Polymeric Bioadhesive Patch Based on Ketoprofen-Hydrotalcite Hybrid for Local Treatments

Development and Evaluation of Self-Emulsifying Drug-Delivery System-Based Tablets for Simvastatin, a BCS Class II Drug

Background

Self-emulsifying drug-delivery systems (SEDDSs) are designed to improve the oral bioavailability of poorly water-soluble drugs. This study aimed at formulating and characterization of SEDDS-based tablets for simvastatin using castor and olive oils as solvents and Tween 60 as surfactant.

Methods

The liquids were adsorbed on microcrystalline cellulose, and all developed formulations were compressed using 10.5 mm shallow concave round punches.

Results

The resulting tablets were evaluated for different quality-control parameters at pre- and postcompression levels. Simvastatin showed better solubility in a mixture of oils and Tween 60 (10:1). All the developed formulations showed lower self-emulsification time (˂200 seconds) and higher cloud point (˃60°C). They were free of physical defects and had drug content within the acceptable range (98.5%-101%). The crushing strength of all formulations was in the range of 58-96 N, and the results of the friability test were within the range of USP (≤1). Disintegration time was within the official limits (NMT 15 min), and complete drug release was achieved within 30 min.

Conclusion

Using commonly available excipients and machinery, SEDDS-based tablets with better dissolution profile and bioavailability can be prepared by direct compression. These S-SEDDSs could be a better alternative to conventional tablets of simvastatin.

Effect of Organomontmorillonite-Cloisite® 20A Incorporation on the Structural and Drug Release Properties of Ureasil-PEO Hybrid

This paper presents the influence of the presence of a modified organoclay, Cloisite^® 20A (MMTA) on the structural and drug release properties of ureasil organic-inorganic hybrid. Sol-gel process was used to prepare the hybrid nanocomposites containing sodium diclofenac (DCF) at 5% wt. The effect of the amount of MMTA incorporated into the ureasil hybrid matrix was evaluated and characterized in depth by different techniques such as X-ray diffraction (XRD), small angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), and swelling properties. The influence of MMTA on ureasil nanocomposites release profile was evaluated by in situ UV-vis. The diffraction patterns of the UPEO-MMTA nanocomposites showed a synergistic contribution effect that led to an intensity increase and narrowed the diffraction peaks, evidencing a crystallite PEO growth as a function of the modified nanoclay content. The interactions between polyether chains and the hydrogenated tallow of MMTA led to an easy intercalation process, as observed in UPEO-MMTA nanocomposites containing low (1% wt) or high (20% wt) nanoclay content. The waterway (channels) created in UPEO-MMTA nanocomposites contributed to a free volume increase in the swollen network compared to UPEO without MMTA. The hypothesis of the channels created after intercalation of the PEO phase in the interlayer of MMTA containing organoammonium ions corroborates with the XRD results, swelling studies by SAXS, and release assays. Furthermore, when these clay particles were dispersed in the polymeric matrix by an intercalation process, water uptake improvement was observed, with an increased amount of DCF release. The design of ureasil-MMTA nanocomposites containing modified nanoclay endows them with tunable properties; for example, swelling degree followed by amount of controlled drug release, opening the way for more versatile biomedical applications.

Novel Pullulan/Gellan Gum Bilayer Film as a Vehicle for Silibinin-Loaded Nanocapsules in the Topical Treatment of Atopic Dermatitis

In this study a novel gellan gum/pullulan bilayer film containing silibinin-loaded nanocapsules was developed for topical treatment of atopic dermatitis (AD). The bilayer films were produced by applying a pullulan layer on a gellan gum layer incorporated with silibinin nanocapsules by two-step solvent casting method. The bilayer formation was confirmed by microscopic analysis. In vitro studies showed that pullulan imparts bioadhesitvity for the films and the presence of nanocapsules increased their occlusion factor almost 2-fold. Besides, the nano-based film presented a slow silibinin release and high affinity for cutaneous tissue. Moreover, this film presented high scavenger capacity and non-hemolytic property. In the in vivo study, interestingly, the treatments with vehicle film attenuated the scratching behavior and the ear edema in mice induced by 2,4-dinitrochlorobenzene (DNCB). However, the nano-based film containing silibinin modulated the inflammatory and oxidative parameters in a similar or more pronounced way than silibinin solution and vehicle film, as well as than hydrocortisone, a classical treatment of AD. In conclusion, these data suggest that itself gellan gum/pullulan bilayer film might attenuate the effects induced by DNCB, acting together with silibinin-loaded nanocapsules, which protected the skin from oxidative damage, improving the therapeutic effect in this AD-model.

MgAl and ZnAl-Hydrotalcites as Materials for Cosmetic and Pharmaceutical Formulations: Study of Their Cytotoxicity on Different Cell Lines

The knowledge about the effect of hydrotalcites (HTlcs), largely used in pharmaceutics, on non-malignant cell lines is limited. The effect of MgAl-HTlc-and ZnAl-HTlc- (NO3−/Cl−/CO32−) on the cell viability of HaCat, fibroblasts and HepG2 was studied by MTT assay. Cells were incubated either with HTlc suspensions in the culture media and with the supernatant obtained from the suspension being centrifuged. MgAl-HTlcs suspensions resulted in being cytotoxic. As SEM and TEM analyses showed the presence of sub-micrometric particles in all the MgAl-HTlc examined, it could be hypothesized that this fraction can be internalized into cells reducing the viability. MgAl-HTlc-NO3 is the most cytotoxic probably due to the additional effect of NO3− anions. ZnAl-HTlcs are cytotoxic, especially for HaCat and HepG2 cells (viability <60% at all the concentrations assayed). The effect is attributable both to the sub-micrometric fraction (identified by TEM) and to the high Zn2+ levels found in the culture medium by ICP-OES analysis, suggesting that ZnAl-HTlcs are less stable than MgAl-HTlc in the used media. The obtained results suggest that it is very important to perform ad hoc studies in order to evaluate HTlc safety before to be introduced in a formulation.

Development and Characterization of Xanthan Gum and Alginate Based Bioadhesive Film for Pycnogenol Topical Use in Wound Treatment

Pycnogenol (PYC) is a concentrate of phenolic compounds derived from French maritime pine; its biological activity as antioxidant, anti-inflammatory and antibacterial suggests its use in the treatment of open wounds. A bioadhesive film, loaded with PYC, was prepared by casting, starting with a combination of two biopolymer acqueous solutions: xanthan gum (1% wt/wt) and sodium alginate (1.5% wt/wt), in a 2.5/7.5 (wt/wt) ratio. In both solutions, glycerol (10% wt/wt) was added as plasticizing agent. The film resulted in an adhesive capable to absorb a simulated wound fluid (~ 65% wt/wt within 1 h), therefore suitable for exuding wounds. The mechanical characterization showed that the film is deformable (elastic modulus E = 3.070 ± 0.044 MPa), suggesting adaptability to any type of surface and resistance to mechanical solicitations. PYC is released within 24 h by a sustained mechanism, achieving a maximum concentration of ~0.2 mg/mL, that is safe for keratinocytes, as shown by cytotoxicity studies. A concentration of 0.015 mg/mL is reached in the first 5 min after application, at which point PYC stimulates keratinocyte growth. These preliminary results suggest the use of PYC in formulations designed for topical use.