On the use of the Weibull function for the discernment of drug release mechanisms

A novel self-assembled micelles based on stearic acid modified schizophyllan for efficient delivery of paclitaxel

This study was aimed to design a novel amphiphilic carrier based on schizophyllan (SPG) exopolysacharide for drug delivery. Stearic acid (SA) was used for the esterification of SPG with two degrees of substitutions (SA-SPG0.5 and SA-SPG1). The H NMR and FTIR spectroscopies verified the succesfull esterification of SPG. The polymeric micelles easily self-assembled into nanomicelles by ultrasound method. Fluorescence spectroscopy showed that the critical micelle concentrations (CMCs) of SA-SPG0.5 and SA-SPG1 micelles were 0.068 mg/mL and 0.027 mg/mL, respectively. DLS analyses showed that nanomicelles were ranged from 156 to 175 nm. SEM and TEM images showed that nanomicelles were mostly spherical. Paclitaxel (PTX) as a drug model was successfully loaded into SA-SPG nanomicelles with three different drug/polymer weight ratios of 0.1, 0.2 and 0.3. The highest encapsulation efficiency (75 %) was obtained when the PTX/SA-SPG weight ratio was 0.1. The in vitro release of PTX from SA-SPG micelles represented the sustained release profile over 144 h. MTT assay showed that the PTX-loaded SA-SPG nanomicelles had the higher cytotoxicity against MCF-7 cells than free PTX. These results revealed that the synthesized SA-SPG nanomicelles had a promising potential as a new carrier for efficient delivery of hydrophobic drugs.

Clinical Pharmacokinetic Evaluation of Optimized Liquisolid Tablets as a Potential Therapy for Male Sexual Dysfunction

The study aimed at developing a liquisolid tablet (LST) containing tadalafil (TDL) and dapoxetine (DPX) with improved bioavailability as a potential therapy for male sexual dysfunction. A mixture of nonvolatile solvents, namely PEG 200 and Labrasol®, was utilized to prepare LSTs that were assessed for their quality characteristics. The Box–Behnken design (BBD) was employed to statistically explore the effect of the formulation factors on the quality attributes of LSTs. Furthermore, an in vivo pharmacokinetic study was carried out for the optimized LST in comparison with the marketed tablets on healthy human volunteers. The optimized LST revealed acceptable quality limits with enhanced dissolution for both APIs. The pharmacokinetic parameters after oral administration of the optimized LST indicated that the Cmax of TDL in LSTs was 122.61 ng/mL within 2h compared to the marketed tablets, which reached 91.72 ng/mL after 3 h, indicating the faster onset of action. The AUC was improved for TDL in LST (4484.953 vs. 2994.611 ng/mL∙h in the marketed tablet) and DPX in LST (919.633 vs. 794.699 ng/mL∙h in the marketed tablet). This enhancement in bioavailability potentially minimizes the associated side effects and improves the treatment of male sexual dysfunction, particularly for diabetic patients.

Biodegradable thermoresponsive oligochitosan nanoparticles: Mechanisms of phase transition and drug binding-release

Oligochitosan, a low molecular weight derivative of the cationic biopolymer, chitosan, currently shows a great potential of application as a biodegradable non-toxic stimuli-sensitive drug carrier. This paper aimed to elucidate the thermoresponsive potential of oligochitosan and the temperature-controlled drug binding and release to shed light on oligochitosan potential in stimuli-responsive drug delivery. Mechanisms of thermoresponsive behavior of oligochitosan induced by β-glycerophosphate (GP) were investigated using ITC, DSC, and DLS. Upon heating, the aqueous oligochitosan solution underwent a cooperative transition of the microphase separation type resulting in the formation of stable nano-sized particles. Energetics of the GP-oligochitosan interaction (evaluated by ITC) revealed a positive enthalpy of the GP binding to oligochitosan, which pointed to a notable contribution of dehydration and the related rearrangement of the polysaccharide hydration shell. Energetics of the thermal phase transition of oligochitosan was investigated by DSC upon variation of the solvent dielectric constant and GP concentration. The dependences of the transition parameters on these variables were determined and used for the analysis of the oligochitosan thermoresponsivity mechanism. The binding of ibuprofen to the thermotropic oligochitosan nanogel particles and its release from them were evaluated under near-physiological conditions. Relevantly, the oligochitosan nanoparticles surpassed some reference macromolecular adsorbers by the affinity for the drug and by the delayed release kinetics.

Imaging and Characterization of Sustained Gadolinium Nanoparticle Release from Next Generation Radiotherapy Biomaterial

Smart radiotherapy biomaterials (SRBs) present a new opportunity to enhance image-guided radiotherapy while replacing routinely used inert radiotherapy biomaterials like fiducials. In this study the potential of SRBs loaded with gadolinium-based nanoparticles (GdNPs) is investigated for magnetic resonance imaging (MRI) contrast. GdNP release from SRB is quantified and modelled for accurate prediction. SRBs were manufactured similar to fiducials, with a cylindrical shell consisting of poly(lactic-co-glycolic) acid (PLGA) and a core loaded with GdNPs. Magnetic resonance imaging (MRI) contrast was investigated at 7T in vitro (in agar) and in vivo in subcutaneous tumors grown with the LLC1 lung cancer cell line in C57/BL6 mice. GdNPs were quantified in-phantom and in tumor and their release was modelled by the Weibull distribution. Gd concentration was linearly fitted to the R₁ relaxation rate with a detection limit of 0.004 mmol/L and high confidence level (R² = 0.9843). GdNP loaded SRBs in tumor were clearly visible up to at least 14 days post-implantation. Signal decrease during this time showed GdNP release in vivo, which was calculated as 3.86 ± 0.34 µg GdNPs release into the tumor. This study demonstrates potential and feasibility for SRBs with MRI-contrast, and sensitive GdNP quantification and release from SRBs in a preclinical animal model. The feasibility of monitoring nanoparticle (NP) concentration during treatment, allowing dynamic quantitative treatment planning, is also discussed.

Functional Hybrid Nanoemulsions for Sumatriptan Intranasal Delivery

In recent years, advanced nanohybrid materials processed as pharmaceuticals have proved to be very advantageous. Triptans, such as the commercially available intranasal sumatriptan (SMT), are drugs employed in the treatment of painful migraine symptoms. However, SMT effectiveness by the intranasal route is limited by its high hydrophilicity and poor mucoadhesion. Therefore, we designed hybrid nanoemulsions (NE) composed of copaiba oil as the organic component plus biopolymers (xanthan, pectin, alginate) solubilized in the continuous aqueous phase, aiming at the intranasal release of SMT (2% w/v). Firstly, drug-biopolymer complexes were optimized in order to decrease the hydrophilicity of SMT. The resultant complexes were further encapsulated in copaiba oil-based nanoparticles, forming NE formulations. Characterization by FTIR-ATR, DSC, and TEM techniques exposed details of the molecular arrangement of the hybrid systems. Long-term stability of the hybrid NE at 25°C was confirmed over a year, regarding size (~ 120 nm), polydispersity (~ 0.2), zeta potential (~ −25 mV), and nanoparticle concentration (~ 2.10¹⁴ particles/mL). SMT encapsulation efficiency in the formulations ranged between 41–69%, extending the in vitro release time of SMT from 5 h (free drug) to more than 24 h. The alginate-based NE was selected as the most desirable system and its in vivo nanotoxicity was evaluated in a zebrafish model. Hybrid NE treatment did not affect spontaneous movement or induce morphological changes in zebrafish larvae, and there was no evidence of mortality or cardiotoxicity after 48 h of treatment. With these results, we propose alginate-based nanoemulsions as a potential treatment for migraine pain.

Application of Supercritical Solvent Impregnation for Production of Zeolite Modified Starch-Chitosan Polymers with Antibacterial Properties

In the present study, supercritical solvent impregnation (SSI) has been applied to incorporate thymol into bio-composite polymers as a potential active packaging material. Thymol, a natural component with a proven antimicrobial activity, was successfully impregnated into starch-chitosan (SC) and starch-chitosan-zeolite (SCZ) films using supercritical carbon dioxide (scCO₂) as a solvent. Experiments were performed at 35 °C, pressures of 15.5 and 30 MPa, and an impregnation time in the range of 4–24 h. The highest impregnation yields of SC films with starch to chitosan mass ratios of 1:1 and 1:2 were 10.80% and 6.48%, respectively. The addition of natural zeolite (15–60%) significantly increased the loading capacity of films enabling thymol incorporation in a quantity of 16.7–27.3%. FTIR and SEM analyses were applied for the characterization of the films. Mechanical properties and water vapor permeability of films before and after the impregnation were tested as well. Thymol release kinetics in deionized water was followed and modeled by the Korsmeyer-Peppas and Weibull model. SCZ films with thymol loading of approximately 24% exhibited strong antibacterial activity against E. coli and methicillin-resistant Staphylococcus (S.) aureus (MRSA).

Logic of Selecting Suitable Dissolution Parameters in New Drug Formulations Based on A BCS Approach

Since the biopharmaceutical quality of generic drug formulations depends on the quality of the reference products and also information about the in-vitro release performance of drugs under different conditions is scarce in the literature, a dissolution study of four reference tablets was performed. Each drug was representative of one Class of the Biopharmaceutical Classification System. The in-vitro release performance of propranolol-HCl, carbamazepine, ranitidine-HCl, and metronidazole was evaluated using a USP basket and paddle apparatus at different agitation rates (50, 75, and 100 rpm) with two doses of each drug. In all experiments, pharmacopeial dissolution media was used and the samples were taken with automatic equipment at specific times up to 60 min, except for propranolol-HCl, for which the samples were taken up to 30 min. The dissolution profiles were compared by model-independent, model-dependent, and ANOVA-based comparisons. The three methods of data comparison showed that low vs. high doses were significantly different (P < 0.05), which may influence cases in which biowaivers of propranolol-HCl and ranitidine-HCl are requested. Additionally, the results showed that despite different hydrodynamic environments produced by the basket and paddle apparatus, under certain conditions, both types of equipment generated comparable in-vitro results. Variables such as the dose, agitation rate, and type of dissolution apparatus are important factors to consider in designing dissolution tests for drug products. This information can be used to test a new dosage when there is no pharmacopeial method available to perform a dissolution study. Further researches on the in-vitro release performance of reference drug products are required.

Metal alginates for polyphenol delivery systems: Studies on crosslinking ions and easy-to-use patches for release of protective flavonoids in skin

Incorporation of bioactive natural compounds like polyphenols is an attractive approach for enhanced functionalities of biomaterials. In particular flavonoids have important pharmacological activities, and controlled release systems may be instrumental to realize the full potential of these phytochemicals. Alginate presents interesting attributes for dermal and other biomaterial applications, and studies were carried here to support the development of polyphenol-loaded alginate systems. Studies of capillary viscosity indicated that ionic medium is an effective strategy to modulate the polyelectrolyte effect and viscosity properties of alginates. On gelation, considerable differences were observed between alginate gels produced with Ca2+, Ba2+, Cu2+, Fe2+, Fe3+ and Zn2+ as crosslinkers, especially concerning shrinkage and morphological regularity. Stability assays with different polyphenols in the presence of alginate-gelling cations pointed to the choice of calcium, barium and zinc as safer crosslinkers. Alginate-based films loaded with epicatechin were prepared and the kinetics of release of the flavonoid investigated. The results with calcium, barium and zinc alginate matrices indicated that the release dynamics is dependent on film thicknesses, but also on the crosslinking metal used. On these grounds, an alginate-based system of convenient use was devised, so that flavonoids can be easily loaded at simple point-of-care conditions before dermal application. This epicatechin-loaded patch was tested on an ex-vivo skin model and demonstrated capacity to deliver therapeutically relevant concentrations on skin surface. Moreover, the flavonoid released was not modified and retained full antioxidant bioactivity. The alginate-based system proposed offers a multifunctional approach for flavonoid controllable delivery and protection of skin injured or under risk.

Surface Heterogeneous Nucleation-Mediated Release of Beta-Carotene from Porous Silicon

We demonstrate that the release of a poorly soluble molecule from nanoporous carriers is a complex process that undergoes heterogeneous surface nucleation events even under significantly diluted release conditions, and that those events heavily affect the dynamics of release. Using beta-carotene and porous silicon as loaded molecule and carrier model, respectively, we show that the cargo easily nucleates at the pore surface during the release, forming micro- to macroscopic solid particles at the pores surface. These particles dissolve at a much slower pace, compared to the rate of dissolution of pure beta-carotene in the same solvent, and they negatively affect the reproducibility of the release experiments, possibly because their solubility depends on their size distribution. We propose to exploit this aspect to use release kinetics as a better alternative to the induction time method, and to thereby detect heterogenous nucleation during release experiments. In fact, release dynamics provide much higher sensitivity and reproducibility as they average over the entire sample surface instead of depending on statistical analysis over a small area to find clusters.

Injectable Poly(ethylene glycol) Hydrogels Cross-Linked by Metal-Phenolic Complex and Albumin for Controlled Drug Release

Injectable hydrogel is advantageous as a drug reservoir for controlled drug release since its injectability provides minimally invasive access to internal tissues and irregular-shaped target sites. Herein, we fabricated pH-responsive injectable hydrogels constructed of a supramolecular cross-link network, which contained tannic acid (TA), Fe(III), poly(ethylene glycol) (PEG), and bovine serum albumin (BSA) for controlled drug release. The hydrogel precursors rapidly turned into a gel when co-injected with NaOH in a time scale of seconds. The hydrogel properties and drug release profiles are all tunable by adjusting the concentrations of BSA, NaOH, and doxorubicin (DOX). The Young's moduli range from 3.19 ± 0.93 to 43.24 ± 1.37 kPa that match internal soft tissues. The hydrogel lasts more than 3 weeks and gradually releases doxorubicin up to 123.6 ± 1.7 μg at pH 6.4. The results of the physical properties and drug release suggest supramolecular interactions that correspond to Fourier transform infrared (FTIR) results. In vitro cytotoxicity was also assessed using L929 cells, and the results demonstrated the material biocompatibility. The tunable properties, controlled release profiles, and biocompatibility of injectable poly(ethylene glycol) hydrogels support that they have great potential as a drug-releasing material for localized treatments.

Development and Characterization of Orally Disintegrating Tablets Containing a Captopril-Cyclodextrin Complex

Captopril is the first angiotensin I-converting enzyme inhibitor widely used for the treatment of hypertension. Based on the well-known benefits of cyclodextrin inclusion complexes, the present study investigated the ability of β-cyclodextrin to include captopril. Solid inclusion complexes of captopril with β-cyclodextrin in a 1:2 molar ratio were prepared by using the paste method of complexation. For comparison purposes, a simple physical mixture with the same molar ratio was also prepared. Fourier-transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and simultaneous thermal analysis were used to characterize the raw materials, physical mixture and solid inclusion complex. In order to provide the drug in a more accessible and patient-compliant form following masking its bitter taste, as well as ensuring the appropriate release kinetics, the investigated complex was formulated as orally disintegrating tablets. The study of captopril dissolution in both compendial and simulated saliva media suggested the Noyes Whitney model as the best mathematical model to describe the release phenomena. A clinical study on healthy volunteers also highlighted the taste improvement of the new formulation as compared to conventional tablets.

Supramolecular self-assembled drug delivery system (SADDs) of vancomycin and tocopherol succinate as an antibacterial agent: in vitro, in silico and in vivo evaluations

In this study self-assembled drug delivery system (SADDs) composed of a hydrophobic d-α-tocopherol succinate (TS) and a hydrophilic vancomycin (VCM) were formulated, and its potential for enhancing the antibacterial activity of VCM against Staphylococcus aureus (SA) and Methicillin-resistant Staphylococcus aureus (MRSA) were explored. The SADDs were synthesized via supramolecular complexation, then characterized for in silico, in vitro and in vivo studies. In silico studies confirmed the self-assembly of VCM/TS into NPs. The size, surface charge and drug loading of the SADDs was ˂100 nm, -27 mV and 68%, respectively. The SADDs were non-hemolytic and biosafe. A sustained release of VCM from SADDs was noted, with 52.2% release after 48 hr. The in vitro antibacterial test showed a twofold decrease in Minimum inhibitory concentration (MIC) against SA and MRSA, and a significantly higher reduction in MRSA biofilms compared to bare VCM. Further, in silico studies confirmed strong and stable binding of TS to MRSA efflux pumps. The in vivo study using mice skin infection models showed a 9.5-fold reduction in bacterial load after treatment with SADDs, in comparison with bare VCM. These findings affirmed that VCM/TS NPs as a promising novel nano-delivery for treating bacterial infections.

Effects of Starch Incorporation on the Physicochemical Properties and Release Kinetics of Alginate-Based 3D Hydrogel Patches for Topical Delivery

The development of printable hydrogel inks for extrusion-based 3D printing is opening new possibilities to the production of new and/or improved pharmaceutical forms, specifically for topical application. Alginate and starch are natural polysaccharides that have been extensively exploited due to their biocompatibility, biodegradability, viscosity properties, low toxicity, and relatively low cost. This research work aimed to study the physicochemical and release kinetic effects of starch incorporation in alginate-based 3D hydrogel patches for topical delivery using a quality by design approach. The incorporation of a pregelatinized starch is also proposed as a way to improve the properties of the drug delivery system while maintaining the desired quality characteristics. Critical material attributes and process parameters were identified, and the sensitivity and adequacy of each parameter were statistically analyzed. The impact of alginate, starch, and CaCl₂·2H₂O amounts on relevant quality attributes was estimated crosswise. The amount of starch revealed a synergetic impact on porosity (p = 0.0021). An evident increase in the size and quantity of open pores were detected in the as printed patches as well as after crosslinking (15.6 ± 5.2 µm). In vitro drug release studies from the optimized alginate-starch 3D hydrogel patch, using the probe Rhodamine B, showed an initial high burst release, followed by a controlled release mechanism. The results obtained also showed that the viscoelastic properties, printing accuracy, gelation time, microstructure, and release rates can be modulated by varying the amount of starch added to the system. Furthermore, these results can be considered an excellent baseline for future drug release modulation strategies.

N-(9-Fluorenylmethoxycarbonyl)-L-Phenylalanine/nano-hydroxyapatite hybrid supramolecular hydrogels as drug delivery vehicles with antibacterial property and cytocompatibility

The intrinsic fragility of hydroxyapatite (HAP) restricts its wider applications for local delivery of antibiotics. The composites formed by integrating HAP with hydrogels can improve the properties of HAP. However, these reported composites not only require tedious preparation and employ organic solvent and toxic reagents, but also hardly have inherent antimicrobial property. In this study, N-(9-Fluorenylmethoxycarbonyl)-L-Phenylalanine/nano-hydroxyapatite (Fmoc-L-Phe/nHAP) hybrid supramolecular hydrogels with antibacterial property and cytocompatibility was prepared by integrating nHAP as reinforcement with Fmoc-L-Phe supramolecular hydrogels. The results showed that nHAP bounds in the chamber of the gel network and adheres to the fiber of Fmoc-L-Phe due to intermolecular interaction, remarkably improving the mechanical strength of Fmoc-L-Phe supramolecular hydrogels. The results of inhibition zone experiment and MTT experiment showed that the Fmoc-L-Phe/nHAP hybrid supramolecular hydrogels possess antimicrobial property and cytocompatibility. In vitro release experiment of chlorogenic acid (CGA) from the hybrid supramolecular hydrogels was performed. The study of the release kinetics indicated that the release behavior of CGA from the hybrid supramolecular hydrogels is following Weibull model and release mechanism involved Fickian diffusion and erosion of the surface of hydrogel matrix. The release of CGA shows a good inhibition effect on S. aureus. The results show that the Fmoc-L-Phe/nHAP hybrid hydrogels with antibacterial property and cytocompatibility have promising applications as drug delivery carrier. Due to the intrinsic fragility of hydroxyapatite (HAP), the properties of HAP could be improved by incorporation into hydrogels. However, these reported composites not only require tedious preparation and employ organic solvent and toxic reagents, but also hardly have inherent antimicrobial property. We prepared N-(9-Fluorenylmethoxycarbonyl)-L-Phenylalanine/nano-hydroxyapatite (Fmoc-L-Phe/nHAP) hybrid supramolecular hydrogels by integrating nHAP as reinforcement with Fmoc-L-Phe supramolecular hydrogels. The results showed that nHAP bounds in the chamber of the gel network and adheres to the fiber of Fmoc-L-Phe due to intermolecular interaction, remarkably improving the mechanical strength of Fmoc-L-Phe supramolecular hydrogels. The results of inhibition zone experiment and MTT experiment showed that the Fmoc-L-Phe/nHAP hybrid supramolecular hydrogels possess antibacterial property and cytocompatibility. In vitro release experiment of chlorogenic acid (CGA) from the hybrid supramolecular hydrogels was performed. The study of the release kinetics indicated that the release behavior of CGA from the hybrid supramolecular hydrogels is following Weibull model and release mechanism involved Fickian diffusion and erosion of the surface of hydrogel matrix. The release of CGA shows a good inhibition effect on S. aureus. The results show that the Fmoc-L-Phe/nHAP hybrid hydrogels with antibacterial property and cytocompatibility have promising applications as drug delivery carrier.

Optimized Nanostructured Lipid Carriers Integrated into In Situ Nasal Gel for Enhancing Brain Delivery of Flibanserin

Background and Aim

Flibanserin (FLB) is a multifunctional serotonergic agent used for treating hypoactive sexual desire disorder in premenopausal women via oral administration. FLB has a reported limited oral bioavailability of 33% that could be attributed to the drug’s first-pass metabolism. In addition, FLB has a pH-dependent solubility that could be a challenging factor for drug dissolution in the body neutral fluid, and consequently, absorption via mucosal barriers. Thus, this work aims at investigating the potential of utilizing nanostructured lipid carriers (NLCs) to overcome the aforementioned drawbacks and to enhance nose-to-brain drug delivery.

Methods

Box-Behnken design was applied to explore the impact of solid lipid % (SL%, X₁), liquid lipid % (LL%, X₂), and sonication time (ST, X₃) on particle size. The optimized NLC formulation was characterized and incorporated into gellan gum in situ gel. The prepared gel was subjected to in vitro drug release, in vivo pharmacokinetic performance, and histopathological assessment in rats.

Results

Statistical analysis revealed a significant negative effect for both SL% and ST on NLCs size. In contrast, a significant positive effect was observed for the LL%. The optimized formulation showed spherical shape with vesicular size of 114.63 nm. The optimized FLB-NLC in situ gel exhibited adequate stability and enhanced in vitro release compared to raw FLB control gel. The plasma and brain concentrations of the drug after nasal administration in rats increased by more than 3–6-fold, respectively, compared to raw FLB in situ gel. In addition, the histopathological studies revealed the absence of any pathological signs.

Conclusion

The aforementioned results highlight the safety of FLB-NLC in situ nasal gel and its potential to improve the drug bioavailability and brain delivery.

Hybrid nanofilms as topical anesthetics for pain-free procedures in dentistry

Topical anesthetics are widely applied in order to relieve the discomfort and anxiety caused by needle insertion and other painful superficial interventions at the oral cavity. So far, there are no commercially available effective topical anesthetic formulations for that purpose, and the most of developments are related to hydrophilic and low mucoadhesive forms. Therefore, we have prepared different hybrid nanofilms composed of biopolymer matrices (chitosan, pectin, and chitosan-pectin) blended with nanostructured lipid carriers (NLC) loading the eutectic mixture of 5% lidocaine-prilocaine (LDC-PLC), in order to fulfill this gap in the market. These dual systems were processed as hybrid nanofilms by the solvent/casting method, and its mucoadhesive, structural and mechanical properties were detailed. The most appropriate hybrid nanofilm combined the advantages of both pectin (PCT) and NLC components. The resultant material presented sustained LDC-PLC release profile for more than 8 h; permeation across porcine buccal mucosa almost twice higher than control and non-cytotoxicity against 3T3 and HACAT cell lines. Then, the in vivo efficacy of PCT/NLC formulation was compared to biopolymer film and commercial drug, exhibiting the longest-lasting anesthetic effect (> 7 h), assessed by tail flick test in mice. These pectin-based hybrid nanofilms open perspectives for clinical trials and applications beyond Dentistry.

Design, modeling and 3D printing of a personalized cervix tissue implant with protein release function

Cervical cancer induced by human papillomavirus (HPV) causes severe morbidity worldwide. Although cervical conization has been widely accepted as the most conventional surgery against cervical cancer, tissue defects and high recurrence rates have a significant negative impact on women's mental and physical health. Herein we developed an implantable, personalized cervical implant with drug release function using 3D printing technology. The cervical implant was designed in cone-shape with hieratical porous structures according to the clinical data, 3D-printed using polyurethane by low-temperature deposition manufacturing (LDM), and finished by lyophilization. Anti-HPV protein was loaded into the porous structure under negative pressure afterwards. Elastic biomedical polyurethane and the porous structure ensured that these cervical implants were equipped with tailored mechanical properties comparable to physiological cervix tissue. Cytotoxicity and cytocompatibility tests indicated that these 3D-printed cervical implants supported cell adhesion and growth. More importantly, the cervical implants with regulated pores could help to quantitatively control the loading and release of anti-HPV protein to inhibit dissociative viruses near the cervix validly. As a result, the 3D-printed cervical implants in the present study showed considerable potential for use as functional tissue implants against HPV infection after cervical conization.

Organogel Nanoparticles as a New Way to Improve Oral Bioavailability of Poorly Soluble Compounds

PURPOSE

The aim of the study was to evaluate organogel nanoparticles as a lipophilic vehicle to increase the oral bioavailability of poorly soluble compounds. Efavirenz (EFV), a Biopharmaceutical Classification System (BCS) Class II, was used as drug model.

METHODS

Organogel nanoparticles loaded with EFV were formulated with sunflower oil, 12-hydroxystearic acid (HSA) and polyvinyl alcohol (PVA). Various parameters have been investigated in the current study such as (i) the release profile of organogel assessed by USP 4 cell flow dialysis, (ii) the impact of organogel on intestinal absorption, using Caco-2 cells as in vitro model and jejunum segments as ex vivo assay and (iii) the bioavailability of organogel following oral pharmacokinetic study.

RESULTS

250-300 nm spherical particles with a final concentration of 4.75 mg/mL drug loading were obtained, corresponding to a thousand fold increase in EFV solubility, combined to a very high encapsulation efficiency (>99.8%). Due to rapid diffusion, drug was immediately released from the nanoparticles. The biopharmaceutical evaluation on ex vivo jejunum segments demonstrated an increased absorption of EFV from organogel nanoparticles compare to a native EFV suspension. In vitro assays combining Caco-2 cell cultures with TEM and confocal microscopy demonstrated passive diffusion, while paracellular integrity and endocytosis activity remain expelled. Oral pharmacokinetics of EFV organogel nanoparticles improve oral bioavailability (F_r: 249%) and quick absorption compared to EFV suspension.

CONCLUSION

Organogel nanoparticles increase the bioavailability of BCS Class II drugs. The main phenomena is simply oil transfer from the gelled particles through the cell membrane.

Controlled Release of Thymol from Poly(Lactic Acid)-Based Silver Nanocomposite Films with Antibacterial and Antioxidant Activity

Thymol and silver nanoparticles (Ag-NPs) were used to develop poly(lactic acid) (PLA)-based films with antioxidant and antibacterial performance. Different amounts of thymol (6 and 8 wt%) and 1 wt% Ag-NPs were added to PLA to produce the active films. Ag-NPs and thymol were successfully identified in the nanocomposite structures using spectroscopic techniques. A kinetic study was performed to evaluate the release of thymol and Ag-NPs from the nanocomposites to an aqueous food simulant (ethanol 10%, v/v) at 40 °C. The diffusion of thymol from the polymer matrix was affected by the presence of non-migrating Ag-NPs, which showed non-Fickian release behavior. The ternary system including 1 wt% Ag-NPs and 8 wt% thymol showed clear antibacterial performance by reducing the cell viability of Escherichia coli and Staphylococcus aureus by around 40% after 3 and 24 h of storage at 4, 25, and 37 °C compared to neat PLA. Significant antioxidant behavior of all active films was also confirmed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The obtained nanocomposite films based on PLA and the addition of Ag-NPs and thymol were proven to have combined antioxidant and antibacterial performance, with controlled release of thymol. These formulations have potential applications in the development of innovative and customized active packaging systems to increase the shelf-life of food products.

Pioglitazone-Loaded Nanostructured Hybrid Material for Skin Ulcer Treatment

Pioglitazone, a popular antidiabetic drug, which was recently shown to be effective in the treatment of skin ulcers, was successfully encapsulated in polysaccharide nanoparticles and used as a bioactive component of the wound-dressing material based on modified bacterial nanocellulose. Alginate and hydroxypropyl cellulose were used as a matrix for the nanoparticulate drug-delivery system. The matrix composition and particles’ size, as well as drug encapsulation efficiency and loading, were optimized. Pioglitazone hydrochloride (PIO) loaded particles were coated with chitosan introduced into the crosslinking medium, and covalently attached to the surface of bacterial nanocellulose functionalized with carboxyl groups. PIO was released from the surface of the hybrid material in a controlled manner for 5 days. Preliminary cytotoxicity studies confirmed safety of the system at PIO concentrations as high as 20 mg/mL. The obtained hybrid system may have potential application in the treatment of skin ulcers e.g., in diabetic foot.

Drug polarity effect over the controlled release in casein and chondroitin sulfate-based hydrogels

This study compared the controlled release of two drugs: vitamin-B12, and l-dopa from hydrogels based on 50% of casein (CAS, a protein), 50% of chondroitin sulfate (CS, a polysaccharide) and different amounts of SiO2. The results indicated that the incorporation of 5% of SiO2 to the materials, allowed the best organization, distribution, and diameter of the pores, which are responsible for ensuring a more controlled release. Also, the matrices were not efficient in releasing vitamin-B12, but it successfully released l-dopa. It happened because vitamin-B12 is highly hydrophilic, interacting more with the medium than with the CAS/CS matrix, while l-dopa is less polar than vitamin-B12, interacting more with the CAS/CS matrix. It is worth mentioning that all synthesized hydrogels were non-toxic to the cells as showed by the in vitro assay. This work also demonstrated the importance of evaluating drug delivery devices using drugs of different polarities before stating if they are efficient or not.

Trimethoprim-Loaded Microspheres Prepared from Low-Molecular-Weight PLGA as a Potential Drug Delivery System for the Treatment of Urinary Tract Infections

Commonly, therapy of urinary tract infections suffers from increasing resistance to antibiotics and the ability of uropathogenic Escherichia coli (UPEC) to invade bladder cells and cause recurring infections. As an alternative strategy for instillation into the bladder, trimethoprim-loaded microparticles with poly(d,l-lactic-co-glycolic acid) (PLGA) as a matrix were prepared. To reduce particle loss by washout, their surface was grafted with bioadhesive wheat germ agglutinin, providing biomimicry akin to UPEC. Since PLGA 503H has shown a slow drug release profile, the low-molecular-weight PLGA 2300 was studied. Whereas the drug loading of PLGA 503H particles amounted to 2.8%, the drug content of PLGA 2300 particles was twice as high. Although the drug release pattern started with an initial burst of 30% after 24 h for both PLGA types, half of the trimethoprim content was released after 4 days from PLGA 503H microparticles as opposed to 2 days in the case of PLGA 2300. Higher drug loading and accelerated release render PLGA 2300 a viable alternative to PLGA 503H.

In Situ Gelling Ophthalmic Drug Delivery System for the Optimization of Diagnostic and Preoperative Mydriasis: In Vitro Drug Release, Cytotoxicity and Mydriasis Pharmacodynamics

Mydriasis is required prior to many eye examinations and ophthalmic surgeries. Nowadays, phenylephrine hydrochloride (PHE) and tropicamide (TPC) are extensively used to induce mydriasis. Several pharmaceutic dosage forms of these two active ingredients have been described. However, no optimal therapeutic strategy has reached the market. The present work focuses on the formulation and evaluation of a mucoadhesive ion-activated in situ gelling delivery system based on gellan gum and hydroxyethylcellulose (HEC) for the delivery of phenylephrine and tropicamide. First, in vitro drug release was studied to assess appropriate sustained drug delivery on the ocular surface region. Drug release mechanisms were explored and explained using mathematical modeling. Then, in situ gelling delivery systems were visualized using scanning electron microscopy illustrating the drug release phenomena involved. Afterward, cytotoxicity of the developed formulations was studied and compared with those of commercially available eye drops. Human epithelial corneal cells were used. Finally, mydriasis intensity and kinetic was investigated in vivo. Mydriasis pharmacodynamics was studied by non-invasive optical imaging on vigilant rabbits, allowing eye blinking and nasolacrimal drainage to occur physiologically. In situ gelling delivery systems mydriasis profiles exhibited a significant increase of intensity and duration compared with those of conventional eye drops. Efficient mydriasis was achieved following the administration of a single drop of in situ gel reducing the required amount of administered active ingredients by four- to eight-fold compared with classic eye drop regimen.

Investigating the potential of utilizing glycerosomes as a novel vesicular platform for enhancing intranasal delivery of lacidipine

Lacidipine is a potent dihydropyridine calcium channel blocker used for management of hypertension and atherosclerosis. The drug has low and fluctuating oral bioavailability owing to its extensive hepatic first-pass metabolism and reduced water solubility. Accordingly, this work aimed at overcoming the aforementioned challenges through the formulation of intranasal nano-sized lacidipine glycerosomes. Box-Behnken was successfully employed for the formulation and in vitro optimization of the glycerosomes. Statistical analysis revealed that cholesterol concentration exhibited a significant effect on the vesicle size, while Phospholipon® 90G and glycerol concentrations exhibited significant effects on both entrapment efficiency and deformability index. The optimized formulation showed spherical shape, good deformability, vesicular size of 220.25 nm, entrapment efficiency of 61.97%, and enhanced ex vivo permeation by 3.65 fold compared to lacidipine suspension. Confocal laser scattering microscope revealed higher penetration depth via nasal mucosa for rhodamine labelled glycerosomes (up to 60 µm) in comparison to rhoadamine dye solution (26 µm). In addition, the optimized lacidipine glycerosomes caused significant reduction in methylprednisolone acetate-induced hypertension in rats for up to 24 h in comparison to oral drug suspension. Histopathological assessment showed intact nasal mucosal epithelial lining with no signs of inflammation or necrosis confirming the safety and tolerability of the proposed glycerosomes. The declared results highlights the potential of utilizing the proposed glycerosomes as safe and effective platform for intranasal delivery of lacidipine.

In vitro attenuation of astrocyte activation and neuroinflammation through ibuprofen-doping of poly(3,4-ethylenedioxypyrrole) formulations

Neuroinflammation is often associated with poor functional recovery and may contribute to or initiate the development of severe neurological disorders, such as epilepsy, Parkinson's disease or Alzheimer's disease. Ibuprofen (IBU), being one of the most commonly used non-steroidal anti-inflammatory drugs, is known to possess neuroprotective activity and serve as a promising therapeutic for the treatment of neuroinflammation. In this study, the potential of an IBU-loaded poly(3,4-ethylenedioxypyrrole) (PEDOP) matrix has been assessed as a neural interface material with an aim to control astrocyte activation and suppress neuroinflammation in vitro. Three types of drug immobilization protocols were investigated, leading to the fabrication of IBU-loaded PEDOP matrices exhibiting a broad spectrum of electrical characteristics, drug release profiles, as well as biological responses. Among all investigated PEDOP formulations, PEDOP matrices formed through a three-step immobilization protocol exhibited the highest charge storage capacity (30 ± 1 mC/cm²) as well as a double layer capacitance of 645.0 ± 51.1 µF, associated with a relatively enlarged surface area. Demonstrating a total drug loading capacity of 150 µg/ml and a release rate constant of 0.15 1/h, this coating formulation may be employed as a safe electrical conducting drug eluting system.

Carvacrol loaded nanostructured lipid carriers as a promising parenteral formulation for leishmaniasis treatment

Leishmaniasis are a group of neglected infectious diseases caused by protozoa of the genus Leishmania with distinct presentations. The available leishmaniasis treatment options are either expensive and/or; cause adverse effects and some are ineffective for resistant Leishmania strains. Therefore, molecules derived from natural products as the monoterpene carvacrol, have attracted interest as promising anti-leishmania agents. However, the therapeutic use of carvacrol is limited due to its low aqueous solubility, rapid oxidation and volatilization. Thus, the development of nanostructured lipid carriers (NLCs) was proposed in the present study as a promising nanotechnology strategy to overcome these limitations and enable the use of carvacrol in leishmaniasis therapy. Carvacrol NLCs were obtained using a warm microemulsion method, and evaluated regarding the influence of lipid matrix and components concentration on the NLCs formation. NLCs were characterized by DSC and XRD as well. In addition, to the in vitro carvacrol release from NLCs, the in vitro cytotoxicity and leishmanicidal activity assays, and the in vivo pharmacokinetics evaluation of free and encapsulated carvacrol were performed. NLCs containing carvacrol were obtained successfully using a warm microemulsion dilution method. The NLCs formulation with the lowest particle size (98.42 ± 0.80 nm), narrowest size distribution (suitable for intravenous administration), and the highest encapsulation efficiency was produced by using beeswax as solid lipid (HLB=9) and 5% of lipids and surfactant. The in vitro release of carvacrol from NLCs was fitted to the Korsmeyer and Peppas, and Weibull models, demonstrating that the release mechanism is probably the Fickian diffusion type. Moreover, carvacrol encapsulation in NLCs provided a lower cytotoxicity in comparison to free carvacrol (p<0.05), increasing its in vitro leishmanicidal efficacy in the amastigote form. Finally, the in vivo pharmacokinetics of carvacrol after IV bolus administration suggests that this phenolic monoterpene undergoes enterohepatic circulation and therefore presented a long half-life (t_1/2) and low clearance (Cl). In addition, C₀, mean residence time (MRT) and V_dss of encapsulated carvacrol were higher than free carvacrol (p < 0.05), favoring a higher distribution of carvacrol in the target tissues. Thus, it is possible to conclude that the developed NLCs are a promising delivery system for leishmaniasis treatment.

Preparation, Optimization, and Evaluation of Methoxy Poly(ethylene glycol)-co-Poly(ε-caprolactone) Nanoparticles Loaded by Rivastigmine for Brain Delivery

The objective of this study was to formulate and investigate the neuropharmacokinetics and pharmacodynamics of rivastigmine (Riv) loaded methoxy poly(ethylene glycol)-co-poly(ε-caprolactone) (MPEG-PCL) nanoparticles (Riv-NPs) in rats after IV administration. The MPEG-PCL was synthesized via ring-opening polymerization of ε-caprolactone by MPEG and used to prepare Riv-NPs by the nanoprecipitation method. Response surface D-optimal design was applied to optimize Riv-NPs drug delivery system. The optimized formulation showed a particle size (PS) of 98.5 ± 2.1 nm, drug loading (DL) of 19.2 ± 1.1%, and sustained release behavior of the drug. Moreover, the optimized Riv-NPs were characterized by AFM and DSC analyses. A simple and sensitive HPLC-DAD method for bioanalysis was developed and successfully applied to the pharmacokinetic study. The neuropharmacokinetic study in rats indicated that the integration plot was linear, and the brain uptake clearance of the drug-loaded in MPEG-PCL NPs was significantly higher than the free drug. Furthermore, results of pharmacodynamic studies using the Morris water maze test demonstrated faster regain of memory loss with Riv-NPs when compared to the free drug solution. The results revealed that the mentioned biodegradable nanoparticle holds promise as a suitable drug carrier for brain drug delivery.

Micro vs. nano: PLGA particles loaded with trimethoprim for instillative treatment of urinary tract infections

Recurring infections and increasing resistances continue to complicate treatment of urinary tract infections. To investigate alternative treatment options, trimethoprim loaded micro- (D[4;3] of 1-9 µm) and nanoparticles (Z-Avg of 200-400 nm) were prepared from two types of poly(d,l-lactic-co-glycolic acid) (PLGA) for instillative therapy. While PLGA 503H microparticles could not be loaded with more than 2.6% trimethoprim, PLGA 2300 entrapped 22%. When preparing nanoparticles, both types displayed an even higher drug load of up to 29% using PLGA 2300, while PLGA 503H drug load stagnated at 10%. After eight hours, drug release from microparticles amounted to 55% (503H) and 35% (2300) whereas total drug release occurred after 8 (503H) and 9 days (2300). In case of nanoparticles, trimethoprim was liberated much faster with 60% after 2 h and a complete release after 24 h from both polymers. PLGA 2300 seems to be the better choice for entrapment of trimethoprim in microparticles considering the drug load. Both polymers, however, seem to be viable options for nanoparticles. Due to the higher overall drug load, nanoparticles seem to be advantageous over microparticles for instillative therapy, especially when prepared with PLGA 2300.