The kinetics of photostabilization of cyanocobalamin in liposomal preparations

Abstract

Cyanocobalamin (B 12 ) is a photosensitive vitamin, and its photodegradation to hydroxocobalamin (B 12b ) in liposomes has been investigated. The values of apparent first-order rate constants (k obs ) for the photodegradation of B 12 in liposomes (nine preparations) are in the range of (0.52-2.24) × 10 -3 min -1 , compared to 3.21 × 10 -3 min -1 for B 12 in aqueous solution (pH 5.0). The entrapment efficiency of B 12 in liposomes is 26.4-38.8%. The values of k obs show a linear relation with phosphatidylcholine (PC) content in liposomes, indicating the influence of PC in inhibiting the rate of photolysis of B 12 . The value of the bimolecular rate constant for photochemical interaction of B 12 and PC is 0.32 M -1 min -1 , indicating the stabilizing effect of PC on the photolysis of B 12 . The ratio of B 12 stabilization in liposomal preparations is in the range 2-6 compared to that of the unentrapped vitamin The stabilization of B 12 is mediated by a photoinduced charge-transfer B 12 -PC complex that leads to the reduction of B 12 to B 12r , which is then oxidized to B 12b that has low susceptibility to photolysis. The extent of stabilization of B 12 probably depends on the degree of interaction between the two compounds under the reaction conditions, indicated by the loss of B 12 fluorescence.

Cyanocobalamin Ultraflexible Lipid Vesicles: Characterization and In Vitro Evaluation of Drug-Skin Depth Profiles

“…This happens because the entrapment is more efficient if the compound is retained in the phospholipid bilayers, which depends on its primary affinity [ 48 , 81 ]. Arsalan et al reported a maximum entrapment efficacy of 40% in B12 liposomes when maximizing the amount of lipid included during the vesicle formulation [ 40 ]. This result is clearly superior to our L1 data ( Figure 2 a).…”

“…Biomedical research has led to the development of modified lipid vesicles that include surfactants (transfersomes) or ethanol (ethosomes) in their composition, which provide greater flexibility, causing different carrier–skin interactions and thus enhancing skin drug delivery [ 38 , 39 ]. Cyanocobalamin liposomes have already been prepared by Arsalan et al to improve its photostability and by Vitetta et al to achieve systemic absorption after oral administration [ 40 , 41 ].…”

Use of Vitamin B12 as a Nontoxic and Natural Catalyst for the Synthesis of Benzoxazoles via Catechols and Primary Amines in Water under Aerobic Oxidation

“…On the basis of previous reports, ,,− we proposed mechanistic details for the formation of C–N and C–O bonds. According to the articles reported in recent years, cyanocobalamin as a vitamin B 12 is converted to hydroxycobalamin in the presence of heat, water, and oxygen. ,,, …”

“…According to the articles reported in recent years, cyanocobalamin as a vitamin B 12 is converted to hydroxycobalamin in the presence of heat, water, and oxygen. 20,68,72,73 The central cobalt cation in vitamin B 12 forms has an oxidation state of +3. Co(II) and hydroxyl radical are generated as a result of the homolytic cleavage of hydroxycobalamin.…”

Vitamin B12 in Foods, Food Supplements, and Medicines—A Review of Its Role and Properties with a Focus on Its Stability

“…Unfortunately, the conditions used did not allow for the observation of the stabilizing effect of B 12 nanoencapsulation, while the stabilization effect of nanoencapsulation was observed for vitamin C. Maiorova et al emphasized the applicability of nanosystems as carriers for CNCbl by the development and evaluation of nanoengineered polymer capsules and lyotropic liquid-crystalline nanosystems [258]. The incorporation of vitamin B 12 into liposomes has also been shown as an effective approach for its protection from the effect of destabilizing factors [259][260][261]. Liposomes are closed spherical vesicles with a unique structure, composed of a phospholipid bilayer, enabling vitamin B 12 incorporation inside the center aqueous phase, which protects it from degradation.…”