6-Methoxyflavone antagonizes chronic constriction injury and diabetes associated neuropathic nociception expression.

Neuropathy is a disturbance of function or a pathological change in nerves causing poor health and quality of life. A proportion of chronic pain patients in the community suffer persistent neuropathic pain symptoms because current drug therapies may be suboptimal so there is a need for new therapeutic modalities. This study investigated the neuroprotective flavonoid, 6-methoxyflavone (6MF), as a potential therapeutic agent and gabapentin as the standard comparator, against neuropathic models. Thus, neuropathic-like states were induced in Sprague-Dawley rats using sciatic nerve chronic constriction injury (CCI) mononeuropathy and systemic administration of streptozotocin (STZ) to induce polyneuropathy. Subsequent behaviors reflecting allodynia, hyperalgesia, and vulvodynia were assessed and any possible motoric side-effects were evaluated including locomotor activity, as well as rotarod discoordination and gait disruption. 6MF (25-75 mg/kg) antagonized neuropathic-like nociceptive behaviors including static- (pressure) and dynamic- (light brushing) hindpaw allodynia plus heat/cold and pressure hyperalgesia in the CCI and STZ models. 6MF also reduced static and dynamic components of vulvodynia in the STZ induced polyneuropathy model. Additionally, 6MF reversed CCI and STZ suppression of locomotor activity and rotarod discoordination, suggesting a beneficial activity on motor side effects, in contrast to gabapentin. Hence, 6MF possesses anti-neuropathic-like activity not only against different nociceptive modalities but also impairment of motoric side effects.

The antioxidant N-(2-mercaptopropionyl)-glycine (tiopronin) attenuates expression of neuropathic allodynia and hyperalgesia.

The current pharmacotherapy of neuropathic pain is inadequate as neuropathic pain involves varied clinical manifestations with multifactorial etiology, modulated by a cascade of physical and molecular events leading to different clinical presentations of pain. There is an accumulating evidence of the involvement of oxidative stress in neuropathy, and antioxidants have shown promise in mitigating neuropathic pain syndromes. To explore the evidence supporting this beneficial proclivity of antioxidants, this study investigated the antinociceptive effectiveness of N-(2-mercaptopropionyl)glycine or tiopronin, a well-recognized aminothiol antioxidant, in a refined chronic constriction injury (CCI) rat model of neuropathic pain. Tiopronin (10, 30, and 90 mg/kg, i.p.) and pregabalin (30 mg/kg, i.p.) were administered daily after CCI surgery. The neuropathic paradigms of mechanical/cold allodynia and mechanical/heat hyperalgesia were assessed on days 3, 7, 14, and 21 post-nerve ligation. At the end of study, malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH) levels were estimated in the sciatic nerve, dorsal root ganglion, and spinal cord for assessing the extent of oxidative stress. The expression of neuropathic nociception was attenuated by tiopronin which was observed as a significant attenuation of CCI-induced allodynia and hyperalgesia. Tiopronin reversed the neuronal oxidative stress by significantly reducing MDA, and increasing SOD, CAT, and GSH levels. Pregabalin also showed similar beneficial propensity on CCI-induced neuropathic aberrations. These findings suggest prospective neuropathic pain attenuating efficacy of tiopronin and further corroborated the notion that antioxidants are effective in mitigating the development and expression of neuropathic pain and underlying neuronal oxidative stress.

Isolation and preliminary evaluation of Mulva Neglecta mucilage: a novel tablet binder

ABSTRACT The aim of this study was to evaluate binding potential of Mulva neglecta mucilage (MNM) with subsequent comparison to PVP K30. Eight batches of Diclofenac sodium tablets were prepared by wet granulation technique keeping different concentrations (4, 6, 8 & 10% w/w) of Mulva neglecta mucilage (extracted from leaves of Mulva neglecta) and PVP K30 as standard binder. The granules of formulated batches showed bulk density (g/mL) 0.49 ± 0.00 to 0.57 ± 0.00, tapped density (g/mL) 0.59 ± 0.01 to 0.70 ± 0.01, Carr's index 09.27 ± 0.95 to 19.65 ± 0.59, Hausner's ratio 1.12 ± 0.00 to 1.24 ± 0.01 and angle of repose 30.37 ± 2.90 °C to 36.86 ± 0.94 °C. Tablets were compressed to hardness 7.50 to 7.95 kg/cm2. The tablets showed 0.39 ± 0.02 to 0.39 ± 0.01% friability and 7:20 to 14:00 min disintegration time. Granules and post-compression evaluation revealed that parameters assessed were all found to be within the pharmacopoeial limits. The results (hardness, disintegration and dissolution) proved that Mulva neglecta mucilage has better binding capacity for preparation of uncoated tablet dosage form as compared to PVP K30. Among all the formulations, MN-1 to MN-4 showed slow release as compared to PV-1 to PV-4 and thereby Mulva neglecta mucilage exhibited satisfactory drug release phenomenon tablets of diclofenac sodium.

RESUMO O objetivo deste estudo foi avaliar o potencial de ligação de mucilagem de Mulva neglecta (MNM), com posterior comparação ao PVP K30. Oito lotes de comprimidos de diclofenaco de sódio foram preparados pela técnica de granulação úmida, mantendo diferentes concentrações (4, 6, 8 e 10% w/w) de mucilagem de Mulva neglecta (extraída de folhas de Mulva neglecta) e PVP K30 como ligante padrão. Os grânulos de lotes formulados mostraram densidade aparente (g/mL) 0.49 ± 0.00-0.57 ± 0.00, densidade compactada (g/mL) 0.59 ± 0.01-0.70 ± 0.01, índice de Carr 09.27 ± 0.95-19.65 ± 0.59, a relação de Hausner 1.12 ± 0.00-1.24 ± 0.01 e ângulo de repouso 30.37 ± 2.90 °C a 36.86 ± 0.94 °C. Os comprimidos foram prensados à dureza de 7.50-7.95 kg/cm2. Os comprimidos apresentaram 0.39 ± 0.02-0.39 ± 0.01% friabilidade e 7:20-14:00 min de tempo de desintegração. A avaliação de grânulos e pós-compressão revelou que todos os parâmetros estavam dentro dos limites da farmacopeia. Os resultados (dureza, desintegração e dissolução) provaram que a mucilagem de Mulva neglecta tem maior capacidade de ligação na preparação da forma de dosagem de comprimido não revestido em relação à PVP K30. Entre todas as formulações, MN-1 e MN-4 mostraram liberação lenta em comparação com PV-1 e PV-4 e, assim, a mucilagem de Mulva neglecta exibiu liberação do fármaco satisfatória para os comprimidos de diclofenaco de sódio.