Betamethasone valerate (BV or BET), also called betamethasone 17-valerate [2], is a commonly used anti-inflammatory corticosteroid, used to manufacture dermatological drug products for topical applications [3] [1]. Its IC50 in normal rats is 3.4±0.5 nM [4].  BV can reduce glucose-6-phosphate dehydrogenase (G-6-PDH) activity in vitro [5].
G-6-PDH (EC.1.1.1.49) is an enzyme that catalyzes the first step in the pentosephosphate pathway [6].
The presence of BV at a concentration of 4.6 mM/l provoked a still further diminuition of the G-6-PDH-activity of human skin homogenates that followed the incubation for 120 min at 37°C in media containing 5% dimethylformamide and in which the concentration of G-6-PDH changed from about 55 mU/ml to 9 mU/ml [5].
Compared with sodium cromoglycate (SCG, 80mg daily), treatment of betamethasone valerate (BV, 800μg daily) for 4 weeks made children requiring bronchodilators for perennial asthma significantly require less bronchodilator drugs, and have fewer symptoms and higher daily peak expiratory flow rates [7]. Compared with coal tar (10% LCD) cream, after a 2 week wash-out period, treatment with betamethasone valerate cream (0.1%) twice daily for 6 weeks made patients with stable, mild-moderate plaque psoriasis get more mean reduction of PASI score from baseline. The final effect of betamethasone valerate was significantly greater clearance and improvement [8].
References:
[1]. Hayam Mahmoud Lotfy, Hesham Salem, Mohammad Abdelkawy, et al. Spectrophotometric methods for simultaneous determination of betamethasone valerate and fusidic acid in their binary mixture. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015, 140: 294-304.
[2]. J. Hywel Jones, M. Atkinson, A. Morton Gill, et al. Betamethasone 17-Valerate and Prednisolone 21-Phosphate Retention Enemata in Proctocolitis. British Medical Journal, 1971, 3: 84-86.
[3]. Jayalakshmi Somuramasami, Yu-Chien Wei, Emad F. Soliman, et al. Static headspace gas chromatographic method for the determination of low and high boiling residual solvents in Betamethasone valerate. Journal of Pharmaceutical and Biomedical Analysis, 2011, 54: 242-247.
[4]. Makoto Muramatsu, Makoto Tanaka, Susumu Otomo, et al. Characteristics of Binding of a New Anti-Inflammatory Glucocorticoid, Hydrocortisone 17-Butyrate 21-Propionate (HBP), to Glucocorticoid Receptors of Rat liver. Japan. J. Pharmacol., 1985, 37: 143-150.
[5]. W. P. Raab and B. M. Gmeiner. Inhibition of Glucose-6-Phosphate Dehydrogenase Activity by Betamethasone and Three of its Esters with Dermatological Importance. Arch. Derm. ges., 1975, 253: 113-118.
[6]. Mohamed Amara Camara, Miaomiao Tian, Liping Guo, et al. Application of capillary enzyme micro-reactor in enzyme activity and inhibitors studies of glucose-6-phosphate dehydrogenase. J. Chromatogr. B, 2015, 990: 174-180.
[7]. S. H. Ng, C. H. Dash and Suzanne J. Savage. Betamethasone valerate compared with sodium cromoglycate in asthmatic children. Postgraduate Medical Journal, 1977, 53: 315-320.
[8]. Prasutr Thawornchaisit and Kitiphong Harncharoen. A Comparative Study of Tar and Betamethasone Valerate in Chronic Plaque Psoriasis: A Study in Thailand. J Med Assoc Thai, 2007, 90 (10): 1997-2002.