Effect of a 5% naproxen patch on reducing pain caused by separators prior to fixed orthodontic treatment

BACKGROUND: The pain involved in orthodontic treatments may involve inflammatory processes. This study evaluated the effect of using a naproxen patch for pain reduction in the separating stage of fixed orthodontic treatment. METHODS: In this double-blind, randomized, controlled clinical trial of 35 orthodontic patients (age: 14–19 years) who had pain during separator placement, each patient randomly placed naproxen and placebo patches in the first permanent molar region, in opposite quadrants of the same jaw. Patches were replaced every 8 hours until 3 days after separator placement. Patients recorded their pain perception at 2, 6, and 24 hours, and on days 2 (6 PM), 3 (10 AM and 6 PM), and 7 (10 AM and 6 PM), using a visual analog scale. Mean pain scores were compared for the two patches, and effects of sex and age thereon determined. RESULTS: Data from 29 patients (21 girls, eight boys) were analyzed. Mean pain values decreased over time for both patches (P < 0.001). Recorded pain did not differ significantly between the sexes (P = 0.059) or between those aged <16 and those ≥16 years (P = 0.106). Mean pain recorded with naproxen patches was statistically significantly less than that with placebo patches at all time points (P = 0.004). CONCLUSION: The naproxen patch was more efficient than the placebo patch for reducing pain at all time points. The highest pain score was recorded at 6 hours, and the least pain was recorded at the 7th day after separator placement.

Traditional and modern aspects of hemorrhoid treatment in Iran: a review / 中西医结合学报

Hemorrhoidal disease is a prevalent anorectal condition which is generally not managed well with current pharmacologic interventions. However, in Iranian traditional medicine (ITM) there are numerous plants with hemorrhoid-healing properties. The present research assembled plants with hemorrhoid-healing properties in ITM; their related pharmacological effects, phytochemical constituents and mechanisms of action in the modern medicine were also gathered. For this purpose, leading ITM textbooks were searched for plants with hemorrhoid-healing effects. Further, in vitro, in vivo and clinical studies on the most cited species were considered using scientific databases. Studying ITM textbooks revealed 37 medicinal plants with hemorrhoid-healing effects. Among the mentioned herbal medicines, six species, including Allium ampeloprasum, Phyllanthus emblica, Aloe vera, Terminalia chebula, Vitis vinifera and Commiphora mukul, had the largest number of related pharmacological effects documented in scientific databases. These herbs from ITM should be considered as important resources for producing novel drugs for hemorrhoid treatment.

simple and specific stability- indicating RP-HPLC method for routine assay of adefovir dipivoxil in bulk and tablet dosage form

A simple and reliable stability-indicating RP-HPLC method was developed and validated for analysis of adefovir dipivoxil [ADV].The chromatographic separation was performed on a C[18] column using a mixture of acetonitrile-citrate buffer [10 mM at pH 5.2] 36:64 [%v/v] as mobile phase, at a flow rate of 1.5 mL/min. Detection was carried out at 260 nm and a sharp peak was obtained for ADV at a retention time of 5.8 +/- 0.01 min. No interferences were observed from its stress degradation products. The method was validated according to the international guidelines. Linear regression analysis of data for the calibration plot showed a linear relationship between peak area and concentration over the range of 0.5-16 micro g/mL; the regression coefficient was 0.9999 and the linear regression equation was y = 24844x-2941.3. The detection [LOD] and quantification [LOQ] limits were 0.12 and 0.35 micro g/mL, respectively. The results proved the method was fast [analysis time less than 7 min], precise, reproducible, and accurate for analysis of ADV over a wide range of concentration. The proposed specific method was used for routine quantification of ADV in pharmaceutical bulk and a tablet dosage form

Preparation and characterization of rifampin loaded mesoporous silica nanoparticles as a potential system for pulmonary drug delivery

The goal of this research is to determine the feasibility of loading rifampin into mesoporous silica nanoparticles. Rifampin was selected as a model lipophilic molecule since it is a well-documented and much used anti tuberculosis drug. The mesoporous silica nanoparticles were prepared by using tetraethyl ortho silicate and cetyltrimethyl ammonium bromide [as surfactant]. The prepared nanoparticles were characterized in terms of their particle size measurement and porosimetry. The results showed that the particle size is 218 +/- 46 nm [mean +/- SD] and surface area is 816 m[2]g[-1]. In order to load rifampin within the mesopores, adsorption experiments using three different solvents [methanol, water and dimethyl sulfoxide] were carried out. The loading procedure resulted in a significant improvement in the amount of rifampin loaded into mesoporous silica nanoparticles and methanol was found to be a suitable solvent, providing a drug entrapment efficiency of 52 %. Rifampin loaded nanoparticles underwent different in-vitro tests including, SEM and drug release. The in-vitro drug release was investigated using buffer phosphate [pH=7.4]. Regarding the drug release study, a biphasic pattern of release was observed. The drug-loaded mesoporous silica nanoparticles were capable of releasing 95% of their drug content after 24 h, following a faster release in the first four hours. The prepared rifampin loaded nanoparticles seem to have potential for use as a pulmonary drug delivery

Preparation and in-vitro evaluation of rifampin-loaded mesoporous silica nanoaggregates by an experimental design

The goal of this research is preparation, optimization and in-vitro evaluation of rifampinloaded silica nanoparticles in order to use in the pulmonary drug delivery. Nanoparticles are exhaled because of their small size. Preparation of nanoaggregates in a micron-size scale and re-dispersion of them after deposition in the lung is an approach to overcome this problem. We used this approach in our research. Rifampin was selected as a model lipophilic molecule since it was a well-documented and much used anti tuberculosis drug. A half factorial design was used to identify significant parameters of the spray drying process. The results showed that feed concentration, feed pH and the interaction between feed flow rate and gas atomizer flow rate had statistically significant effects on the particle size of nanoaggregates. The Box-Behnken design was employed to optimize the spray drying process. Finally, a quadratic equation which explains the relation between independent variables and aerodynamic diameter of nanoaggregates was obtained. Rifampin-loaded silica nanoaggregates underwent different in-vitro tests including: SEM, Aerosol performance and drug release. The in-vitro drug release was investigated with buffer phosphate [pH=7.4]. Regarding the drug release study, a triphasic pattern of release was observed. The rifampin-loaded silica nanoaggregates were capable of releasing 90% drug content after 24 h in combination patterns of release. The prepared rifampin-loaded nanoaggregates seem to have a potential to be used in a pulmonary drug delivery

Design and evaluation of ocular controlled delivery system for diclofenac sodium

Diclofenac sodium as ophthalmic dosage form is used for the treatment of the pain, swelling and redness of patients' eyes recovering from cataract surgery; however, it faces the bioavailability limitation of eye drops due to effective protective mechanisms and corneal barrier functions in the eyes. Therefore, this investigation was aimed to develop ocular film formulations to achieve controlled drug release. Drug films were prepared using polymers, namely hydroxypropyl methylcellulose [HPMC] and polyvinyl pyrrolidone [PVP], Eudragit RL PO, and Eudragit RS PO by solvent casting method considering parameters such as drug: polymer ratio, different polymer combinations as well as plasticizer effect. Ocular films were evaluated for various physicochemical parameters such as physical characters, film thickness, uniformity of weight, drug content, swelling index, mucoadhesion time and in-vitro release study. Ocular films complied with all physicochemical parameters underwent in-vitro release study. Finally, the film formulation with HPMC: Eudragit RS PO 1:1 ratio, Drug: Polymer ratio 1:45 and glycerin as plasticizer showed controlled and prolonged release following the zero order and non-Fickian transport

investigation into the drug release from ibuprofen matrix tablets with ethylcellulose and some poly-acrylate polymers

This study was performed to achieve sustained-release Ibuprofen matrix tablets with a zero-order release kinetic while most of the previous formulations have shown Higuchi release kinetic. Considering the results from previous studies, ethyl cellulose, Carbopol 934P, Carbopol 974P, and Pemulen TR-1 were used at different amounts for preparation of the tablets by direct compression. The release profiles were studied in a two-stage release test using nonlinear regression analysis. Carbopols 934P and 974P could not sustain the release adequately while Pemulen TR-1 had too strong sustaining effect. Therefore, combination formulations were considered and studied. The release profiles of ethyl cellulose formulation and the combination formulation consisting Carbopol 934P and Pemulen TR-1 best fitted in Higuchi model, although the zero-order model was not completely rejected. However, the kinetic model of release from the combination formulation consisting Carbopol 974P and Pemulen TR-1 changed to zero-order indicating the most constant release rate among formulations. This was speculated to be due to some erosion of the gel, as well as some interaction of the hydrophobic chain of Pemulen TR-1 with Ibuprofen. Therefore, this formulation is suggested for directly compressed sustained-release matrix tablets of Ibuprofen with a more constant release rate.

Formulation and In-vitro characterization of sustained release matrix type ocular timolol maleate mini-tablet

The purpose of this study was preparation and evaluation of sustained release matrix type ocular mini-tablets of timolol maleate, as a potential formulation for the treatment of Glaucoma. Following the initial studies on timolol maleate powder, it was formulated into ocular mini-tablets. The polymers investigated in this study included cellulose derivatives [HEC, CMC, EC] and Carbopol971P. Mannitol was used as the solubilizing agent and magnesium stearate as the lubricant. Mini-tablets were prepared by through mixing of the ingredients, followed by direct compression. All the prepared formulations were evaluated in terms of physicochemical tests, including uniformity of weight, thickness, crushing strength, friability and in-vitro drug release. Four groups of formulations were prepared. The presence of different amounts of cellulose derivatives or Carbopol 971P, alone, was studied in group A formulations. In group B formulations, the effect of adding Carbopol 971P alongside different cellulose derivatives was investigated. Group C formulations were made by including mannitol as the solubilizing agent, alongside Carbopol 971P and a cellulose derivative. In group D formulations, mini-tablets were made using Carbopol 971P, alongside two different cellulose derivative. The selected formulation [C1] contained ethyl cellulose, Carbopol 971P, mannitol and magnesium stearate, which showed almost 100% drug release over 5 h. Based on kinetic studies, this formulation was found to best fit the zero-order model of drug release. However, the Higuchi and Hixson -Crowell models also showed a good fit. Hence, overall formulation C1 was chosen as the best formulation

Effect of a combination of omeprazole plus sustained release baclofen versus omeprazole alone on symptoms of patients with gastroesophageal reflux disease [GERD]

Previous studies have reported the efficacy of baclofen in the treatment of Gastroesophageal Reflux Diseases [GERD]. The objective of present study is to evaluate the effect of co-administration of omeprazole 20 mg/d plus sustained Release baclofen [SR baclofen] vs. omeprazole 20 mg/d plus placebo on alleviation of symptoms in patients with a diagnosis of GERD. A prospective, double blind, placebo controlled trial included 60 patients with diagnosis of GERD have been done. Patients were randomly selected to receive either SR baclofen or a placebo in addition to omeprazole 20 mg/d for a period of 2 weeks. Patients were questioned regarding heartburn, regurgitation, chest pain and hoarseness at the base line and after 2 weeks. All patients tolerated the medications and no patients failed to complete the study due to adverse drug reactions. A total of 53 patients completed the study, 25 in SR baclofen and 28 in placebo group. After 2 weeks, 1 patient [4%] in SR baclofen group reported heartburn and regurgitation. However 13[46.4%] and 15 [53.6%] of patients in the placebo group had heartburn and regurgitation respectively. The analysis of the data shows that there is a significant difference between the two groups in heartburn and regurgitation [p < 0.0001, p < 0.0001 respectively]. Statistical analysis revealed a significant difference in two groups regarding total GERD score [p <0.0001]. The results of the present study suggest that a combination of SR baclofen and omeprazole may be a more effective treatment for heartburn and regurgitation than omeprazole alone

Optimization of a method to prepare liposomes containing HER2/Neu-derived peptide as a vaccine delivery system for breast cancer

The purpose of this study was to optimize a method for the encapsulation of P5 peptide, a new designed peptide containing MHC class I epitopes from rat HER2/neu protein, into liposomes as an approach for breast cancer vaccine formulation. The efficiency of liposomal encapsulation of peptides is generally low and development of an optimized method to increase encapsulation efficiency is a big challenge. In this study, P5 peptide was encapsulated into liposomes using the following three different methods based on film-hydration procedure. In method A, the lipid film containing P5 was hydrated using buffer and then extruded to 100 nm using polycarbonate filter. In method B all the steps were the same as method A, except that the lipid film was hydrated in buffer containing 10% [v/v] of DMSO and P5 peptide. In method C, P5 peptide was added to preformed liposomes [40 mM] in the presence of ethanol [30% v/v] and incubated at 25 [degree sign]C for 1h. The highest peptide encapsulation efficiency was achieved using method C [44%]. The presence of P5 peptide in purified liposomes was also confirmed using SDS- PAGE analysis. Investigation on the effects of procedure parameters of method C on encapsulation efficiency demonstrated that method is an optimized procedure for encapsulating P5 peptide. Maximal recovery from liposomes for the accurate quantification of peptide was discovered using acidified isopropanol at 1:2 of sample to solvent ratio [v/v]. In conclusion, the optimal methods of encapsulation and peptide content determination in liposomes can accelerate the development of liposomal vaccine formulations

Development and validation of a reversed-phase HPLC method for assay of the decapeptide cetrorelix acetate in bulk and pharmaceutical dosage forms

A gradient reversed-phase high performance liquid chromatography [HPLC] method was developed for the assay of cetrorelix acetate, a synthetic decapeptide with gonadotropin-releasing hormone [GnRH] antagonistic activity used in infertility treatment. The HPLC method, which is used to determine cetrorelix in bulk and pharmaceutical dosage forms, was validated per ICH guidelines. The chromatographic separation was achieved on a C18 reversed-phase column using acetonitrile, water and trifluoroacetic acid [TFA] as mobile phase and wavelength was set at 275 nm. The calibration curve was linear [r[2] = 0.999] over cetrorelix concentrations ranging from 62.50 to 12.50 micro g/mL [n = 6]. The limits of detection [LOD] and quantification [LOQ] were calculated from the peak-to-noise ratio as 15.6 and 62.5 micro g/mL, respectively. The method had an accuracy of > 97% and intra- and inter-day RSD of < 0.3% and < 1.6%, respectively and was validated with excellent specificity, sensitivity, and stability. The validated method was successfully applied for determination of cetrorelix in bulk and pharmaceutical dosage forms

Formulation and in-vitro evaluation of tretinoin microemulsion as a potential carrier for dermal drug delivery

In this study, tretinoin microemulsion has been formulated based on phase diagram studies by changing the amounts and proportions of inactive ingredients, such as surfactants, co-surfactants and oils. The effects of these variables have been determined on microemulsion formation, particle size of the dispersed phase and release profile of tretinoin from microemulsion through dialysis membrane. In released studies, static Franz diffusion cells mounted with dialysis membrane were used. Sampling was conducted every 3 h at room temperature over a period of 24 h. The amount of released drug was measured with UV-spectrophotometer and the percentage of drug released was calculated. Based on the results obtained, the oil phase concentration had a proportional effect on particle size which can consequently influence on drug release. The particle size and the amount of released drug were affected by the applied surfactants. The components of the optimized microemulsion formulation were 15% olive oil, 12% propylene glycol [as co-surfactant], 33% Tween 80 [as surfactant] and 40% distilled water, which was tested for viscosity and rheological behavior. The prepared tretinoin microemulsion showed pseudoplastic-thixotropic behavior. The profile of drug release follows zero order kinetics. The optimized tretinoin microemulsion showed enhanced in-vitro release profile compared to the commercial gels and creams

Precipitation reaction of SDS and potassium salts in flocculation of a micronized megestrol acetate suspension

In this work attempts were made to evaluate K[+]-SDS and hydrocolloid polymer-SDS interactions in flocculation of megestrol acetate dispersions to enhancetheir stability as a part of suspension formulation. Different dispersions of micronized megestrol acetate and SDS were prepared. KCl and KH[2]PO[4] and their corresponding sodium salts were added to the dispersions and the preparations were evaluated using general physicochemical and stability tests including appearance, sedimentation volume, sedimentation rate and redispersibility. Addition of polyols and hydrocolloid polymers to the SDS containing dispersions was also investigated for possible instabilities.SDS deflocculated the initial megestrol acetate dispersions. The use of potassium salts unlike the sodium salts flocculated the dispersion particles due to precipitation reaction of potassium ions and the adsorbed SDS. Additionally the uncharged hydrocolloid polymers MC and HPMC in contrast to the ionic polymers xanthan gum and NaCMC showed incompatibility due to their interaction with SDS. K[+]- SDS interactions have proved useful in protein and DNA analysis studies and we found this precipitation reaction to be applicable in flocculation of pharmaceutical suspensions containing SDS

Development and in-vitro evaluation of a contraceptive vagino-adhesive propranolol hydrochloride gel

The objective of the present investigation was to develop and evaluate a contraceptive vagino-adhesive propranolol hydrochloride gel. To achieve this, various mucoadhesive polymers including guar gum [1-4% w/w], sodium alginate [4-7% w/w], xanthan gum [2-5% w/w], HPMC 4000 [3-5% w/w], Na CMC [4-7% w/w], carbomer 934 and carbomer 940 both in the range of 0.5-2.0% w/w, were dispersed in an aqueous-based solution containing the drug [1.6% w/w]. The mucoadhesive properties of the gels were assessed on sheep vaginal mucosa [as model mucosa] in pH 4.5 citrate-phosphate buffer at 37°C. Formulations containing charged functional groups in their polymeric structure, showed higher mucoadhesive strengths in comparison to those composed of neutral polymers. In-vitro drug release profiles of the gels were determined in pH 4.5 citrate-phosphate buffer. Results indicated that, only formulation F13 [containing sodium alginate 6.5% w/w], could release its drug over 12 h, with a burst release at the initial phase followed by a sustained release pattern. This formulation, which showed a good mucoadhesive strength [386.97 +/- 9.31 mN], was considered as the final formulation and underwent complementary tests including determination of drug content and duration of mucoadhesion. Its drug content was found to be 101.05 +/- 0.106% [n = 3] and it attached to the model mucosa for more than 10 h. In conclusion, formulation F13 was considered as the most desirable formulation as it exhibited appropriate mucoadhesive properties while having the potential of providing an immediate contraceptive effect, followed by a prolonged drug release which is assumed to render longer contraceptive efficacy

Physical and chemical stability of mycophenolate mofetil [MMF] suspension prepared at the hospital

To evaluate the physical and chemical stability of a suspension of mycophenolate mofetil [MMF] prepared in the hospital from commercially available MMF capsules and tablets. Extemporaneous pharmacy was used as a feasible method in this experimental study to prepare suspension form of MMF. Suspension formulations were prepared from both tablets and capsules forms of MMF. Thereafter the stability parameters such as pH, microbial control, thermal and physical stability and particle sizes were evaluated. The amount of MMF, in the suspension was measured at various time points by HPLC. The HPLC method showed that concentration of suspensions prepared from tablets and capsules were 49 mg/mL and 50 mg/mL at time 0, respectively. The effective amount of suspensions prepared from capsules was 101% at time 0, 100% after 7 days, 98% after 14 days, and less than 70% after 28 days. According to the obtained results in this study, capsule-based suspension was stable for as long as 14 days at 5°C. This formulation appears to be clinically acceptable and provides a convenient dosage form for pediatric patients and for adults during the early postoperative period

Fluoxetine competes with cortisol for binding to human serum albumin

Human serum albumin [HSA] is an important protein that carries variety of substances like some hormones and drugs in blood. Pharmacological studies of the interaction of many drugs and HSA are reported during several decades, specially recently years. Interaction of cortisol and fluoxetine hydrochloride [FLX] [as a common anti-stress drug] with HSA [as their carrier in blood] has been studied separately by using different spectroscopic techniques. Here, considering the increment of anti-stress drugs consumption, conformational change of HSA in presence of cortisol and FLX in 50 mM tris buffer, at pH = 7.5 and 37°C, is investigated via pH meter, UV absorption and fluorescence spectroscopy and circular dichroism methods. pH meter findings indicate that the acid denaturation of HSA in the presence of drug and cortisol occurs in the similar manner and this pattern is different relative to the denaturation of HSA in the absence of two reagents. The results of the other techniques consistent with the pH meter findings show that FLX effects on the physiochemical properties of HSA are as that of Cortisol. In-vivo study in Rats confirms in-vitro findings which means blood cortisol level increased in the presence of FLX. Experimental results indicate that FLX and cortisol alter the structural aspects of HSA in similar manner, so, this findings lead to the following reasonable "FLX is a competitive ligand for the binding of cortisol to HSA. Binding of FLX to HSA interferes to the interaction of cortisol-HSA"

release behavior and kinetic evaluation of diltizem HCI from various hydrophilic and plastic based matrics

In this study, the effects of various hydrophilic [HPMC and Carbopol 971] and plastic [Ethylcellulose and Eudragit RL100] polymers on the release profile of diltiazem HCl from matrix tablets were evaluated in-vitro. For this purpose, tablets containing 60 mg of diltiazem HCl along with various amounts of the aforementioned polymers were prepared using the wet granulation technique. Tablets prepared were placed in a USP apparatus I dissolution tester containing a pH-1.5 HCl solution for the first 2 h and a pH-6.8 phosphate buffer for the next 10 h of the study. The amount of drug released was determined at 237 nm by a UV-visible spectrophotometer. The results showed that all the polymers used in this study could slow down the release of diltiazem HCl from the matrices prepared. This effect, except for HPMC, generally increased proportionately with the amount of polymer. HPMC imparted the best control over drug release and could sustain it for approximately 6 h. All the matrices prepared had a burst release initially; however, it was minimum with HPMC-containing formulations. Fitting of release data to different kinetic models showed that HPMC-matrices conformed best to Hixson-Crowell model, ethylcellulose-matrices to Higuchi and both Eudragit RL100 and Carbopol 971-formulations to either of Hixson-Crowell, Higuchi and first-order kinetics. Release exponent [n] derived from Korsmeyer-Peppas equation for the studied formulations implied that the release of diltiazem HCl from HPMC-matrices was non-Fickian [0.62-0.66] and that of ethylcellulose-formulations was Fickian [n tilde 0.4]. The values of n for Eudragit RL100 and Carbopol 971-matrices ranged from 0.46-0.59, indicating that the drug release was mainly governed by diffusion. Briefly, HPMC was found to be suitable for sustaining the release of diltiazem HCl from matrix-type tablets. Nevertheless, to achieve better results with this polymer, further investigations seem to be necessary

influence of various silicones on the rheological parameters of AZG containing silicone-based gels

Aluminium zirconium tetrachlorohydrex glycine [AZG] is a popular antiperspirant/deodorant agent, formulated in various forms including the clear gels. Silicones are used for the preparation of these gels, giving them desirable characteristics. The aim of this study was to investigate the influence of various silicones, when used in combination, on the rheological properties of the resulting AZG gels prepared. Based on preliminary studies, various AZG containing silicone-based gel formulations were prepared. Silicones used [as ternary mixtures] included ABIL[R] EM 97, ABIL[R] 8839 and ABIL[R] 8852. Formulations prepared were then examined rheologically and their plastic viscosity and yield values determined. Results showed that the amount of ABIL[R] EM 97 [used as an emulsifier] present within the gel formulation is critical. An increase in the amount of this silicone, corresponding to a small decrease in the amount of the hydrophobic structure building [gelling agent] ABIL[R] B8839, increased the plastic viscosity and yield values of the gel. On the other hand, an excess amount of ABIL[R] B8852, as a hydrophilic co-surfactant, reduced the viscosity and yield values of the resulting gel. Eventually, among the formulations prepared, formulation F5 with suitable aesthetic and skin feel properties, spreadability and rheological behaviors, was selected for further studies. By constructing the up-curve and down-curve of this formulation, presence of a plastic thixotropic behavior was confirmed. Inclusion of various amounts of the hydrophobic silicone-based agent, dimethicone, within formulation F5 showed that by increasing the amount of dimethicone present, the plastic viscosity and yield values of the gel would be reduced. This reduction was significant at dimethicone concentrations above 0.5%. Furthermore, by increasing the amount of dimethicone present, the calculated "percentage of reduction in plastic viscosity" also increased. This means that the extent of thixotropicity of the gel formulation increases by the addition of dimethicone. This finding was also backed up by the resulting rheograms constructed. Overall, addition of 0.75% dimethicone produced the most acceptable product in terms of an appropriate viscosity, yield value and extent of thixotropicity. In conclusion, this study shows that in-depth rheological assessment of AZG gels prepared from silicones could be used as an important tool during their formulation and characterization in order to obtain an effective formulation with desirable properties

Preparation and evaluation of diphtheria toxoid-containing microspheres

Preparation of chitosan [CS] microspheres as a novel drug delivery vehicle for intranasal immunization using high, medium and low CS molecular weight [MW] was investigated in this study. Diphtheria toxoid [DT] was used as a model antigen. The emulsion-solidification method was adopted for microencapsulation of DT. In the first step, following the purification of semi-crude DT by the ion-exchange column chromatography technique, the antigenicity and biological characteristics of DT were investigated by the bicinchoninic acid protein assay, ELISA and western blot techniques. Results showed that the purification process was successful and the purified toxoid gave an activity of 1500 Lf/ml; which was three times more than that of the semi-crude toxoid. Next, DT-loaded microspheres were prepared and characterized for their surface morphology, particle size distribution, loading efficiency and in-vitro antigenically active DT release. This study showed that the loading efficiency of CS microspheres depends on the MW, as well as the type of cross-linker used, such that, microspheres prepared by high MW CS and glutaraldehyde [cross-linking agent] had the highest DT loading level [95.61 +/- 3.57 percent]. Size distribution studies showed that the particle size of microspheres prepared by low and medium MW CS solutions with a concentration of 1%w/v was below 10 micro m. These microspheres also had a smoother surface morphology than those prepared using high MW CS solutions with concentrations above 1%w/v. In addition, by investigating the antigenicity of the prepared CS microsphere, no significant reduction in the activity of DT before and after microencapsulation was noted. Finally, in-vitro release studies showed an initial burst effect followed by an extended release of antigenically active DT over a period of 15 days