Porous corn starch granules as effective host matrices for encapsulation and sustained release of curcumin and resveratrol

Type 2 Diabetes Mellitus (T2DM) is a carbohydrate-rich diet-regulated ailment with carbohydrates digested and absorbed rapidly. Hence, modulating carbohydrate digestion is warranted; to this end, polyphenols from plant sources are handy. However, polyphenols' instability and low bioavailability limit their wholesome use, and thus, encapsulating them into an inexpensive and suitable wall material would be the best strategy. Herein, the potential of porous starch granules is demonstrated. Curcumin and resveratrol were chosen as the test polyphenols due to their proven health benefits, and porous corn starch granules were chosen as the wall material. Porous corn starch granules were prepared through enzymatic modification with 11, 22, and 33 units of amyloglucosidase at three reaction times of 2, 4, and 6 h. The polyphenols were loaded at 100, 200, and 500 mg concentrations in 1 g of starch for 21 days and were characterized through Scanning Electron Microscope (SEM) and Fourier Transform Infrared spectroscopy (FTIR) analyses. The encapsulation efficiency was determined, the rate of starch digestion was calculated through the Englyst test, and polyphenols' in vitro release behavior in gastric and intestinal fluids was measured. Results suggest that 33 enzyme units for a 2 h reaction time were optimal for forming spherical-oval pores on corn starch granules with the maximum encapsulation efficiency of 80.16 % and 88.33 % for curcumin and resveratrol, respectively. The FTIR results suggest the entrapment of polyphenols inside the starch matrix. The inclusion significantly reduced starch digestion and increased the percentage of resistant starch up to 41.11 % and 66.36 % with curcumin and resveratrol, respectively. The in vitro release behavior demonstrated good stability in the simulated gastric fluids and sustained release in simulated intestinal fluids. The encapsulated polyphenols showed a complex Fickian type of diffusion mechanism. Overall, the results suggest that porous corn starch granules could be a potential delivery system for curcumin and resveratrol and will aid in developing novel functional foods to address the T2DM concerns.

Encapsulation of Triphasia trifolia extracts by pH and thermal dual-sensitive chitosan hydrogels for controlled release

Recent studies have developed varied delivery systems incorporating natural compounds to improve the limitations of plant extracts for clinical use while enabling their controlled release at treatment sites. For the first time, ethanolic limeberry extract (Triphasia trifolia) has been successfully encapsulated in thermo-sensitive chitosan hydrogels by a facile in situ loading. The extract-incorporated chitosan hydrogels have a pH value of nearly 7.00, gelation temperatures in the range of 37-38 °C, and exhibit an open-cell porous structure, thus allowing them to absorb and retain 756 % of their mass in water. The in vitro extract release from the hydrogels is driven by both temperature and pH, resulting in more than 70 % of the initial extract being released within the first 24 h. Although the release half-life of hydrogels at pH 7.4 is longer, their release capacity is higher than that at pH 6.5. Upon a 2 °C increase in temperature, the time to release 50 % initial extract is sharply reduced by 20-40 %. The release kinetics from the hydrogels mathematically demonstrated that diffusion is a prominent driving force over chitosan relaxation. Consequently, the developed hydrogels encapsulating the limeberry extract show their heat and pH sensitivity in controlled release for treating chronic wounds.

Preparation and in vitro characterization of curcumin loaded Chitosan-Hyaluronic acid polyelectrolyte complex based hydrogels

OBJECTIVE

The manuscript aims to prepare and comprehensively characterize curcumin-loaded chitosan-hyaluronic acid polyelectrolyte complex (PEC) hydrogels through in vitro assessments. By elucidating the formulation process, physicochemical attributes, and drug release kinetics, the study contributes to the producing of curcumin loaded new drug delivery system.

SIGNIFICANCE

This approach shows the unique synergy of the chosen polymers with curcumin. The meticulous in vitro analysis of the hydrogels cements their novel attributes, underlining their potential as efficacious and biocompatible curcumin carriers.

METHODS

To configure the optimum formulation variables, viscosity, swelling ratio, porosity, in vitro release, cell viability, and migration rate were determined. In addition, FTIR and SEM analyses were also carried out to define the characteristic of formulations.

RESULTS

Release kinetic determination is essential in estimating the release behavior of formulation in the body. All formulations showed Higuchi release kinetics, indicating that drug release from the semi-solid matrix was diffusion controlled.

CONCLUSION

As a result, in this study, a new formulation was produced based on a simple concept with acceptable quality parameter results promising to be conducted in the industry.

Hyaluronic Acid-Alginate Homogeneous Structures with Polylactide Coating Applied in Controlled Antibiotic Release

The use of a controlled-release drug carrier is an innovative solution for the treatment of local infections, in particular in dentistry, skin diseases, and in open wounds. The biocompatibility, biodegradability, the possibility of a large amount of drug adsorbed (especially those with hydrophilic properties), and the ability to create structures of any shape and size are the reasons for hydrogels to be frequently studied. The main disadvantage of hydrogel carriers is the rapid rate of drug release; hence, in this study, an attempt was made to additionally chemically cross-link 1-ethyl-3-(3-dimethyl aminopropyl)-1-carbodiimide hydrochloride (EDC) with the hyaluronic acid-alginate (HA-SAL) structure. The answer to significantly reduce the mass flux typical for hydrogel structure was to surround it with a polymer layer using a dry cover. By coating the carriers with polylactide, the release time was increased by around forty times. As the carriers were designed to reduce local bacterial infections, among others in dentistry, the released antibiotics were amoxycillin, metronidazole, and doxycycline.

Dynamic investigation of zein-based degradable and hemocompatible coatings for drug-eluting stents: a microfluidic approach

Biodegradable stent coatings have shown great potential in terms of delivering drugs to a damaged vessel wall, and their release profiles are key elements governing the overall performance of drug-eluting stents (DESs). However, release and degradation kinetics are usually not tested under simulated physiological conditions or in dynamic environments, both essential aspects in the design of novel DESs. To bridge this gap, fused silica-based microfluidic systems, with either round or square channel cross-sections, were designed to mimic the microenvironment of a stented vessel. In particular, we fabricated and characterized microfluidic chips based on customizable channels, which were spray-coated with a naturally-derived, rutin-loaded zein solution, to perform a comprehensive study under flow conditions. Dynamic assays after 6 hours showed how the degradation of the zein matrix was affected by the cross-sectional conformation (∼69% vs. ∼61%, square and round channel, respectively) and the simulated blood fluid components (∼55%, round channel with a more viscous solution). The released amount of rutin was ∼81% vs. ∼77% and ∼78% vs. ∼74% from the square and round channels, using the less and more viscous blood-simulated fluids, respectively. Fitting the drug release data to Korsmeyer-Peppas and first-order mathematical models provided further insight into the mechanism of rutin release and coating behavior under flowing conditions. More importantly, whole blood tests with our newly developed microfluidic platforms confirmed the hemocompatibility of our zein-based coating. In detail, in-flow and static studies on the blood cell behavior showed a significant reduction of platelet adhesion (∼73%) and activation (∼93%) compared to the stainless-steel substrate, confirming the benefits of using such naturally-derived coatings to avoid clogging. Overall, our microfluidic designs can provide a key practical tool for assessing polymer degradation and drug release from degradable matrices under flowing conditions, thus aiding future studies on the development of hemocompatible, controlled-release coatings for DESs.

Study of the synergistic influence of zwitterionic interactions and graphene oxide on water diffusion mechanism and mechanical properties in hybrid hydrogel network

Hybrid hydrogels based on n-isopropylacrylamide, zwitterionic comonomer, and graphene oxide were synthesized to study their physical and mechanical properties. The compositional variation largely influenced the swelling characteristics of the hybrid hydrogels compared to mechanical properties, i.e., elongation and compression. Additionally, Rheometric swelling measurements on the swollen hydrogels were performed until they reached equilibrium showed a very low phase angle δ indicating strong covalent network, which intrun increases with increasing content of zwitterions and GO. Swelling kinetics were studied and found to follow Fickian dynamics, albeit zwitterion-containing gels showed a peculiar 2-step swelling pattern. Interestingly, differences in the swelling mechanism are also clear for the hydrogels with 2D GO (Graphene oxide) nano-fillers from its 1D nano-filler CNTs (Carbon nanotubes). In elongation, the samples break in a brittle fashion at Hencky strains ε_max around 0.4-0.65 with the maximum stress being observed for samples with high Zw-content and 0.2% GO, which can be explained by the stress-rising properties of sharp edges of GO. In contrast, the data in compression profits from higher GO-contents as crack growth is less important in this deformation mode. This work will contribute to future composite gel applications.

Controlled Release of Felodipine from 3D-Printed Tablets with Constant Surface Area: Influence of Surface Geometry

In this study, 3D-printed tablets with a constant surface area were designed and fabricated using polylactic acid (PLA) in the outer compartment and polyvinyl alcohol and felodipine (FDP) in the inner compartment. The influences of different surface geometries of the inner compartment, namely, round, hexagon, square, and triangle, on drug release from 3D-printed tablets were also studied. The morphology and porosity of the inner compartment were determined using scanning electron microscopy and synchrotron radiation X-ray tomographic microscopy, respectively. Additionally, drug content and drug release were also evaluated. The results revealed that the round-shaped geometry seemed to have the greatest total surface area of the inner compartment, followed by square-shaped, hexagon-shaped, and triangle-shaped geometries. FDP-loaded 3D-printed tablets with triangle and hexagon surface geometries had the slowest drug release (about 80% within 24 h). In the round-shaped and square-shaped 3D-printed tablets, complete drug release was observed within 12 h. Furthermore, the drug release from triangle-shaped 3D-printed tablets with double the volume of the inner compartment was faster than that of a smaller volume. This was due to the fact that a larger tablet volume increased the surface area contacting the medium, resulting in a faster drug release. The findings indicated that the surface geometry of 3D-printed tablets with a constant surface area affected drug release. This study suggests that 3D printing technology may be used to develop oral solid dosage forms suitable for customized therapeutic treatments.

Structure and interaction roles in the release profile of chalcone-loaded liposomes

The structures and molecular interactions of established synthetic chalcones were correlated with their release profiles from asolectin liposomes. The effects of chalcones on the properties of liposomes were evaluated by dynamic light scattering (DLS), ultraviolet-visible spectroscopy (UV-VIS), horizontal attenuated total reflection Fourier transform infrared (HATR-FTIR), ³¹P nuclear magnetic resonance (³¹P NMR), zeta (ζ) potential and differential scanning calorimetry (DSC). The profiles and mechanisms of release were accessed according to the Korsmeyer-Peppas model. Results obtained allowed the establishment of a relationship between the chalcone release profile and 1) the ordering effects of chalcones in different membrane regions, 2) their polar or interfacial location in the lipid layer, 3) the influence of hydroxy and methoxy substituents, 4) their effect on reorientation of lipid choline-phosphate regions. The obtained data may improve the development of chalcone-based systems to be used in the therapy of chronic and acute diseases.

Artificial intelligence-assisted development of in situ forming nanoparticles for arthritis therapy via intra-articular delivery

Intra-articular (IA) injection is grasping much interest due to the poor drug bioavailability at the targeted site of action which minimizes the effect of the orally administered moiety. Based on the integral role of non-steroidal anti-inflammatory drugs (NSAIDs) in the treatment of Rheumatoid Arthritis (RA), much effort is exerted to develop novel localized drug delivery systems to increase their bioavailability and minimize their side effects. Artificial intelligence (AI) is acquiring an increasing role in the design of experiments being an effective tool for saving both time and resources. Hence, the aim of this work was to develop, characterize and optimize targeted in-situ forming nano particles (ISNs) for IA delivery of piroxicam using Design^® Expert as an AI-based application where a 3³ full factorial experimental design was adopted. Morphological investigation, injectability, rheological studies, Fourier Transform Infrared Radiation (FTIR) as well as biological, histopathological, and biochemical examinations were performed to evaluate the optimized-ISNs. The optimized formulation, exhibiting a nano-sized particle size with a dense core, showed significant improvement in the histopathological findings compared to both the oral solution and the placebo. Additionally, the once-a-week IA administration of the optimized-ISNs proved a significant reduction in the protein expression of both STAT-3 and RANKL and the levels of anti-CCP and MCP-1 by almost 54 and 73%, respectively, coupled with a marked decline in the content of IL-17, MMP-3, NF-κB and TNF-α as compared to the positive control. In conclusion, the use of ISNs for intra-articular injection has demonstrated their effectiveness in piroxicam delivery for RA treatment.

Cost Function Analysis Applied to Different Kinetic Release Models of Arrabidaea chica Verlot Extract from Chitosan/Alginate Membranes

This work focuses on the mathematical analysis of the controlled release of a standardized extract of A. chica from chitosan/alginate (C/A) membranes, which can be used for the treatment of skin lesions. Four different types of C/A membranes were tested: a dense membrane (CA), a dense and flexible membrane (CAS), a porous membrane (CAP) and a porous and flexible membrane (CAPS). The Arrabidae chica extract release profiles were obtained experimentally in vitro using PBS at 37 °C and pH 7. Experimental data of release kinetics were analyzed using five classical models from the literature: Zero Order, First Order, Higuchi, Korsmeyer–Peppas and Weibull functions. Results for the Korsmeyer–Peppas model showed that the release of A. chica extract from four membrane formulations was by a diffusion through a partially swollen matrix and through a water filled network mesh; however, the Weibull model suggested that non-porous membranes (CA and CAS) had fractal geometry and that porous membranes (CAP and CAPS) have highly disorganized structures. Nevertheless, by applying an explicit optimization method that employs a cost function to determine the model parameters that best fit to experimental data, the results indicated that the Weibull model showed the best simulation for the release profiles from the four membranes: CA, CAS and CAP presented Fickian diffusion through a polymeric matrix of fractal geometry, and only the CAPS membrane showed a highly disordered matrix. The use of this cost function optimization had the significant advantage of higher fitting sensitivity.

Solulan C24- and Bile Salts-Modified Niosomes for New Ciprofloxacin Mannich Base for Combatting Pseudomonas-Infected Corneal Ulcer in Rabbits

Keratitis is a global health issue that claims the eye sight of millions of people every year. Dry eye, contact lens wearing and refractive surgeries are among the most common causes. The resistance rate among fluoroquinolone antibiotics is >30%. This study aims at formulating a newly synthesized ciprofloxacin derivative (2b) niosomes and Solulan C24-, sodium cholate- and deoxycholate-modified niosomes. The prepared niosomal dispersions were characterized macroscopically and microscopically (SEM) and by percentage entrapment efficiency, in vitro release and drug release kinetics. While the inclusion of Solulan C24 produced something discoidal-shaped with a larger diameter, both cholate and deoxycholate were unsuccessful in forming niosomes dispersions. Conventional niosomes and discomes (Solulan C24-modified niosomes) were selected for further investigation. A corneal ulcer model inoculated with colonies of Pseudomonas aeruginosa in rabbits was developed to evaluate the effectiveness of keratitis treatment of the 2b-loaded niosomes and 2b-loaded discomes compared with Ciprocin^® (ciprofloxacin) eye drops and control 2b suspension. The histological documentation and assessment of gene expression of the inflammatory markers (IL-6, IL1B, TNFα and NF-κB) indicated that both 2b niosomes and discomes were superior treatments and can be formulated at physiological pH 7.4 compatible with the ocular surface, compared to both 2b suspension and Ciprocin^® eye drops.

Hydrogels Based on Alginates and Carboxymethyl Cellulose with Modulated Drug Release-An Experimental and Theoretical Study

New hydrogels films crosslinked with epichlorohydrin were prepared based on alginates and carboxymethyl cellulose with properties that recommend them as potential drug delivery systems (e.g., biocompatibility, low toxicity, non-immunogenicity, hemostatic activity and the ability to absorb large amounts of water). The characterization of their structural, morphological, swelling capacity, loading/release and drug efficiency traits proved that these new hydrogels are promising materials for controlled drug delivery systems. Further, a new theoretical model, in the framework of Scale Relativity Theory, was built with to offer insights on the release process at the microscopic level and to simplify the analysis of the release process.

Bacterial cellulose nanofibrils-reinforced composite hydrogels for mechanical compression-responsive on-demand drug release

Herein, we propose a cellulose-reinforced hybrid hydrogel system that not only increases mechanical strength, but also allows on-demand drug release. This hybrid hydrogel is specialized by its semi-interpenetrating network structure in which bacterial cellulose nanofibers (BCNFs) penetrate through a polyacrylamide (PAM) mesh. We showed that the interpenetrating BCNFs with a higher aspect ratio of 240 increased the compression strength of PAM/BCNF composite hydrogels approximately 3-fold, compared with that prepared with PAM only, stemming from the reinforcing effect of the rigid natural nanofibers between PAM meshes. We also observed that the swelling kinetics depended on the mechanical properties determined by the BCNF aspect ratio. From further studies on drug release, we demonstrated that the tailored composition of BCNFs with PAM retarded drug release by a factor of two compared to PAM only while enabling on-demand drug release in response to the applied compressive stress. These results highlight that our BCNFs-reinforced hydrogel system can be applied as a mechanical stress-responsive smart drug delivery patch.

Formulations Based on Drug Loaded Aptamer-Conjugated Liposomes as a Viable Strategy for the Topical Treatment of Basal Cell Carcinoma-In Vitro Tests

Topical liposomal drug formulations containing AS1411-aptamer conjugated liposomes were designed to deliver in a sustained way the 5-fluorouracil to the tumor site but also to increase the compliance of patients with basal cell carcinoma. The 5-fluorouracil penetrability efficiency through the Strat-M membrane and the skin irritation potential of the obtained topical liposomal formulations were evaluated in vitro and the Korsmeyer Peppas equation was considered as the most appropriate to model the drug release. Additionally, the efficiency of cytostatic activity for targeted antitumor therapy and the hemolytic capacity were performed in vitro. The obtained results showed that the optimal liposomal formulation is a crosslinked gel based on sodium alginate and hyaluronic acid containing AS1411-aptamer conjugated liposomes loaded with 5-fluorouracil, which appeared to have favorable biosafety effects and may be used as a new therapeutic approach for the topical treatment of basal cell carcinoma.

Silk fibroin hydrogel/dexamethasone sodium phosphate loaded chitosan nanoparticles as a potential drug delivery system

The application of nanoparticles-loaded hydrogel as a novel formulation has gotten much attention for a potential drug delivery method for desire drug controlling and targeting. This study prepared a sustained release formulation using dexamethasone sodium phosphate-loaded chitosan nanoparticles embedded in silk fibroin hydrogel. Dexamethasone sodium phosphate-loaded chitosan nanoparticles (DEX-CSNPs) was developed using the ionotropic-gelation technique and inserted in the silk fibroin hydrogel (SFH). Mean particle size, polydispersity index (PDI), and zeta potential of DEX-CSNPs were 488.05±38.69 nm, 0.15±0.07, 32.12±2.42 mV, respectively. The encapsulation efficiency (EE), drug loading capacity (LC), and the cumulative amount of released drug of DEX-loaded CSNPs, which detected in phosphate buffer saline (PBS) solution, were 67.6±6.7%, 15.7±5.7%, and 75.84%, respectively. The DEX-CSNPs were then mixed with silk fibroin (SF) solution and induced gelation by sonication to prepare a drug-releasing system. As a result, the scanning electron microscopy (SEM) image shows that the prepared drug delivery system had a properly interconnected porous structure. Smaller pore size, greater porosity, higher water uptake, and swelling ratio were achieved by incorporating CSNPs and DEX-loaded CSNPs. The cytotoxicity study was performed for the L929 fibroblast cell line. The drug release kinetics study was performed on a prepared drug delivery system. Finally, the release test results showed a suitable extended-release of DEX from the carrier over 16 days. Overall, the developed drug-releasing system can be a promising candidate for drug delivery applications.

Effect of temperature and pH on the encapsulation and release of β-carotene from octenylsuccinated oat β-glucan micelles

Effect and working mechanism of temperature and pH on encapsulation and release of β-carotene from octenylsuccinated-oat-β-glucan-micelles (OSβG-Ms) were investigated. The stability and solubility of β-carotene, and changes in surface hydrophilicity, core hydrophobicity, and size of β-carotene-loaded-OSβG-Ms were determined. When exposed to temperature (25-45 °C) and pH (4.5-8.5), β-carotene solubilization changed in parabolic manners. Size and absolute zeta-potential of β-carotene-loaded-OSβG-Ms decreased with temperature, while they gave parabolic changing patterns with pH. Those results were ascribed to their hydrophilicity, hydrophobicity, and core/shell compactness via regulating molecule mobility, orientation, and interactions by temperature/pH. The higher temperature concluded with higher β-carotene release, while a U-shaped release profile was observed with pH. Besides its diffusion, erosion-induced shrinking and collapsing of OSβG-Ms favored β-carotene release at pH 1.2-4.5, which was replaced by swelling-induced structural-relaxation at pH 6.8-8.5. The results were favourable in controlling the behavior of β-carotene-loaded-OSβG-Ms by selectively applying environmental parameters.

Antitumoral Drug: Loaded Hybrid Nanocapsules Based on Chitosan with Potential Effects in Breast Cancer Therapy

Cancer remains one of the world's most devastating diseases and is responsible for more than 20% of all deaths. It is defined as uncontrolled proliferation of cells and spreads rapidly to healthy tissue. Controlled drug delivery systems offers great opportunities for the development of new non-invasive strategies for the treatment of cancers. The main advantage of these systems is their capacity to accumulate in tumors via enhanced permeability and retention effects. In the present study, an innovative hybrid drug delivery system based on nanocapsules obtained from the interfacial condensation between chitosan and poly(N-vinyl pyrrolidone-alt-itaconic anhydride) and containing both magnetic nanoparticles and an antitumoral drug was developed in order to improve the efficiency of the antitumoral treatment. Using dynamic light scattering, it was observed that the mean diameter of these hybrid nanocapsules was in the range of 43 to 142 nm. SEM confirmed their nanometric size and their well-defined spherical shape. These nanocapsules allowed the encapsulation of an increased amount of 5-fluorouracil and provided controlled drug release. In vitro studies have revealed that these drug-loaded hybrid nanocapsules were able to induce a cytostatic effect on breast carcinoma MCF-7 cell lines (Human Caucasian breast adenocarcinoma - HTB-22) comparable to that of the free drug.

Chemical and physical chitosan hydrogels as prospective carriers for drug delivery: a review

This review summarizes and discusses recent research progress in chemical and physical chitosan hydrogels for drug delivery.

"In vitro" behaviour of aptamer-functionalized polymeric nanocapsules loaded with 5-fluorouracil for targeted therapy

New type of nanocapsules based on carboxymethyl chitosan functionalized with AS1411 aptamer and poly(N-vinylpyrrolidone-alt-itaconic anhydride) loaded with 5-Fluorouracil (5-FU) were developed, with the potential to improve the treatment of cancer. Functionalization of nanocapsules with AS1411 aptamer will enhance their recognition by tumor cells, due to the interaction with nucleolin, and subsequent endocytosis. Nanocapsules were prepared by interfacial condensation method in the absence of any toxic crosslinking agents. The condensation reaction took place at the interface between the organic and aqueous phases by opening the anhydride cycles from the copolymer, under the action of the NH₂ groups from mixture of chitosan/aptamer-functionalized carboxymethyl chitosan. The nanocapsules diameter varied between 100 and 267 nm as a function of the molar ratio of the polymers. SEM images have revealed that nanocapsules were spherical and presented relatively low dimensional polydispersity. Nanocapsules swelling degree was found between 1000 and 1680% in PBS solution (pH = 7.4) and they allowed the encapsulation of an important amount of 5-Fluorouracil (5-FU). The release efficiency of 5-FU was studied, the processes being controlled by the drug diffusion through the polymeric membrane, as confirmed by the theoretical analysis of the drug release. The cytotoxicity and haemolysis tests performed on the nanocapsules proved their lack of toxicity and their excellent hemocompatibility. The obtained results were encouraging, showing that these original 5-FU-loaded nanocapsules were able to induce a more pronounced cytotoxic effect on neoplastic MCF-7 cells, the occurrence of dead cells being more rapidly than in the case of free 5-FU.

Coacervation of Interfacial Adhesive Proteins for Initial Mussel Adhesion to a Wet Surface

Coacervation of mussel adhesive proteins (MAPs) is proposed as a potential strategy that mussels may use during secretion due to their high concentration density, lack of dispersion into seawater, and low interfacial tension. Particularly, coacervations of interfacial MAPs, foot protein type-3 fast variant (fp-3F) and type-5 (fp-5), are important in the initial mussel adhesion process due to the relationship between the easy secretion/surface wetting properties of the coacervate and primer-like surface adhesive role of interfacial MAPs, which directly contact the marine surface. To the best of the authors' knowledge, this is the first report on coacervate formation of major recombinant interfacial MAPs with high charge densities and the highest 3,4-dihydroxyphenylalanine (Dopa) contents. Specifically, salt-induced coacervation of fp-3F is observed at low pH values corresponding to the acidified environment of the distal depression during mussel secretion. In addition, it shows enthalpy driven upper critical solution temperature behavior, possibly relying on bridging interactions between like-charged cationic fp-3Fs including salt-bridge and cation-π/π-π interactions in the presence of specific counterions, supported by Raman spectroscopy. It is believed that this study has broadened the scope of the understanding of coacervation of MAPs and may provide new insight for responsive biomaterial design.

In Situ Gel Formulation for Enhanced Ocular Delivery of Nepafenac

Nepafenac is a water-insoluble nonsteroidal antiinflammatory drug that is available as an ophthalmic suspension (Nevanac®). Suspensions are undesirable for 2 reasons: they tend to cause foreign body sensation and lacrimation, which could limit residence time and drug bioavailability. This decreases the amount of time the drug has to reach the site of action, the cornea. Previously, we improved the solubility and ocular permeability of nepafenac by complexing the drug with hydroxypropyl-β-cyclodextrin. In this study, we used the complex to formulate an ion-activated in situ gel system using sodium alginate, Protanal PH 1033, to increase the residence time and to reduce repeat eye drop instillation. Rheological properties of the formulations revealed that the viscosity of the optimized formulation was increased 30-fold when exposed to the simulated tear fluid (35°C). Permeation studies showed that the drug concentration of the in situ formulations were approximately 10 times higher than the commercial product, Nevanac® (p < 0.001). In addition, the in situ gel formulations had 5-fold higher concentrations of nepafenac retained in the cornea when compared to Nevanac® (p <0.001). Finally, ex vivo drug distribution studies in the porcine eye perfusion model revealed a higher drug retention in various ocular tissues such as cornea, sclera, retina, as compared to Nevanac®.

Aspects Regarding the Pharmaceutical Waste Management in Romania

The issue of drug disposal, as well as the development and implementation of efficient collection strategies, represents an important concern at the highest European level. This research looks into the factors that could have an impact on the efficiency of pharmacies in collecting and disposing the medicinal waste of the population. There were 521 pharmacists from all over the country who filled in a questionnaire on their opinion/attitude related to the system of collecting and disposing the pharmaceutical waste of the population. Of the surveyed pharmacists, 16% work in pharmacies that do not collect unused/expired drugs from the population, and nearly 33% of those investigated have refused, at least once, to take the unused medicines from the people. Pharmacists’ most important reasons for refusing to collect the pharmaceutical waste were the lack of procedure, incomplete legislation, exceeding the amount contracted with the operators, and high costs. Results show that pharmacies in Romania face several deficiencies in the pharmaceutical waste collection services. The lack of implemented programs has contributed considerably to lower standards of pharmaceutical waste management in Romania. This study is the first research on this topic in Romania, a country where the management of drug-based waste generated by the population is at the beginning. The results shown in this survey can provide a reference point for competent authorities in developing and implementing a take-back program for waste medicine whose efficiency is superior to the existing ones.

Anisotropy Influences on the Drug Delivery Mechanisms by Means of Joint Invariant Functions

In the frame of Higuchi's type functionality, this paper presents the anisotropy influences on the drug delivery mechanisms through the joint invariant functions to the simultaneous actions of the two SL(2R) isomorphic groups. Then, a new equation for drug delivery mechanism, independent of the type of polymer matrix and/or drug, is proposed.

A multiscale mechanism of drug release from polymeric matrices: confirmation through a nonlinear theoretical model

In this paper, we propose a new approach for the dynamics of drug delivery systems, assimilated to complex systems, an approach based on concepts like fractality, non-differentiability, and multiscale evolution. The main advantage of using these concepts is the possibility of eliminating the approximations used in the standard approach by replacing complexity with fractality, that imposes, in mathematical terms, the mandatory use of the non-differential character of defined physical quantities. The theoretical model presented, validated for other physical systems, demonstrates its functionality also for drug delivery systems, highlighting, in addition, new insights into the complexity of this system. The spatio-temporal scales of system evolution are characterized through the fractality degree, as a measure of the complexity of the phenomena occurring at each scale. Numerical analysis of the experiment showed that the overall drug release kinetics can be obtained by composing "smaller release kinetics" occurring at scales appropriate for each phase of the drug release mechanism, phases whose expansion depends on the system density. Moreover, the uncertainties in establishing the exact limits of the phases were removed by applying the principle of scale superposition, resulting in a global fractality degree corresponding to the entire release kinetics. Even if the theoretical model is perfectible by identifying constants specific to each delivery system, this paper is intended to be the beginning of an alternative approach to drug delivery mechanisms.