Liposomes and transferosomes in the delivery of papain for the treatment of keloids and hypertrophic scars

Hypertrophic scars and keloids are characterized by an excessive collagen deposition. The available treatment options are invasive and can result in recurrence of scar formation. Using liposomes and transferosomes for the topical delivery of papain, a proteolytic enzyme, can be effective treatment. The objective of the study is to formulate papain-loaded liposomes and transferosomes, characterize the formulations, and study in vitro permeation using shed snake skin and Sprague-Dawley rat skin as models for stratum corneum and full thickness skin. Papain-loaded liposomes and transferosomes were formulated using the thin-film hydration method for the delivery of papain across the stratum corneum barrier. An in vitro permeation study carried out using shed-snake skin and Sprague-Dawley rat skin models showed that transferosomes were able to deliver papain across the stratum corneum barrier, while papain solution and papain liposomes were not able to cross the barrier. However, transferosomes were not able to deliver papain across the full thickness rat skin model suggesting the deposition of papain loaded transferosomes in the epidermal or dermal layer of skin. In addition, an ex-vivo model was used to analyze the effect of papain exposure on the morphology of the epidermis taken from rat skin exposed to papain solution, papain in transferosomes and papain in liposomes. Papain in solution resulted in a noticeable degradation of the epidermis, but when embedded in either transferosomes or liposomes there was no noticeable change when compared to control animals. The cytotoxicity study performed using HeLa cells showed that the cells were viable at papain concentrations lower than 0.01 mg/ml.

Transformation of dolutegravir into an ultra-long-acting parenteral prodrug formulation

Ultra-long-acting integrase strand transfer inhibitors were created by screening a library of monomeric and dimeric dolutegravir (DTG) prodrug nanoformulations. This led to an 18-carbon chain modified ester prodrug nanocrystal (coined NM2DTG) with the potential to sustain yearly dosing. Here, we show that the physiochemical and pharmacokinetic (PK) formulation properties facilitate slow drug release from tissue macrophage depot stores at the muscle injection site and adjacent lymphoid tissues following single parenteral injection. Significant plasma drug levels are recorded up to a year following injection. Tissue sites for prodrug hydrolysis are dependent on nanocrystal dissolution and prodrug release, drug-depot volume, perfusion, and cell-tissue pH. Each affect an extended NM2DTG apparent half-life recorded by PK parameters. The NM2DTG product can impact therapeutic adherence, tolerability, and access of a widely used integrase inhibitor in both resource limited and rich settings to reduce HIV-1 transmission and achieve optimal treatment outcomes.

Comparative evaluation of the Munt-Dash air-interface diffusion chamber and Franz chamber for the in vitro examination of topical spray formulations

In vitro diffusion testing of topical formulations has long been examined using Franz diffusion chambers, however, Franz chambers are typically used with relatively large volumes, lack the air/membrane interface present in vivo, and do not account for changes in formula characteristics as solvent evaporates. Here we present our patented Munt-Dash diffusion chamber designed for direct spray application onto a model membrane. Diffusion characteristics from topical spray formulations utilizing both the Munt-Dash chamber and Franz diffusion chambers were evaluated and compared. Using diclofenac sodium and lidocaine hydrochloride as model drugs and shed snakeskin as a model for stratum corneum, test solutions were applied to Franz diffusion chambers using a pipette and to the Munt-Dash chamber using a high-speed syringe pump and sprayer. Both chambers presented permeability data consistent with previously reported in vitro and in vivo studies. Significant differences were observed in permeability by formulation and temperature. This suggests that although Franz chambers produce relevant data, the failure to account for small volumes and drying during application may produce misleading results. The Munt-Dash chamber may improve in vitro testing by providing these factors. This data suggests the Munt-Dash chamber is a suitable alternative to the Franz chamber for topical spray formulations.

The effects of phosphocreatine disodium salts plus blueberry extract supplementation on muscular strength, power, and endurance

BACKGROUND

Numerous studies have demonstrated the efficacy of creatine supplementation for improvements in exercise performance. Few studies, however, have examined the effects of phosphocreatine supplementation on exercise performance. Furthermore, while polyphenols have antioxidant and anti-inflammatory properties, little is known regarding the influence of polyphenol supplementation on muscular strength, power, and endurance. Thus, the purpose of the present study was to compare the effects of 28 days of supplementation with phosphocreatine disodium salts plus blueberry extract (PCDSB), creatine monohydrate (CM), and placebo on measures of muscular strength, power, and endurance.

METHODS

Thirty-three men were randomly assigned to consume either PCDSB, CM, or placebo for 28 days. Peak torque (PT), average power (AP), and percent decline for peak torque (PT%) and average power (AP%) were assessed from a fatigue test consisting of 50 maximal, unilateral, isokinetic leg extensions at 180°·s^- 1 before and after the 28 days of supplementation. Individual responses were assessed to examine the proportion of subjects that exceeded a minimal important difference (MID).

RESULTS

The results demonstrated significant (p < 0.05) improvements in PT for the PCDSB and CM groups from pre- (99.90 ± 22.47 N·m and 99.95 ± 22.50 N·m, respectively) to post-supplementation (119.22 ± 29.87 N·m and 111.97 ± 24.50 N·m, respectively), but no significant (p = 0.112) change for the placebo group. The PCDSB and CM groups also exhibited significant improvements in AP from pre- (140.18 ± 32.08 W and 143.42 ± 33.84 W, respectively) to post-supplementation (170.12 ± 42.68 W and 159.78 ± 31.20 W, respectively), but no significant (p = 0.279) change for the placebo group. A significantly (p < 0.05) greater proportion of subjects in the PCDSB group exceeded the MID for PT compared to the placebo group, but there were no significant (p > 0.05) differences in the proportion of subjects exceeding the MID between the CM and placebo groups or between the CM and PCDSB groups.

CONCLUSIONS

These findings indicated that for the group mean responses, 28 days of supplementation with both PCDSB and CM resulted in increases in PT and AP. The PCDSB, however, may have an advantage over CM when compared to the placebo group for the proportion of individuals that respond favorably to supplementation with meaningful increases in muscular strength.

Physical-Chemical Characterization and Formulation Considerations for Solid Lipid Nanoparticles

Pure glyceryl mono-oleate (GMO) (lipid) and different batches of GMO commonly used for the preparation of GMO-chitosan nanoparticles were characterized by modulated differential scanning calorimetry (MDSC), cryo-microscopy, and cryo-X-ray powder diffraction techniques. GMO-chitosan nanoparticles containing poloxamer 407 as a stabilizer in the absence and presence of polymers as crystallization inhibitors were prepared by ultrasonication. The effect of polymers (polyvinyl pyrrolidone (PVP), Eudragits, hydroxyl propyl methyl cellulose (HPMC), polyethylene glycol (PEG)), surfactants (poloxamer), and oils (mineral oil and olive oil) on the crystallization of GMO was investigated. GMO showed an exothermic peak at around -10°C while cooling and another exothermic peak at around -12°C while heating. It was followed by two endothermic peaks between 15 and 30 C, indicative of GMO melting. The results are corroborated by cryo-microscopy and cryo-X-ray. Significant differences in exothermic and endothermic transition were observed between different grades of GMO and pure GMO. GMO-chitosan nanoparticles resulted in a significant increase in particle size after lyophilization. MDSC confirmed that nanoparticles showed similar exothermic crystallization behavior of lipid GMO. MDSC experiments showed that PVP inhibits GMO crystallization and addition of PVP showed no significant increase in particle size of solid lipid nanoparticle (SLN) during lyophilization. The research highlights the importance of extensive physical-chemical characterization for successful formulation of SLN.

Effect of Simultaneous Administration of Dihydroxyacetone on the Diffusion of Lawsone Through Various In Vitro Skin Models

Unprotected sunlight exposure is a risk factor for a variety of cutaneous cancers. Topically used dihydroxyacetone (DHA) creates, via Maillard reaction, chemically fixed keratin sunscreen in the stratum corneum with significant protection against UVA/Soret radiation. When used in conjunction with naphthoquinones a naphthoquinone-modified DHA Maillard reaction is produced that provides protection across the UVB/UVA/Soret spectra lasting up to 1 week, resisting sweating and contact removal. The aim of this study was to examine a simplified version of this formulation for effect on UV transmission and to determine if penetration levels merit toxicity concerns. Permeability was demonstrated for freshly prepared DHA (30 mg/mL) and lawsone (0.035 mg/mL) alone and in combination using a side-by-side diffusion apparatus at 37°C over 48 h across shed snake skin and dermatomed pig skin. These samples were then examined for effectiveness and safety. Concentrations were determined by HPLC and UPLC monitored from 250-500 nm. Lawsone flux significantly decreased across pig skin (20.8 (± 4.8) and 0.09 (± 0.1) mg/cm(2) h without and with DHA, respectively) but did not change across shed snake skin in the presence of DHA. Significantly reduced lawsone concentration was noted in donor chambers of combined solutions. Damage was not observed in any skins. Darker coloration with greater UV absorbance was observed in skins exposed to the combined solution versus individual solutions. This study confirmed that combined DHA and lawsone provided effective blocking of ultraviolet light through products bound in keratinized tissue. DHA permeation levels in pig skin suggest further in vitro and in vivo study is required to determine the safety of this system.

Antitumor efficacy, tumor distribution and blood pharmacokinetics of chitosan/glyceryl-monooleate nanostructures containing paclitaxel

AIMS

This investigation compared the tumor distribution, efficacy, blood pharmacokinetic parameters and hematological alterations following treatment with chitosan/glyceryl-monooleate (GMO) nanostructures containing paclitaxel (PTX) to a conventional formulation of PTX (Taxol(®)) in BALB/c female mice.

MATERIALS & METHODS

The tumor and blood concentrations of PTX were evaluated by HPLC and the pharmacokinetic parameters were determined through noncompartmental methods. Tumor development was evaluated by histopathological methods and hematological composition was monitored through differential white blood cells counts.

RESULTS

Lower localized or intravenous doses of PTX-chitosan/GMO nanostructures significantly increased the antitumor activity of paclitaxel. The tumor distribution studies showed effective concentrations in the tumors with the chitosan/GMO formulation while systemic blood levels remained lower than after administration of the conventional formulation.

CONCLUSION

Delivery systems consisting of chitosan/GMO and PTX are safe and effective administered locally (intratumorally) or intravenously.