BrSPR-20-P1 peptide isolated from Brevibacillus sp. developed into liposomal hydrogel as a potential topical antimicrobial agent.

A novel BrSPR-20-P1 antimicrobial peptide (P1-AMP; NH2-VVVNVLVKVLPPPVV-COOH) isolated from Brevibacillus sp. SPR-20 was encapsulated in a liposome containing varying proportions of l-α-phosphatidylcholine (PC) and cholesterol (CH). P1-AMP liposomes were incorporated into a chitosan hydrogel to achieve a peptide concentration of 0.02%. P1-AMP has been tested for its antibacterial and in vitro wound healing activities. The physicochemical characteristics of liposomes and hydrogel were investigated, including in vitro drug release, permeability, cell toxicity, antimicrobial activities, and stability studies. P1-AMP showed higher antimicrobial and wound-healing activities than the negative control. A toxicity test of P1-AMP in keratinocyte cell lines revealed cell viability of 100% at a concentration range of 1.96-1000 µg mL-1. The empty liposomes exhibited an average particle size ranging from 324.5 ± 8.6 to 1823.7 ± 288.2 nm. The size range of P1-AMP liposomes was 378.6 ± 14.0 to 2363.0 ± 255.6 nm. The zeta potential of the blank liposome ranged from -40.43 ± 2.51 to -60.17 ± 0.93 mV and it decreased to -57.33 ± 0.72 to -70.33 ± 0.15 mV of the liposome loaded with peptide. SEM images showed liposomes were ovoid spheres with smooth surfaces. The chosen formulation, composed of PC to CH in an 18 : 1 ratio (formulation F3), had the highest entrapment effectiveness with small particle size and possessed an acceptable zeta potential. The developed P1-AMP liposome-loaded hydrogels exhibited a yellowish-clear appearance with a viscosity of 758.0 ± 149.8 cPs. The P1-AMP was rapidly released from the P1-AMP-loaded liposome hydrogel formulation. The P1-AMP-loaded liposome showed high permeability compared to P1-AMP alone or P1-AMP in hydrogel without the incorporation of liposomes. The minimum inhibitory concentration (MIC) against Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) of P1-AMP-loaded liposome hydrogel was 2 µg mL-1, equivalent to P1-AMP. It completely killed S. aureus at 10× and 5× MIC after 6 and 12 h of incubation, respectively. The formulation did not induce cytotoxicity to the tested keratinocyte cell and remained stable for at least 6 months under the studied conditions.

Effect of Terpenes on the Enhancement of Skin Permeation of Lipophilic Drugs: A Systematic Review.

Objectives: The stratum corneum (SC) remains an obstacle to the passage of drugs applied topically. Several investigations have focused on enhancing the penetration of drugs through the SC by integrating permeation enhancers (PE) into the drug formulation. Terpenes are among the PE utilized in formulations and are categorized by the regulatory bodies as generally recognized as safe (GRAS). This study aimed to comparatively analyze the skin permeation enhancing effect of terpenes on lipophilic drugs. Methods: The present study reviewed the effects of terpenes on the permeation of lipophilic small-molecule drugs through the skin using original research published between 2000 - 2022 retrieved from PubMed®. The search phrase used was (lipophilic drug) AND (terpene) AND (permeation enhancer). Results: Terpenes increase the percutaneous permeation of lipophilic small molecule drugs by 1.06 - 256.80-fold. Linear correlation analysis of terpenes' cLog P with enhancement ratio (ER) revealed moderate and strong positive correlations in pig skin (r = 0.21) and mouse skin (r = 0.27), and rat skin (r = 0.41) and human skin (r = 0.67), respectively. Drug cLog P is a poor (r = -0.06) predictor of permeation enhancement. Terpenes with cLog P higher than 2.40 had ER greater than 10. Higher ERs (>30) were recorded for nerolidol, carvacrol, borneol, terpineol, limonene, menthone, pulegone, and menthol among the terpene-chemical penetration enhancers. Conclusion: cLog P of terpene-based chemical permeation enhancers (CPE) is strongly correlated with ER of lipophilic drugs across human skin. Non-polar groups in terpenes and hydrogen bond interactions by terpenes with SC lipid enhance cutaneous drug penetration of lipophilic drugs.

Effective formative assessment for pharmacy students in Thailand: lesson learns from a school of pharmacy in Thailand.

INTRODUCTION: Formative assessment (FA) is an assessment concept that is of interest in education. The Doctor of Pharmacy program is one of the programs in which FA is usually implemented. This study aimed to describe the correlation between FA scores and summative assessment (SA) scores and to suggest possible key success factors that affect the effectiveness of FA. METHODS: This study employed a retrospective design using mixed methods for data collection. Data in the semesters 1/2020 and 2/2020 of the Doctor of Pharmacy curriculum in a Thailand pharmacy school were used. Three sets of data were gathered, including the course information (e.g. FA methods, FA scores, and SA scores) from 38 records, self-reports from 326 students and 27 teachers, and 5 focus group discussions. The quantitative data were statistically analyzed using descriptive statistics and Pearson correlation, while the qualitative data were analyzed using a content analysis framework. RESULTS: The analysis revealed five main methods that were used for FA, including individual quizzes, individual reports, individual skill assessments, group presentations, and group reports. Of all 38 courses, 29 (76.32%) had significant correlations between FA and SA scores at p-values < 0.05. The individual FA score was related to the correlation coefficient of the courses (p-value = 0.007), but the group FA score was not related (p-value = 0.081). In addition, only the frequency of individual quiz had a significant effect on the correlation coefficient. Moreover, the key success factors which affected the effectiveness of FA were divided into six themes, including the appropriate method, an effective reflection, frequency of assessment, the appropriate score, the adequate support system, and teacher knowledge management. CONCLUSION: The subjects that used individual FA methods provided a significant correlation between FA and SA, while those who used group FA methods did not show a significant correlation. Additionally, the key success factors in this study were appropriate assessment methods, frequency of assessment, effective feedback, appropriate scoring, and a proper support system.

Development of Oral Microemulsion Spray Containing Pentacyclic Triterpenes-Rich Centella asiatica (L.) Urb. Extract for Healing Mouth Ulcers.

Several publications have shown that Centella asiatica (L.) Urb. and its active constituents (pentacyclic triterpenes) are effective in wound healing. The pentacyclic triterpenes-rich C. asiatica extract (PRE) was prepared following a previous study by microwave-assisted extraction (MAE) and fractionation with macroporous resin. This method provided the pentacyclic triterpene content in the extract up to 59.60% w/w. The PRE showed potent anti-inflammatory activity by inhibiting nitric oxide (NO) production with an IC50 value of 20.59 ± 3.48 µg/mL and a potent fibroblast proliferative effect (165.67%) at concentrations of 10 µg/mL. The prepared microemulsion consisted of a water: oil: surfactant mixture of 2: 2: 6, using coconut oil: clove oil (1:1) as the oil phase and Tween 20: Span 20 (2:1) as the surfactant mixture and 1.0, 2.5, and 5.0% PRE. Cell proliferation, migration, and collagen production of the microemulsion base and microemulsions containing 1.0%, 2.5%, and 5.0% PRE were evaluated. The results revealed that the microemulsion containing 1% PRE had the highest proliferation effect (136.30 ± 3.93% to 152.65 ± 3.48% at concentrations of 10 µg/mL), migration activities (100.00 ± 0.0% at 24 h), and collagen production in human dermal fibroblast (HDF) and human gingival fibroblast (HGF) cells when compared with other formulations or blank. Moreover, the anti-inflammatory activity of microemulsions containing 1% PRE was slightly lower than standard indomethacin. Anti-inflammation of the microemulsion containing PRE exhibited a dose-dependent trend, while 5% PRE was more potent than the standard drug. Considering the potent wound-healing activities and the good anti-inflammatory activity of the microemulsion containing PRE, the microemulsion with 1% PRE was identified as the most suitable oral spray formulation for oral ulcer treatment.

Potential of Stratum Corneum Lipid Liposomes for Screening of Chemical Skin Penetration Enhancers.

The evaluation of effective skin chemical penetration enhancers (CPEs) is a crucial process in the development of transdermal and dermal formulations with the capacity to overcome the stratum corneum barrier. In the present study, we aimed to investigate the potential of stratum corneum lipid liposomes (SCLLs) as an alternative tool for the screening of various types and concentrations of CPEs. SCLLs were prepared using a thin-film hydration technique, and two types of fluorescent probes (sodium fluorescein [FL] or 1,6-diphenyl-1,3,5-hexatriene [DPH] were entrapped separately into SCLLs (FL-SCLL and DPH-SCLL, respectively). FL leakage from SCLLs as well as the fluidity of DPH-SCLLs were determined after incubating with various types of CPEs as a function of their concentrations. The obtained results showed a concentration-dependent relationship for most CPEs both for FL leakage and the fluidity of SCLLs. When observing these data in detail, however, the concentration profiles could be classified into five main categories depending on the mode of action of the CPEs. These results strongly suggest the usefulness of SCLLs for high-throughput screening of effective CPEs as well as the understanding of their possible mode of action, especially in the early stage of skin formulation development.

High-Throughput Screening of Potential Skin Penetration-Enhancers Using Stratum Corneum Lipid Liposomes: Preliminary Evaluation for Different Concentrations of Ethanol.

In this study, we developed a technique for high-throughput screening (HTS) of skin penetration-enhancers using stratum corneum lipid liposomes (SCLLs). A fluorescent marker, sodium fluorescein (FL), entrapped in SCLLs was prepared to provide a preliminary evaluation of the effect of different concentrations of ethanol on the disruption effect of SCLLs, which is an alternative for skin penetration-enhancing effects. In addition, SCLLs containing a fluorescent probe (DPH, TMA-DPH, or ANS) were also prepared and utilized to investigate SCLL fluidity. The results using SCLL-based techniques were compared with conventional skin permeation and skin impedance test using hairless rat skin. The obtained correlations were validated between FL leakage, SCLL fluidity with various probes, or skin impedance and increases in the skin permeation enhancement ratio (ER) of caffeine as a model penetrant. As a result, FL leakage and SCLL fluidity using ANS were considered to be good indices for the skin penetration-enhancing effect, suggesting that the action of ethanol on the SC lipid and penetration-enhancing is mainly on the polar head group of intercellular lipids. In addition, this screening method using SCLL could be utilized as an alternative HTS technique for conventional animal tests. Simultaneously, the method was found to be time-saving and sensitive compared with a direct assay using human and animal skins.