Exploring pullulan-poly(vinyl alcohol) interpenetrating network microspheres as controlled release drug delivery device

Pullulan-Based Spray-Dried Mucoadhesive Microparticles for Sustained Oromucosal Drug Delivery

Mucoadhesive microparticles for oromucosal drug delivery offer several advantages, including intimate contact with the mucosa, delivery to less accessible regions, extended residence time, sustained drug release, reduced irritation, and improved patient compliance. In this study, pullulan was used to prepare mucoadhesive spray-dried microparticles for delivering benzydamine hydrochloride (BZH) to oral mucosa. The BZH-pullulan spray-dried microparticles had a mean size of <25 μm with an angle of repose values between 25.8-36.6°. Pullulan markedly extended drug-release time to >180 min, ~9 times greater than the duration (i.e., 20 min) reportedly achieved by chitosan. Kinetic analysis showed the drug-release rate was concentration dependent and jointly controlled by drug diffusion and polymer chain relaxation. Further, pullulan was mucoadhesive and was able to retain up to 78.8% w/w of microencapsulated gold nanoparticle probes at the mucosal membrane. These data strongly suggest that BZH-pullulan microparticles have great potential for oromucosal drug delivery, by providing elongated residence time in situ and sustained drug release for the treatment of local diseases.

Poly(vinyl alcohol)/Pullulan Composite Hydrogels as a Potential Platform for Wound Dressing Applications

Hydrogels are 3D networks with an excellent ability to retain a high amount of water or biological fluids, representing suitable candidates for wound dressing applications. They can provide a protective barrier and a moist environment, facilitating wound treatment. The present paper focuses on physical hydrogels obtained from poly(vinyl alcohol) (PVA) and pullulan (PULL) mixtures in different weight ratios by using the freezing/thawing method. Hybrid hydrogels of similar polymer compositions were prepared in the presence of 0.5% Laponite^® RD. The influence of polysaccharide and clay addition on the properties of PVA hydrogels was investigated. Scanning electron microscopy showed evidence of the inner porous structure. The viscoelastic properties were investigated in different shear conditions and revealed the influence of the hydrogel composition on the network strength. The swelling behavior was followed in physiological saline solutions at 37 °C and pH = 7.4. For all samples, a quasi-Fickian diffusion mechanism was found. The delivery of neomycin sulfate was studied in similar conditions as for the swelling tests (0.15 M NaCl solutions; 37 °C; pH = 7.4) and different kinetic models were used to determine the release mechanism. The Peppas-Sahlin approach described very well the in vitro drug release mechanism from the polymeric hydrogels in the absence of clay. However, the hybrid polymer/clay hydrogels showed the best fit with the Korsmeyer-Peppas model. According to the present study, the porous membranes containing 40-60% PULL (in absence of clay) are suitable for the release of therapeutic agents at wound sites in physiological conditions.

Dual functional pullulan-based spray-dried microparticles for controlled pulmonary drug delivery

Two main challenges are associated with current spray-dried microparticles for inhalation, including the enhancement of aerosolization performance of microparticles and the creation of sustained drug release for continuous treatment on-site. For achieving these purposes, pullulan was explored as a novel excipient to prepare spray-dried inhalable microparticles (with salbutamol sulphate, SS, as a model drug), which were further modified by additives of leucine (Leu), ammonium bicarbonate (AB), ethanol and acetone. It was demonstrated that all pullulan-based spray-dried microparticles had improved flowability and enhanced aerosolization behavior, with the fine particle (<4.46µm) fraction of 42.0-68.7% w/w, much higher than 11.4% w/w of lactose-SS. Moreover, all modified microparticles showed augmented emitted fractions of 88.0-96.9% w/w, over 86.5% w/w of pullulan-SS. The pullulan-Leu-SS and pullulan-(AB)-SS microparticles demonstrated further increased fine particle (<1.66µm) doses of 54.7µg and 53.3µg respectively, surpassing that (49.6µg) of pullulan-SS, suggesting an additionally increased drug deposition in the deep lungs. Furthermore, pullulan-based microparticles revealed sustained drug release profiles with elongated time (60mins) over the control (2mins). Clearly, pullulan has a great potential to construct dual functional microparticles for inhalation with improved pulmonary delivery efficiency and sustained drug release on-site.

Natural Gums in Drug-Loaded Micro- and Nanogels

Gums are polysaccharide compounds obtained from natural sources, such as plants, algae and bacteria. Because of their excellent biocompatibility and biodegradability, as well as their ability to swell and their sensitivity to degradation by the colon microbiome, they are regarded as interesting potential drug carriers. In order to obtain properties differing from the original compounds, blends with other polymers and chemical modifications are usually applied. Gums and gum-derived compounds can be applied in the form of macroscopic hydrogels or can be formulated into particulate systems that can deliver the drugs via different administration routes. In this review, we present and summarize the most recent studies regarding micro- and nanoparticles obtained with the use of gums extensively investigated in pharmaceutical technology, their derivatives and blends with other polymers. This review focuses on the most important aspects of micro- and nanoparticulate systems formulation and their application as drug carriers, as well as the challenges related to these formulations.

Investigating the Role of the Reduced Solubility of the Pirfenidone-Fumaric Acid Cocrystal in Sustaining the Release Rate from Its Tablet Dosage Form by Conducting Comparative Bioavailability Study in Healthy Human Volunteers

Pirfenidone (PFD) is the first pharmacological agent approved by the US Food and Drug Administration (FDA) in 2014 for the treatment of idiopathic pulmonary fibrosis (IPF). The recommended daily dosage of PFD in patients with IPF is very high (2403 mg/day) and must be mitigated through additives. In the present work, sustained-release (SR) formulations of the PFD-FA cocrystal of two different strengths such as 200 and 600 mg were prepared and its comparative bioavailability in healthy human volunteers was studied against the reference formulation PIRFENEX (200 mg). A single-dose pharmacokinetic study (200 mg IR vs 200 mg SR) demonstrated that the test formulation exhibited lower C_max and T_max in comparison to the reference formulation, which showed that the cocrystal behaved like an SR formulation. Further in the multiple-dose comparative bioavailability study (200 mg IR thrice daily vs 600 mg SR once daily), the test formulation was found bioequivalent to the reference formulation. In conclusion, the present study suggests that cocrystallization offers a promising strategy to reduce the solubility of PFD and opens the door for potential new dosage forms of this important pharmaceutical.

Fabrication and characterization of Pickering emulsion gels stabilized by zein/pullulan complex colloidal particles

BACKGROUND

Zein particles are unsuitable as stabilizers of Pickering emulsions because of their high hydrophobicity. However, few studies have reported on the use of a strong hydrophilic neutral polysaccharide to regulate its wettability. In this work, zein/pullulan complex particles (ZPPs) were formulated by an anti-solvent method to fabricate Pickering emulsions.

RESULTS

The presence of pullulan increased the size, decreased the zeta, and provided excellent resistance to the gravitational separation of zein. Scanning electron microscopy (SEM) revealed that the shape of zein particles changed from spherical as they became aggregated ZPP nanoparticles. Fourier transform infrared (FTIR) spectroscopy indicated that the flocculation phenomenon of ZPPs was related to the hydrogen bond between zein and pullulan. Moreover, the hydrophobicity of zein was modified by hydrophilic pullulan to endow the ZPPs with nearly neutral wettability when the mass ratio was 15:1, allowing for the preparation of stable Pickering emulsions. In contrast to zein, the ZPPs contributed to building a compact interface layer around the droplets and smaller emulsion droplets. Under a certain ZPP concentration, the size and viscosity of emulsion increased with an increase in the oil volume fraction, indicating that the Pickering emulsions stabilized by ZPPs showed better stability against coalescence. Confocal laser scanning microscopy (CLSM) revealed that the ZPPs constructed a dense filling layer on the surface of oil droplets, thus further emphasizing that ZPPs can potentially be used in fabricating Pickering emulsion gels.

CONCLUSION

Zein/pullulan complex particles are an excellent Pickering emulsion gel stabilizer that can be used in the delivery system of bioactive substances in food formulations. © 2020 Society of Chemical Industry.

Recent progress and challenges for polymeric microsphere compared to nanosphere drug release systems: Is there a real difference?

Polymeric microspheres (MSs) and nanospheres (NSs) composed of synthetic and natural polymers can encapsulate anticancer drugs, among other therapeutics, acting as drug carriers to release them at controlled rates over long periods of time. These carriers present several potential advantages including simple preparation methods, suitable control over the sustained release of medications or stem cells, triggered release resulting from stimulus-responsive delivery, improved physical properties such as porosity and stable scaffolds for tissue engineering, and possible applications as microreactors and nanoreactors compared to conventional drug delivery systems. Moreover, many of these factors can impact drug release rates by polymeric MSs and NSs. Herein, drug delivery systems based on polymeric MSs and NSs are described and compared according to recent advances and challenges, and poignant thoughts on what the field needs to progress are presented.

Formulation of Extended-Release Beads of Lamotrigine Based on Alginate and <i>Cassia fistula</i> Seed Gum by QbD Approach

AIM

This study was focused on the formulation of the multi-unit extended-release peroral delivery device of lamotrigine for better management of epilepsy.

BACKGROUND

The single-unit extended-release peroral preparations often suffer from all-or-none effect. A significant number of multi-unit delivery systems have been reported as a solution to this problem. But most of them are found to be composed of synthetic, semi-synthetic or their combination having physiological toxicity as well as negative environmental impact. Therefore, fabrication and formulation of multi-unit extended-release peroral preparations with natural, non-toxic, biodegradable polymers employing green manufacturing processes are being appreciated worldwide.

OBJECTIVE

Lamotrigine-loaded extended-release multi-unit beads have been fabricated with the incorporation of a natural polysaccharide Cassia fistula seed gum in calcium-cross-linked alginate matrix employing a simple green process and 23 full factorial design.

METHODS

The total polymer concentration, polymer ratio and [CaCl2] were considered as independent formulation variables with two different levels of each for the experiment-design. The extended-release beads were then prepared by the ionotropic gelation method using calcium chloride as the crosslinkerions provider. The beads were then evaluated for drug encapsulation efficiency and drug release. ANOVA of all the dependent variables such as DEE, cumulative % drug release at 2h, 5h, 12h, rate constant and dissolution similarity factor (f2) was done by 23 full factorial design using Design-Expert software along with numerical optimization of the independent variables in order to meet USP-reference release profile.

RESULTS

The optimized batch showed excellent outcomes with DEE of 84.7 ± 2.7 (%), CPR2h of 8.41± 2.96 (%), CPR5h of 36.8± 4.7 (%), CPR12h of 87.3 ± 3.64 (%) and f2 of 65.9.

CONCLUSION

This approach of the development of multi-unit oral devices utilizing natural polysaccharides might be inspiring towards the world-wide effort for green manufacturing of sustained-release drug products by the QbD route.

Synthesis of polyacrylonitrile nanoflowers and their controlled pH-sensitive drug release behavior

A novel controlled drug release system based on pH sensitive polyacrylonitrile (PAN) nanoflowers in different kinds of solvents was successfully prepared with azobisisobutyronitrile (AIBN) as the initiator and without any emulsifier or stabilizer by a one step static polymerization method. The composition and structure of the PAN nanoflowers were analyzed by FTIR, XRD, SEM, TEM, and laser particle size analysis. The polymer particles consisted of a number of lamellae, with a sheet thickness of about 10 nm, and were similar to the shape of flowers with a particle diameter of about 350 nm. The mechanism of the polymerization reaction and the formation were studied. Moreover, the effects of monomer ratio, initiator concentration, reaction time, dispersion medium and co-monomer on the morphology and particle size of the nanoflowers were also discussed. A relatively large specific surface area was formed during the formation of the nanoflowers, which favored drug adsorption. The results of the in vitro experiments revealed that PAN(TBP) nanoflowers, containing BSA in buffer solution of pH 7.4, demonstrated good sustained-release and the cumulative release rate was about 83% after 260 h. The results also showed that the sustained-release from the PAN(TBP) nanoflowers best fitted the Riger-Peppas model. This study indicated that PAN(TBP) nanoflowers provided a theoretical base for the development of carriers for sustainable drug-release.

The schematic preparation of a new kind of pH-sensitive PAN nanoflower and its potential application for UC therapy. PAN (TBP) nanoflowers at pH 7.4 showed good sustained-release (t_83% = 260 h), which best fitted the Riger–Peppas model.

Therapeutically Effective Controlled Release Formulation of Pirfenidone from Nontoxic Biocompatible Carboxymethyl Pullulan-Poly(vinyl alcohol) Interpenetrating Polymer Networks

The present study was conducted to develop therapeutically effective controlled release formulation of pirfenidone (PFD) and explore the possibility to reduce the total administered dose and dosing regimen. For this purpose, pH-sensitive biomaterial was prepared by inducing carboxymethyl group on pullulan by Williamson ether synthesis reaction, and further, interpenetrating polymeric network microspheres were prepared by glutaraldehyde-assisted water-in-oil (w/o) emulsion cross-linking method, which showed higher swelling ratio in acidic and basic pH. The formation of microspheres was confirmed by different spectral characterization techniques, and thermal kinetic study indicated the formation of thermally stable microspheres. Cell viability and biocompatibility studies on hepatocellular carcinoma (HepG2) cell showed the polymeric matrix to be biocompatible. In vitro dissolution of optimized formulation (F5) showed releases of 54.09 and 76.37% in 0.1 N HCl after 2 h and phosphate buffer (pH 6.8) up to 8 h, respectively. In vivo performances of prepared microsphere and marketed product of PFD were compared in rabbit. T max (time taken to reach peak plasma concentration) was found to be achieved at 0.83 h, compared to 0.5 h for Pirfenex with no significant difference complementing the immediate action, while area under curve was significantly greater for optimized formulation (9768 ± 1300 ng h/mL) compared to Pirfenex (4311 ± 110 ng h/mL), complementing the sustained action. In vivo pharmacokinetic study suggested that the prepared microsphere could be a potential candidate for therapeutically effective controlled delivery of PFD used in dyspnea and cough management due to idiopathic pulmonary fibrosis.