Degradation mechanism and stability of 5‐aminolevulinic acid

Bunke, A.; Zerbe, Oliver; Schmid, Helene; Burmeister, G.; Merkle, Hans P.; Gander, Bruno

doi:10.1002/1520-6017(200010)89:10<1335::aid-jps11>3.0.co;2-#

Cited by 68 publications

(29 citation statements)

References 17 publications

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“…The direction of the method development was changed into a simplified approach that does not need derivatization. Therefore, low temperature ELS detection was chosen according to physico-chemical properties of ALA (Bunke et al 2000).…”

Section: Methods Developmentmentioning

confidence: 99%

“…Several methods for quantifying 5-ALA in solutions, plasma, body fluids, and skin extracts, such as high performance liquid chromatography (HPLC) with fluorescent detection (Ogasawara et al 2003;Araujo, Thomazine, and Lopez 2010), MS=MS detection , as well as capillary electrophoresis (Bunke et al 2000), have been developed. However, the method of capillary electrophoresis was not validated until the end as it was appointed for the determination of 5-ALA degradation products.…”

Section: Introductionmentioning

confidence: 99%

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Application of HPLC-ELSD for the Quantification of 5-Aminolevulinic Acid after Penetration into Human SkinEx Vivo

et al. 2013

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4Voke Branch, Lithuanian Institute for Agriculture and Forestry, Lithuania 5-Aminolevulinic acid (5-ALA) has been used for treatment of different skin diseases (e.g., skin cancer, actinic keratosis (AK), psoriasis, and acne). The quality of the treatment is directly associated to the amount of 5-ALA that penetrates into skin. 5-ALA was extracted from skin samples after performing the experiment with Bronaugh cells for 4 hours. Two methods were developed by applying different column systems and mobile phase compositions: YMC-Pack Hydrosphere C18 column (250 Â 4 mm, 5 lm) in series with Hichrom Hypersil H5ODS (150 Â 4 mm, 5 lm), mobile phase consisted of 0.1% TFA in water with 2% of ACN (method A); ACE 3AQ column (150 Â 4 mm, 3 lm) eluted with 0.05% TFA in water (method B). Exploratory fluorimetric analysis requiring pre-column or post-column derivatization did not warrant the expectations of simple and effective analysis; therefore, ELS detection for 5-ALA was considered. Parallel chromatography was applied for double-validation of the methods in order to correctly evaluate the possibility of ELSD application for 5-ALA detection and the quantification amount in skin extracts. The retention time and adequate lowest limit of quantification (LLOQ) of 5-ALA were determined in both methods: 5.5 min and 20 lg/ml (method A); 6.2 min and 8.4 lg/ml (method B). Both HPLC-ELSD methods proved to be simple, accurate, precise, reliable, and showed reproducible values in the concentration range of 20-200 lg/ml in human skin extracts.

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Section: Methods Developmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Application of HPLC-ELSD for the Quantification of 5-Aminolevulinic Acid after Penetration into Human SkinEx Vivo

et al. 2013

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“…The studies encompass the effects of pH, concentration, oxygen, and temperature (Novo et al 1996;Elfsson et al 1998;Bunke et al 2000;de Blois et al 2002;Hunter et al 2005; for a review, see Donnelly et al 2007). ALA is stable for years upon storage in solid form as the hydrochloride salt, and at least months upon dissolution in water given that the pH of the resulting aqueous stock solution is quite low (pH~2.3).…”

Section: Handling Of Alamentioning

confidence: 99%

Simple Formation of an Abiotic Porphyrinogen in Aqueous Solution

Lindsey

Ptaszek

Taniguchi

2009

Orig Life Evol Biosph

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Porphyrins have long been proposed as key ingredients in the emergence of life yet plausible routes for forming their essential pyrrole precursor have heretofore not been identified. Here we show that the anaerobic reaction of δ-aminolevulinic acid (ALA, 1-5 mM) with the β-ketoester methyl 4-methoxyacetoacetate (2-40 mM) in water (pH5-7) at 70-100°C for >6 h affords the porphyrinogen, which upon chemical oxidation gives the corresponding porphyrin in overall yield of up to 10%. The key intermediate is the α-methoxymethyl-substituted pyrrole, which undergoes tetramerization and macrocycle formation under kinetic control. The resulting type-I porphyrin bears four propionic acid and four carbomethoxy groups, is distinct from porphyrins (e.g., uroporphyrin or coproporphyrin) derivable from ALA alone via the extant universal biosynthetic path to tetrapyrroles, and is photoactive upon assembly into cationic micelles in aqueous solution. The simple self-organization of eight acyclic molecules into a tetrapyrrole macrocycle, from which a porphyrin is derived that is photoactive in lipid assemblies, augurs well for the spontaneous origin of catalysts and pigments essential for prebiotic metabolism and proto-photosynthesis.

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“…Among these different approaches, the use of liposomes or niosomes as topical drug carriers can offer several advantages, providing a sustained release and acting as permeation enhancer (Fang et al, 2001). In the case of ALA, an additional benefit could be the protection of the molecule, which suffers a rapid degradation in physiological conditions (Bunke et al, 2000). However, in spite of the promising results in improving drug skin penetration, liposomal formulations of ALA exhibited low entrapment efficiency values, together with typical problems of limited stability (Pierre et al, 2001, Kosobe et al, 2005Casas and Batlle, 2006;Fang et al, 2008a and2008b;Oh et al, 2011).…”

Section: Introductionmentioning

confidence: 99%