A phase III randomized-controlled study of safety and immunogenicity of DTwP-HepB-IPV-Hib vaccine (HEXASIIL®) in infants

A fully liquid hexavalent containing Diphtheria (D), Tetanus (T) toxoids, whole cell Pertussis (wP), Hepatitis B (Hep B), type 1, 2, 3 of inactivated poliovirus (IPV) and Haemophilus influenzae type b (Hib) conjugate vaccine (DTwP-HepB-IPV-Hib vaccine, HEXASIIL®) was tested for lot-to-lot consistency and non-inferiority against licensed DTwP-HepB-Hib + IPV in an open label, randomized Phase II/III study. In Phase III part, healthy infants received DTwP-HepB-IPV-Hib or DTwP-HepB-Hib + IPV vaccines at 6, 10 and 14 weeks of age. Blood samples were collected prior to the first dose and 28 days, post dose 3. Non inferiority versus DTwP-HepB-Hib + IPV was demonstrated with 95% CIs for the treatment difference for seroprotection/seroconversion rates. For DTwP-HepB-IPV-Hib lots, limits of 95% CI for post-vaccination geometric mean concentration ratios were within equivalence limits (0.5 and 2). Vaccine was well-tolerated and no safety concerns observed.Clinical Trial Registration - CTRI/2019/11/022052.

Understanding the Sociocognitive Determinants Underlying Intentions to Exercise for Postconcussion Symptom Relief: An Application of the Theory of Planned Behavior

CONTEXT

This study investigated individual sociocognitive factors from the theory of planned behavior and their relationship to exercise for postconcussion recovery.

DESIGN AND METHODS

Four hundred and fifty-nine Australian adults, two-thirds of whom had no concussion history (66%), completed an online survey of their beliefs and attitudes toward exercise for postconcussion recovery. Secondary questions evaluated program design features that could affect engagement (eg, session frequency).

RESULTS

Structured equation modeling found that subjective norms were the strongest significant predictor of intention to participate in exercise for postconcussion recovery. Perceived behavioral control was also a significant predictor of intention to participate but to a lesser extent. Attitude did not predict participation intention. The design features identified as key were personalization and being supervised during the program.

CONCLUSIONS

This study found that people's intention to participate in a program of exercise postconcussion recovery is shaped by individual psychological factors and identified program design features that could be adjusted for increased engagement. Program success could be maximized through strategies such as supporting individuals to have a stronger sense of control over their participation through the choice of session timing or frequency and harnessing the influence of significant others via supportive messaging from key professionals.

A - 166 Predictors of Intention to Participate in Programmed Exercise for Postconcussion Recovery

OBJECTIVE

Programmed exercise has been proposed for postconcussion recovery, but willingness to engage in such programs has not been explored. This study investigated sociocognitive factors from the Theory of Planned Behavior (TPB) and their relationship to exercise intention for postconcussion recovery (intention).

METHOD

Four hundred and fifty-nine adults completed an online survey (Age = 18-72 years, 34% concussion history). All participants received information about mTBI, postconcussion symptoms, and programmed exercise. The measures assessed TPB constructs including intention, and evaluated program design features that could affect engagement (e.g., session frequency).

RESULTS

Structured equation modelling found that intention was significantly predicted (p < 0.05) by subjective norms (strongest predictor) and perceived behavioral control (weaker predictor). Attitudes did not significantly predict intention. The model accounted for approximately half of the variance in exercise intention (R2 = 0.506). The addition of moderators (habitual exercise, concussion history) did not have any effect. Key program design features were personalization and supervision.

CONCLUSIONS

People's intention to undertake programmed exercise for postconcussion recovery is shaped by individual psychological factors, especially subjective norms and perceived behavioral control. This could be considered in the program design (e.g., building program connections with significant others; fostering a sense of control through personalization/session timetabling). Further research is needed to establish the effect of such additions on engagement with programmed exercise for postconcussion recovery.

Exercise Parameters for Postconcussion Symptom Rehabilitation: A Systematic Review

CONTEXT

Exercise rehabilitation for postconcussion symptoms (PCS) has shown some benefits in adolescent athletes; but a synthesis of evidence on exercise per se has been lacking.

OBJECTIVE

This systematic review aimed to determine if unimodal exercise interventions are useful to treat PCS and if so, to identify a set of clearly defined and effective exercise parameters for further research.

EVIDENCE ACQUISITION

Relevant health databases and clinical trial registries were searched from inception to June 2022. The searches used a combination of subject headings and keywords related to mild traumatic brain injury (mTBI), PCSs, and exercise. Two independent reviewers screened and appraised the literature. The Cochrane Collaboration's Risk of Bias-2 tool for randomized controlled trials was used to assess methodological quality of studies.

EVIDENCE SYNTHESIS

Seven studies were included in the review. Four studies were assessed to have a low overall risk of bias, 2 with low risk and 1 with some concerns. Participants in the studies comprised mostly adolescents with sports-related concussion. The review found exercise to be more beneficial than control conditions in 2 studies investigating acute PCS and 2 studies investigating persistent PCS. Within-group differences showing symptom improvement over time were observed in all 7 studies. In general, the review found support for programmatic exercise that commences after an initial period of rest for 24 to 48 hours. Recommendations for exercise parameters that can be explored in subsequent research include progressive aerobic exercise starting from 10 to 15 minutes at least 4 times a week, at a starting intensity of 50% HR of the subsymptom threshold, with length of program depending on recovery.

CONCLUSION

The evidence in support of exercise rehabilitation for PCSs is moderate based on the small pool of eligible studies. Further research can be guided by the exercise parameters identified in this review.

Sports fans, wagering, and concussion knowledge: implications for injury nondisclosure

OBJECTIVE

Athletes perceive sports fans as a source of concussion nondisclosure pressure. Sports fans are exposed to injury depictions from the media that could lead them to underestimate its seriousness. This study examined the concussion knowledge of non-sports fans, sports fans, and wagering sports fans, as knowledge is a modifiable factor that can influence injury disclosure.

SETTING AND PARTICIPANTS

A convenience sample of 443 Australian adults completed an online survey.

DESIGN

Cross-sectional.

MAIN MEASURES

Self-rated and actual concussion knowledge (the Rosenbaum Concussion Knowledge and Attitudes Survey; RoCKAS).

RESULTS

There was no significant difference in the concussion knowledge of self-identified sports (n = 157) and non-sports (n = 286) fans; but sports fans rated their knowledge as significantly higher than non-sports fans (p < .05). Wagering sports fans (n = 24) had significantly less concussion knowledge than non-wagering sports fans (η2 = .03, small effect).

DISCUSSION

Athletes who feel nondisclosure pressure from sports fans may be influenced by people with incomplete concussion knowledge, particularly wagering sports fans. Sports fans over-estimated their knowledge, and this could contribute to the nondisclosure pressure felt by athletes. Programmes to increase injury disclosure by athletes should take these factors into consideration.

Research Letter: Concussion Knowledge Is Difficult to Predict From Self-Reported Exposure, Sports Participation, and Education

OBJECTIVES

Increasing concussion knowledge could contribute to improving injury outcomes. Understanding the predictors of concussion knowledge could determine the areas of educational need. This study examined whether individual factors, prior brain injury, prior concussion education, and contact-sports participation predicted concussion knowledge.

DESIGN AND SETTING

Cross-sectional study with recruitment of community volunteers.

PARTICIPANTS

An online survey was completed by 525 adults, 443 of whom provided useable responses.

MAIN MEASURES

The respondents provided background information and completed the Concussion Knowledge Index from the Rosenbaum Concussion Knowledge and Attitudes Survey (RoCKAS).

RESULTS

On average, the participants answered 19.8 out of 25 items correctly. A multiple regression model with demographic, injury, and sport-related variables did not significantly predict concussion knowledge.

CONCLUSION

This community sample had higher than expected concussion knowledge (restricted range), but some important misconceptions were still present. The model reflecting a combination of self-reported factors did not predict concussion knowledge. The implications for concussion education are discussed, including the need for targeted education to address specific misconceptions.

A-284 A Systematic Review of Exercise for the Management of Post-Concussion Symptoms

Objective: Exercise rehabilitation for post-concussion symptoms (PCS) has shown benefits, but a synthesis of evidence has been lacking. This systematic review aimed to review the evidence from randomised control trials (RCTs) of exercise-only interventions for PCS and identify the most promising parameters for further investigation.

Data Selection: Electronic databases (CINAHL, EBSCOhost, MEDLINE, etc) and trial registries (ProQuest Dissertation & Theses Global Database, etc) were searched from inception to November 2020. Keyword searches was carried out using terms specifying “mild traumatic brain injury”, “post-concussion symptoms”, and “exercise”. Only RCTs using solely exercise interventions and published in English were considered. Studies with multi-disciplinary interventions were excluded. Two independent researchers screened and reviewed the literature. Methodological quality was assessed using the Cochrane’s Risk-of-Bias-2 tool. Eight studies were identified for the final review.

Data Synthesis: The review found moderate support for exercise interventions to be effective in treating PCS. Based on the 8 studies, exercise programs that led to favourable outcomes commenced after an initial period of rest for 24-48 hours post-concussion, used progressive aerobic exercise for at least 4 times a week for 10-15 minutes during each session, required an intensity of at least 50% of the heart rate of the sub-symptom threshold, and lasted for at least 4 weeks or resolution of symptoms.

Conclusions: Exercise rehabilitation for PCS may be beneficial but further research is required on wider population groups apart from adolescents and athletes before more generalised recommendations can be made.

Postconcussion discharge advice does not improve concussion knowledge in a community sample

OBJECTIVE

Poor concussion knowledge in the community has been linked to reduced injury identification. This study investigated if concussion knowledge could be improved by providing standard postinjury advice (written brochure).

METHODS

This study was a prospective, controlled study, with random allocation of 199 Australian adults to receive either a concussion information (CI, n=101), or non-CI (n=98). All participants completed the Rosenbaum Concussion Knowledge and Attitudes Survey on three occasions: pre-education and posteducation, and 1 week later.

RESULTS

A 2 (condition) × 3 (occasion) mixed analysis of variance with concussion knowledge as the dependent variable did not find a statistically significant interaction (p>0.05). This result was unchanged: (1) with the covariate addition of background education and; (2) in a subgroup analysis (individuals with initially 'low' self-rated knowledge). Some key misconceptions about concussion were identified.

CONCLUSION

The community knowledge of concussion was not significantly improved by the concussion advice. Since injury recognition relies ton an extent on community knowledge, the identified misconceptions should be addressed. This could occur via public health messaging. In clinical settings and for future research, the next steps should also include regular updating of concussion information to keep pace with advances in the field.

Traumatic Brain Injury Rehabilitation: An Exercise Immunology Perspective

Traumatic brain injury (TBI) is the largest cause of death and disability globally. The physical and psychosocial consequences after TBI can persist for prolonged periods, and lead to increased health care and economic burden. Exercise has shown promise over recent years as a mode of rehabilitation that alleviates multiple TBI symptoms; but there is a lack of controlled large-scale studies and limited research into the underlying mechanisms. This critical review draws from animal and human studies on exercise immunology to speculate on possible mechanisms that could underlie beneficial outcomes of exercise after TBI. The anti-inflammatory role of exercise, protective role offered by pre-injury exercise, and the need for more objective studies on biomarker analysis are expected to be useful considerations to develop optimal post-TBI exercise rehabilitation programs. Future studies can consider investigating the specific immunological processes induced by exercise in consideration of individual differences and non-aerobic exercise modalities.

A-98 Public Misconceptions about Concussion Are Not Improved by Standard Post-Injury Advice

Objective

Insufficient public knowledge of concussion is thought to contribute to poor injury recognition and management, particularly in community sports. It is not clear whether such knowledge can be improved by standard post-injury discharge advice. This study determined if a widely used concussion leaflet would improve concussion knowledge in a community sample of adults.

Method

Prospective, controlled study, with random allocation to advice conditions. One hundred and ninety-nine Australian adults received either concussion (CA, n = 101) or non-concussion advice (NCA, n = 98). All volunteers completed the Rosenbaum Concussion Knowledge and Attitudes Survey (RoCKAS) on three occasions (baseline, immediately post-advice, and after a one-week delay). Standard scores were derived, including for the 25-item Concussion Knowledge Index.

Results

A 2 (condition) X 3 (occasion) mixed ANOVA did not find a statistically significant interaction or any main effects on concussion knowledge (p &lt; 0.05). On all three occasions, both groups obtained a RoCKAS total score of ~80% correct; but they also held some key misconceptions about concussion.

Conclusions

Compared to giving non-concussion information, public knowledge of concussion was not significantly improved by the concussion advice. The leaflet may not have conveyed the information needed to improve test scores, or the baseline performance of the groups could have suppressed the effect. Since correct injury recognition and management relies on community knowledge, alternate means of improving public knowledge of concussion should be explored. Concussion advisories should also be reviewed to ensure they can correct public misconceptions about concussion.

Method development and validation of HPLC tandem/mass spectrometry for quantification of perindopril arginine and amlodipine besylate combination in bulk and pharmaceutical formulations

A well-characterized and fully validated ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometric (UHPLC-ESI-MS/MS) method was developed to reliably analyze combination of perindopril arginine and amlodipine besylate in bulk and tablet formulations. The chromatographic separation was achieved on a Waters ACQUITY UPLC^® BEH C18 column with 1.7 μm particle packing which enabled the higher peak capacity, greater resolution, increased sensitivity, and higher speed of analysis using a volatile mobile phase ideally being at least 2 pH units below and above the perindopril arginine and amlodipine besylate pKa, respectively. Mass spectrometric detection was performed using electrospray ion source in positive ion polarity to profile the abundances of perindopril arginine and amlodipine besylate, using the transitions m/z 369 → m/z 172, and m/z 409 → m/z 238 for perindopril arginine and amlodipine besylate, respectively. Calibration curve was constructed over the range 0.25 – 500 ng/mL and 1.0 – 100 ng/mL for perindopril arginine and amlodipine besylate, respectively. The method was precise and accurate, and provided recovery rates > 80% for both compounds. Furthermore, the intra- and inter-assay precision in terms of % RSD was in between 0.1 – 3.7 for both perindopril arginine and amlodipine besylate. A specific, accurate, and precise UHPLC-MS/MS method for the determination of perindopril arginine and amlodipine besylate in bulk and tablet formulation.

Development and characterization of surface modified PLGA nanoparticles for nasal vaccine delivery: effect of mucoadhesive coating on antigen uptake and immune adjuvant activity

In this study, the efficacy of mucoadhesive polymers, i.e., chitosan and glycol chitosan as a mucoadhesive coating material in nasal vaccine delivery was investigated. The Hepatitis B surface Antigen (HBsAg) encapsulated PLGA, chitosan coated PLGA (C-PLGA), and Glycol chitosan coated PLGA (GC-PLGA) nanoparticles (NPs) were prepared. The formulations were characterized for particle size, shape, surface charge, and entrapment efficiency. The mucoadhesive ability of coated and non-coated NPs was determined using in vitro mucoadhesion and nasal clearance test. In addition, the systemic uptake and bio-distribution were also evaluated to understand the fate of NPs following nasal delivery. The immuno-adjuvant ability of various formulations was compared by measuring specific antibody titer in serum and secretory. The results indicated that PLGA NPs exhibit negative surface charge, whereas C-PLGA and GC-PLGA NPs exhibited positive surface charge. The GC-PLGA NPs demonstrated lower clearance and better local and systemic uptake compared to chitosan coated and uncoated PLGA NPs. In vivo immunogenicity studies indicated that GC-PLGA NPs could induce significantly higher systemic and mucosal immune response compared to PLGA and C-PLGA NPs. In conclusion, GC-PLGA NPs could be a promising carrier adjuvant for the nasal vaccine delivery for inducing a potent immune response at mucosal surface(s) and systemic circulation.

Strong systemic and mucosal immune responses to surface-modified PLGA microspheres containing recombinant Hepatitis B antigen administered intranasally

Surface-modified DL-lactide/glycolide copolymer (PLGA) microspheres with chitosan (CS) were developed for nasal immunization using recombinant Hepatitis B (HBsAg) surface protein for the induction of humoral, cellular and mucosal immunity. Modified PLGA microspheres were characterized in vitro for their size, shape, entrapment efficiency and zeta potential. The nasal clearance rate was evaluated by gamma scintigraphy in rabbits. The antigen integrity, in vitro release and its stability at 37 degrees C were also evaluated. The designed cationic microspheres possessed 27.2 mV zeta potential and an average size less than 10 microm with antigen loading efficiency of 80+/-5%. However, zeta potential of unmodified PLGA microspheres was measured to be negative (-8.7 mV). The modified PLGA microspheres showed the lowest nasal clearance rate when compared with unmodified PLGA microspheres and lactose powder. The antigen integrity was retained intact in encapsulated form as well as on release. The immune-stimulating activity was studied by measuring anti-HBsAg titre, secretory IgA level in serum, vaginal, nasal and salivary secretions (mucosal secretions) and cytokine level (interleukin-2 (IL-2) and interferon-gamma (IFN-gamma)) in spleen homogenates following nasal administration of modified PLGA microspheres in Balb/c mice and compared with alum-HBsAg vaccine injected subcutaneously. The serum anti-HBsAg titre obtained after nasal administration of modified PLGA microspheres was comparable with titre recorded after alum-HBsAg was administered subcutaneously. Moreover, alum-HBsAg vaccine did not elicit sIgA in mucosal secretions as it was induced and measured in the case of nasal administration of modified PLGA microspheres. Similarly, there was no cellular response (cytokine level) in case of alum-HBsAg vaccine. Modified PLGA microspheres (cationic microspheres) thus produced humoral (both systemic and mucosal) and cellular immune responses upon nasal administration. These data demonstrate high potential of modified PLGA microspheres for their use as a carrier adjuvant for nasal subunit vaccines.

Aerosolized liposome-based delivery of amphotericin B to alveolar macrophages

The present study was aimed at preparation, characterization, and performance evaluation of amphotericin B (Amp B)-loaded aerosolized liposomes for their selective presentation to lungs (alveolar macrophages), that being the densest site of Aspergillosis infection. Egg phosphatidylcholine (PC)- and cholesterol (Chol)-based liposomes were modified by coating them with alveolar macrophage-specific ligands (O-palmitoyl mannan, OPM, and O-polmitoyl pullulan, OPP). The prepared formulations were characterized in vitro for vesicle morphology, mean vesicle size, vesicle size distribution and percent drug entrapment. Pressurized packed systems based on preformed liposomal formulations in chlorofluorocarbon aerosol propellants were prepared. In vitro airways penetration efficiency of the liposomal aerosols was determined by percent dose reaching the peripheral airways, it was recorded 1.4-1.6 times lower as compared to plain drug solution-based aerosol. In vivo tissue distribution studies on albino rats suggested the preferential accumulation of OPM- and OPP-coated formulations in the lung macrophages. Higher lung drug concentration was recorded in case of ligand-anchored liposomal aerosols as compared to plain drug solution and plain liposome-based aerosols. The drug was estimated in the lung in high concentration even after 24 h. The drug-localization index calculated after 6 h was nearly 1.42-, 4.47-, and 4.16-fold, respectively, for plain, OPM-, and OPP-coated liposomal aerosols as compared to plain drug solution-based aerosols. These results suggest that the ligand anchored liposomal aerosols are not only effective in rapid attainment of high-drug concentration in lungs with high population of alveolar macrophages but also maintain the same over prolonged period of time. The significance of targeting potential of the developed systems was established.

Development of a single dose tetanus toxoid formulation based on polymeric microspheres: a comparative study of poly(d,l-lactic-co-glycolic acid) versus chitosan microspheres

Stable polymeric microspheres capable of controlled release of tetanus toxoid (TT) for periods ranging from days to over months were developed. TT was stabilized, encapsulated in microspheres prepared from poly(D,L)-lactide-co-glycolide (PLGA) and chitosan by using protein stabilizer (trehalose) and its immune response was compared. The influence of co-encapsulated protein stabilizer on tetanus toxoid's stability and release from the microspheres was studied. The protein stabilizer (trehalose) prevented structural losses and aggregation of microencapsulated TT. To neutralize the acids liberated by the biodegradable lactic/glycolic acid-based polymer, we also co-incorporated into the polymer an antacid, (Mg(OH)2), which neutralized the acidity during degradation of the polymer and also prevented TT structural losses and aggregation. The in vitro release experiments with PLGA and chitosan microspheres were performed and the release of TT was increased up to 80-90%. The antigen integrity was investigated by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by coomassie brilliant blue staining. The SDS-PAGE analysis confirmed that antigen integrity was not affected by the encapsulation procedure. In addition, the immunogenicity of PLGA and chitosan microspheres based single dose vaccine was evaluated in guinea pigs and compared with multiple doses of alum adsorbed TT. Results indicated that a single injection of PLGA and chitosan microspheres containing TT could maintain the antibody response at a level comparable to the booster injections of conventional alum adsorbed vaccines. The both PLGA and chitosan based stable vaccine formulations produced an equal immune response. Hence chitosan can be used to replace the expensive polymer PLGA. This approach should have potential application in the field of vaccine delivery.

Development of a single-dose stabilized poly(D,L-lactic-co-glycolic acid) microspheres-based vaccine against hepatitis B

The purpose of this study was to develop a stable single-dose vaccine based on recombinant hepatitis B surface antigen (HBsAg) in poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres, in which HBsAg was stabilized by a protein stabilizer (trehalose) and an antacid (Mg(OH)2). The microspheres were prepared by the double emulsion method and characterized by scanning electron microscopy. To neutralize the acids liberated by the biodegradable lactic/glycolic acid based polymer, we coincorporated into the polymer an antacid, Mg(OH)2, which neutralized the acidity during degradation of the polymer and also prevented HBsAg structural losses and aggregation. The antigen integrity after encapsulation was examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis followed by silver staining, isoelectric focusing and Western blotting techniques, which confirmed that antigen remained intact after encapsulation. In-vitro release experiments were performed in phosphate-buffered saline (pH 7.4) and the release of antigen was found to be improved by the protein stabilizer (trehalose). In stability studies, performed at 37 degrees C, the microspheres were found to be stable for 16 days. The immunogenicity of stable microsphere formulations bearing HBsAg was compared with the conventional alum-absorbed HBsAg vaccine in a guinea-pig model. The antibody titre indicated that a single injection of stabilized HBsAg-PLGA microspheres produced a better immune response than two injections of alum-formulated HBsAg vaccine. The findings suggest that recombinant HBsAg can be stabilized by use of a protein stabilizer and antacid during entrapment, and this stabilized preparation can be useful for antigen delivery.

Modified push-pull osmotic system for simultaneous delivery of theophylline and salbutamol: development and in vitro characterization

An oral osmotic system which can deliver theophylline and salbutamol sulphate simultaneously for extended period of time was developed and characterized in a view to reduce the problems associated with the multidrug therapy of asthma. Simple controlled porosity osmotic pump contained both drugs (in freely soluble form) did not provide satisfactory extended release of theophylline. A modified two-layered, push-pull osmotic system was developed by using the basic designs of various oral osmotic pumps, such as controlled porosity osmotic pump (CPOP), elementary osmotic pump (EOP) and push-pull osmotic pump (PPOP). Scanning electron microscopy of cellulose acetate coating membrane after dissolution revealed that 25% (w/w) of sorbitol can be used as an optimized concentration of pore forming agent with 25% (w/w) of plasticizer, which was kept constant. Formulations were initially developed for theophylline and the release was optimized by using two different soluble forms of theophylline with varying amount of hydrophilic polymer mixture in upper layer and polyethylene oxide (expandable hydrogel) in lower layer. Further, the release of salbutamol sulphate was optimized by keeping the drug in upper or lower layer or both layers. In vitro release studies showed satisfactory controlled release profiles of both drugs. The release profiles of both drug statistically compared with respective marketed controlled release formulations. An optimized system was selected to study the effect of concentration of pore forming agent and orifice diameter on the release of both drugs.

Cholera toxin B subunit conjugated bile salt stabilized vesicles (bilosomes) for oral immunization

Bile salt stabilized vesicles, bilosomes appear to be a promising and potential carrier system for oral delivery of peptides and proteins. Bilosomes containing bovine serum albumin (BSA), a model antigen, were prepared and conjugated with cholera toxin B subunit (CTB) in order to enhance their affinity towards M cells of Peyer's patches. Stability studies were undertaken to ascertain the effect of simulated gastric fluid (SGF, pH 1.2), simulated intestinal fluid (SIF, pH 7.5) and different concentrations of bile salts. Intactness and biological activity of CTB were checked by hemagglutination test. A single oral dose of CTB-conjugated bilosomes produced almost equivalent response compared to parenteral administration of antigen with Freund's complete adjuvant (FCA). However, in contrast to FCA, oral administration of bilosomes is convenient and devoid of any adverse effects that are observed with parenteral administration of FCA. Serum IgG titers after single administration were significantly better (P < 0.05) than oral administration of antigen with other systems for 3 consecutive days, suggesting an effective stimulation of systemic immune response. Mucosal IgA titers obtained advocated a possible application of CTB-conjugated bilosomes as oral vaccine delivery system.

Osmotically regulated asymmetric capsular systems for simultaneous sustained delivery of anti-tubercular drugs

Sustained release asymmetric membrane capsular systems were developed for simultaneous oral delivery of rifampicin and isoniazid sodium in order to reduce the problems associated with the multi drug therapy of tuberculosis. Dense semipermeable membrane coating capsules were also prepared for the delivery of these drugs by adopting two different filling approaches. In vitro release studies were carried out for both types of systems and the results were compared. Asymmetric membrane capsules provided sustained release of rifampicin associated with initial burst release, where isoniazid release rates were comparatively high due to higher aqueous solubility. Dense semipermeable membrane systems provided controlled release of both drugs but were devoid of initial burst release of isoniazid. To overcome these drawbacks, a modified asymmetric system was developed by adding appropriate amount of hydrophilic polymer mixture with isoniazid. The system provided satisfactory sustained release of rifampicin and isoniazid with initial burst release may be sufficient to achieve minimum effective concentration in blood. In vitro dissolution kinetics of the systems followed first order kinetics and statistical analysis of release rate data proved that modified asymmetric system was better amongst the developed systems.

Controlled Porosity Osmotic Pumps of Highly Aqueous Soluble Drug Containing Hydrophilic Polymers as Release Retardants

Controlled porosity osmotic pumps (CPOPs) are devoid of delivery orifice to release core contents and essentially possess pore-forming agent(s) in coating composition. When the pump comes in contact with aqueous media, pore-forming agent(s) generate pores through which core contents are delivered. Diltiazem hydrochloride (DLTZ) is a freely water-soluble drug and the release rates of DLTZ are higher from oral osmotic pumps including CPOPs, in which the drug release is controlled by concentration of pore-forming agents. The effect of appropriate concentration of hydroxypropyl methyl cellulose and sodium carboxy methyl cellulose mixture on the release of DLTZ from CPOPs was studied. In vitro drug release profiles were compared with that of different marketed controlled release formulations and statistically analysed to examine the suitability of CPOP for twice or once daily administration. Dissolution models were applied to drug release data in order to establish the mechanism of drug release and kinetics. Drug release from the CPOPs was effectively modified with the concentration of pore-forming agent in membrane and concentration of hydrophilic polymers in the core. CPOPs showed minimum 65% of consistent DLTZ release at 16 h. Statistical analysis confirmed that with an increase in the amount of hydrophilic polymers release rate decreased. Drug release from the systems follows Hixson-Crowell cube root model and mechanism of release follow non-Fickian diffusion.