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Natural polymers are an efficient class of eco-friendly and biodegradable polymers, because they are readily available, come from natural sources, inexpensive and can be chemically modified with the correct reagents. Guar gum (GG) is a natural polymer with great potential to be used in pharmaceutical formulations due to its unique composition and lack of toxicity. GG can be designed to suit the needs of the biological and medical engineering sectors. In the development of innovative drug delivery systems, GG is commonly utilized as a rate-controlling excipient. In this review, different properties of GG including chemical composition, extraction methods and its usefulness in diabetes, cholesterol lowering, weight control, tablet formulations as well as its food application were discussed. The other purpose of this study is to evaluate potential use of GG and its derivatives for advanced nanomedicine such as drug delivery, tissue engineering and nanosensing. It should be noted that some applicable patents in medical area have also been included in the rest of this survey to extend knowledge about guar gum and its polymeric nature.

Nano crystalline cellulose (NCC) modified with cationic surfactant CTAB (N-Cetyl-N, N, N-trimethyl ammonium bromide) proved as effective drug delivery excipient for sustained release of non-steroidal anti-inflammatory drugs (NSAIDs). In the present work, our purpose was to study the effect of another cationic surfactant TBAB (tetra-n-butyl ammonium bromide) used to modify NCC on binding and sustained release of hydrophobic NSAIDs. NCC modified TBAB was characterized by FTIR & TGA analysis. TBAB-NSAID interactions have been assessed using CHEM3D. The sustained release character was monitored by time dependent serum protein protecting and time dependent anti-cathepsins activities. The NCC-TBAB exhibited the binding efficiency for NSAIDs in the range of 42–25% depending upon the hydrophobicity of NSAID and released the drug up to 60 min. The research problem added to the existing knowledge of suitable surfactants required to change the hydrophilic nature of NCC to act as carrier for hydrophobic drugs. TBAB surfactant having shorter alkyl chain length exhibited lower binding efficiency and decreased sustain release of drugs as compared to CTAB having longer alkyl chain length.

The present study was intended to develop a papain grafted S-protected hyaluronic acid-lithocholic acid co-block (PAP-HA-ss-LCA) polymeric excipient as an amphiphilic muco permeating stabilizer for targeting breast cancer epithelial cells overexpressed with CD44 receptors. The mucopermeating, stabilizing and targeting capability of the PAP-HA-ss-LCA polymeric excipient was investigated by manufacturing tamoxifen (TMX) loaded self-nanoemulsifying drug delivery system (SNEDDS). TMX loaded PAP-HA-ss-LCA incorporated SNEDDS (TMX-PAP-HA-ss-LCA SNEDDS) were characterized for their surface chemistry, drug release, permeation enhancement, biocompatibility and antitumor activity. FTIR spectroscopic analysis showed successful synthesis of PAP-HA-ss-LCA polymer. X-ray diffraction (XRD) showed the amorphous form of TMX inside SNEDDS. The observed hydrodynamic diameter of TMX-PAP-HA-ss-LCA SNEDDS was 367.5 nm. Furthermore, Hyaluronic Acid-based Mucoadhesive Self Nanoemulsifying Drug Delivery System (SNEDDS) of TMX showed homogeneity in synthesis with low polydispersity and negative zeta potential due to stabilization with PAP-HA-ss-LCA polymer. The distinct spherical shape of the nanodroplets was evident by transmission electron microscopy (TEM). In vitro release kinetics indicated approximately >80% release within 48 h under sink conditions. Ex-vivo permeation study displayed 7.11-folds higher permeation of TMX by TMX-PAP-HA-ss-LCA in contrast to pure TMX. The biocompatibility study proved that SNEDDS formulation was safe and compatible against macrophages. In vitro cytotoxicity studies demonstrated that TMX-PAP-HA-ss-LCA SNEDDS could efficiently kill MCF-7 breast cancer cells as compared to the native TMX drug. Systemic toxicity studies proved the non-toxic nature of TMX-PAP-HA-ss-LCA in contrast to pure TMX. Based on these evidences, TMX-PAP-HA-ss-LCA SNEDDS formulation seems to be promising mucopermeating, augmented intracellular uptake with strong targeting potential for anti-proliferative activity.

Nano crystalline cellulose (NCC) has gained attention in the pharmaceutical industry owing to its biodegradable nature and high mechanical properties. In the present work we reported preparation of NCC from cellulose isolated from a bio-waste, its modification and exploration as drug delivery excipient for sustained release of non-steroidal anti-inflammatory drugs (NSAIDs). Cellulose extracted from Citrus limetta albedo was subjected to alkali treatment, bleaching and hydrolysis by sulfuric acid to obtain NCC of particle size ranging from 1 to 10 nm. Further, modification with a cationic surfactant cetyltrimethylammonium bromide (CTAB) resulted in NCC-CTAB with enhanced surface area and high aspect ratio which was investigated as sustained release drug delivery system (DDS) for NSAID. Drug loading capacity correlated well with log P value of NSAID. NSAID-loaded NCC-CTAB acted as sustained release DDS over a period of 3hr. The results were confirmed as serum protein protecting and anti-cathepsins activities. CTAB-NSAID interactions have been assessed using CHEM3D.

In this study, a biological macromolecule obtained from seeds of Manilkara zapota was co-processed with hypromellose (cop-MPH)/sodium carboxymethylcellulose (cop-MPN)/polyvinylpyrrolidone (cop-MPP) in a 1:1 ratio and characterized for powder and mucoadhesive properties. The semi-crystalline nature of co-processed excipients and physical interaction between the component molecules were confirmed by X-ray diffraction and infrared spectroscopy analysis. The morphological study by scanning electron and atomic force microscopy showed spherical and polygonal-shaped particles with predominant smooth surfaces. Thermogravimetric analysis revealed thermal stability to a temperature of 200 °C followed by depolymerization. Zeta potential measurements showed that cop-MPP was anionic, whereas cop-MPH and MPN were non-ionic. Texture analysis revealed that work of adhesion (mN·s) for both cop-MPH (390 ± 0.0018) and MPN (304 ± 0.0024) enhanced the mucoadhesion compared with the un-processed hypromellose (300 ± 0.0019) and sodium carboxymethylcellulose (280 ± 0.0012), whereas cop-MPP (240 ± 0.0028) showed mucoadhesion similar to un-processed polyvinylpyrrolidone (250 ± 0.0022). In addition, the swelling studies showed enhancement in water absorbance for all co-processed excipients. Cytotoxicity against human cells revealed >99% of cell viability. These findings demonstrate that the co-processed biological macromolecule extracted from M. zapota seed could be further explored as an effective alternative drug delivery excipient for pharmaceutical applications.

The use of chitosan as a potential excipient in pharmaceutical formulations for the delivery of drugs produced via direct compression tableting has been investigated. Chitosan, N-cinnamyl substituted O-amine functionalized chitosan (cinnamyl-chitosan) and microcrystalline cellulose (MCC) were formulated, alongside acetaminophen as the active pharmaceutical ingredient (API), and magnesium stearate (Mg-St) as lubricant in a series of formulated blends. A control blend of MCC, acetaminophen (20 wt%) and Mg-St (0.5 wt%) was studied alongside two chitosan-bearing blends, containing 20 wt% chitosan and 20 wt% cinnamyl-chitosan separately. Particle size, shape and morphology of the raw powders were studied along with flowability of both raw powders and formulated powder blends. A single-punch tablet machine was used for tablet compaction. The relationship between tablet hardness and compression pressure was evaluated, while the plasticity factor (PF) and elasticity factor (EF) were derived from force-displacement curves. Disintegration and dissolution studies were also carried out to investigate the drug delivery potential of the blends. Blends containing chitosan and cinnamyl-chitosan possess good compaction properties with high elasticity due to their large particle sizes, and show excellent dissolution properties, releasing >80% API within 30 min. With good mechanical strength and superior drug delivery performance, in addition to its enhanced antibacterial and antioxidative effect gained though chemical modification, cinnamyl-chitosan exhibits potential to be used as a new cost-effective pharmaceutical excipient in direct compression tableting.

The aim of this study was to synthesize novel polymeric excipients forming mucoadhesive films for treatment of vaginal microbial infections. 2-(2-Amino ethyldisulfanyl) nicotinic acid was conjugated with gellan gum via amide bond formation. The structure of the resulting S-protected gellan gum was confirmed by 1H NMR. S-protected gellan gum variants were characterized for thiol content, cytotoxicity, rheological behaviour and film forming capability. Depending on the added amount of AMENA degree of thiolation was 81 ± 13 (S-GG 81) and 174 ± 16 (S-GG 174) μmol/g, respectively. Vaginal films were casted from S-protected gellan gum variants and studied for adherence to vaginal mucosa, drug release and antimicrobial activity. S-protected gellan gum remained biocompatible showing >87% cell viability. S-GG 81 and S-GG 174 exhibited 1.84- and 4.3-fold increased dynamic viscosity in porcine mucus in comparison to unmodified gellan gum, respectively. Compared to gellan gum films, thiol functionalized gellan gum films showed 3-fold improved adhesion on mucosal surface over a period of 3 h along with significant antimicrobial activity. Moreover, S-protected gellan gum provided a sustained release of metronidazole. According to these results, S-protected gellan gum proved to be a promising novel excipient for casting vaginal films, exhibiting strongly improved mucoadhesive and antimicrobial properties.

Pelleted preparations were formulated from sacran (Sac), an anionic, sulfated, carboxyl-containing polysaccharide, which is extracted from the Japanese indigenous cyanobacterium Aphanothece sacrum, and surface-deacetylated chitin nanofibers (SDACNF). The use of this material as an extended-release excipient for tetrahydrocurcumin (THC), a model drug that is used to treat wounds via its radical scavenging ability was examined. The THC used in the study was complexed with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), which increases its water solubility. The radical scavenging activity of the THC/HP-β-CD complex (molar ratio of 1:1) was significantly higher than the values for SDACNF or Sac alone. The rate of release of THC from the Sac/SDACNF pellets containing the THC/HP-β-CD complex decreased with increasing Sac content in the pellet, suggesting that Sac/SDACNF (1:1) and Sac alone pellets function as extended-release excipients for THC. The findings reported here indicate that this can be attributed to the ability of the Sac component to retain fluids, thus extending the effects of the drug. In view of the above experimental outcomes, i.e. wound healing efficacy, fluid absorption, retention and the extended drug release of the system indicates that this preparation, in the appropriate ratios, has the potential for use as a controlled-release drug in wound healing.

This study described the rheological and mucoadhesive properties of one natural water-soluble polysaccharide from Bletilla striata (BSP). The rheological characteristics of BSP in aqueous solutions and BSP mixed with other polymers were investigated under various conditions, including concentration, temperature, pH, and salt addition. Viscometric studies and ex vivo mucoadhesion tests were also conducted to examine the mucoadhesive properties of BSP. Results indicated that BSP behaved as a shear-thinning fluid at various concentrations, and its viscosity decreased at high temperatures. The viscous flow properties of the BSP mixtures changed at high pH (>5.0). Conversely, the viscosity of the BSP solutions was slightly affected by electrolytes. The viscosities of the BSP mixtures with four other commonly used polymers (sodium alginate, sodium carboxymethyl cellulose, hypromellose, and chitosan) were enhanced. The synergistic viscosity of BSP/mucin mixtures increased as BSP concentrations increased, and the maximum value was observed in the SIF medium without enzymes. The adhesive abilities of 5.0% and 10.0% BSP were almost equivalent to that of 0.5% sodium alginate, suggesting that BSP exhibited a certain mucoadhesive property, although it was weaker than that of the other commonly used mucoadhesive materials. BSP showed potential for pharmaceutical excipient applications in bioadhesive drug delivery systems.

Compressed tablet formation from granular drug require binder with Cohesiveness property. Plants mucilage as pharmaceutical excipients are available. In this study, biocompatible date palm mucilage was encapsulated with silver nano particles for sustained drug release to provoke an immune response. Nano formulated mucilage was characterized by UV/VIS, FTIR, XRD, SEM/EDX spectrophotometry. UV/VIS spectra revealed an intense surface plasmon resonance peak at 406 nm for spherical mono dispersed silver nano formulated mucilage resulted from efficient reduction of silver ions to AgNPs. Zeta sizer disclosed the emergence of single peak at 139.7 nm with 100% intensity. Crude mucilage exhibited number of peaks in the region of 4000-500 cm−1 by FT-IR spectroscopy whereas purified as well as nano formulated samples showed somewhat different pattern of peaks in addition to peaks of crude sample. XRD spectra of crude mucilage revealed somewhat regular pattern while purified and modified mucilage displayed irregular structure. In SEM analysis, crude mucilage was appeared as granular that turned into porous network with entangled tiny silver nano spheres. A controlled release of drug levofloxacin hemihydrate was evaluated using crude/ nano formulated mucilage as excipient. Nano formulated mucilage delayed the onset exposure of drug in gastric medium giving recommendations as value added bio binder for drug to the target organ.

AS (Aquasolv) Lignin produced via Liquid Hot Water Pretreatment and Enzymatic Hydrolysis has shown potential as an active pharmaceutical ingredient and/or excipient in solid dosage forms. Moreover, lignin is safe to consume and presents antioxidant and antidiabetic capacity, properties that can add to solid dosage forms in pharmaceuticals. This work aimed to evaluate the performance of tablets produced via direct compression and wet granulation when lignin is used in combination with commercial excipients. In order to find optimal tablet performance, different lignin formulations were assessed, and the concentrations were given by extreme vertices mixture design (13 formulations). The blends were composed of AS Lignin, Microcrystalline Cellulose, and Lactose monohydrate and the optimized blend was found to be 14.53 w/w% of disintegrant, 26.57 w/w% of binder and 58.9 w/w% of AS lignin. This proportion was further used to evaluate the performance of lignin-based tablets in drug release, using Ibuprofen as a drug model (50 w/w% and 70 w/w%) and for comparison of direct compression with wet granulation. Direct compressed tablets resulted in higher drug dissolution rates when compared with wet granulation, nevertheless; both tableting techniques showed promising results for lignin. More than 5 formulations tested in this work are compliant with International Pharmacopoeia regulations for solid dosage pharmaceutical forms, thus AS Lignin shows potential to be used as an excipient in pharmaceutical formulations. INDUSTRIAL RELEVANCE: Industrially, AS Lignin appears as promising excipient in the pharmaceutical technologies as well as boost in the biorefining technologies in the following years. Lignin produced is free of sulfur, can be labelled as clean and environmentally-friendly and in this study, was proven this non-cytotoxic AS lignin can be used for excipients and drug carriers. The findings in this paper showed the use of product formulation for life science purposes, thus stressing one of possibilities for lignin valorization in biorefineries.

Encapsulation of essential oils represents a good strategy to protect and to transform them in free-flowing particles. Core-shell systems containing peppermint essential oil have been obtained by inverse ionotropic gelation. An O/W emulsion composed of essential oil (O) and aqueous CaCl2 solution enriched with hydroxyethylcellulose (W) was dripped in an alginate solution added of a secondary excipient (maltodextrin or shellac gum) at two concentrations. The qualitative/quantitative modifications of capsule shell composition had a limited impact on the essential oil content (it was more than 50% w/w), while they affected other dried capsule properties like dimensions, shell thickness, hardness and swelling behavior. Neither the type nor the amount of secondary excipient influenced wet capsule particle size (about 4 mm). After drying, particle size decreased (it was about 2 mm) and while shellac gum amount did not affect dried capsule dimensions, an increase in maltodextrin amount corresponded to an increase in their diameters. Capsule hardness diminished by increasing the amount of secondary excipient in the formulations. In addition, the amount of maltodextrin included in the formulations affected the swelling behavior of the dried capsules in water and this leads considering maltodextrin a useful excipient to modulate swelling according to the needs of the different applications.

This study focuses on the effect of co-processing on physicochemical and drug release properties of starch mixtures. Different mixtures of native maize and potato starch were pregelatinized for different time intervals. The pregelatinized starch mixture was observed to have higher amylose content than that of native starches. The flow properties of starch mixtures were found to improve after pregelatinization. FTIR and XRD showed changes in structure and crystallinity of native starch due to pregelatinization. The FESEM images showed complete disruption of granular structure of native starch. Native starch was found to be more viscous than pregelatinized starch and all starch samples exhibited Non-Newtonian shear thinning behaviour. The tablets prepared from native starch showed rapid release of drug compared to the modified starches, and increase in the amount of potato starch resulted in sustained drug release. This indicates the utility of pregelatinized starch mixtures with high proportion of potato starch in sustained drug delivery systems.

In this work Cassia obtustifolia seed mucilage isolated and evaluated as novel excipient for drug delivery. Seed mucilage was evaluated qualitatively and quantitatively for presence of polysaccharide. A novel biodegradable film based on mucilage obtained from seeds of Cassia obtustifolia was fabricated and characterized. The microstructure, mechanical and thermal properties of the film were determined. Results of the scanning electron microscopy revealed a smooth and regular surface morphology. DSC and X-ray diffraction studies revealed an amorphous structure of Cassia obtustifolia seed mucilage films. In vitro degradation simulated body fluids and oral acute toxicity studies with high LD50 value of >2 g/kg of body weight demonstrate its safety as excipient. Diclofenac loaded film exhibited sustained drug release due to swelling and diffusion of film. These findings demonstrated that the Cassia obtustifolia seed mucilage had potential to use as film forming excipient with enhanced characteristics for drug delivery application.

The aim of the present study was the development of a novel gellan gum derivative exhibiting mucoadhesive properties for nasal application. Accomplishing this, amino groups have been introduced to the polymeric backbone. The resulting synthesis products were characterized in terms of the amount of attached amino groups, regarding hydration, zeta potential and gel characteristics. Mucoadhesiveness was assessed studying rheological synergism, by rotating cylinder and regarding tensile studies. Next to erythrocyte-/cytotoxicity evaluation, the impact on ciliary beat frequency of nasal epithelial cells was investigated. Results revealed coupling rates up to 1259.50 ± 75.98 μmol/g polymer as well as accelerated hydration of the derivatives. Comparing aminated with unmodified gellan, enhanced mucoadhesion was verified by a 32-fold increase in viscosity of polymer/mucus mixtures and by a 14-fold extended mucosal adhesion time. Tensile studies demonstrated a 9-fold higher total work of adhesion and a 3.75-fold elevated maximum detachment force. Cellular membrane was not seriously impaired. CBF studies proved a reversible inhibition due to the application of the novel derivative. According to the outlined findings, aminated gellan gum can be considered as a promising excipient for nasal dosage forms improving drug bioavailability by superior adhesive features.

Excipient plays an essential role in drug delivery system, which promotes the drug to reach a particular site of action. Excipients directly or indirectly affect the duration and rate of drug release and absorption. In the current study, physicochemical properties, flow properties and release characteristics of native and modified pink potato starches were investigated to determine their excipient characteristics. Amylose content, water holding capacity, swelling and solubility properties were found to increase after pregelatinization and retrogradation. The SEM micrographs reveals the loss of granular structure of native after thermal modification. The FT-IR study confirms the gelatinization characteristics of the pregelatinized starch. X-ray diffraction pattern confirms the reduction of crystallinity after thermal modification. Tablets containing Paracetamol as a model drug showed that native, pregelatinized and modified pink potato starch could be useful for the manufacturing of immediate release formulation.

Starch mixture is an important approach in designing drug delivery system with modulated properties. The aim of the present work is to study the effect of pregelatinization on starch mixture by varying the concentration of palmyrah and maize starch. All the starch mixtures were statistically designed using 32 full factorial design. Further, the mixtures were characterized for physicochemical and drug release properties. The amylose content, water holding capacity (WHC), swelling and solubility power tend to increase with increase in pregelatinization time. The X-ray diffractogram (XRD) confirmed the reduction in crystallinity of starch mixture with increase in pregelatinization time. The FT-IR study confirmed the gelatinization characteristics of the mixture. All the pregelatinized starch mixture exhibited shear-thinning behavior. Micromeritic property of various starch mixture showed the good flow properties. Formulation with this novel excipient system, using paracetamol as model drug indicated its utility for immediate release dosage form.

Antibody formulation often necessitates the protein concentration to be increased above 100 mg/ml, because of the large therapeutic doses of antibodies required and the volume limitations of subcutaneous injections. However, high concentrations of antibody lead to opalescent states in solution, resulting in safety and application problems. In this study, we investigated the effect of additives on opalescence in IgG solutions. Arginine (Arg) was observed to most effectively suppress opalescence in IgG solutions among the additives tested, which included guanidine hydrochloride, NaCl, and other amino acids. Moreover, Arg also suppressed liquid–liquid phase separation (LLPS) of highly concentrated IgG solutions during incubation at low temperature. Comparative analysis showed that the effects of Arg on opalescence and LLPS in IgG solutions result from its unique structure, which comprises an amino acid main chain, a guanidinium group, and a counter ion. These results indicate that Arg has high potency as an excipient in antibody drug formulations for the suppression of opalescence and LLPS as well as protein aggregation.

The premise of the present study was to suitably select or modify the constitution of the polymer matrix to achieve significantly high entrapment of hydrophilic drugs within polymeric nanoparticles (NPs). Glycyrrhizin (GL), the bioactive drug was selected as a representative hydrophilic drug. Ionotropic gelation technique was used for the preparation of glycyrrhizin-loaded NPs. Concentration of polymers were optimized by 3-level factorial design which affected the particle size and encapsulation efficiency. The formulation was subjected to morphological, physiochemical and in vitro drug release studies. Mean particle size of nanoparticles was around 181 nm as estimated with particle size analyzer. TEM observations revealed spherical shape and size in the range of 140-200 nm. Fourier transform-infrared analysis did not reveal any chemical interaction among the drug and polymers used for the nano-formulation. A release study conducted in vitro over a period of 24 h indicated primarily burst release after that controlled release of glycyrrhizin from the formulation. Antibacterial activities of glycyrrhizin, blank chitosan-gum arabic NPs and glycyrrhizin-loaded chitosan-gum arabic NPs were tested against two Gram negative and two Gram positive bacteria. The study demonstrates the benefit of excipient screening techniques in improving entrapment efficiency of a hydrophilic drug.

Increasing demand and considerable attention to the non-conventional sources of starches leads to explore new sources. Starches of Dioscorea (Da1 and Da2) from Jharkhand, North Eastern region of India have been studied for its physicochemical properties. An attempt has been made to study the carboxymethylated derivatives of starches from two varieties of Dioscorea of this region. Different concentration of monochloroacetate was used to study the effect of degree of substitution (DS) on the physicochemical properties of starches. A considerable effect of DS was noticed on the ash content, amylose content, water-holding capacity, swelling and solubility power of carboxymethylated derivatives. Morphological studies showed the increase in the deformation of structure of the starch granule with an increase in the degree of substitution. FTIR confirmed the carboxymethylation reaction. TGA data of carboxymethylated starches revealed the stability to the temperature. Micromeritics of starch powder and granules showed the value which makes these starches to be utilized as an excipient. With the increase in DS, the % release of drug was found to be decreased. This further makes the carboxymethyl derivatives of Dioscorea a good source to be used as an excipient for sustained release formulations.

The objective of the present study was to isolate and evaluate the morphological, physicochemical and drug release properties of starch from the rhizome of Indian Palo (Curcuma angustifolia Roxb.). Morphological study revealed that the shape of the isolated starch varied from oval to elliptical. Isolated starch showed high water-holding capacity. Mineral content and Ash value were found to be very low. Amylose content was found to be 12.12 ± 0.01%. FTIR data confirmed polysaccharide nature of the starch. Swelling and solubility was found to be increase with an increase in the temperature. Initially, paste clarity was high, and gradually it decreased with the increase of storage time. TGA showed that the starch is thermally stable up to 250 °C. In-vitro release study revealed that the starch retarded the release of drug in the acidic pH of the stomach; therefore, it can be used as an excipient in a sustained-release formulation.

The objective of the present research work was to isolate, purify and characterize Cordia dichotoma gum and investigate its disintegration property in oral tablets. The isolated gum was tested for physicochemical characteristics such as solubility, pH (1% w/w in water), swelling index, loss on drying, ash value, bulk and tapped density, Carr's index, Hausner's ratio and angle of repose. The Orodispersible tablets of valsartan were prepared by direct compression method and evaluated for average weight (mg), drug content (%), thickness (mm), hardness (kg/cm(2)), friability (%), wetting time (sec), water absorption ratio (%) and disintegration time (sec). FTIR studies revealed that there was no interaction between drug, gum and other excipients used in the study. The F4 batch with disintegration time 26.34 ± 0.78 s and in vitro release 99.64 ± 0.43% was selected as optimized formulation. This formulation was compared with conventional marketed formulation and was found superior. Batch F4 was subjected to stability studies for three months and was tested for its disintegration time, drug contents and dissolution behaviour. Batch F4 was found stable for three months at accelerated temperature.

Chronotherapeutically programmed hydroxyethylcellulose (HEC) based compression coated doxazosin tablets were prepared and the influence of disintegrants croscarmellose sodium, L-hydroxypropylcellulose (L-HPC), gellan gum on drug release and in vivo performance were investigated. Infrared spectroscopy and differential scanning calorimetric studies did not indicate any excipient incompatibility in the tablets. The disintegrants induced a continuous water influx resulting in a rapid expansion of the membrane. The subsequent formation of fractures into the coats leads to a fast drug release after an initial lag time. Release rates indicated that croscarmellose sodium and L-HPC were directly proportional to their concentration in the formulations. In vitro optimized croscarmellose sodium-HEC matrix showed significantly faster (p0.05) drug release (t90% = 46 min) after an initial lag of 243 min. Disintegrant-HEC blended matrices were found significantly superior (p0.05) in terms of in vitro release and bioavailability in comparison to plain HEC matrices. Drug release kinetics followed modified power law and Weibull model (r0.99). The mechanism involved in release was anomalous transport and super case II transport with matrix swelling. The pulsatile tablets showed no changes either in physicochemical appearance, drug content or in dissolution pattern during its accelerated stability studies.

Lesser usages of native starch has attracted attention in the modification of starch to incorporate its benefits for pharmaceutical application. A work has been carried out to study the influence of carboxymethylation on the morphological, physico-chemical, powder, spectroscopical and drug discharge characteristics of native starch. Various amount of monochloroacetic acid was used to study the influence of degree of substitution (DS) on the diverse characteristics of modified starch. Amylose content was found to be reduced with the increase in degree of substitution. An enhanced degree of structure deformation was observed with the increment in the DS by the help of scanning electron micrographs. The FT-IR spectra established the polysaccharide nature and the carboxymethylation of the chemically modified starch molecules through the new bands at 1602cm-1, and 1418.69cm-1. The stability of carboxymethyl starches pertaining to the temperature has been revealed by thermogravimetric analysis. Micromeritics of carboxymethylated starches shows their effectiveness as excipients in tablet formulation. The delayed % release of the drug, with the rise in degree of substitution from the tablets prepared marks that the carboxymethyl derivatives of Kyllinga nemoralis rhizomes starch may be used as a suitable source of excipient for sustained release formulations.

Seed galactomannans are neutral, heterogeneous polysaccharides widely distributed in nature. The Mannose/Galactose ratios differ from gum to gum, resulting in a change in structure, which in turn, determines the various industrial applications of seed galactomannans. Senna tora (Family: Fabaceae) is a fast growing and spreading under shrub of which seeds, pods and leaves are extensively used for medicinal applications. The seeds have been found to be an alternative source of commercial gums. The present investigation deals with isolation, purification and characterization of galactomannans from the seeds of Senna tora (S. tora). The galactomannan extraction was based on mechanical separation of the endosperm, water dissolution, centrifugation and precipitation with acetone. The polysaccharide obtained from S. tora seeds was characterized by using physicochemical and chromatographic procedures, as well as FTIR, Mass, (13)C NMR and (1)H NMR spectroscopy. The results indicated that the gum has the basic structure of galactomannans with a main chain of (1→4)-linked β-D-mannopyranosyl units to which single α-(1→6)-D-linked galactopyranosyl units are attached through block pattern. The rheological studies indicated that the S. tora gum (1%, w/w) solution possesses pseudoplastic flow. The viscosity and other rheological properties confirmed its suitability as an excipient in the development of sustained release delivery systems.

Chitosan was physicochemically modified for its potential use as a matrix for an implantable antibiotic delivery system that could sustain bactericidal concentrations in the vicinity of an implant or prosthesis. Deacetylation and depolymerization of chitosan were implemented in order to increase the number or accessibility of the reactive amino groups on the polymer backbone for better polymer–drug interaction. The deacetylation process involved reaction of particulate chitosan/depolymerized chitosan with alkali. The rate of deacetylation of chitosan was directly proportional to the reaction temperature up to 80°C; beyond 80°C, rapid degradation of the polymer occurred. The depolymerization of chitosan involved acid digestion of the polymer followed by application of mechanical agitation. This depolymerized product, although water insoluble, possessed a molecular weight that was one to two orders of magnitude lower than that of commercially available chitosans. These products not only exhibited improved reactivity, but also showed increased crystallinity when compared with the parent chitosan. The reactivity was found to be inversely proportional to chitosan’s molecular weight. The depolymerization and deacetylation treatments afforded formation of chitosan having a greater number of amino groups available for interactions with the anionic actives.

A controlled release excipient based on sodium trimetaphosphate (STMP) crosslinked high amylose starch has been examined by 13C CP/MAS NMR. The dry excipient powder is pressed to a hard tablet whose volume increase in H2O runs parallel to the STMP concentration used. The known polymorph resonances of single helix ‘V’ starch (hydrated) and double helix ‘B’ starch (hydrated) both contribute to the spectrum corresponding to the swollen tablet. The wet tablet when loaded with a pharmaceutical agent provides a near zero-order release profile for up to 20 h. The swelling and drug release behaviour is explained in terms of self-assembly of the STMP treated starch nanomolecular particles. These particles are drawn together by “self-assembly” due to formation of amylose double helices as water penetrates the tablet. An optimum level of chemical crosslinking ensures the integrity of the swollen tablet whose sponge-like structure enclosed by a membranous surface is responsible for sustained release.