Miscibility characterization of zein/methacrylic acid copolymer composite films and plasticization effects

Cholecalciferol-load films for the treatment of nasal burns caused by cauterization of the hypertrophied inferior turbinate: formulation, in vivo study, and clinical assessment

Nasal turbinate hypertrophy is among the most common nasal obstruction disorders, affecting the patient's quality of life significantly. Endoscopic submucosal diathermy is a prevalent cauterization procedure for treating turbinate hypertrophy. Regrettably, the nasal burn associated with diathermy typically heals slowly causing facial pain and nasal bleeding and possibly resulting in synechiae formation. In the current study, we have developed, for the first time, a polymeric film loaded with cholecalciferol for local treatment of nasal burns. The casting method was used to prepare films of different compositions of polymers such as chitosan, polyvinyl alcohol (PVA), Carbopol 971p (CP971p), and hydroxypropyl methylcellulose (HPMC) as well as a plasticizer. Several characterizations were performed for the cholecalciferol-loaded films (e.g. weight, thickness, content uniformity, surface pH, folding endurance, disintegration time, and in vitro release) to select the optimal formulation. The optimal formulation (F4) displayed compatibility between the used polymers and the drug. In vivo animal study was carried out to assess the healing efficacy of the formulated cholecalciferol-loaded film. The rabbits treated with the cholecalciferol-loaded film demonstrated significantly higher mRNA expression of the growth factor TGF-β and significantly lower mRNA expression of the proinflammatory cytokine TNF-α and IL-1β compared to the plain film treated group and the untreated control group. A randomized, single-blinded, parallel, controlled clinical trial was conducted on 20 patients scheduled to undergo endoscopic submucous diathermy. The results of the clinical study demonstrated significant reductions in facial pain and nasal bleeding scores for the nostrils treated with cholecalciferol-loaded films in comparison to the nostrils treated with plain films. Furthermore, the endoscopic examination showed good healing for 95% of the cholecalciferol-loaded film-treated nostrils. In conclusion, the optimized film can be considered an opportune approach for enhancing the healing rate of nasal burns and thus reducing the downsides of the diathermy procedure.

Fabrication of biodegradable blend plastic from konjac glucomannan/zein/ PVA and understanding its multi-scale structure and physicochemical properties

Exploration and synthesis of degradable plastics can alleviate and avoid environmental pollution induced by petroleum-based plastics. In this study, a konjac glucomannan (KGM)/zein/PVA ternary blend plastic was successfully prepared by casting. The results showed that, despite the presence of particle aggregation from incompatible components in blend plastic, the addition of KGM and zein improved its compatibility which is consistent with the formation of continuous dark regions and the reduction of roughness average (Ra) results in the AFM characterization. Also, XRD and FT-IR results indicated that the addition of KGM and zein disrupted the molecular and crystalline structure of PVA, induced stretching vibration of alcohol and hydroxyl groups, and crystallinity reduction. In addition, KGM deacetylation (d-KGM) reduced the intramolecular hydroxyl groups, reduced the water absorption and water vapor transmission rate of the blend plastics, and increased the crystallization temperature (Tc) and melting temperature (Tm). Furthermore, the blended plastics exhibited the best tensile strength (TS), elongation at break (E), and elastic modulus (EM) when the proportion of KGM to zein was 9:1. Notably, the blended plastic with KGM and zein added displayed more pores and cracks after soil burial, implying that the lack of degradability of pure PVA plastic was improved.

Fabrication of delayed release hard capsule shells from zein/methacrylic acid copolymer blends

Hard capsule shells with an inherent delayed release action are useful for oral administration of active ingredients, which are acid-labile and/or enzymatically degradable in the gastric environment, without the need of film coating. The objective of this study was to fabricate delayed release hard capsule shells by the dip coating method. The film coating formulations comprised blends of zein and methacrylic acid copolymer (Eudragit® L100-55), with and without the addition of the plasticizer, polyethylene glycol 1000. The rheology parameters (loss modulus (G'), storage modulus (G") and loss tangent (tan δ, G"/G')) of the film coating solution were measured to investigate the processability. Central composite design was used to investigate the main, interaction and quadratic effects of the proportion of methacrylic acid copolymer, solid content of the film formers and level of polyethylene glycol 1000 on the capsule wall thickness and mechanical strength. Multiple response optimization was further conducted, and the design space was established. The in vitro drug release in simulated gastric and intestinal fluids of three different formulations in the design space was compared. The results showed that the tan δ value after the gelation point should be < 0.9 in order to form a thin and sturdy capsule shell. The gelation time and viscosity of the coating solution were related to the thickness of the capsule shell. The study showed that drug release from the capsule with a specified thickness and mechanical strength can be modulated by varying the ratio of zein to methacrylic acid copolymer. The delayed drug release profile was achieved through the capsule shell fabricated from zein to methacrylic acid copolymer at the ratios of 75:25 and 83.2:16.8, with 10% polyethylene glycol 1000.

Improvement of mechanical properties of zein porous scaffold by quenching/electrospun fiber reinforcement

As a novel bone substitute material, zein-based scaffolds (ZS) should have suitable mechanical properties and porosity. ZS has shown good compressive properties matching cancellous bone, but there is still a demand to improve its mechanical properties, especially tensile and bending properties without adding plasticizers. The present study explored two simple and environment-friendly factors for this purpose: fiber reinforcement and quenching. Addition of electrospun zein fibers enhanced all mechanical properties significantly including compressive, tensile, and bending moduli; compressive and bending strengths of ZS with both higher (70-80%) and lower (50-60%) porosities, no matter whether heating treated or not treated. Especially, all these parameters were further enhanced significantly by addition of heating treated fibers. AFM provided evidence that high temperature modification could significantly alter the micro-elastic properties of zein electrospun fibers, i.e., increased stiffness of fibers. Quenching treatment also enhanced compressive, tensile, and bending strengths significantly. Finally, quenching treated ZS were implanted into critical-sized bone defects (15 mm) of the rabbit model to compare the repair efficacy with a commercial β-tricalcium phosphate product. The results demonstrated that there were no remarkable differences in bone reconstructions between these two materials.