Pharmacokinetic and pharmacodynamic evaluation of Solid self-nanoemulsifying delivery system (SSNEDDS) loaded with curcumin and duloxetine in attenuation of neuropathic pain in rats.

The present investigation is focused on improving oral bioavailability of poorly soluble and lipophilic drugs, curcumin (CRM) and duloxetine (DXH), through the solid self-nanoemulsifying drug delivery system (S-SNEDDS) and identifying their potential against attenuation of NP in chronic constriction injury (CCI)-induced rats through the solid self-nanoemulsifying drug delivery system (S-SNEDDS). The optimized batch of S-SNEDDS reported was containing CRM and DXH (30 mg each), castor oil (20% w/w), tween-80 (40% w/w), transcutol-P (40% w/w), and syloid 244 FP (1 g). The high dose of each of naïve CRM (NCH), naïve DXH (NDH), physical mixture of DXH and CRM (C-NCM-DXH), S-SNEDDS-CRM (SCH), S-SNEDDS-DXH (SDH), and S-SNEDDS-CRM-DXH (C-SCH-SDH) was subjected for MTT assay. The developed formulations were subjected to pharmacokinetic studies and results showed about 8 to 11.06 and 2-fold improvement in oral bioavailability of CRM and DXH through S-SNEDDS. Furthermore, CCI-induced male Wistar rats were treated with SSNEDDS containing CRM and DXH, S-SNEDDS containing individual drug, individual naïve forms, and their combination from the day of surgery for 14 days and evaluated for behavioral at pre-determined time intervals. On the terminal day, animals were sacrificed to assess tissue myeloperoxidase, superoxide anion, protein, tumor necrosis factor-α, total calcium levels, and histopathological changes. Pronounced effect was observed in rats treated with S-SNEDDS containing both drugs with respect to rats receiving any of other treatments owing to enhanced oral bioavailability through S-SNEDDS. Therefore, it can be concluded that S-SNEDDS of both drugs and their coadministration can accelerate the prevention of NP.

Flavonoids as Potential Therapeutic Agents for the Management of Diabetic Neuropathy.

Flavonoids are secondary metabolites that are widely distributed in plants. These phenolic compounds are classified into various subgroups based on their structures: flavones, flavonols, isoflavones, flavanones, and anthocyanins. They are known to perform various pharmacological actions like antioxidant, anti-inflammatory, anticancer, antimicrobial, antidiabetic and antiallergic, etc. Diabetes is a chronic progressive metabolic disorder that affects several biochemical pathways and leads to secondary complications such as neuropathy, retinopathy, nephropathy, and cardiomyopathy. Among them, the management of diabetic neuropathy is one of the major challenges for physicians as well as the pharmaceutical industries. Naturally occurring flavonoids are extensively used for the treatment of diabetes and its related complications due to their antioxidant properties. Moreover, flavonoids inhibit various pathways that are involved in the progression of diabetic neuropathy like the reduction of oxidative stress, decrease in glycogenolysis, increase glucose utilization, decrease in the formation of advanced glycation end products, and inhibition of the α-glucosidase enzyme. This review entails current updates on the therapeutic perspectives of flavonoids in the treatment of neuropathic pain. This manuscript explains the pathological aspects of neuropathic pain, the chemistry of flavonoids, and their application in amelioration of neuropathic pain through preclinical studies either alone or in combination with other therapeutic agents.

Comparison of sildenafil, fluoxetine and its co-administration against chronic constriction injury induced neuropathic pain in rats: An influential additive effect.

Current drug treatment available for neuropathic pain (NP) provides meager and partial pain relief due to incomplete efficacy and dose-dependent adverse effect. Hence, combination therapy can provide prolongation in analgesic effect with milder side effects. The present investigation aimed at observing the effects of sildenafil (SD) on Fluoxetine (FLX) in attenuation of chronic constriction injury (CCI) induced NP in rats. CCI was achieved in rats by placing four loose ligations around the sciatic nerve and rats were received respective treatments on SD and FLX till 14 days further behaviors parameters like heat hyperalgesia and allodynia, pin prick and acetone drop test were executed in order to access thermal, mechanical and cold allodynia, respectively, on a predetermined time interval. On the 21st day the animals were sacrificed for determination of total protein, myeloperoxidase activity in the adjoining muscular tissues while glutathione and TNF-α in the sciatic nerve. Co-administration of SD + FLX + CCI gave the pronounced effect that was superior over individual responses of SD and FLX in all behavioral as well as biochemical parameters. It was observed that attenuation in the altered behavioral pattern of CCI induced rats was modified prominently from 3rd day only in a group of rats treated with SD + FLX + CCI. The whole study was finally supported by histopathological results. Finally, it was concluded that SD produces an additive effect when given with FLX in attenuation of NP may be due to elevation in the level of intracellular concentrations of cyclic guanosine monophosphate which further causes downregulation of calcium channel.

A three-pronged formulation approach to improve oral bioavailability and therapeutic efficacy of two lipophilic drugs with gastric lability.

The aim of present study was to co-administer curcumin (CRM) liquisolid pellets and coated duloxetine hydrochloride (DXH) pellets in rats to treat neuropathic pain (NP) associated with chronic constriction injury (CCI). To formulate liquisolid pellets of CRM, it was first dissolved in Tween-80 and then adsorbed on the porous surface of MCC PH102 and Syloid XDP that were used as carrier and coating materials, respectively. Central composite design was used to optimize the liquisolid formulation. The results of powder X-ray diffraction studies, differential scanning calorimetry, and scanning electron microscopy showed complete solubility of drug in Tween-80 followed by its complete adsorption on the porous surface of Syloid XDP and MCC PH102. Both DXH and liquisolid CRM powders were converted into pellets using extrusion-spheronization. DXH pellets were further coated with Eudragit S100 to bypass the gastric pH. About 32.31-fold increase in dissolution rate of CRM present in liquisolid formulation was observed as compared to its unprocessed form. Similarly, the dissolution profile in 0.1 N HCl for Eudragit S100-coated DXH showed complete protection of drug for 2 h and complete release after its introduction in buffer medium (0.2 M phosphate buffer pH 6.8). he pharmacokinetic studies carried out on rats revealed 7.3-fold increase in bioavailability of CRM present in liquisolid pellets and 4.1-fold increase in bioavailability of DXH present in coated pellets was observed as compared to their unprocessed pellets. This increase in bioavailability of drugs caused significant amelioration of CCI-induced pain in rats as compared to their unprocessed forms. The histological sections showed better improvement in regeneration of nerve fibers in rats.

Solidification of liquid Modified Apple Polysaccharide by its adsorption on solid porous carriers through spray drying and evaluation of its potential as binding agent for tablets.

In the present study application of Modified Apple Polysaccharide (MAP) as tablet binder was evaluated. Liquid MAP was extracted from apple and solidified by adsorbing it on porous surface of Aerosil-200 and trehalose and this dispersion was dried using spray dryer. The concentration of excipients as well as spray drying conditions was optimised by using Box Behnken Design to achieve desirable powder characteristics. The optimised batch of solid MAP was characterized by DSC, PXRD, SEM, and FT-IR studies that confirmed complete adsorption of liquid MAP on the surface of Aerosil-200 and trehalose. This solid MAP was investigated for its binding efficacy for tablet formulation and its binding potential was compared with acacia and polyvinyl pyrrolidone K-30. Mesalamine (model drug) granules containing different concentration of binders were prepared by wet granulation. The granules were evaluated for micromeritic properties and results were found within the pharmacopoeial limits. The prepared tablets were subjected for post compression studies such as hardness, friability, disintegration, dissolution, physical stability, content uniformity and percentage elastic recovery and their results were found good. At 2.5% w/w concentration in tablet, the solid MAP has shown shorter disintegration time and faster dissolution profile as compared to other concentrations used including good physico-mechanical properties.