w emulsion. LMN-loaded microcapsules (LMN-MCs) were prepared by adjusting the pH and freeze-drying for solidification. The electrostatic interactions of CTS and ES100 to form IPECs were highly dependent on pH, changing in the microscopic images of emulsion droplets and zeta potential. The NH₃⁺ group of CTS and the COO^- group of ES100 caused the electrostatic interactions at a specific pH. The formation mechanism of LMN-MCs was successfully validated using instrumental analysis, charge density, and energy dispersive X-ray spectrometer (EDS) mapping. Encapsulation efficiency, loading content, and release rates of LMN-MCs varied according to the ratios of CTS and ES100, demonstrating optimal performance at a 1:1 ratio. The current LMN-MCs could provide a simple manufacturing process with high performance in terms of encapsulation efficiency (>94%), drug loading, yield and sustained release of volatile perfume for 120 h.

Double-Controlled Release of Poorly Water-Soluble Paliperidone Palmitate from Self-Assembled Albumin-Oleic Acid Nanoparticles in PLGA in situ Forming Implant

Purpose

To investigate the effects of solvents on the formation of self-assembled nanonization of albumin-oleic acid conjugates (AOCs) using a solvent exchange mechanism for the construction of in situ forming implants (ISFI).

Methods

A poorly water-soluble drug, paliperidone palmitate (PPP), was chosen as the model drug. AOC was synthesized with the 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) reaction. Dichloromethane, tetrahydrofuran, ethanol, N-methyl-2-pyrrolidone, dimethyl sulfoxide, and deionized water were selected to investigate the formation of self-assembled AOC nanoparticles (AONs). The volume ratios of organic solvents against water could determine the miscibility, injectability, and in situ nanonizing capability without aggregation.

Results

As the polarity of the organic solvents increased, the AONs exhibited a spherical shape, and the larger the volume of the solvent, the smaller the size of the AONs. To use AOC in ISFI for controlled release of PPP, poly(d,l-lactide-co-glycolide) (PLGA) was combined with the AOC in 2 mL of N-methyl-2-pyrrolidone and water solution (1.8/0.2 ratio). The release rates of all formulations exhibited similar curve patterns overall but were more controlled in decreasing order as follows: AOC, PLGA, and AOC/PLGA for 14 days.

Conclusion

A combined formulation of AOC and PLGA was found to effectively control the initial burst release of the drug.

Synergistic Effect of Growth Factor Releasing Polymeric Nanoparticles and Ultrasound Stimulation on Osteogenic Differentiation

Mesenchymal stem cells (MSCs) have been extensively used in the tissue regeneration therapy. Ex vivo therapy with well-differentiated osteogenic cells is known as an efficient treatment for musculoskeletal diseases, including rheumatoid diseases. However, along with its high cost, the current therapy has limitations in terms of restoring bone regeneration procedures. An efficient process for the cell differentiation to obtain a large number of functionalized osteogenic cells is necessary. Therefore, it is strongly recommended to develop strategies to produce sufficient numbers of well-differentiated osteogenic cells from the MSCs. In general, differentiation media with growth factors have been used to facilitate cell differentiation. In the present study, the poly (lactic-co-glycolic acid) (PLGA) nanoparticles incorporating the growth factors were included in the media, resulting in releasing growth factors (dexamethasone and β-glycerophosphate) in the media in the controlled manner. Stable growth and early differentiation of osteogenic cells were achieved by the PLGA-based growth factor releasing system. Moreover, low intensity pulsed ultrasound was applied to this system to induce cell differentiation process. The results revealed that, as a biomarker at early stage of osteogenic cell differentiation, Lamin A/C nuclear protein was efficiently expressed in the cells growing in the presence of PLGA-based growth factor reservoirs and ultrasound. In conclusion, our results showed that the ultrasound stimulation combined with polymeric nanoparticles releasing growth factors could potentially induce osteogenic cell differentiation.

Doxycycline hyclate-loaded in situ forming gels composed from bleached shellac, Ethocel, and Eudragit RS for periodontal pocket delivery

Polymeric material plays an important role as a matrix former in the modulation of drug release of antimicrobial-loaded in situ forming gel (ISG) for efficient periodontitis treatment. This study was conducted to compare three polymers, namely bleached shellac (BS), Ethocel (EC) and Eudragit RS (ERS), as matrix formers of doxycycline hyclate (DH)-loaded solvent exchange-induced ISG. All prepared ISGs, except 25% EC ISG, exhibited the Newtonian flow behaviour. Transformation from solution into matrix-like was achieved rapidly within 5 min. Increasing the amount of these polymers extended the release of DH. DH-loaded EC and ERS ISG systems exhibited high antimicrobial activity, and all ISGs were effective in inhibiting the growth of Staphylococcus aureus, Escherichia coli, Streptococcus mutans, Porphyromonas gingivalis and Candida albicans. By comparison, the DH-loaded ERS ISG, through the solvent exchange mechanism, was found to be ease in injection with low viscosity and sustained the release with higher concentration, meanwhile, it also exhibited interesting in vitro degradability and antimicrobial activities. Therefore, the DH-loaded ERS ISG exhibited a potential use for localized periodontal drug delivery system for the treatment periodontitis.

Injectable In-Situ Forming Depot of Doxycycline Hyclate/α-Cyclodextrin Complex Using PLGA for Periodontitis Treatment: Preparation, Characterization, and In-Vitro Evaluation

BACKGROUND

Doxycycline (DOX) is used in treating a bacterial infection, especially for periodontitis treatment.

OBJECTIVE

To reduce irritation of DOX for subgingival administration and increase the chemical stability and against enzymatic, the complex of α-cyclodextrin with DOX was prepared and loaded into injectable in situ forming implant based on PLGA.

METHODS

FTIR, molecular docking studies, X-ray diffraction, and differential scanning calorimetry was performed to characterize the DOX/α-cyclodextrin complex. Finally, the in-vitro drug release and modeling, morphological properties, and cellular cytotoxic effects were also evaluated.

RESULTS

The stability of DOX was improved with complex than pure DOX. The main advantage of the complex is the almost complete release (96.31 ± 2.56 %) of the drug within 14 days of the implant, whereas in the formulation containing the pure DOX and the physical mixture the DOX with α-cyclodextrin release is reached to 70.18 ± 3.61 % and 77.03 ± 3.56 %, respectively. This trend is due to elevate of DOX stability in the DOX/ α-cyclodextrin complex form within PLGA implant that confirmed by the results of stability.

CONCLUSION

Our results were indicative that the formulation containing DOX/α-cyclodextrin complex was biocompatible and sustained-release with minimum initial burst release.

Meloxicam-loaded solvent exchange-induced in situ forming beta-cyclodextrin gel and microparticle for periodontal pocket delivery

The in situ forming system has attracted attention for periodontitis treatment owing to its sustainable drug release localisation at a periodontal pocket. Given its low aqueous solubility, beta-cyclodextrin (β-CD) may serve as a matrix former of solvent exchange-induced in situ forming gel (ISG) and microparticle (ISM). Meloxicam (Mex)-loaded-β-CD ISG and ISM were prepared using β-CD in dimethyl sulphoxide (ISG) as the internal phase and camellia oil comprising 5% glyceryl monostearate as the external phase (ISM). Mex-loaded β-CD systems comprising 40% β-CD were easily injected via a 24-gauge needle. During solvent exchange with phosphate buffer saline (pH 6.8), the highly concentrated β-CD ISG promoted the phase inversion of β-CD aggregates into matrix-like. Upon exposure to aqueous phase, the ISM system comprising 40% β-CD transformed into microparticles and extended the drug release to 7 days with minimised initial burst release following Fickian diffusion. Moreover, the potential degradability was evident from the high weight loss. High maximum deformation force with high viscous character initiated the slow diffusion rate of the solvent from the ISM system. Therefore, 40% β-CD ISM is a potential local Mex-controlled release system of anti-inflammatory drug for periodontitis treatment.