Application of surface ionization methods for highly sensitive and selective analysis of benzodiazepine derivatives

Khasanov, U.; Расулев, У. Х.; Usmanov, Dilshadbek T.; Iskhakova, S. S.; Nabiev, Ulugbek

doi:10.1016/j.jpba.2004.09.026

Cited by 11 publications

(11 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The measuring system is based on the highly efficient selective ionization of caffeine molecules, adsorbed on an emitter surface. By heating this emitter, the molecules became selectively ionized [28]. The lower detection limit of the SI/MS method is 1 ng caffeine ml −1 .…”

Section: Methodsmentioning

confidence: 99%

The role of hair follicles in the percutaneous absorption of caffeine

Otberg

Patzelt

Расулев

et al. 2007

Brit J Clinical Pharma

Self Cite

191

134

View full text Add to dashboard Cite

What is already known about this subject • In recent years, it has been suggested that hair follicles represent important shunt routes into the skin for drugs and chemicals [1–3]. • In vitro studies have shown the importance of skin appendages for skin penetration by hydrophilic compounds [4]. Investigation of follicular penetration in vivo has been difficult due to the absence of appropriate analytical methods or suitable animal model systems. • Recently, a new method was described that quantifies follicular penetration in vivo by using selective closure of hair follicles [5]. • Caffeine is frequently used in skin penetration experiments as a model for highly water‐soluble compounds. Occlusion [6] and skin thickness [7] seem to have little influence on the penetration of caffeine. However, percutaneous absorption rates for caffeine exhibit regional skin differences in humans in vivo[1]. What this study adds • The results of the present study demonstrate that a fast drug delivery of caffeine occurs through shunt routes. Therefore, hair follicles are considerable weak spots in our protective sheath against penetration into the body by hydrophilic substances. • We showed that there is a quantitative distinction between follicular penetration and interfollicular diffusion of caffeine in vivo. • These findings are of importance for the development and optimization of topically applied drugs and cosmetics. In addition, such properties must be considered in the development of skin protection measures. Aims The skin and its appendages are our protective shield against the environment and are necessary for the maintenance of homeostasis. Hypotheses concerning the penetration of substances into the skin have assumed diffusion through the lipid domains of the stratum corneum. It is believed that while hair follicles represent a weakness in the shield, they play a subordinate role in the percutaneous penetration processes. Previous investigation of follicular penetration has mostly addressed methodical and technical problems. Our study utilized a selective closure technique of hair follicle orifices in vivo, for the comparison of interfollicular and follicular absorption rates of caffeine in humans. Methods Every single hair follicle within a delimited area of skin was blocked with a microdrop of a special varnish‐wax‐mixture in vivo. Caffeine in solution was topically applied and transcutaneous absorption into the blood was measured by a new surface ionization mass spectrometry (SI/MS) technique, which enabled a clear distinction to be made between interfollicular and follicular penetration of a topically applied substance. Results Caffeine (3.75 ng ml−1) was detected in blood samples, 5 min after topical application, when the follicles remained open. When the follicles were blocked, caffeine was detectable after 20 min (2.45 ng ml−1). Highest values (11.75 ng caffeine ml−1) were found 1 h after application when the follicles were open. Conclusions Our findings demonstrate that hair follicles are considerable weak spot...

show abstract

Section: Methodsmentioning

confidence: 99%

The role of hair follicles in the percutaneous absorption of caffeine

Otberg

Patzelt

Расулев

et al. 2007

Brit J Clinical Pharma

Self Cite

191

134

View full text Add to dashboard Cite

show abstract

“…Each extract was analyzed by a highly sensitive technique, a mass spectrometer with a surface ionization system (SI/MS) developed at the Arifov Institute of Electronics of the Uzbek Academy of Sciences, Tashkent, Uzbekistan [19] . The detection limit of the SI/MS method for caffeine was 1 ng/ml.…”

Section: Methodsmentioning

confidence: 99%

Follicular Penetration of Topically Applied Caffeine via a Shampoo Formulation

Otberg¹,

Teichmann²,

Rasuljev³

et al. 2007

Skin Pharmacol Physiol

View full text Add to dashboard Cite

Aims: Follicular drug delivery is the prerequisite for an effective treatment of androgenetic alopecia or other reasons of premature hair loss. Methods: The follicular penetration of caffeine, applied topically in a shampoo formulation for 2 min, was measured with highly sensitive surface ionization in combination with mass spectroscopy, a selective method for the detection of very small quantities of transcutaneously absorbed substances in the blood. An experimental protocol, developed to selectively block the follicular pathway within the test area, was used. Based on this principle, a clear distinction between interfollicular and follicular penetration of topically applied caffeine was feasible. Results: After 2 min, caffeine penetrated via the hair follicles and stratum corneum. Conclusion: It was found that the penetration via hair follicles was faster and higher compared with the interfollicular route and that hair follicles are the only pathway for fast caffeine absorption during the first 20 min after application.

show abstract

“…A fragment ion with m/z 242 was a main line in the mass spectrum. The SI mass spectra of obtained under vacuum conditions 32 and by EI except the ion line [M-H] þ are completely different from each other.…”

Section: Medazepammentioning

confidence: 84%

“…In our early work, medazepam was studied by the SI method under vacuum conditions. 32 The SI mass spectrum of medazepam in air atmosphere within the fragmen- Supplementary Fig. 5.…”

Section: Medazepammentioning

confidence: 99%

Examination of the effect of air atmosphere on heterogeneous reactions under surface ionization of psychotropic drug molecules

Khasanov

Iskhakova

Usmanov

2020

Eur J Mass Spectrom (Chichester)

View full text Add to dashboard Cite

The results of mass spectrometric studies of surface ionization of molecules of psychotropic drugs such as chlorpromazine, amitriptyline and medazepam in an air atmosphere have been presented. The channels of heterogeneous reactions occurring during the molecule adsorption on the hot surface of the thermoemitter from refractory metal oxides have been revealed, as well as the influence of air atmosphere on these reactions. A strong influence of the air atmosphere on the heterogeneous association reactions with the emission of [M + H]+ ions has been found. This ion line is the main in the mass spectra of all the substances under study instead of the characteristic main line in the surface ionization mass spectra obtained in vacuum. The effect of air on the reactions of dehydrogenation and dissociation of adsorbed molecules of organic compounds has been insignificant. In the surface ionization mass spectra of all the substances studied under atmospheric conditions the adduct cluster ions М⋅[М−R]+, М⋅[М−Н]+ and М⋅[М+Н]+ (where М is the molecule, R is the radical, H is the hydrogen atom) up to М⋅[М+Н]+⋅HCl. They are probably formed by adhesion of analyte molecules to the primary ions [М−R]+, [М−Н]+ and [М+Н]+. A comparative analysis has been also performed with the data obtained by chromato-mass spectrometry with electron ionization, as well as with the surface ionization data for these preparations obtained under high vacuum.

show abstract

Application of surface ionization methods for highly sensitive and selective analysis of benzodiazepine derivatives

Cited by 11 publications

References 6 publications

The role of hair follicles in the percutaneous absorption of caffeine

The role of hair follicles in the percutaneous absorption of caffeine

Follicular Penetration of Topically Applied Caffeine via a Shampoo Formulation

Examination of the effect of air atmosphere on heterogeneous reactions under surface ionization of psychotropic drug molecules

Contact Info

Product

Resources

About