Effect of carboxymethylation on physicochemical, micromeritics and release characteristics of Kyllinga nemoralis starch

Reinvention of starch for oral drug delivery system design

Starch is a polysaccharide with varying amylose-to-amylopectin ratios as a function of its biological sources. It is characterized by low shear stress resistance, poor aqueous/organic solubility and gastrointestinal digestibility which limit its ease of processing and functionality display as an oral drug delivery vehicle. Modulation of starch composition through genetic engineering primarily alters amylose-to-amylopectin ratio. Greater molecular properties changes require chemical and enzymatic modifications of starch. Acetylation reduces water solubility and enzymatic digestibility of starch. Carboxymethylation turns starch acid-insoluble and aggregative at low pHs. The summative effects are sustaining drug release in the upper gut. Acid-insoluble carboxymethylated starch can be aminated to provide an ionic character essential for hydrogel formation which further reduces its drug release. Ionic starch can coacervate with oppositely charged starch, non-starch polyelectrolyte or drug into insoluble, controlled-release complexes. Enzymatically debranched and resistant starch has a small molecular size which confers chain aggregation into a helical hydrogel network that traps the drug molecules, protecting them from biodegradation. The modified starch has been used to modulate the intestinal/colon-specific or controlled systemic delivery of oral small molecule drugs and macromolecular therapeutics. This review highlights synthesis aspects of starch and starch derivatives, and their outcomes and challenges of applications in oral drug delivery.

Synthesis and characterization of citrate soft rice starch: A new strategy of producing disintegrating agent for design drug and resistant starch

Assam soft rice starch (ASRS) and Citric acid-esterified Assam soft rice starch (c-ASRS) were studied extensively. FTIR, CHN, DSC, XRD, SEM, TEM and optical microscope studies were performed for native and modified starches. Powder rearrangements, cohesiveness and flowability were studied by the Kawakita plot. Moisture and ash content was around 9 % and 0.5 %. In vitro digestibility of ASRS and c-ASRS produced functional RS. Paracetamol tablets were prepared using ASRS and c-ASRS as granulating-disintegrating agents through wet granulation methods. The prepared tablets' physical properties, disintegrant properties, in vitro dissolution and dissolution efficiency (DE) were performed. The average particle size was obtained at 6.59 ± 0.355 μm and 8.15 ± 0.168 μm for ASRS and c-ASRS, respectively. All the results were statistically significant at p < 0.05, p < 0.01 and p < 0.001. The amylose content was 6.78 %, classifying it as a low amylose type of starch. The disintegration time was reduced with the increasing concentration of ASRS and c-ASRS and facilitated the immediate release of the model drug from the tablet compact to improve its bioavailability. Therefore, the current investigation concludes that ASRS and c-ASRS can be used as novel and functional materials in pharmaceutical industries due to their unique physicochemical attributes. HYPOTHESIS: The central hypothesis of the current work was to develop citrated starch through a one-step reactive extrusion method and investigate its disintegrants property for pharmaceutical tablets. Extrusion is a continuous, simple, high-speed, low-cost, producing very limited wastewater and gas. Characterization was done through different instrumental techniques to confirm successful esterification. The flow properties were evaluated, and tablets were prepared at a different level of ASRS and c-ASRS (disintegrating agent), followed by the evaluation of tablets to confirm the model drug's dissolution and disintegration efficiency. Finally, in vitro digestibility of both ASRS and c-ASRS was analyzed to establish their potential nutritional benefits.

Ampholytic and Polyelectrolytic Starch as Matrices for Controlled Drug Delivery

The potential of the polyampholytic and polyelectrolytic starch compounds as excipients for drug controlled release was investigated using various tracers differing in terms of solubility and permeability. Ampholytic trimethylaminecarboxymethylstarch (TMACMS) simultaneously carrying trimethylaminehydroxypropyl (TMA) cationic groups and carboxymethyl (CM) anionic groups was obtained in one-step synthesis in aqueous media. Trimethylaminestarch (TMAS) and carboxymethylstarch (CMS) powders were also synthesized separately and then homogenized at equal proportions in liquid phase for co-processing by spray drying (SD) to obtain polyelectrolytic complexes TMAS-CMS (SD). Similarly, equal amounts of TMAS and CMS powders were dry mixed (DM) to obtain TMAS:CMS (DM). Monolithic tablets were obtained by direct compression of excipient/API mixes with 60% or 80% drug loads. The in vitro dissolution tests showed that ampholytic (TMACMS) and co-processed TMAS-CMS (SD) with selected tracers (one from each class of Biopharmaceutical Classification System (BCS)), were able to control the release even at very high loading (80%). The presence of opposite charges located at adequate distances may impact the polymeric chain organisation, their self-assembling, and implicitly the control of drug release. In conclusion, irrespective of preparation procedure, ampholytic and polyelectrolytic starch materials exhibited similar behaviours. Electrostatic interactions generated polymeric matrices conferring good mechanical features of tablets even at high drug loading.