Preparasi Salbutamol Sulfat dalam Pembawa Vesikuler Etosom

Tujuan penelitian ini adalah memperoleh formula dan metode preparasi yang sesuai untuk preparasi salbutamol sulfat ke dalam pembawa vesikuler etosom. Preparasi dilakukan dengan metode panas (40oC) dan metode dingin (30oC) dengan variasi konsentrasi fosfatidilkolin sebagai pembentuk vesikel (2% dan 3%) dan etanol sebagai peningkat penetrasi ke dalam kulit (20%, 30%, dan 40%). Karakteristik vesikel yang dianalisis adalah ukuran, bentuk, dan efisiensi penjerapan vesikel. Ukuran dan bentuk vesikel diamati dengan mikroskop optik binokuler. Analisis efisiensi penjerapan dilakukan dengan metode spektrofotometri pada panjang gelombang 275.6 nm. Vesikel yang dihasilkan dari kedua metode berupa Small Unilamellar Vesicle (SUV) dengan ukuran vesikel pada metode panas adalah 31,3-48,8 nm dan metode dingin adalah 25,4-44,9 nm. Nilai efisiensi penjerapan salbutamol sulfat dalam vesikel etosom yang dipreparasi dengan metode panas yaitu 42,66% dan pada metode dingin yaitu 53,83%. Disimpulkan bahwa metode dingin lebih sesuai digunakan untuk preparasi salbutamol sulfat dalam pembawa vesikular etosom dengan konsentrasi fosfatidilkolin 2% dan etanol 40%.

The Cyt1Aa toxin from Bacillus thuringiensis inserts into target membranes via different mechanisms in insects, red blood cells, and lipid liposomes

Bacillus thuringiensis subsp. israelensis produces crystal inclusions composed of three-domain Cry proteins and cytolytic Cyt toxins, which are toxic to different mosquito larvae. A key component is the Cyt toxin, which synergizes the activity of the other Cry toxins, thereby resulting in high toxicity. The precise mechanism of action of Cyt toxins is still debated, and two models have been proposed: the pore formation model and the detergent effect. Here, we performed a systematic structural characterization of the Cyt toxin interaction with different membranes, including in Aedes aegypti larval brush border membrane vesicles, small unilamellar vesicle liposomes, and rabbit erythrocytes. We examined Cyt1Aa insertion into these membranes by analyzing fluorescence quenching in solution and in the membrane-bound state. For this purpose, we constructed several Cyt1Aa variants having substitutions with a single cysteine residue in different secondary structures, enabling Cys labeling with Alexa Fluor 488 for quenching analysis using I-soluble quencher in solution and in the membrane-bound state. We identified the Cyt1Aa residues exposed to the solvent upon membrane insertion, predicting a possible topology of the membrane-inserted toxin in the different membranes. Moreover, toxicity assays with these variants revealed that Cyt1Aa exerts its insecticidal activity and hemolysis through different mechanisms. We found that Cyt1Aa exhibits variable interactions with each membrane system, with deeper insertion into mosquito larva membranes, supporting the pore formation model, whereas in the case of erythrocytes and small unilamellar vesicles, Cyt1Aa's insertion was more superficial, supporting the notion that a detergent effect underlies its hemolytic activity.

Optimasi Kadar Fenilbutazon dalam Pembawa Vesikular Etosom (Optimization of Concentration of Phenylbutazone in Ethosomes Vesicular Carrier)

Background: Phenylbutazone is a class of non-steroidal anti-inflammatory drugs (NSAIDs) used in the treatment of rheumatoid arthritis. Phenylbutazone is used by the transdermal route to reduce the irritating effect on the gastrointestinal tract. Purpose: This study aims to obtain phenylbutazone suspensions with optimal levels in the ethosome vesicular carrier. Methods: Preparation was carried out by the hot method (40oC) and cold method (30oC) as well as variations in the concentration of phosphatidylcholine (2% and 3%) and ethanol (30%, 35%, and 40%). Characterization of vesicles, namely the shape and size of vesicles using optical microscopy and entrapment efficiency using the spectrophotometer method with λ maks 266.6 nm. Optimization of phenylbutazone levels was carried out at a concentration of 0.1%; 0.15%; 0.2%; and 0.25%. The optimum formula was obtained at a concentration of phosphatidylcholine 3% and ethanol 35% prepared by the hot method. Results:. The form of a Small Unilamellar Vesicle (SUV), a size of 23.7 nm, and entrapment efficiency is 88.358%. Optimization of phenylbutazone levels was obtained at a concentration of 0.1% with entrapment efficiency of 88.358%. Conclusion: The optimum level of phenylbutazone in the vesicular carrier ethosome was 0.1%.Keywords: ethosome, optimation, phenylbutazone, transdermal ABSTRAKLatar Belakang: Fenilbutazon merupakan golongan obat antiinflamasi non stroid (AINS) yang digunakan pada pengobatan penyakit rheumatoid arthritis. Fenilbutazon digunakan melalui rute transdermal untuk mengurangi efek iritasi pada saluran cerna. Tujuan: Penelitian ini bertujuan memperoleh suspensi fenilbutazon dengan kadar yang optimal dalam pembawa vesikular etosom. Metode: Preparasi dilakukan dengan metode panas (40oC) dan metode dingin (30oC) serta variasi konsentrasi fosfatidilkolin (2% dan 3%) dan etanol (30%, 35%, dan 40%). Karakterisasi vesikel yaitu bentuk dan ukuran vesikel menggunakan mikroskop optik serta efisiensi penjerapan menggunakan metode spektrofotometer pada λmaks 266,6 nm. Optimasi kadar fenilbutazon dilakukan pada konsentrasi 0,1%; 0,15%; 0,2%; dan 0,25%. Diperoleh formula optimum pada konsentrasi fosfatidilkolin 3% dan etanol 35% yang dipreparasi dengan metode panas Hasil: Vesikel yang diperoleh berbentuk Small Unilamellar Vesicle (SUV), ukuran 23,7 nm, dan efisiensi penjerapan 88,358%. Optimasi kadar fenilbutazon diperoleh pada konsentrasi 0,1% dengan efisiensi penjerapan 88,358%. Kesimpulan: Disimpulkan bahwa kadar optimum fenilbutazon dalam pembawa vesikular etosom adalah 0,1%.Kata kunci: etosom, optimasi, fenilbutazon, transdermal

Preparasi Teofilin dalam Pembawa Vesikular Etosom untuk Penggunaan Transdermal

Theophylline is a methyl xanthine of alkaloid derivative compound has been used as a bronchodilator in the treatment of chronic lung disorders, especially asthma. Oral administration of theophylline causes inconvenient for patients including bitter taste, narrow therapeutic range, and indigestion due to increased of gastric acid secretion. Therefore, other administration of theophylline has been developed as transdermal delivery system. This study disscused about preparation of theophylline in ethosome as vesicular carrier. Preparation of ethosome was used hot method (40oC) and cool method (30oC). Characterization of ethosomes includes observation of shape and size of vesicles by microscopic method and the vesicles were fractionated by centrifugation then entrapment efficiency (% EE) were measured by spectrophotometric method. Then optimazed theophylline that entrapped in ethosome. Based on the results, ethosomes preparation by hot method were produced Small Unilamellar Vesicle (SUV), the size were 0,0522-0,100 µm, and the highest value of % EE was 98.95%, while ethosomes preparation by cold method were produced Small Unilamellar Vesicle (SUV), the size were 0.0522-0.100 μm, and the highest value of % EE was 99.80%. The optimum concentration of theophylline was entrapped in etosom was 0.1%. It was concluded that cold method was the appropriate method for preparation of theophylline in ethosome as vesicular carrier.Keywords: Etosome, theophylline, vesicular, transdermal

14-helical β-peptides Elicit Toxicity againstC. albicansby Forming Pores in the Cell Membrane and Subsequently Disrupting Intracellular Organelles

SummarySynthetic peptidomimetics of antimicrobial peptides are promising as antimicrobial drug candidates because they promote membrane disruption and exhibit greater structural and proteolytic stability. We previously reported selective antifungal 14-helical β-peptides, but the mechanism of antifungal toxicity of β-peptides remains unknown. To provide insight into the mechanism, we studied antifungal β-peptide binding to artificial membranes and livingCandida albicanscells. We investigated the ability of β-peptides to interact with and permeate small unilamellar vesicle models of fungal and bacterial membranes. The partition coefficient supported a pore-mediated mechanism characterized by the existence of a critical β-peptide concentration separating low and high partition coefficient regimes. Live cell intracellular tracking of β-peptides showed that β-peptides translocated into the cytoplasm, and then disrupted the nucleus and vacuole sequentially, leading to cell death. This understanding of the mechanisms of antifungal activity will facilitate design and development of peptidomimetic AMPs, including 14-helical β-peptides, for antifungal applications.Graphical Abstract

Application of (1)H and (31)P NMR to topological description of a model of biological membrane fusion: topological description of a model of biological membrane fusion.

The process of biological membrane fusion can be analysed by topological methods. Mathematical analysis of the fusion process of vesicles indicated two significant facts: the formation of an inner, transient structure (hexagonal phase - H(II)) and a translocation of some lipids within the membrane. This shift had a vector character and only occurred from the outer to the inner layer. Model membrane composed of phosphatidylcholine (PC), phosphatidylethanolamine (PE) and phosphatidylserine (PS) was studied. (31)P- and (1)H-NMR methods were used to describe the process of fusion. (31)P-NMR spectra of multilamellar vesicles (MLV) were taken at various temperatures and concentrations of Ca(2+) ions (natural fusiogenic agent). A (31)P-NMR spectrum with the characteristic shape of the H(II) phase was obtained for the molar Ca(2+)/PS ratio of 2.0. During the study, (1)H-NMR and (31)P-NMR spectra for small unilamellar vesicle (SUV), which were dependent on time (concentration of Pr(3+) ions was constant), were also recorded. The presence of the paramagnetic Pr(3+) ions permits observation of separate signals from the hydrophilic part of the inner and outer lipid bilayers. The obtained results suggest that in the process of fusion translocation of phospholipid molecules takes place from the outer to the inner layer of the vesicle and size of the vesicles increase. The NMR study has showed that the intermediate state of the fusion process caused by Ca(2+) ions is the H(II) phase. The experimental results obtained are in agreement with the topological model as well.