In silico modeling and empirical study of 4-n-Butylresorcinol nanoliposome formulation

A study to incorporate in silico modeling with an empirical experiment has been carried out to formulate nanoliposome containing 4-n-butylresorcinol as the active ingredient. The in silico modeling was performed using molecular dynamics simulation followed by radius of gyration observation to provide insight into the mechanisms of 4-n-butylresorcinol stabilization by liposome due to their nano-size. The empirical experiment was conducted by formulating the nanoliposome using soy lecithin phospholipid formula as suggested by the in silico modeling followed by determining its particle size as well as its shape. From their incorporation, it was found that 3200 phospholipid molecules were selected in formulating nanoliposome containing 4-n-butylresorcinol. The results of the nanoliposomes size observation in the modeling of 3200 lipid molecules was 87.01 (± 0.59) nm, whereas the size from the empirical study was 87.57 (± 0.06) nm. Communicated by Ramaswamy H. Sarma.

An open-label, investigator-initiated, single-center, prospective, pilot clinical study to evaluate the efficacy of a skin whitening serum applied twice daily combined with a spot-preventing SPF50+ sunscreen in healthy female subjects with melasma hyperpigmentation

Background

Melasma is a common skin disorder characterized by alterations in normal skin pigmentation. The objective was to evaluate the efficacy and safety of a skin whitening serum containing niacinamide, hydroxyphenoxy propionic acid, dipotassium glycyrrhizate, glycolic acid, and 4‐n‐butylresorcinol applied twice daily combined with a spot‐preventing SPF50+ sunscreen for treatment of melasma.

Methods

Twelve healthy Caucasian women with melasma (Fitzpatrick skin types II−IV) were enrolled in this pilot clinical study. Efficacy evaluations were performed at baseline and weeks 4, 8, and 12 of treatment and included clinical and instrumental assessments.

Results

All endpoints for melasma hyperpigmentation showed a statistically significant improvement from baseline to the end of the study. There was only one dropout. No signs of irritation or discomfort were observed at baseline, w4, w8, or w12. An overall improvement in melasma was observed both clinically and on reflectance confocal microscopy (RCM).

Conclusion

This topical skin whitening serum had favorable outcomes for the treatment of melasma hyperpigmentation in adult women, as demonstrated on investigator and instrumental assessments. The results of this pilot study need to be confirmed in randomized, controlled studies with a larger sample size.

4-n-Butylresorcinol-Based Linear and Graft Polymethacrylates for Arbutin and Vitamins Delivery by Micellar Systems

A novel initiator, bromoester modified 4-n-butylresorcinol (4nBREBr₂), was prepared and utilized in controlled atom transfer radical polymerization (ATRP) to obtain three series of amphiphilic copolymers. The V-shaped copolymers of methyl methacrylate (MMA), 2-hydroxyethyl methacrylate (HEMA), and poly(ethylene glycol) methyl ether methacrylate (MPEGMA), abbreviated to P(HEMA-co-MMA), P(HEMA-co-MPEGMA), and P(MMA-co-MPEGMA), were synthesized. Moreover, P((HEMA-graft-PEG)-co-MMA) graft copolymers were prepared by combining the pre-polymerization modification of HEMA and a "click" reaction using a "grafting onto" approach. All copolymers could form micelles with encapsulated active substances (vitamin C (VitC), vitamin E (VitE), arbutin (ARB)), which are used in cosmetology. In vitro studies carried out in a PBS solution (pH 7.4) demonstrates that in most cases the maximum release of active substance was after 1 h. The polymeric systems presenting satisfactory encapsulation characteristics and release profiles are attractive micellar carriers of cosmetic substances, which show a positive effect on the skin condition.

4-n-butylresorcinol enhances proteolytic degradation of tyrosinase in B16F10 melanoma cells

OBJECTIVE

4-n-butylresorcinol is a competitive inhibitor of tyrosinase and has been used as an antimelanogenic agent. However, its inhibition mechanism in intact cells is not fully understood. To elucidate the cellular mechanism, we compared in vitro and in vivo inhibitory effects of 4-n-butylresorcinol on tyrosinase activity.

METHODS

B16F10 melanoma cells were cultured in media containing α-MSH in the presence or absence of 4-n-butylresorcinol. Tyrosinase mRNA levels, protein levels and activity in B16F10 cells were compared by real-time PCR, immunostaining combined with western blot and colorimetric analysis, respectively. Melanin concentration was measured by colorimetry both in the cells and in the media. Tyrosinase glycosylation and proteolytic degradation were analysed by immunoblotting after cells were treated with Endo H/PNGase F and E64/proteasome inhibitors, respectively.

RESULTS

4-n-butylresorcinol inhibited tyrosinase activity and melanin synthesis more effectively in intact cells than in cell lysates. Western blotting and real-time RT-PCR showed that 4-n-butylresorcinol reduced protein levels, but not mRNA levels, of tyrosinase in B16F10 cells. 4-n-butylresorcinol showed no effect on the processing of tyrosinase glycosylation or on trafficking to melanosomes. However, treatment of B16F10 cells with E64 or proteasome inhibitor abrogated the 4-n-butylresorcinol-induced decrease of tyrosinase. Moreover, 4-n-butylresorcinol activated p38 MAPK, resulting in increased ubiquitination of tyrosinase.

CONCLUSION

4-n-butylresorcinol inhibits melanogenesis by enhancing proteolytic degradation of tyrosinase as well as competitive binding to tyrosinase. These findings will help to develop new, effective and safe chemicals for the treatment of hyperpigmentation disorders.

Assessment of efficacy, safety, and tolerability of 4-n-butylresorcinol 0.3% cream: an Indian multicentric study on melasma

Introduction

Melasma is one of the commonly reported pigmentory disorders in the Indian population. Numerous therapeutic modalities are available. However, very few have produced complete satisfactory response. 4-n-Butylresorcinol 0.3% cream has recently been introduced in India as a new hypopigmenting agent. It is a resorcinol derivative and acts by inhibiting both tyrosinase and tyrosinase-related protein-1.

Objective

The available published literatures are with 4-n-butylresorcinol 0.1% cream, and there is paucity of clinical studies with 4-n-butylresorcinol 0.3% cream. Furthermore, considering the fact that Indian skin is more prone to irritation with hypopigmenting agents, our study explores the efficacy, safety, and tolerability of 4-n-butylresorcinol 0.3% cream in Indian subjects with melasma.

Methods

Fifty-two subjects with melasma participated in this open-label, single arm, observational study. All the patients were advised twice daily application of 4-n-butylresorcinol 0.3% cream for 8 weeks over the areas of melasma. Assessment parameters included modified Melasma Area Severity Index (mMASI) score. Digital photographs of all the patients at baseline, week 4, and week 8 were taken. During this 8-week study period, all the adverse events were observed and recorded.

Results

All the 52 subjects completed the study. Out of 52 subjects, 90.38% were females. The mean age of patients was 38.5±7.8 years. Mean ± standard error of MASI score measurements showed a significant decrease from baseline score of 14.73±0.59 to 11.09±0.53 after week 4 (P<0.001) and 6.48±0.43 at week 8 (P<0.001). The digital photographs of the study subjects taken at week 4 and week 8 also showed decrease in melasma pigmentation compared to baseline photograph and correlated with the changes in the mMASI score. The treatment was well tolerated by all the study subjects. No adverse reactions were reported throughout the study period.

Conclusion

Our data suggest that the 4-n-butylresorcinol 0.3% cream is safe, effective, and well tolerated in Indian patients with melasma.

The Efficacy and Safety of 4-n-butylresorcinol 0.1% Cream for the Treatment of Melasma: A Randomized Controlled Split-face Trial

BACKGROUND

Melasma is a common acquired symmetrical hypermelanosis that occurs on sun-exposed areas, and it is frequently observed among women. Various treatment modalities have been tried, but none are completely satisfactory. 4-n-butylresorcinol, which is a resorcinol derivative that has an inhibitory effect on both tyrosinase and tyrosinase-related protein-1, was introduced in 1995 and it has received increasing attention as a new hypopigmenting agent. However, the hypopigmenting effect of 4-n-butylresorcinol in human subjects has only been shown in a few studies.

OBJECTIVE

The aim of this study was to investigate the hypopigmenting efficacy and safety of 4-n-butylresorcinol 0.1% cream for the treatment of melasma.

METHODS

Twenty patients with melasma were enrolled to this randomized, double-blind, vehicle-controlled, split-face comparative study. The patients were instructed to apply 4-n-butylresorcinol 0.1% cream or vehicle to each side of the face twice daily for 8 weeks. Mexameter measurements were performed along with photography at baseline, 4 weeks and 8 weeks. Adverse events were observed and recorded throughout the study.

RESULTS

All the patients completed the study. Mexameter measurements demonstrated that the melanin index of the treated side showed a significant decrease when compared with that of the vehicle-treated side after 4 weeks (p=0.006) and after 8 weeks (p<0.0005). All the adverse reactions were mild and transient.

CONCLUSION

4-n-butylresorcinol 0.1% cream showed rapid efficacy and it was well tolerated when used for the treatment of melasma.