Tailoring the Release Rates of Fluconazole Using Solid Dispersions in Polymer Blends

Augmentation of antifungal activity of fluconazole using a clove oil nanoemulgel formulation optimized by factorial randomized D-optimal design

In the present study, fluconazole (FLU) showed the highest solubility in clove oil and was selected as the oil phase for the FLU-loaded nanoemulsion (FLU-NE). Among the studied cosurfactants, Labrafac was better than ethanol at providing globules with acceptable sizes and a lower polydispersity index (PDI) when Tween 80 was the surfactant. This optimized FLU-NE was thermodynamically stable. Furthermore, FLU-NE stored at 40 ± 2 °C and 75 ± 5% relative humidity for 6 months demonstrated good stability. The FLU-NE was converted to a FLU-loaded nanoemulsion gel (FLU-NEG) using 2% w/v sodium carboxymethyl cellulose. The FLU-NEG was acceptable in terms of visual appearance and spreadability. Rheological studies revealed pseudoplastic behavior for FLU-NEG. The viscosity of FLU-NEG decreased when the applied rpm was increased. FLU-NEG showed greater drug release than that from a FLU-GEL formulation. Furthermore, the FLU release from FLU-NEG followed the Higuchi model. The results from the in vitro antifungal evaluation of FLU-NEG on Candida albicans ATCC 76615 strain confirmed the increase in the antifungal activity of FLU by clove oil. Significant differences were observed in the zones of inhibition produced by FLU-NEG compared to those produced by the blank nanoemulsion gel (B-NEG), fluconazole suspension (FLU-SUS), and nystatin samples. Thus, the increase in the antifungal activity of FLU using clove oil as the oil phase in its nanoemulsion formulation was quite evident from our results. Therefore, the developed FLU-NEG could be considered a potential candidate for further preclinical and clinical studies.

Novel 3D-Printed Dressings of Chitosan-Vanillin-Modified Chitosan Blends Loaded with Fluticasone Propionate for Treatment of Atopic Dermatitis

In the present study, the blends of CS and Vanillin-CS derivative (VACS) were utilized for the preparation of printable inks for their application in three-dimensional (3D) printing procedures. Despite the synergic interaction between the blends, the addition of ι-carrageenan (iCR) as a thickening agent was mandatory. Their viscosity analysis was conducted for the evaluation of the optimum CS/VACS ratio. The shear thinning behavior along with the effect of the temperature on viscosity values were evident. Further characterization of the 3D-printed structures was conducted. The effect of the CS/VACS ratio was established through swelling and contact angle measurements. An increasing amount of VACS resulted in lower swelling ability along with higher hydrophobicity. Fluticasone propionate (FLU), a crystalline synthetic corticosteroid, was loaded into the CS/VACS samples. The drug was loaded in its amorphous state, and consequently, its in vitro release was significantly enhanced. An initial burst release, followed by a sustained release profile, was observed.

Investigation of Molecular Weight, Polymer Concentration and Process Parameters Factors on the Sustained Release of the Anti-Multiple-Sclerosis Agent Teriflunomide from Poly(ε-caprolactone) Electrospun Nanofibrous Matrices

In the current work, a series of PCL polyesters with different molecular weights was synthesized and used for the fabrication of nanofibrous patches via electrospinning, as sustained release matrices for leflunomide’s active metabolite, teriflunomide (TFL). The electrospinning conditions for each sample were optimized and it was found that only one material with high Mn (71,000) was able to produce structures with distinct fibers devoid of the presence of beads. The successful preparation of the fibers was determined by scanning electron microscopy (SEM).TFL (10, 20 and 30 wt%) in three different concentrations was incorporated into the prepared nanofibers, which were used in in vitro drug release experiments. The drug-loaded nanofibrous formulations were further characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and powder X-ray diffractometry (XRD).It was found that TFL was incorporated in an amorphous form inside the polymeric nanofibers and that significant molecular interactions were formed between the drug and the polyester. Additionally, in vitro dissolution studies showed that the PCL/TFL-loaded nanofibers exhibit a biphasic release profile, having an initial burst release phase, followed by a sustained release until 250 h. Finally, a kinetic analysis of the obtained profiles revealed that the drug release was directly dependent on the amount TFL incorporated into the nanofibers.

Development and characterization of lyophilized cefpodoxime proxetil-Pluronic® F127/polyvinylpyrrolidone K30 solid dispersions with improved dissolution and enhanced antibacterial activity

The aim of this study was the development of hard-cellulose capsules containing cefpodoxime proxetil (CEF) (BCS Class II) loaded novel Pluronic® F127 (P127)/Polyvinylpyrrolidone K30 (PVP) solid dispersions (SDs) using ultrasonic probe induced solvent-lyophilization method for effective antibacterial treatment by means of improved saturated aqueous solubility, dissolution rate, reduced particle size, and wettability. SDs were evaluated for physical and solid-state analyses. The solubility of pure CEF was calculated as 0.269 ± 0.005 mg/mL, SDs formulated with P127/PVP exhibited increased solubility from 3.5- to 8-fold. Molecular distribution of CEF in SDs and formation of CEF loaded amorphous polymeric network were confirmed with morphological study, thermal analysis, Fourier-transform infrared spectroscopy (FT-IR), and 1H-NMR studies. Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), and Klebsiella pneumoniae (ATCC 700603) were used to investigate the antibacterial effectiveness of the SDs. The minimum inhibitory concentration (MIC) values of the P127/PVP SDs were found 2-8 times lower than the pure CEF. All SDs from hard-cellulose capsules exhibited significantly faster release than unprocessed CEF. The profiles of SDs and reference were detected to be dissimilar according to difference (f1) and similarity factor (f2). Hard-cellulose capsules containing CEF loaded P127/PVP SDs appear to be feasible alternative to commercially available CEF tablets for effective antibacterial therapy at lowest dose.

Facile preparation of solid dispersions by dissolving drugs in N-vinyl-2-pyrrolidone and photopolymerization

Drug solid dispersions improve the dissolution of drugs in aqueous media for enhancement of oral bioavailability. The current preparation methods of drug solid dispersions mainly involve the evaporation of solvents or the melting of drugs and matrix. Here, we create a new and simple method for the preparation of drug solid dispersions by dissolving drugs in N-vinyl-2-pyrrolidone (NVP) and then NVP photopolymerization. A variety of drugs were explored to find whether they were suitable for this method and only some of them were soluble in NVP and formed transparent and hard solid dispersions, including fluconazole, ketoconazole, bifonazole, miconazole nitrate, sulfamethoxazole, aspirin, ibuprofen and artesunate. The formation of photocuring solid dispersions was highly related to the free radical scavenging function of drugs. Those drugs with strong free radical scavenging capability, including curcumin, resveratrol, quercetin, genistein, puerarin, nicergoline, olanzapine, indomethacin, did not form solid dispersions. They scavenged 2,2-diphenyl-1-picrylhydrazyl free radicals, which was demonstrated by ultraviolet spectrometry and electron spin resonance. The scavenging of free radicals stopped the chain polymerization of NVP. The Fourier transform infrared spectra, X-ray diffraction and differential scanning calorimetry of ibuprofen solid dispersions and artesunate solid dispersions showed the molecularly miscible state of the drugs and the hydrogen bonding between the drugs and polyvinyl pyrrolidone. The NVP-based solid dispersions of the two drugs had faster and more complete dissolution than their traditional solid dispersions. The NVP photopolymerization-based solid dispersion method provides a new choice for the production of solid dispersions in the research and industrial fields.

Novel drug-loaded film forming patch based on gelatin and snail slime

Gelatin-based films enriched with snail slime are proposed as novel biodegradable and naturally bioadhesive patches for cutaneous drug delivery. Films (thickness range 163-248 μm) were stretchable and they adhered firmly onto the wetted skin, especially those with high amount (70% V/V) of snail slime extract. Fluconazole was selected as model drug and added to films containing the highest amount of snail slime. The presence of Fluconazole (4.53 ± 0.07% w/w) did not modify significantly the mechanical properties, the swelling degree and the bioadhesive performances of the films. Structural investigations demonstrated that the crystalline form III of the drug changed to the amorphous one, forming an amorphous solid dispersion. Moreover, snail slime prevented the drug recrystallization over time. In vitro permeation studies showed that film exhibited a cumulative drug concentration (over 60% in 24 h) similar to that of the control solution containing 20% w/V of ethanol. Fluconazole-loaded gelatin films proved to be effective towards clinical isolates of Candida spp. indicating that the drug maintained its remarkable antifungal activity once formulated into gelatin and snail slime-based films. In conclusion, snail slime, thanks to its peculiar composition, has proved to be responsible of optimal skin adhesion, film flexibility and of the formation of a supersaturating drug delivery system able to increase skin permeation.

Applications of polymer blends in drug delivery

Background

Polymers are essential components of many drug delivery systems and biomedical products. Despite the utility of many currently available polymers, there exists a demand for materials with improved characteristics and functionality. Due to the extensive safety testing required for new excipient approval, the introduction and use of new polymers is considerably limited. The blending of currently approved polymers provides a valuable solution by which the limitations of individual polymers can be addressed.

Main body

Polymer blends combine two or more polymers resulting in improved, augmented, or customized properties and functionality which can result in significant advantages in drug delivery applications. This review discusses the rationale for the use of polymer blends and blend polymer-polymer interactions. It provides examples of their use in commercially marketed products and drug delivery systems. Examples of polymer blends in amorphous solid dispersions and biodegradable systems are also discussed. A classification scheme for polymer blends based on the level of material processing and interaction is presented.

Conclusion

The use of polymer blends represents a valuable and under-utilized resource in addressing a diverse range of drug delivery challenges. It is anticipated that new drug molecule development challenges such as bioavailability enhancement and the demand for enabling excipients will lead to increased applications of polymer blends in pharmaceutical products.

Graphical abstract

Microencapsulation of Fluticasone Propionate and Salmeterol Xinafoate in Modified Chitosan Microparticles for Release Optimization

Chitosan (CS) is a natural polysaccharide, widely studied in the past due to its unique properties such as biocompatibility, biodegradability and non-toxicity. Chemical modification of CS is an effective pathway to prepare new matrices with additional functional groups and improved properties, such as increment of hydrophilicity and swelling rate, for drug delivery purposes. In the present study, four derivatives of CS with trans-aconitic acid (t-Acon), succinic anhydride (Succ), 2-hydroxyethyl acrylate (2-HEA) and acrylic acid (AA) were prepared, and their successful grafting was confirmed by FTIR and ¹H-NMR spectroscopies. Neat chitosan and its grafted derivatives were fabricated for the encapsulation of fluticasone propionate (FLU) and salmeterol xinafoate (SX) drugs, used for chronic obstructive pulmonary disease (COPD), via the ionotropic gelation technique. Scanning electron microscopy (SEM) micrographs demonstrated that round-shaped microparticles (MPs) were effectively prepared with average sizes ranging between 0.4 and 2.2 μm, as were measured by dynamic light scattering (DLS), while zeta potential verified in all cases their positive charged surface. FTIR spectroscopy showed that some interactions take place between the drugs and the polymeric matrices, while X-ray diffraction (XRD) patterns exhibited that both drugs were encapsulated in MPs’ interior with a lower degree of crystallinity than the neat drugs. In vitro release studies of FLU and SX exposed a great amelioration in the drugs’ dissolution profile from all modified CS’s MPs, in comparison to those of neat drugs. The latter fact is attributed to the reduction in crystallinity of the active substances in the MPs’ interior.

Effect of Poly(vinyl alcohol) on Nanoencapsulation of Budesonide in Chitosan Nanoparticles via Ionic Gelation and Its Improved Bioavailability

Chitosan (CS) is a polymer extensively used in drug delivery formulations mainly due to its biocompatibility and low toxicity. In the present study, chitosan was used for nanoencapsulation of a budesonide (BUD) drug via the well-established ionic gelation technique and a slight modification of it, using also poly(vinyl alcohol) (PVA) as a surfactant. Scanning electron microscopy (SEM) micrographs revealed that spherical nanoparticles were successfully prepared with average sizes range between 363 and 543 nm, as were measured by dynamic light scattering (DLS), while zeta potential verified their positive charged surface. X-ray diffraction (XRD) patterns revealed that BUD was encapsulated in crystalline state in nanoparticles but with a lower degree of crystallinity than the neat drug, which was also proven by differential scanning calorimetry (DSC) and melting peak measurements. This could be attributed to interactions that take place between BUD and CS, which were revealed by FTIR and by an extended computational study. An in vitro release study of budesonide showed a slight enhancement in the BUD dissolution profile, compared to the neat drug. However, drug release was substantially increased by introducing PVA during the nanoencapsulation procedure, which is attributed to the higher amorphization of BUD on these nanoparticles. The release curves were analyzed using a diffusion model that allows estimation of BUD diffusivity in the nanoparticles.

The antifungal pipeline: the need is established. Are there new compounds?

Our review summarizes and compares the temporal development (eras) of antifungal drug discovery as well as antibacterial ventures. The innovation gap that occurred in antibacterial discovery from 1960 to 2000 was likely due to tailoring of existing compounds to have better activity than predecessors. Antifungal discovery also faced innovation gaps. The semi-synthetic antibiotic era was followed closely by the resistance era and the heightened need for new compounds and targets. With the immense contribution of comparative genomics, antifungal targets became part of the discovery focus. These targets by definition are absolutely required to be fungal- or even lineage (clade) specific. Importantly, targets need to be essential for growth and/or have important roles in disease and pathogenesis. Two types of antifungals are discussed that are mostly in the FDA phase I–III clinical trials. New antifungals are either modified to increase bioavailability and stability for instance, or are new compounds that inhibit new targets. One of the important developments in incentivizing new antifungal discovery has been the prolific number of publications of global and country-specific incidence. International efforts that champion global antimicrobial drug discovery are discussed. Still, interventions are needed. The current pipeline of antifungals and alternatives to antifungals are discussed including vaccines.

Stabilisation and Growth of Metastable Form II of Fluconazole in Amorphous Solid Dispersions

The crystallisation of metastable drug polymorphs in polymer matrices has been reported as a successful approach to enhance the solubility of poorly water-soluble drug molecules. This can be achieved using different polymers, drug to polymer ratios and formulation techniques enabling the formation of stable nuclei and subsequent growth of new or metastable drug polymorphs. In this work we elucidated the polymorphism behaviour of a model compound fluconazole (FLU) embedded in solid dispersions with amorphous Soluplus^® (SOL) obtained using spray drying and fusion methods. The effect of humidity on the stability of FLU in the obtained dispersions was also evaluated. FLU at a drug content below 40 wt. % stayed amorphous in the dispersions prepared using the fusion method and crystallised exclusively into metastable form II at a drug content above 40 wt. % and 70% relative humidity (RH) conditions. In contrast, a mixture of forms I, II and hydrate of FLU was detected in the spray dried formulations after 14 days of storage at 40 °C/40% RH, with preferential growth of thermodynamically stable form I of FLU. This study highlights the importance of preparation techniques and the drug:polymer ratio in the formulation of amorphous solid dispersions and provides further understanding of the complex crystallisation behaviour of amorphous pharmaceuticals encapsulated in the polymer matrixes.

SBA15-Fluconazole as a Protective Approach Against Mild Steel Corrosion: Synthesis, Characterization, and Computational Studies

A SBA15-Fluconazole composite (SBA15-Flu) was prepared to formulate a self-healing coating for mild steel. The composite was obtained by dispersing SBA15 in a methanolic solution containing Fluconazole (Flu). The materials were characterized by using different techniques. Electrochemical impedance spectroscopy (EIS) was used for protective behavior evaluation of the coatings on mild steel substrates in an electrolytic solution prepared from sodium chloride and ammonium sulfate. The EIS results indicate that the inhibitor trapped in the SiO2 matrix is released when it comes into contact the aggressive solution, thus protecting the metal. To understand the inhibitor release mechanism, docking studies were used to model the SBA15-Flu complex, which allowed us to further determine polar and non-polar contributions to the binding free energy. An analysis of the electron density within the quantum theory of atoms in molecules and the non-covalent interaction index frameworks were also carried out for the most favorable models of SBA15-Flu. The results indicate that the liberation rate of the Flu molecules is mainly determined by the formation of strong O-H⋅⋅⋅O, O-H⋅⋅⋅N, and O-H⋅⋅⋅F hydrogen bonds.

Role of chitosan on controlling the characteristics and antifungal activity of bioadhesive fluconazole vaginal tablets

Vaginal fluconazole (FLZ) prolonged release tablets containing chitosan in physical blends with other bioadhesive polymers were designed. Chitosan was mixed with hydroxypropyl methylcellulose (HPMC), guar gum or sodium carboxymethyl cellulose (NaCMC) at different ratios and directly compressed into tablets. In-vitro release profiles of FLZ were monitored at pH 4.8. Compressing chitosan with HPMC at different ratios slowed FLZ release, however, time for 80% drug release (T80) did not exceed 4.3 h for the slowest formulation (F11). Adding of chitosan to guar gum at 1:2 ratio (F3) showed delayed release with T80 17.4 h while, in presence of PVP at 1:2:1 ratio (F5), T80 was 8.8 h. A blend of chitosan and NaCMC at 1:2 ratio (F15) showed prolonged drug release with T80 11.16 h. Formulations F5 and F15 showed fair physical characteristics for the powder and tablets and were subjected to further studies. Fast swelling was observed for F15 that reached 1160.53 ± 13.02% in 4 h with 2 h bioadhesion time to mouse peritoneum membrane compared with 458.83 ± 7.09% swelling with bioadhesion time exceeding 24 h for F5. Extensive swelling of F15 could indicate possible dehydration effect on vaginal mucosa. Meanwhile, antifungal activity against C. albicans was significantly high for F5.

Spray drying formulation of amorphous solid dispersions

Spray drying is a well-established manufacturing technique which can be used to formulate amorphous solid dispersions (ASDs) which is an effective strategy to deliver poorly water soluble drugs (PWSDs). However, the inherently complex nature of the spray drying process coupled with specific characteristics of ASDs makes it an interesting area to explore. Numerous diverse factors interact in an inter-dependent manner to determine the final product properties. This review discusses the basic background of ASDs, various formulation and process variables influencing the critical quality attributes (CQAs) of the ASDs and aspects of downstream processing. Also various aspects of spray drying such as instrumentation, thermodynamics, drying kinetics, particle formation process and scale-up challenges are included. Recent advances in the spray-based drying techniques are mentioned along with some future avenues where major research thrust is needed.

Sustained-release formulation of sarpogrelate hydrochloride

Sarpogrelate HCl (SGL) has been used clinically as an anti-platelet drug for the prevention of thrombus, proliferation of vascular smooth muscle cells and platelet aggregation. This study was to investigate the bioavailability of sustained-release solid dispersion (SR-SD) formulation of SGL to sustain the drug release for up to 24 h. The SR-SD formulations with various drug-to-polymer ratios were prepared by hot-melt coating method. Waxy material carriers such as Compritol 888 ATO and stearyl alcohol were added to SGL and different amounts of HPMC K 15 (HPMC) were mixed. Dissolution profile and bioavailability were compared to SGL powder. Compritol 888 ATO showed the controlling effect of the initial release rate of drug from the formulation and the controlling effect was increased for 24 h by addition of HPMC. As the amount of HPMC increased, the drug release rate from SR-SD decreased because HPMC formed gel layer in aqueous media. Pharmacokinetic study showed that the AUC and Tmax of SGL in SR-SD formulation increased as compared to the SGL powder. These data suggest that the SR-SD formulation effectively controls the drug release rate for 24 h, hoping to be useful for the development of once-a-day formulation of SGL.