Ankit Kumar Yadav

A novel dissolution method for evaluation of polysaccharide based colon specific delivery systems: A suitable alternative to animal sacrifice

The most extensively used test for predicting in-vivo release kinetics of a drug from its orally administered dosage forms is dissolution testing. For polysaccharide based, colon targeted oral delivery systems, the entire path of the gut traversed by the dosage form needs to be simulated for assessing its in-vivo dissolution pattern. This includes the dissolution testing sequentially in simulated gastric fluid (SGF), simulated intestinal fluid (SIF) and simulated colonic fluid (SCF). For SGF and SIF, simple and standardized composition is well-known. However, preparation of SCF requires addition of either the colonic contents of rodents or human faecal slurry. A method is proposed, wherein a mixture of five probiotics cultured in the presence of a prebiotic under anaerobic conditions is able to surrogate the colonic fluid. Release profiles of drug from colon targeted delivery systems in this medium were studied and compared to those generated in the conventionally used media containing rodent caecal contents and human faecal slurry. The results from the three studies were found to be quite similar. These findings suggest that the proposed medium may prove to be useful not only as a biorelevant and discriminatory method but may also help in achieving the 3Rs objective regarding the ethical use of animals.

Effect of co-administration of probiotics with polysaccharide based colon targeted delivery systems to optimize site specific drug release.

Significant clinical success of colon targeted dosage forms has been limited by their inappropriate release profile at the target site. Their failure to release the drug completely in the colon may be attributed to changes in the colonic milieu because of pathological state, drug effect and psychological stress accompanying the diseased state or, a combination of these. Alteration in normal colonic pH and bacterial picture leads to incomplete release of drug from the designed delivery system. We report the effectiveness of a targeted delivery system wherein the constant replenishment of the colonic microbiota is achieved by concomitant administration of probiotics along with the polysaccharide based drug delivery system. Guar gum coated spheroids of sulfasalazine were prepared. In the dissolution studies, these spheroids showed markedly higher release in the simulated colonic fluid. In vivo experiments conducted in rats clearly demonstrated the therapeutic advantage of co-administration of probiotics with guar gum coated spheroids. Our results suggest that concomitant use of probiotics along with the polysaccharide based delivery systems can be a simple strategy to achieve satisfactory colon targeting of drugs.

Solid self-nanoemulsifying drug delivery systems for oral delivery of polypeptide-k: Formulation, optimization, in-vitro and in-vivo antidiabetic evaluation

&NA; Development of self‐nanoemulsifying drug delivery systems (SNEDDS) of polypeptide‐k (PPK) is reported with the aim to achieve its oral delivery. Box‐Behnken design (BBD) was adopted to develop and optimize the composition of SNEDDS. Oleoyl polyoxyl‐6 glycerides (A), Tween 80 (B), and diethylene glycol monoethyl ether (C) were used as oil, surfactant and co‐surfactant, respectively as independent variables. The effect of variation in their composition was observed on the mean droplet size (y1), polydispersity index (PDI) (y2), % drug loading (y3) and zeta potential (y4). As per the optimal design, seventeen SNEDDS prototypes were prepared. The optimized composition of SNEDDS formulation was 25% v/v Oleoyl polyoxyl‐6 glycerides, 37% v/v Tween 80, 38% v/v diethylene glycol monoethyl ether, and 3% w/v PPK. The optimized formulation revealed values of y1, y2, y3, and y4 as 31.89 nm, 0.16, 73.15%, and −15.65 mV, respectively. Further the optimized liquid SNEDDS were solidified through spray drying using various hydrophilic and hydrophobic carriers. Among the various carriers, Aerosil 200 was found to provide desirable flow, compression, disintegration and dissolution properties. Both, liquid and solid‐SNEDDS have shown release of >90% within 10 min. The formulation was found stable with change in pH, dilution, temperature variation and freeze thaw cycles in terms of droplet size, zeta potential, drug precipitation and phase separation. Crystalline PPK was observed in amorphous state in solid SNEDDS when characterized through DSC and PXRD studies. The biochemical, hematological and histopathological results of streptozotocin induced diabetic rats shown promising antidiabetic potential of PPK loaded in SNEDDS at its both the doses (i.e. 400 mg/kg and 800 mg/kg) as compared to its naïve form at both the doses. The study revealed successful formulation of SNEDDS for oral delivery of PPK. Graphical abstract Figure. No caption available.

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.

A Novel Three-pronged Approach for Colon Delivery of Sulfasalazine: Concomitant Use of pH- Responsive, Microbially Triggered Polymers and Liquisolid Technology

OBJECTIVE A major challenge in targeting orally administered drugs to colon is their passage through the long gastrointestinal path comprising highly variant conditions in terms of pH, viscosity, gut motility and microbial flora. Approaches to pH controlled release and microbially triggered release have proved to be successful in achieving colon targeting only to a partial extent. METHODS In an attempt to improve targeting, both these approaches have been combined together with the approach of liquisolid technology which, hitherto, remains unexplored for colon targeting. The combination of these three approaches is being reported for the first time to achieve colon targeting along with a burst release of a Biopharmaceutical Classification System (BCS) Class IV drug at the target site. pH controlled polymer, Eudragit® S-100 was used to prevent the release of sulfasalazine in the gastric region while microbially triggered polymers, pectin and guar gum were used to ferry the system through the intestinal region. RESULTS Liquisolid formulation was designed to provide a burst release of sulfasalazine in colon on the digestion of polysaccharide coating. CONCLUSION The results support the premise that the combination of pH sensitive, microbially triggered polymers and liquisolid formulation technique appears to be a pragmatic approach for colonic delivery of orally administered drugs.

Novel biorelevant dissolution medium as a prognostic tool for polysaccharide-based colon-targeted drug delivery system

To overcome the limitations of the conventionally used methods for evaluation of orally administered colon-targeted delivery systems, a novel dissolution method using probiotics has been recently reported. In the present study, universal suitability of this medium composed of five different probiotics is established. Different delivery systems – mini tablets, liquisolid compacts, and microspheres coated with different polysaccharides – were prepared and subjected to sequential dissolution testing in medium with and without microbiota. The results obtained from fluid thioglycollate medium (FTM)-based probiotic medium for all the polysaccharide-based formulations showed statistically similar dissolution profile to that in the rat and goat cecal content media. Hence, it can be concluded that the developed FTM-based probiotic medium, once established, may eliminate the need for further animal sacrifice in the dissolution testing of polysaccharide-based colon-targeted delivery system.

In-vitro and In-vivo Pharmacokinetic Evaluation of Guar Gum-Eudragit® S100 Based Colon-targeted Spheroids of Sulfasalazine Co-administered with Probiotics

BACKGROUND Polysaccharide based delivery systems have been successfully used to target drugs to colon. In some recent reports, the superiority of concomitant administration of probiotics with such systems has been established. However, the pharmacokinetics of such symbiotic therapy remain unexplored hitherto. METHODS This study deciphers the pharmacokinetic parameters of guar gum based colon targeted spheroids of sulfasalazine with co-administration of probiotics in experimental rats. Thirty rats were divided into five groups using Latin square design. These were subjected to treatment with delayed release formulation, uncoated spheroids, coated spheroid and coated spheroids along with probiotics. RESULTS In case of delayed release formulation, negligible presence of sulfasalazine in plasma was observed in first 2h, followed by significant increase in sulfasalazine concentration after 3h. Higher plasma concentrations of sulfasalazine were detected for uncoated spheroids with and without probiotics. Negligible release of drug upto 5h and delayed Tmax in case of guar-gum coated sulfasalazine spheroids with or without probiotics clearly indicated successful formulation of colon targeted spheroids. Further, for coated spheroids (both with and without probiotics), the value of Tmax is found to be significantly higher than those with the other treatments. CONCLUSION Colon targeted spheroids were therefore, found to reduce absorption of drug which, in turn, is expected to reduce the side effects as only local action in colon is required for treatment of colitis. This is the first report on pharmacokinetic study of a colon targeted delivery system co-administered with probiotics.