Physicochemical characterization of emulgel formulated with SepineoP 600, SepineoSE 68 and cosolvent mixtures.

The combined properties of SepineoP 600 (S600), a self-gelling dispersion and SepineoSE 68 (M68), a natural liquid crystal forming surfactant, were utilized in the development of emulgel base for topical application. The emulgels were prepared in water alone or combined with propylene glycol (PG), polyethylene glycol 400 (PEG400) and glycerol (G) as cosolvents. Emulgels were characterized for their optical and flow behavior. Two model drugs: caffeine (CF) and methylparaben (MP) were used in the evaluation of drug permeation across the stratum corneum (SC). The results showed that emulgel prepared using 70% PG:water (1:1) and 30% S600 has the best flow behavior compared to other cosolvents. Also the permeability coefficient of CF was found to be higher than that of MP and the addition of 3% M68 improved the physical stability of the emulgel, but it did not affect the drug diffusion profile.

Evaluation of tadalafil nanosuspensions and their PEG solid dispersion matrices for enhancing its dissolution properties.

The aim of this work was to prepare and evaluate Tadalafil nanosuspensions and their PEG 4000 solid dispersion matrices to enhance its dissolution rate. Nanosuspensions were prepared by precipitation/ultrasonication technique at 5°C where different stabilizers were screened for stabilization. Nanosuspensions were characterized in terms of particle size and charge. Screening process limited suitable stabilizers into structurally related surfactants composed of a mixture of Tween80 and Span80 at 1:1 ratio (in percent, weight/volume) in adjusted alkaline pH (named TDTSp-OH). The surfactant mixture aided the production of nanosuspensions with an average particle size of 193 ± 8 nm and with short-term stability sufficient for further processing. Solid dispersion matrices made of dried Tadalafil nanosuspensions or dried Tadalafil raw powder suspensions and PEG 4000 as a carrier were prepared by direct compression. Drying was performed via dry heat or via freeze dry. Drug release studies showed that, in general, tablet formulations made of freeze-dried product exhibited faster initial release rates than the corresponding tablets made of oven-dried products which could be attributed to possible larger crystal growth and larger crushing strengths of oven-dried formulations. At best, 60% of drug was released from solid dispersion matrices, while more than 90% of drug was released from TDTSp-OH nanosuspension within the first 5 min. In conclusion, Tadalafil nanosuspensions obtained using a mixed surfactant system provided rapid dissolution rates of Tadalafil that can theoretically enhance its bioavailability.

Sustained release tablets containing soluble polymethacrylates: comparison with tableted polymethacrylate IPEC polymers.

The objective of this study was to compare a novel sustained release tablet formulation that has the potential to be used for drugs of different physicochemical properties using a binary mixture of polymethacrylate polymers in their salt forms with the polymethacrylate interpolyelectrolyte complex (IPEC) tablets in terms of drug release and compactness. Also, we aimed to compare this formulation with an IPEC tablet in terms of drug release. Tablets prepared using Eudragit E-Citrate and Eudragit L-Sodium were more convenient, easier to prepare, and showed better sustained release and compactness characteristics compared to IPEC tablets of similar concentrations and preparation methods.

Novel combination of anionic and cationic polymethacrylate polymers for sustained release tablet preparation.

The objectives of this study were to prepare and evaluate a novel sustained release tablet formulation using a binary mixture of polymethacrylate polymers: Eudragit E-100 (EE) and Eudragit L-100 (EL) in their salt forms. Tablets prepared using EE-citrate and EL-Na showed the highest degree of swelling among other combinations of EE and EL. The drug release rates were independent of the pH of the dissolution medium as the release profiles exhibited a continuous release pattern with no burst effect when changing the pH of the medium. These results, along with other test results, indicated the presence of an ionic interaction between both polymers when combined in the salt forms.