Sodium Alginate Formulations Research Articles

Novel dry powder preparations of whole inactivated influenza virus for nasal vaccination

The purpose of these studies was to enhance mucosal and systemic antibody production in response to increased local residence time of a whole inactivated influenza virus administered as a dry powder nasal vaccine formulation. Spray-freeze-drying (SFD) particles suitable for nasal delivery were characterized for physico-chemical properties and stability. Mucoadhesive compounds (MA) were characterized for their effects on nasal residence time of vaccine powders in rats compared with published in vitro data and elicited immune responses. SFD particles (D(50) = 26.9 microm) were spherical with a specific surface area of 1.25 m(2)/g. Thermal analysis indicated SFD powders were amorphous and demonstrated improved stability with respect to liquid formulations under various storage conditions. In vitro physico-chemical studies and in vivo scintigraphic imaging experiments indicated sodium alginate (SA) and carboxymethylcellulose-high molecular weight (CMC-HMW) powder formulations most significantly increased residence time in Brown Norway rats. Intramuscular delivery provided equivalent serum antibody titers to intranasal (IN) powder without MA, in the presence of CMC-HMW, SA, and hydroxypropyl methylcellulose (HPMC-HMW) after initial dosing and all formulations except IN powder with chitosan after boosting. IN liquid provided equivalent serum antibody titers to all IN powders after the initial vaccination and significantly greater serum antibody titers than IN powder with chitosan after boosting. Trends were consistent between residence time studies and immune response; however, no statistically significant differences between powder and liquid formulations were observed. It was concluded that enhanced serum and mucosal antibody responses were elicited by a dry powder nasal vaccine, specifically, administered in the presence of sodium alginate.

Oral Controlled Release Formulation for Highly Water‐Soluble Drugs: Drug–Sodium Alginate–Xanthan Gum–Zinc Acetate Matrix

An oral controlled release formulation matrix for highly water‐soluble drugs was designed and developed to achieve a 24‐hour release profile. Using ranitidine HCl as a model drug, sodium alginate formulation matrices containing xanthan gum or zinc acetate or both were investigated. The caplets for these formulations were prepared by direct compression and the in vitro release tests were carried out in simulated intestinal fluid (SIF, pH7.5) and simulated gastric fluid (SGF, pH1.2). The release of the drug in the sodium alginate formulation containing only xanthan gum completed within 12 hours in the SIF, while the drug release in the sodium alginate formulation containing only zinc acetate finished almost within 2 hours in the same medium. Only the sodium alginate formulation containing both xanthan gum and zinc acetate achieved a 24‐hour release profile, either in the SIF or in the pH change medium. In the latter case, the caplet released in the SGF for 2 hours was immediately transferred into the SIF to continue the release test. The results showed that the presence of both xanthan gum and zinc acetate in sodium alginate matrix played a key role in controlling the drug release for 24 hours. The helical structure and high viscosity of xanthan gum might prevent zinc ions from diffusing out of the ranitidine HCl–sodium alginate–xanthan gum–zinc acetate matrix so that zinc ions could react with sodium alginate to form zinc alginate precipitate with a cross‐linking structure. The cross‐linking structure might control a highly water‐soluble drug to release for 24 hours. Evaluation of the release data showed the release mechanism for the novel formulation might be attributed to the diffusion of the drug.

The Macromolecular Polymers for the Preparation of Hydrodynamically Balanced Systems—Methods of Evaluation

Evaluation of macromolecular polymers used as excipients for the preparation of hydrodynamically balanced systems (HBS) was carried out. Hard gelatine capsules were filled with polymeric substances belonging to various chemical groups (chitosan, sodium alginate, hydroxypropylmethycellulose—HPMC). The following properties of the HBS were investigated: density, hydration, erosion and floating force. The solvent penetration process into the HBS was visualized using magnetic resonance imaging (MRI) technique. Densities of the HBS in hydrochloric acid (0.1 M) ranged from 0.37 g/cm3 to 0.71 g/cm3. Each polymer demonstrated different hydration/erosion abilities and floating properties. The maximum floating force (Ffloat max) for capsules size 0, ranged from 26.7 mN (sodium alginate) to 64.7 mN (chitosan). HBS formulations also varied in time to reach maximum floating force (Tfloat max). HPMC and sodium alginate formulation reached Ffloat max within half an hour after immersion, while in the case of chitosan formulations (deacetylation degree (d.d.) 66% and d.d. 93%), the time was 184 minutes and 218 minutes respectively. The floating properties of the dosage forms were reliant on type of the polymer and the medium—fasted state simulated gastric fluid (FaSSGF) or fed state simulated gastric fluid (FeSSGF). The size of the HBS influenced the floating force value. The mechanisms of erosion and swelling of the polymeric matrices play a dominant role in flotation of the dosage forms.

Oral sustained delivery of paracetamol from in situ-gelling gellan and sodium alginate formulations

The purpose of this study was to evaluate the potential for the oral sustained delivery of paracetamol of two formulations with in situ gelling properties. Oral administration of aqueous solutions of either gellan gum (1.0%, w/v) or sodium alginate (1.5%, w/v) containing calcium ions in complexed form resulted in the formation of gel depots in rabbit and rat stomachs as a consequence of the release of the calcium ions in the acidic environment. In vitro studies demonstrated diffusion-controlled release of paracetamol from the gels over a period of 6 h. The bioavailability of paracetamol from the gels formed in situ in the stomachs of rabbits following oral administration of the liquid formulations was similar to that of a commercially available suspension containing an identical dose of paracetamol.

Evaluation of antagonistic strains of Fusarium spp. in the biological and integrated control of Fusarium wilt of cyclamen

The ability of antagonistic strains of Fusarium spp. to control Fusarium wilt of cyclamen caused by Fusarium oxysporum f. sp. cyclaminis was tested under glasshouse conditions over three years. Several antagonistic strains of F. oxysporum and one strain of F. moniliforme, applied alone or in mixtures, were able to decrease significantly ( p = 0.05) the incidence of Fusarium wilt. Biological control was consistent especially when the antagonists were applied both by mixing a chlamydospore talc preparation in the potting substrate (3 × 10 4–5 × 10 5 CFU/ml of soil) two weeks before transplant and by dipping plant roots at transplant in a conidial suspension (1 × 10 7–5 × 10 8 CFU/ml). The combination of the benzimidazole fungicide carbendazim and antagonistic Fusarium spp. generally increased the efficacy of control. Carbendazim (0.5 mg a.i./ml of substrate) proved most effective in reducing or delaying the appearance of Fusarium wilt symptoms when the dosage was split into two applications, one at transplant and one 2 months later. Sodium alginate and kaolin formulations of F. oxysporum antagonistic strain 251/2 were not effective in reducing Fusarium wilt on cyclamen, while the same strain applied as chlamydospores dispersed in talc or as conidial suspension controlled the pathogen. The findings are discussed with respect to the most effective application and formulation methods of biocontrol agents under commercial conditions.