Engineering of Nanofibrous Amorphous and Crystalline Solid Dispersions for Oral Drug Delivery

Fiber Technology in Drug Delivery and Pharmaceuticals

The field of fiber technology is a dynamic and innovative domain that offers novel solutions for controlled and targeted therapeutic interventions. This abstract provides an overview of key aspects within this field, encompassing a range of techniques, applications, commercial developments, intellectual property, and regulatory considerations. The foundational introduction establishes the significance of fiber-based drug delivery systems. Electrospinning, a pivotal technique, has been explored in this paper, along with its various methods and applications. Monoaxial, coaxial, triaxial, and side-by-side electrospinning techniques each offer distinct advantages and applications. Centrifugal spinning, solution and melt blowing spinning, and pressurized gyration further contribute to the field's diversity. The review also delves into commercial advancements, highlighting marketed products that have successfully harnessed fiber technology. The role of intellectual property is acknowledged, with patents reflecting the innovative strides in fiber-based drug delivery. The regulatory perspective, essential for ensuring safety and efficacy, is discussed in the context of global regulatory agencies' evaluations. This review encapsulates the multidimensional nature of fiber technology in drug delivery and pharmaceuticals, showcasing its potential to revolutionize medical treatments and underscores the importance of continued collaboration between researchers, industry, and regulators for its advancement.

Optimizing the fabrication of electrospun nanofibers of prochlorperazine for enhanced dissolution and permeation properties

Despite being an approved antiemetic for more than five decades, the clinical usefulness of prochlorperazine is limited by its low solubility and inconsistent absorption in the gastrointestinal tract, which presents challenges for nanotherapeutic interventions. Here, we report the preparation of a highly soluble and permeable nanofiber formulation of prochlorperazine using the Quality-by-Design approach. The final nanofiber formulation with drug entrapment of 88.02 ± 1.14 % was obtained at 20.0 kV, with a flow rate of 0.5 ml/h and tip-to-collector distance of 19.9 cm. Physio-mechanical properties, such as thickness (0.42 ± 0.02 mm), pH resistance (7.04 ± 0.08), folding endurance (54 ± 5), and tensile strength (0.244 ± 0.02 N.mm-2), were appropriate for packaging and application to oromucosal surfaces. The content uniformity (93.48-106.63 %) and weight variation (<1.8 mg) of the optimal nanofiber formulation were within the permissible limits prescribed for orodispersible films. Microscopical investigations confirm a randomly deposited and dense network of woven nanofibers with an average diameter of 363 ± 5.66 nm. The drug particles were embedded homogeneously on the fiber in the nanoform (4.27 ± 1.34 nm). The spectral analysis using TEM-EDS shows diffraction peaks of sulfur and chlorine, the elemental constituents of prochlorperazine. The drug was amorphized in the nanofiber formulation, as led by the decline of the crystallinity index from 87.25 % to 7.93 % due to electrostatic destabilization and flash evaporation of the solvent. The enthalpy of fusion values of the drug in the nanofiber mat decreased significantly to 23.6 J/g compared to its pristine form, which exhibits a value of 260.7 J/g. The nanofibers were biocompatible with oral mucosal cells, and there were no signs of mucosal irritation compared to 1 % sodium lauryl sulfate. The fiber mats rapidly disintegrated within <1 s and released ≈91.49 ± 2.1 % of the drug within 2 min, almost 2-fold compared to the commercial Stemetil MD® tablets. Similarly, the cumulative amount of the drug permeated across the unit area of the oromucosal membrane was remarkably high (31.28 ± 1.30 μg) compared to 10.17 ± 1.11 μg and 13.10 ± 1.79 μg from the cast film and drug suspension. Our results revealed these nanofiber formulations have the potential to be fast-dissolving oromucosal delivery systems, which can result in enhanced bioavailability with an early onset of action due to rapid disintegration, dissolution, and permeation.

Delivery of curcumin in a carboxymethyl cellulose and hydroxypropyl methyl cellulose carrier: Physicochemical properties and biological activity

Curcumin solid dispersions (Cur SDs) were prepared using hydroxypropyl methyl cellulose (HPMC) and sodium carboxymethyl cellulose (CMC) at different dosages. The results of Fourier transform infrared spectroscopy and Raman spectroscopy showed that the characteristic peak of curcumin shifted, and the addition of CMC enhanced this phenomenon. The addition of CMC reduced the contact angle, increased the surface free energy, and improved the solubility of Cur SDs. These changes were positively correlated with the amount of CMC. The surface morphology of Cur SDs changed from needle-like to sheet-like as observed by scanning electron microscopy. Cur SDs prepared by CMC and HPMC retained good biological activity. HT-29 human colon cancer cell analysis showed that the addition of CMC significantly improved the anti-proliferation effect of Cur SDs, thus enhancing the bioavailability of curcumin. Solid dispersions made with CMC and HPMC will be a promising hydrocolloid carrier to improve oral bioavailability and efficacy of curcumin.

Recent Advances in Amorphous Solid Dispersions: Preformulation, Formulation Strategies, Technological Advancements and Characterization

Amorphous solid dispersions (ASDs) are among the most popular and widely studied solubility enhancement techniques. Since their inception in the early 1960s, the formulation development of ASDs has undergone tremendous progress. For instance, the method of preparing ASDs evolved from solvent-based approaches to solvent-free methods such as hot melt extrusion and Kinetisol^®. The formulation approaches have advanced from employing a single polymeric carrier to multiple carriers with plasticizers to improve the stability and performance of ASDs. Major excipient manufacturers recognized the potential of ASDs and began introducing specialty excipients ideal for formulating ASDs. In addition to traditional techniques such as differential scanning calorimeter (DSC) and X-ray crystallography, recent innovations such as nano-tomography, transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray microscopy support a better understanding of the microstructure of ASDs. The purpose of this review is to highlight the recent advancements in the field of ASDs with respect to formulation approaches, methods of preparation, and advanced characterization techniques.

Electrospun PVP-Core/PHBV-Shell Fibers to Eliminate Tailing Off for an Improved Sustained Release of Curcumin

Tailing off release in the sustained release of water-insoluble curcumin (Cur) is a significant challenge in the drug delivery system. As a novel solution, core-shell nanodrug containers have aroused many interests due to their potential improvement in drug-sustained release. In this work, a biodegradable polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and hydrophilic polyvinylpyrrolidone (PVP) were exploited as drug delivery carriers by coaxial electrospinning, and the core-shell drug-loaded fibers exhibited improved sustained release of Cur. A cylindrical morphology and a clear core-shell structure were observed by scanning and transmission electron microscopies. The X-ray diffraction pattern and infrared spectroscopy revealed that Cur existed in amorphous form due to its good compatibility with PHBV and PVP. The in vitro drug release curves confirmed that the core-shell container manipulated Cur in a faster drug release process than that in the traditional PHBV monolithic container. The combination of the material and structure forms a novel nanodrug container with a better sustained release of water-insoluble Cur. This strategy is beneficial for exploiting more functional biomedical materials to improve the drug release behavior.

Electrospun Polymer-Fungicide Nanocomposites for Grapevine Protection

Nowadays, diseases in plants are a worldwide problem. Fungi represent the largest number of plant pathogens and are responsible for a range of serious plant diseases. Esca is a grapevine disease caused mainly by fungal pathogens Phaeomoniella chlamydospora (P. chlamydospora) and Phaeoacremonium aleophilum (P. aleophilum). The currently proposed methods to fight esca are not curative. In this study, polymer composites based on biodegradable polymer containing chemical fungicides with antifungal activity were successfully prepared by electrospinning. The obtained materials were hydrophobic with good mechanical properties. In vitro studies demonstrated that the fungicide release was higher from PLLA/K5N8Q fibrous mats (ca. 72% for 50 h) compared to the released drug amount from PLLA/5-Cl8Q materials (ca. 52% for 50 h), which is due to the better water-solubility of the salt. The antifungal activity of the fibrous materials against P. chlamydospora and P. aleophilum was studied as well. The incorporation of the fungicide in the biodegradable fibers resulted in the inhibition of fungal growth. The obtained materials are perspective candidates for the protection of vines from the penetration and growth of fungal pathogens.

Improved bioavailability of oxcarbazepine, a BCS class II drug by centrifugal melt spinning: In-vitro and in-vivo implications

Poor bioavailability is a major obstacle in the development of an effective dosage form of the poorly soluble drugs. The present study aimed to improve the dissolution rate of a poorly soluble drug oxcarbazepine (OXC) exploiting the approach of surface area enhancement by fabricating drug loaded microfibers via centrifugal melt spinning (CMS) technique. For the generation of OXC loaded fibers, a well-known cotton candy process was used and the prepared fibers were characterized using SEM, DSC, XPRD and FTIR. Drug loaded fibers were also pressed into tablets which were also subjected to various in-vitro and in-vivo characterizations. The results have shown the formations of stable, amorphous, micro sized fibers, with average diameter of 6.0 ± 2 μm, loading efficiency > 80% and overall yield > 85%. In-vitro dissolution of OXC from fibers was > 90% within two minutes, which is ~ 5 times faster than that of pure drug. Pharmacokinetic data showed an improvement of ~ 25% and 35% in C_max and AUC, respectively with two hours earlier T_max. In-vivo studies in human oral cavity showed quick disintegration (45 ± 5 s) with > 90% OXC dissolved. The study concludes that the OXC incorporated in microfibers showed rapid in-vitro and in-vivo (oral) dissolution which resulted in rapid systemic absorption and improved bioavailability parameters. Furthermore, the addition of PVP boosted the extrusion process and stability of fibers and the sucrose base of these fibers has masked the taste of OXC making such formulation palatable, especially for pediatric patients.

Nano-sized Solid Dispersions for Improving the Bioavailability of Poorly Water-soluble Drugs

It has been well established that solid dispersions have a high potential to increase the release rate of poorly water-soluble drugs, resulting in high drug bioavailability. Solid dispersions have been vigorously investigated with various practical approaches in recent decades. Improvements in wettability, molecular interactions and drugs being held in an amorphous state in solid dispersions are the main mechanisms underlying the high drug release rate. Moreover, the synergistic effect of incorporating nanotechnology in solid dispersions is expected to lead to an advanced drug delivery system for poorly water-soluble drugs. However, to date, there is still a lack of reviews providing outlooks on the nano-sized solid dispersions that have been substantially investigated for improving the bioavailability of poorly water-soluble drugs. In the current review, we aim to overview key advantages and approaches for producing nano-sized solid dispersions. The classification of key strategies in developing nano-sized solid dispersions will advance the creation of even more efficient solid dispersions, which will translate into clinical studies.

Influence of Polyvinyl Alcohol (PVA) on PVA-Poly-N-hydroxyethyl-aspartamide (PVA-PHEA) Microcrystalline Solid Dispersion Films

This study was conducted to formulate buccal films consisting of polyvinyl alcohol (PVA) and poly-N-hydroxyethyl-aspartamide (PHEA), to improve the dissolution of the drug through the oral mucosa. Ibuprofen sodium salt was used as a model drug, and the buccal film was expected to enhance its dissolution rate. Two different concentrations of PVA (5% w/v and 7.5% w/v) were used. Solvent casting was used to prepare films, where a solution consisting of drug and polymer was cast and allowed to dry. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) were used to investigate the properties of films. In vitro dissolution studies were also conducted to investigate drug release. SEM studies showed that films containing a higher concentration of PVA had larger particles in microrange. FTIR studies confirmed the presence of the drug in films and indicated that ibuprofen sodium did not react with polymers. DSC studies confirmed the crystalline form of ibuprofen sodium when incorporated within films. In vitro dissolution studies found that the dissolution percentage of ibuprofen sodium alone was increased when incorporated within the film from 59 to 74%. This study led to the development of solid microcrystalline dispersion as a buccal film with a faster dissolution rate than the drug alone overcoming problem of poor solubility.

Biomimetic trace metals improve bone regenerative properties of calcium phosphate bioceramics

The bone regenerative capacity of synthetic calcium phosphates (CaPs) can be enhanced through the enrichment with selected metal trace ions. However, defining the optimal elemental composition required for bone formation is challenging due to many possible concentrations and combinations of these elements. We hypothesized that the ideal elemental composition exists in the inorganic phase of the bone extracellular matrix (ECM). To study our hypothesis, we first obtained natural hydroxyapatite through the calcination of bovine bone, which was then investigated its reactivity with acidic phosphates to produce CaP cements. Bioceramic scaffolds fabricated using these cements were assessed for their composition, properties, and in vivo regenerative performance and compared with controls. We found that natural hydroxyapatite could react with phosphoric acid to produce CaP cements with biomimetic trace metals. These cements present significantly superior in vivo bone regenerative performance compared with cements prepared using synthetic apatite. In summary, this study opens new avenues for further advancements in the field of CaP bone biomaterials by introducing a simple approach to develop biomimetic CaPs. This work also sheds light on the role of the inorganic phase of bone and its composition in defining the regenerative properties of natural bone xenografts.

Hypromellose - A traditional pharmaceutical excipient with modern applications in oral and oromucosal drug delivery

Hydroxypropylmethylcellulose (HPMC), also known as Hypromellose, is a traditional pharmaceutical excipient widely exploited in oral sustained drug release matrix systems. The choice of numerous viscosity grades and molecular weights available from different manufacturers provides a great variability in its physical-chemical properties and is a basis for its broad successful application in pharmaceutical research, development, and manufacturing. The excellent mucoadhesive properties of HPMC predetermine its use in oromucosal delivery systems including mucoadhesive tablets and films. HPMC also possesses desirable properties for formulating amorphous solid dispersions increasing the oral bioavailability of poorly soluble drugs. Printability and electrospinnability of HPMC are promising features for its application in 3D printed drug products and nanofiber-based drug delivery systems. Nanoparticle-based formulations are extensively explored as antigen and protein carriers for the formulation of oral vaccines, and oral delivery of biologicals including insulin, respectively. HPMC, being a traditional pharmaceutical excipient, has an irreplaceable role in the development of new pharmaceutical technologies, and new drug products leading to continuous manufacturing processes, and personalized medicine. This review firstly provides information on the physical-chemical properties of HPMC and a comprehensive overview of its application in traditional oral drug formulations. Secondly, this review focuses on the application of HPMC in modern pharmaceutical technologies including spray drying, hot-melt extrusion, 3D printing, nanoprecipitation and electrospinning leading to the formulation of printlets, nanoparticle-, microparticle-, and nanofiber-based delivery systems for oral and oromucosal application. Hypromellose is an excellent excipient for formulation of classical dosage forms and advanced drug delivery systems. New methods of hypromellose processing include spray draying, hot-melt extrusion, 3D printing, and electrospinning.

Spray-Drying, Solvent-Casting and Freeze-Drying Techniques: a Comparative Study on their Suitability for the Enhancement of Drug Dissolution Rates

PURPOSE

Solid dispersions (SDs) represent the most common formulation technique used to increase the dissolution rate of a drug. In this work, the three most common methods used to prepare SDs, namely spray-drying, solvent-casting and freeze-drying, have been compared in order to investigate their effect on increasing drug dissolution rate.

METHODS

Three formulation strategies were used to prepare a polymer mixture of polyvinyl-alcohol (PVA) and maltodextrin (MDX) as SDs loaded with the following three model drugs, all of which possess a poor solubility: Olanzapine, Dexamethasone, and Triamcinolone acetonide. The SDs obtained were analysed and compared in terms of drug particle size, drug-loading capacity, surface homogeneity, and dissolution profile enhancement. Physical-chemical characterisation was conducted on pure drugs, as well as the formulations made, by way of thermal analysis and infrared spectroscopy.

RESULT

The polymers used were able to increase drug saturation solubility. The formulation strategies affected the drug particle size, with the solvent-casting method resulting in more homogenous particle size and distribution when compared to the other methods. The greatest enhancement in the drug dissolution rate was seen for all the samples prepared using the solvent-casting method.

CONCLUSION

All of the methods used were able to increase the dissolution rate of the pure drugs alone, however, the solvent-casting method produced SDs with a higher surface homogeneity, drug incorporation capability, and faster dissolution profile than the other techniques.

3D-Printed Solid Dispersion Drug Products

With the well-known advantages of additive manufacturing methods such as three-dimensional (3D) printing in drug delivery, it is disappointing that only one product has been successful in achieving regulatory approval in the past few years. Further research and development is required in this area to introduce more 3D printed products into the market. Our study investigates the potential of fixed dose combination solid dispersion drug products generated via 3D printing. Two model drugs-fluorescein sodium (FS) and 5-aminosalicyclic acid (5-ASA)-were impregnated onto a polyvinyl alcohol (PVA) filament, and the influence of solvent choice in optimal drug loading as well as other influences such as the physicochemical and mechanical properties of the resultant filaments were investigated prior to development of the resultant drug products. Key outcomes of this work included the improvement of filament drug loading by one- to threefold due to solvent choice on the basis of its polarity and the generation of a 3D-printed product confirmed to be a solid dispersion fixed dose combination with the two model drugs exhibiting favourable in vitro dissolution characteristics.

Potential of di-aldehyde cellulose for sustained release of oxytetracycline: A pharmacokinetic study

This study focused on the in-vivo sustained release of oxytetracycline (OTC) loaded on di-aldehyde cellulose (DAC). The periodate oxidation method was used for the synthesis of DAC. The prepared DAC-OTC material was characterized by different techniques such as Scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and particle size analyzer. The pharmacokinetic studies were performed on DAC-OTC composite system and commercial tablet (COTA). The results of pharmacokinetic studies demonstrated that DAC-OTC exhibited higher area under the curve (AUC) (482.8 μghmL^-1) as compared to COTA (90.72 μghmL^-1). DAC-OTC composite system has double compartment pattern with improvement in mean residing time (MRT) and area under moment curve (AUMC_0-∞) than the commercial tablet (2.8 and 15.13 folds higher, respectively). Swelling index of DAC-OTC at different pH and pKa of OTC release imply that controlled in-vivo release in DAC-OTC composite system could be due to the simultaneous occurrence of the covalent and hydrogen bond between OTC and di-aldehyde cellulose. These results indicate that di-aldehyde cellulose may improve the in-vivo bioavailability of OTC.

Release Profile of Gentamicin Sulfate from Polylactide-co-Polycaprolactone Electrospun Nanofiber Matrices

The advent and growth of resistance phenomena to antibiotics has reached critical levels, invalidating the action of a majority of antibiotic drugs currently used in the clinical field. Several innovative techniques, such as the nanotechnology, can be applied for creating innovative drug delivery systems designed to modify drug release itself and/or drug administration route; moreover, they have proved suitable for overcoming the phenomenon of antibiotic resistance. Electrospun nanofibers, due to their useful structural properties, are showing promising results as antibiotic release devices for preventing bacteria biofilm formation after surgical operation and for limiting resistance phenomena. In this work gentamicin sulfate (GS) was loaded into polylactide-co-polycaprolactone (PLA-PCL) electrospun nanofibers; quantification and in vitro drug release profiles in static and dynamic conditions were investigated; GS kinetic release from nanofibers was studied using mathematical models. A preliminary microbiological test was carried out towards Staphylococcus aureus and Escherichia coli bacteria.