Effect of flavors on the viscosity and gelling point of aqueous poloxamer solution

The Investigation of Thymol Formulations Containing Poloxamer 407 and Hydroxypropyl Methylcellulose to Inhibit Candida Biofilm Formation and Demonstrate Improved Bio-Compatibility

The aim of this study was to investigate the potential of thymol to inhibit Candida biofilm formation and improve thymol biocompatibility in the presence of hydroxypropyl methylcellulose (HPMC) and poloxamer 407 (P407), as possible drug carriers. Thymol with and without polymers were tested for its ability to inhibit biofilm formation, its effect on the viability of biofilm and biocompatibility studies were performed on HEK 293 (human embryonic kidney) cells. Thymol showed a concentration dependent biofilm inhibition; this effect was slightly improved when it was combined with HPMC. The Thymol-P407 combination completely inhibited the formation of biofilm and the antibiofilm effect of thymol decreased as the maturation of Candida biofilms increased. The effect of thymol on HEK 293 cells was a loss of nearly 100% in their viability at a concentration of 250 mg/L. However, in the presence of P407, the viability was 25% and 85% using neutral red uptake and sulforhodamine B assays, respectively. While, HPMC had less effect on thymol activity the thymol-P407 combination showed a superior inhibitory effect on biofilm formation and better biocompatibility with human cell lines. The combination demonstrates a potential medical use for the prevention of Candida biofilm formation.

Influence of the surface tension of wet massing liquid on the functionality of microcrystalline cellulose as pelletization aid

This study designed to investigate the impact of surface tension of moistening liquid on the functionality of MCC as pelletization aid. For this purpose, sodium dodecyl sulfate (SDS), poloxamer 188 (PL), di-potassium hydrogen phosphate (K₂HPO₄) and combinations thereof were incorporated into the powder blend comprised of MCC and dicalcium phosphate (DCP) at different levels. Physical mixture (PM) and co-processed composite (Cop) of MCC and sodium carboxymethyl cellulose (SCMC) replaced MCC as pelletization aids. The pellets prepared were characterized for their median diameter (D₅₀), particle size distribution (PSD), sphericity, porosity, tensile strength and disintegration. SDS induced a drop in the surface tension of water from 68.7 to 23.7 mN/m at 0.1% (w/w). In contrast, the surface tension values of PL and K₂HPO₄ solutions were 2.08- and 3.07-fold higher than that of SDS solutions, respectively. MCC based pellets obtained with SDS showed wider PSD and lower sphericity than those made with PL, K₂HPO₄ and their combinations. In addition, the PSD and porosity increased with rise of SDS concentration from 0.05 to 0.25% (w/w). It was thus inferred that a critical surface tension of moistening liquid was essential for functionality of MCC as pelletization aid but not for PM and Cop.

Naproxen Microparticulate Systems Prepared Using In Situ Crystallisation and Freeze-Drying Techniques

Poor drug solubility and dissolution rate remain to be one of the major problems facing pharmaceutical scientists, with approximately 40% of drugs in the industry categorised as practically insoluble or poorly water soluble. This in turn can lead to serious delivery challenges and poor bioavailability. The aim of this research was to investigate the effects of the surfactants, poloxamer 407 (P407) and caprol® PGE 860 (CAP), at various concentrations (0.1, 0.5, 1 and 3% w/v) on the enhancement of the dissolution properties of poorly water-soluble drug, naproxen, using in situ micronisation by solvent change method and freeze-drying. The extent at which freeze-drying influences the dissolution rate of naproxen microcrystals is investigated in this study by comparison with desiccant-drying. All formulations were evaluated and characterised using particle size analysis and morphology, in vitro dissolution studies, differential scanning calorimetry (DSC), and Fourier transform infra-red (FT-IR) spectroscopy. An increase in poloxamer 407 concentration in freeze-dried formulations led to enhancement of drug dissolution compared to desiccator-dried formulations, naproxen/caprol® PGE 860 formulations and untreated drug. DSC and FT-IR results show no significant chemical interactions between drug and poloxamer 407, with only very small changes to drug crystallinity. On the other hand, caprol® PGE 860 showed some interactions with drug components, alterations to the crystal lattice of naproxen, and poor dissolution profiles using both drying methods, making it a poor choice of excipient.

Characterization and Antimicrobial Activity of N-Methyl-2-pyrrolidone-loaded Ethylene Oxide-Propylene Oxide Block Copolymer Thermosensitive Gel

The purpose of this study is to investigate the effects of N-methyl-2-pyrrolidone on the thermosensitive properties of aqueous ethylene oxide-propylene oxide block copolymer (Lutrol^® F127) system. Due to the aqueous solubility enhancement and biocompatibility, N-methyl-2-pyrrolidone is an interesting solubilizer for the poorly water soluble drugs to be incorporated in the Lutrol^® F127 system. Effect of N-methyl-2-pyrrolidone on physicochemical properties of Lutrol^® F127 system was investigated using appearance, pH, gelation, gel melting temperature and rheology. The antimicrobial activity of the thermosensitive N-methyl-2-pyrrolidone gel was also tested. Lower N-methyl-2-pyrrolidone amount (≤30%w/w) could shift the sol-gel transition to a lower temperature but the gel-sol transition was shifted to a higher temperature. Higher N-methyl-2-pyrrolidone (≥40%w/w) could shift both sol-gel and gel-sol transitions of the system to a lower temperature. The amount of N-methyl-2-pyrrolidone >60% w/w could reverse the phase of the Lutrol^® F127 system to non-newtonian flow at 4° and Newtonian flow at high temperature. Aqueous Lutrol^® F127 system containing N-methyl-2-pyrrolidone exhibited antimicrobial activities against Staphylococcus aureus, Escherichia coli and Candida albicans with the N-methyl-2-pyrrolidone in a dose-dependent manner.

Novel topical formulations of Terbinafine-HCl for treatment of onychomycosis

Terbinafine hydrochloride (TBF-HCl) is an active substance that is using for treatment of onychomycosis. Onychomycosis is a fungal infection which is the most common disease of nail plate. The nail plate is a barrier which prevents effective topical treatment of ungual disorders. In this study, TBF-HCl loaded liposome and ethosome formulations and also gel form of these formulations were prepared. The formulations were characterized and in vitro and ex vivo release studies were performed. Nail characterization studies were also performed to examine the effect of formulations and experimental conditions on nail surface. As a result, all formulations can serve as efficient formulations for ungual application of TBF-HCl. By the way, the results of the accumulation studies suggested that liposome poloxamer gel formulation could be promising system for ungual drug delivery due to the better accumulation and easier application of the formulation.

Preparation, characterization, and in vitro permeation study of terbinafine HCl in poloxamer 407-based thermogelling formulation for topical application

Upon topical administration, a high penetration rate of antifungal drug into the infected site is desirable to reduce treatment length and systemic side effects which occur especially after a prolonged peroral administration. Thermogelling formulations composed of poloxamer 407, medium chain triglycerides, isopropyl alcohol, dimethyl isosorbide, and water for topical application were developed, and a lipophilic drug terbinafine HCl (TBF) was incorporated. Previously, a remarkable high permeation rate of a hydrophilic drug 5-aminolevulinic acid from this vehicle was evident compared to different creams from German Pharmacopoeia. By varying the composition of vehicle constituents, a broad range of consistencies and appearances was obtained. Up to 4% TBF could be solubilized in the vehicle. TBF fluxes at steady state across human stratum corneum from these formulations were higher than those from the German Pharmacopoeia Basiscreme Deutscher Arzneimittel Codex and a marketed product at similar concentration of 1%. TBF fluxes increased along with a higher content of TBF in the formulation. The amount of TBF retained in stratum corneum was higher compared to those from both standards of comparison (p < 0.01). The thermodynamic activity of TBF in the thermogelling formulation was lower compared to those in other formulations. Therefore, the nature of the vehicle and its interaction with TBF are suggested to play a significant role in explaining higher fluxes along with higher TBF content. Differential scanning calorimetry measurements revealed comparable T2 and T3 endothermic shifts from all examined formulations suggesting equal influences to the skin lipids.

Effect of DMSO on micellization, gelation and drug release profile of Poloxamer 407

The application of many recently developed or approved drugs and pharmaceuticals is seriously hampered by their low solubility in aqueous media. Hence, numerous promising pharmaceutical delivery systems (including novel "smart" systems based on poloxamer gels, which have highly advantageous thermo-reversible characteristics and low toxicity) cannot solubilize required doses of various drugs without additives such as co-solvents or salts. Therefore, we have studied the effects of dimethyl sulphoxide (DMSO) - a commonly used co-solvent during drug development stages - on the micellization, gelation and dissolution properties of aqueous poloxamer solutions. Differential scanning calorimetry and tube inversion experiments clearly showed that DMSO induces reductions in the critical micellization and gelation temperatures of poloxamer systems. In addition, high resolution solid state (1)H Magic Angle Spinning Nuclear Magnetic Resonance (MAS NMR) analyses provided indications of the specific chemical groups in the poloxamer affected by DMSO, and the molecular mechanism involved. The presence of DMSO accelerated dissolution of the pure gel in water and the release of a hydrophobic drug (flufenamic acid) from poloxamer gel, while it reduced the release of a hydrophilic drug (metoprolol tartrate).