A convenient pH-gradient method for the determination of the maximum and minimum pH for microbial growth

1966 ◽  
Vol 32 (1) ◽  
pp. 245-255 ◽  
Author(s):  
E. H. Battley ◽  
Elaine J. Bartlett
Keyword(s):  
Gradient Method ◽  
Microbial Growth ◽  
Ph Gradient

Improving Topical Skin Delivery of Monocrotaline Via Liposome Gel-based Nanosystems

2019 ◽  
Vol 16 (10) ◽  
pp. 940-950 ◽  
Author(s):  
Jiandong Yu ◽  
Zhi Chen ◽  
Yan-zhi Yin ◽  
Chaoyuan Tang ◽  
Enying Hu ◽  
...  
Keyword(s):  
Gradient Method ◽  
Encapsulation Efficiency ◽  
Ph Value ◽  
Topical Administration ◽  
Ph Gradient ◽  
Stability Factor ◽  
Buffer Solution ◽  
Skin Delivery ◽  
Skin Retention

Background: In this study, a liposomal gel based on a pH-gradient method was used to increase the skin-layer retention of monocrotaline (MCT) for topical administration. Methods: Using the Box-Behnken design, different formulations were designed to form liposome suspensions with optimal encapsulation efficiency (EE%) and stability factor (KE). In order to keep MCT in liposomes and accumulate in skin slowly and selectively, MCT liposome suspensions were engineered into gels. Results: A pH-gradient method was used to prepare liposome suspensions. The optimal formulation of liposome suspensions (encapsulation efficiency: 83.10 ± 0.21%) was as follows: MCT 12 mg, soybean phosphatidyl choline (sbPC) 200 mg, cholesterol (CH) 41 mg, vitamin E (VE) 5 mg, and citric acid buffer solution (CBS) 4.0 10 mL (pH 7.0). The final formulation of liposomal gels consisted of 32 mL liposome suspensions, 4.76 mL deionized water, 0.40 g Carbopol-940, 1.6 g glycerol, 0.04 g methylparaben, and a suitable amount of triethanolamine for pH value adjustment. The results of in vitro drug release showed that MCT in liposomal gels could be released in 12 h constantly in physiological saline as a Ritger-Peppas model. Compared with plain MCT in gel form, liposomal MCT in gel had higher skin retention in vitro. Conclusion: In this study, liposomal gels were formed for greater skin retention of MCT. It is potentially beneficial for reducing toxicities of MCT by topical administration with liposomal gel.

scholarly journals Does Non-ionizing Radiant Energy Affect Determination of the Evaporation Rate by the Gradient Method?

1991 ◽  
Vol 96 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Sveinn Kjartansson ◽  
Karen Hammarlund ◽  
Per Åke Öberg ◽  
Gunnar Sedin
Keyword(s):  
Gradient Method ◽  
Evaporation Rate ◽  
Radiant Energy

Simultaneous determination of membrane potential and pH gradient by photodiode array spectroscopy

1986 ◽  
Vol 862 (2) ◽  
pp. 278-284 ◽  
Author(s):  
Tetsuya Konishi ◽  
Naoyuki Murakami ◽  
Yoshihiko Hatano ◽  
Katsuyoshi Nakazato
Keyword(s):  
Membrane Potential ◽  
Simultaneous Determination ◽  
Ph Gradient ◽  
Photodiode Array
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