PKA; PDE
In vitro activity: Bucladesine sodium (also known as Dibutyryl-cAMP) is a cell-permeable PKA activator and a cAMP analog that mimics the action of endogenous cAMP. It is a cyclic nucleotide derivative (structurally similar to cAMP) and is also a phosphodiesterase inhibitor. Dibutyryl-cAMP preferentially activates cAMP-dependent protein kinase. The products releaes butyrate due to intracellular and extracellular esterase action. Butyrate was shown to have distinct biological effects. The compound is used in a wide variety of research applications because it mimics cAMP and can induce normal physiological responses when added to cells in experimental conditions.

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Kinase Assay: Bucladesine sodium (also known as Dibutyryl-cAMP) is a cell-permeable PKA activator and a cAMP analog that mimics the action of endogenous cAMP. It is a cyclic nucleotide derivative (structurally similar to cAMP) and is also a phosphodiesterase inhibitor. Dibutyryl-cAMP preferentially activates cAMP-dependent protein kinase.

In vitro activity: Bucladesine sodium (also known as Dibutyryl-cAMP) is a cell-permeable PKA activator and a cAMP analog that mimics the action of endogenous cAMP. It is a cyclic nucleotide derivative (structurally similar to cAMP) and is also a phosphodiesterase inhibitor. Dibutyryl-cAMP preferentially activates cAMP-dependent protein kinase. The products releaes butyrate due to intracellular and extracellular esterase action. Butyrate was shown to have distinct biological effects. The compound is used in a wide variety of research applications because it mimics cAMP and can induce normal physiological responses when added to cells in experimental conditions.

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Kinase Assay: Bucladesine sodium (also known as Dibutyryl-cAMP) is a cell-permeable PKA activator and a cAMP analog that mimics the action of endogenous cAMP. It is a cyclic nucleotide derivative (structurally similar to cAMP) and is also a phosphodiesterase inhibitor. Dibutyryl-cAMP preferentially activates cAMP-dependent protein kinase.

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A water-free emulsion containing Bucladesine (DB-cAMP) was developed for topical application. The solubility of Bucladesine (DB-cAMP) was determined in various solvents. It was poorly soluble in hydrophobic solvents but showed good solubility in propylene glycol, ethylene glycol, and n-methyl pyrrolidone. The compound was found to be stable when dissolved in n-methyl pyrrolidone, with no observed hydrolysis over 14 days. [3]

Male rats were given either a bilateral infusion of 10 mM or 100 mM of bucladesine, and the results showed a significant reduction in escape latency and distance traveled (indicating improvement in spatial memory) when compared to controls. Male rats' ability to retain spatial memory is enhanced when they receive an infusion of 1 or 5 mM buclodesin minutes after receiving 0.5 mg of nicotine [1]. ChAT and VAChT immunoreactivity in the CA1 region rose significantly when Bucladesine (10 mM/side) and nicotine (0.5 mM/side) were combined. Additionally, there was a considerable increase in the optical density and quantity of ChAT and VAChT immunostaining with nicotine and low-dose Bucladesine therapy. decrease in the rats' escape delay and distance traveled [2]. Following the application of the aqueous solution to the skin-excision site, bucladesine is almost entirely absorbed very quickly. Bucladesine is absorbed more slowly but more quickly in the absence of skin peeling than in the full-thickness abrasion rat model [3]. In a mouse ear edema model caused by arachidonic acid, bucladesine (containing 1.5% emulsion for single or several injections) can considerably reduce inflammatory edema [4].

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Following topical application of a 3% aqueous solution of Buchadesine (30 mg/rat) to rats with intact skin, plasma levels were very low, resulting in a systemic bioavailability of 1.2 ± 0.5%. [2]
When the same 3% aqueous solution was applied to a full-thickness skin abrasion site, Buchadesine was absorbed very rapidly (Tmax = 0.5 h) and almost completely (bioavailability: 93.1 ± 34.3%). [2]
Application of the 3% aqueous solution to stripped skin (stratum corneum removed) resulted in rapid absorption (Tmax = 0.5 h) with a bioavailability of 63.5 ± 14.4%, though the peak plasma concentration (Cmax) was about one-fourth of that in the full-thickness abrasion model. [2]
Topical application of a 3% Buchadesine PEG ointment provided sustained release. When applied to full-thickness abrasions, bioavailability was 31.8 ± 27.4% with a delayed Tmax compared to the aqueous solution. Applied to stripped skin, the PEG ointment resulted in a bioavailability of 10.6 ± 4.1%. [2]
A 3% Buchadesine petrolatum ointment showed very low absorption in both stripped skin (bioavailability: 0.6 ± 1.4%) and full-thickness abrasion models (bioavailability: 3.7 ± 0.7%). [2]
Topical application of Buchadesine bulk powder (30 mg) to stripped skin resulted in rapid and nearly complete absorption (bioavailability: 84.3 ± 18.4%), with a higher Cmax than the aqueous solution. [2]
Formulated powders (PW-1, PW-2, PW-3) applied to stripped skin showed significantly slower and reduced absorption compared to the bulk powder, with bioavailabilities ranging from 2.9% to 13.7%. [2]

PKA assay[5]
Cells were washed twice with 10 mM sodium phosphate buffer, pH 7.4, 0.15 M NaC1, and then scraped from the culture plate in 1 ml of the same buffer. The cells were collected by centrifugation, and then homogenized by brief sonication in cell homogenization buffer [50 mMTris-HC1, pH 7.4, 1 mM EDTA, 1 mM dithiothreitol (DTT), 50 mM leupeptin, and 0.1 mM phenylmethylsulfonyl fluorideI. The particulate fraction was removed by centrifugation in a microcentrifuge at 14,000 rpm at 4°Cfor 20 mm. PKA activity was measured in the supernatant by the method ofRoskoski (1983), using the synthetic peptide substrate Leu-Arg-ArgAla-Ser-Leu-Gly (Kemptide). The reaction mixture of 50 ~.tlcontained cell lysate and a final concentration of 25 mM Tris-HC1 buffer (pH7.4), 5 mM magnesium acetate, 5 mM DTT, 5 mM cAMP, 20 ,~iMKemptide, 0.25 mM isobutylmethylxanthine, and 0.1 mM [y- 32P I ATP (200 cpm/pmol), and, when added, 20 ,uM PKA peptide inhibitor 5-24. Reactions were incubatedfor 10 mm at 30°Candterminated by addition of 50 j.tl of 7.5 mM phosphoric acid. Fifty microliters of the reaction mixture was spotted onto a P81 filter and washed five times with 75 mM phosphoric acid and counted as previously described. The difference in activity in the presence versus absence of PKA peptide inhibitor 5-24 was used to calculate PKA activity.

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PKC assay [5]
Cell lysates were prepared as described for thePKA assay. The reaction mixture of 50 j.el contained cell lysate and a final concentration of 25 mM Tris-HC1 buffer (pH 7.4), 5 mM magnesium acetate, 5 mM DTT, 20 ~.tM synthetic substrate (Pro-Leu-Ser-Arg-Thr-Leu-Ser-Val-Ala-Ala-LysLys), 0.25 mM isobutylmethyixanthine, and 0.1 mM [y32p] ATP (200 cpm/pmol). Reactions were incubated for 10 mm at 30°C,terminated with phosphoric acid, and analyzed as de

The vesicular acetylcholine transporter (VAChT) gene and the choline acetyltransferase (ChAT) gene comprise the cholinergic gene locus. We have studied the coordinate regulation of these genes by cyclic AMP-dependent protein kinase (PKA) in the rat pheochromocytoma cell line PC12 and PC12 PKA-deficient mutants. Both ChAT and VAChT mRNA increased approximately fourfold after treatment of PC12 cells with dibutyryl cyclic AMP (dbcAMP). ChAT and PKA activity were also increased by dbcAMP. The basal levels of ChAT and VAChT mRNAs in the PKA-deficient cell lines were both about six times lower than in wild-type PC12 cells, and were induced less than twofold by addition of dbcAMP. H-89 and H-9, specific inhibitors for PKA, reduced ChAT and VAChT mRNA levels to approximately one-third that of untreated cells and ChAT activity to approximately one-fourth that of untreated PC12 cells. Activation of PKA type II, but not PKA type I, increased ChAT activity approximately threefold. Analysis of reporter gene constructs indicates that PKA affects gene transcription at an upstream site in the cholinergic gene locus. These results demonstrate that the expression of the ChAT and VAChT genes is regulated coordinately at the transcriptional level, and a signaling pathway specifically involving PKA II plays an important role in this process[5].

For topical administration of bucladesine as 5% solution, 20 μl of drug or vehicle solution was administered onto the outer surface of both, left and right ears each, 60 min prior to arachidonic acid challenge. The inflammatory response was induced by administration of 20 μl arachidonic acid (Sigma-Aldrich, Munich, Germany; 5% in acetone) on the outer surface of left ears. The right ears were treated with acetone only to determine the individual differences in ear thicknesses.Na ve male Albino Swiss mice

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Percutaneous Absorption Study in Rats: Male Sprague-Dawley rats (8 weeks old) were used. Abdominal hair was shaved 16 hours prior to the experiment. Rats were anesthetized and fixed. Three skin conditions were created: 1) Normal intact skin. 2) Stripped skin: The stratum corneum was removed by repeated adhesive tape stripping (20 times). 3) Full-thickness abrasion: The abdominal skin was excised with scissors. A plastic cell (internal diameter 3 cm) was affixed to the application site. Buchadesine (30 mg per rat) was applied as a 3% aqueous solution, a 3% PEG ointment, a 3% petrolatum ointment, bulk powder, or various powder formulations (PW-1, PW-2, PW-3). The cell was sealed. Blood samples were collected from the jugular vein at 0.5, 1, 2, 4, and 8 hours after application. Plasma was separated and stored frozen until analysis. [2]
Intravenous Administration for Pharmacokinetic Parameters: Rats were given a single intravenous dose of 3 mg Buchadesine as an aqueous solution. Blood samples were collected periodically for 8 hours to determine baseline pharmacokinetic parameters. [2]

Following a single intravenous injection of Buchadesine (3 mg) into rats, plasma concentrations decreased exponentially. [2] The elimination rate constant (ke) was 8.24 ± 1.25 h⁻¹. [2] The biological half-life was 5.14 ± 0.81 minutes. [2] Absolute bioavailability after topical administration was calculated as the ratio of the area under the plasma concentration-time curve (AUC) for transdermal administration to the AUC for intravenous administration. [2] The bioavailability of 3% aqueous solution applied to normal skin, abraded skin, and full-thickness skin abrasions was 1.2 ± 0.5%, 63.5 ± 14.4%, and 93.1 ± 34.3%, respectively. [2] The bioavailability of 3% polyethylene glycol (PEG) ointment applied to normal skin, abraded skin, and full-thickness skin abrasions was 3.2 ± 0.8%, 10.6 ± 4.1%, and 31.8 ± 27.4%, respectively. [2]
The bioavailability of 3% petrolatum ointment applied to normal skin, peeled skin, and full-thickness skin abrasions was 0.0 ± 0.1%, 0.6 ± 1.4%, and 3.7 ± 0.7%, respectively. [2]
The bioavailability of bulk powder and formulated powders (PW-1, PW-2, PW-3) applied to peeled skin was 84.3 ± 18.4%, 13.4 ± 8.1%, 2.9 ± 1.9%, and 13.7 ± 7.3%, respectively. [2]

Literature indicates that bucladixin (DB-cAMP) has excellent safety profile as a topical treatment for wound healing and has been successfully used in clinical practice. No adverse reactions (such as gastrointestinal reactions like nausea) of PDE4 inhibitors have been found in clinical applications. However, one challenge in its formulation is that hydrolysis may produce butyric acid, resulting in an unpleasant odor. The anhydrous emulsion developed in this study was designed to prevent hydrolysis and remained stable during the observation period, with no signs of hydrolysis or increased odor. [3]

[1]. Post-training intrahippocampal infusion of nicotine-bucladesine combination causes a synergistic enhancement effect on spatial memory retention in rats. Eur J Pharmacol, 2007. 562(3): p. 212-20.

[2]. Mafune, E., M. Takahashi, and N. Takasugi, Effect of vehicles on percutaneous absorption of bucladesine (dibutyryl cyclic AMP) in normal and damaged rat skin. Biol Pharm Bull, 1995. 18(11): p. 1539-43.

[3]. The stable cyclic adenosine monophosphate analogue, dibutyryl cyclo-adenosine monophosphate (bucladesine), is active in a model of acute skin inflammation. Arch Dermatol Res, 2012.

[4]. Effect of bucladesine, pentoxifylline, and H-89 as cyclic adenosine monophosphate analog, phosphodiesterase, and protein kinase A inhibitor on acute pain. Fundam Clin Pharmacol. 2017 Aug;31(4):411-419.

[5]. The cholinergic gene locus is coordinately regulated by protein kinase A II in PC12 cells. J Neurochem. 1998 Sep;71(3):1118-26.

Buchadesine (N⁶,2′-O-dibutyryl cyclic 3′,5′ adenosine monophosphate, DBCAMP) is effective in treating chronic skin ulcers, including pressure ulcers. [2] Studies have shown that Buchadesine transdermal absorption is negligible in intact skin but significant in damaged skin, consistent with its intended use in treating ulcers. [2] The formulation carrier has a significant effect on the rate and extent of absorption through damaged skin. Polyethylene glycol (PEG) ointment provides sustained-release properties, which helps to minimize systemic adverse reactions that may result from peak concentrations. [2] The results support clinical observations that PEG ointment may be more effective than petrolatum ointment in treating pressure ulcers due to its superior drug release properties. [2]

C18H24CAN5O8P

509.463624000549

976.219

938448-87-4

Bucladesine sodium;16980-89-5; 362-74-3

44514776

White to off-white solid

2

22

16

65

751

8

CCCC(=O)NC1=C2C(=NC=N1)N(C=N2)[C@H]3[C@@H]([C@H]4[C@H](O3)COP(=O)(O4)[O-])OC(=O)CCC.CCCC(=O)NC1=C2C(=NC=N1)N(C=N2)[C@H]3[C@@H]([C@H]4[C@H](O3)COP(=O)(O4)[O-])OC(=O)CCC.[Ca+2]

DRYMTGFYEAYJQR-NGVPHMJWSA-N

InChI=1S/2C18H24N5O8P.Ca/c2*1-3-5-11(24)22-16-13-17(20-8-19-16)23(9-21-13)18-15(30-12(25)6-4-2)14-10(29-18)7-28-32(26,27)31-14;/h2*8-10,14-15,18H,3-7H2,1-2H3,(H,26,27)(H,19,20,22,24);/t2*10-,14-,15-,18-;/m11./s1

calcium;[(4aR,6R,7R,7aR)-6-[6-(butanoylamino)purin-9-yl]-2-oxido-2-oxo-4a,6,7,7a-tetrahydro-4H-furo[3,2-d][1,3,2]dioxaphosphinin-7-yl] butanoate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.12 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (5.12 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (5.12 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 4: 10% DMSO +ddH2O: 30 mg/mL

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Solubility in Formulation 5: 110 mg/mL (225.22 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)