Exploration, Development And Optimization Of Ecofriendly Novel Dosage Form – Pastilles

Background:

Now-a-day, there is the need to explore the concept of green chemistry in every field. Many existing conventional and novel drug delivery systems have problems related to green chemistry. To overcome the existing limitations of the different dosage forms, a newer untouched dosage form pastilles was explored.

Objective:

The present study aims to optimize the Glipizide (GPZ) matrix pastilles using waxy erodible polymers integrating the concept of quality by design (QbD) and green chemistry.

Methods:

The pastilles were formulated using the fabricated lab-scale pastillator. GPZ was used as a model drug. The concern related to the drug is low aqueous solubility and short variable half-life. The solubility of the drug was improved by formulating a complex between GPZ and chemically modified ß –cyclodextrin (β-CD) - hydroxypropyl-ß-cyclodextrin (HP- ß -CD). The complex was prepared using the kneading method. The complex was formulated incorporated different stoichiometric ratios of GPZ: complexing agent. Sustained-release pastille formulated using Gelucire 43/01 (GC 43/01) as release retardant polymer. The central composite design had been used to obtain an optimum batch, using the amount of GC 43/01 and temperature as independent variables, while drug release at 2h, 6h, and 10h was chosen as dependent variables. Design batches were evaluated for post-and preformulation parameters. An optimum formulation was evaluated for the influence of hydroalcoholic media on drug release.

Results:

The complex formulated using HP- ß –CD (1:1) shown better solubility (36.5mg/ml) and dissolution. The complex was incorporated in the pastilles with erodible polymer GC 43/01. The formulation was found robust with optimum pre and post formulation parameters. Optimized batch was chosen from the design space of central composite design. The drug release of the optimized formulation was found 29.13%, 57.29% and 85.70% at 2, 6 and 10 hrs respectively which was similar to the drug release of the marketed formulation. As the amount of alcohol increased from 5 to 40 %, the drug release also increased but did not show a dose dumping effect. It is just due to the altered solubility of GPZ in alcohol.

Conclusion:

The untouched formulation, Pastilles of GPZ were developed incorporating the waxy erodible polymer. Pastilles were capable to control drug release up to 12 h. The amount of GC 43/01 and temperature had a significant effect on the formulation of GPZ sustained-release pastille. The newer approach of formulating pastilles might apply to the industry as it is an eco-friendly, single-step process and uses fewer excipients.

Clinical Utility of the Transthoracic Echocardiogram for Isolated Lacunar Infarcts: A Single-Center Experience

BACKGROUND

Stroke is a prominent and financially burdensome disease. Lacunar strokes are traditionally attributed to small vessel disease rather than cardioemboli, which typically occlude larger arteries. Thus, the benefit of screening for potential sources of cardioemboli in lacunar stroke patients is unclear. We evaluated the clinical utility of the transthoracic echocardiogram performed in patients with lacunar strokes.

METHODS

A single-center retrospective analysis of ischemic stroke patients from January 2013 through December 2017 was performed. Brain magnetic resonance imaging was used to select patients with a single lacunar infarct. Patients presenting with acute symptoms of cardiac disease or an abnormal electrocardiogram were excluded. Transthoracic echocardiogram results were reviewed, and their utility in decision-making was evaluated.

RESULTS

Of the 442 patients at our institution diagnosed with ischemic stroke during the inclusion period, 89 met inclusion criteria. Transthoracic echocardiogram detected a patent foramen ovale in 5.6% of patients, mitral annular calcification in 9.0% of patients, and abnormal wall motion in 4.5% of patients. For all patients, there were no findings that prompted anticoagulation, antibiotic, or surgical intervention. The cost of an inpatient transthoracic echocardiogram is $4100, resulting in $364,900 in unnecessary health care spending.

CONCLUSIONS

Transthoracic echocardiogram appears to have minimal therapeutic value in most patients with lacunar strokes. In stroke patients with no acute symptoms of cardiac disease and a normal electrocardiogram, it may be reasonable to forgo the transthoracic echocardiogram if the brain magnetic resonance imaging shows an isolated lacunar infarct.

Abstract WP277: Clinical Utility and Cost-Effectiveness of Transthoracic Echocardiogram in Lacunar Strokes

Background: The average annual cost of inpatient stroke care in the United States exceeds $35 billion. The lack of clear recommendations for the use of transthoracic echocardiography (TTE) in patients with Acute ischemic stroke (AIS) has made this test a universal component of every stroke work-up. We evaluated the clinical utility and cost-effectiveness of TTE performed in patients with lacunar strokes.

Methods: This is a single-center retrospective analysis of AIS patients from October 2015 through December 2017 (27 months). Brain MRI was used to select patients with a single acute/subacute lacunar infarct and no T2FLAIR evidence of previous cortical embolic strokes. Patients with cardiac symptoms (chest pain, shortness of breath, pedal edema) or an abnormal ECG (Atrial fibrillation, other arrhythmias, ST-T changes) on admission were excluded. Results of TTE were reviewed and their utility in decision making was evaluated. TTE associated costs were calculated.

Results: Out of the 442 patients diagnosed with AIS in the given timeframe , 98 met the above criteria for inclusion. Mean age was 55 and 40 patients were female.TTE revealed no patients with an ejection fraction below 40%. Incidence of cardiac thrombus was 0%. Small patent foramen ovale was found in 5 (5.1%) patients, out of which none had right to left shunting or associated atrial septal aneurysm. Obtaining TTE did not change the management in any of the cases. Average cost of inpatient TTE was $2616, totaling $266,832 in all patients. Based on the current incidence of lacunar strokes (15-25%), this corresponds to approximately $500 million of nationwide spending annually.

Conclusion: In AIS patients with no cardiac symptoms and normal ECG, it may be safe and clinically reasonable to obtain MRI brain before deciding about the need for TTE. If MRI shows a lacunar stroke, inpatient TTE done routinely may not change the management but adds up unnecessary cost to the healthcare system. Large multi-center studies are warranted.

Cost savings with a new screening algorithm for pulmonary arterial hypertension in systemic sclerosis

BACKGROUND

Screening for pulmonary arterial hypertension (PAH) in systemic sclerosis (SSc) is now standard care in this disease. The existing Australian Scleroderma Interest Group algorithm (ASIGSTANDARD ) is based on transthoracic echocardiography (TTE) and pulmonary function tests (PFT). Recently, ASIG has derived and validated a new screening algorithm (ASIGPROPOSED ) that incorporates N-terminal pro-B-type natriuretic peptide level together with PFT in order to decrease reliance on TTE, which has some limitations. Right heart catheterisation (RHC) remains the gold standard for the diagnosis of PAH in patients who screen 'positive'.

AIM

To compare the cost of PAH screening in SSc with ASIGSTANDARD and ASIGPROPOSED algorithms.

METHODS

We applied both ASIGSTANDARD and ASIGPROPOSED algorithms to 643 screen-naïve SSc patients from the Australian Scleroderma Cohort Study (ASCS), assuming a PAH prevalence of 10%. We compared the costs of screening, the number of TTE required and both the total number of RHC required and the number of RHC needed to diagnose one case of PAH, and costs, according to each algorithm. We then extrapolated the costs to the estimated total Australian SSc population.

RESULTS

In screen-naïve patients from the ASCS, ASIGPROPOSED resulted in 64% fewer TTE and 10% fewer RHC compared with ASIGSTANDARD , with $1936 (15%) saved for each case of PAH diagnosed. When the costs were extrapolated to the entire Australian SSc population, there was an estimated screening cost saving of $946 000 per annum with ASIGPROPOSED , with a cost saving of $851 400 in each subsequent year of screening.

CONCLUSIONS

ASIGPROPOSED substantially reduces the number of TTE and RHC required and results in substantial cost savings in SSc-PAH screening compared with ASIGSTANDARD .

The association of antiphospholipid antibodies with cardiopulmonary manifestations of systemic sclerosis

OBJECTIVES

To determine the prevalence and correlates of antiphospholipid antibodies (APLA) in systemic sclerosis (SSc).

METHODS

Nine hundred and forty SSc patients were tested for APLA using an ELISA assay at recruitment. Clinical manifestations were defined as present, if ever present from SSc diagnosis. Logistic regression analysis was used to determine the associations of APLA.

RESULTS

One or more types of APLA were present in 226 (24.0%) patients. Anticardiolipin (ACA) IgG (ACA-IgG) antibodies were associated with right heart catheter-diagnosed pulmonary arterial hypertension (PAH), with higher titres corresponding with a higher likelihood of PAH (moderate titre (20-39 U/ml) ACA-IgG odds ratio [OR] 1.70, 95% CI: 1.01-2.93, p=0.047; high titre (>40 U/ml) ACA-IgG OR 4.60, 95% CI:1.02-20.8, p=0.047). Both ACA-IgM (OR 2.04, 95% CI: 1.4-3.0, p<0.0001) and ACA-IgG (OR 1.84, 95% CI: 1.2-2.8, p=0.005) were associated with interstitial lung disease (ILD). Increasing ACA-IgM and IgG titres were associated with increased likelihood of ILD. ACA-IgG was a marker of coexistent pulmonary hypertension and ILD (ILD-PH) (OR 2.10, 95% CI: 1.1-4.2, p=0.036). We also found an association between ACA-IgG and digital ulcers (OR 1.76, 95% CI: 1.16-2.67, p=0.008) and ACA-IgM and Raynaud's phenomenon (OR 2.39, 95% CI: 1.08-5.27, p=0.031). There was no association between APLA and SSc disease subtype, peak skin score, presence of other autoantibodies, mortality or other disease manifestations.

CONCLUSIONS

The association of APLA with PAH, ILD, ILD-PH, Raynaud's phenomenon and digital ulcers suggests that endothelial abnormalities and small vessel thrombosis may be important in the pathogenesis of these disease features.

Long-term catheter angiography after aneurysm coil therapy: results of 209 patients and predictors of delayed recurrence and retreatment

OBJECT

Aneurysm recurrence after coil therapy remains a major shortcoming in the endovascular management of cerebral aneurysms. The need for long-term imaging follow-up was recently investigated. This study assessed the diagnostic yield of long-term digital subtraction angiography (DSA) follow-up and determined predictors of delayed aneurysm recurrence and retreatment.

METHODS

Inclusion criteria were as follows: 1) available short-term and long-term (> 36 months) follow-up DSA images, and 2) no or only minor aneurysm recurrence (not requiring further intervention, i.e., < 20%) documented on short-term follow-up DSA images.

RESULTS

Of 209 patients included in the study, 88 (42%) presented with subarachnoid hemorrhage. On shortterm follow-up DSA images, 158 (75%) aneurysms showed no recurrence, and 51 (25%) showed minor recurrence (< 20%, not retreated). On long-term follow-up DSA images, 124 (59%) aneurysms showed no recurrence, and 85 (41%) aneurysms showed recurrence, of which 55 (26%) required retreatment. In multivariate analysis, the predictors of recurrence on long-term follow-up DSA images were as follows: 1) larger aneurysm size (p = 0.001), 2) male sex (p = 0.006), 3) conventional coil therapy (p = 0.05), 4) aneurysm location (p = 0.01), and 5) a minor recurrence on short-term follow-up DSA images (p = 0.007). Ruptured aneurysm status was not a predictive factor. The sensitivity of short-term follow-up DSA studies was only 40.0% for detecting delayed aneurysm recurrence and 45.5% for detecting delayed recurrence requiring further treatment.

CONCLUSIONS

The results of this study highlight the importance of long-term angiographic follow-up after coil therapy for ruptured and unruptured intracranial aneurysms. Predictors of delayed recurrence and retreatment include large aneurysms, recurrence on short-term follow-up DSA images (even minor), male sex, and conventional coil therapy.

Efficacy of intraoperative vancomycin powder use in intrathecal baclofen pump implantation procedures: single institutional series in a high risk population

We aimed to assess the efficacy of intraoperative vancomycin powder in intrathecal baclofen pump placement patients, a high risk population. A retrospective review was conducted using prospectively collected data at an academic tertiary care unit. The neurosurgical adult patient population was queried for all intrathecal baclofen pump implantation procedures. Patients were then reviewed for the use of intraoperative crystalline vancomycin powder. Those with a history of prior surgical site infection, chronic systemic infections or osteomyelitis were excluded. Anhydrous, crystalline vancomycin was utilized in the wound bed after completion of implantation, distributed evenly in the case of multiple incisions. Patients received 500 mg or 1,000 mg of crystallized vancomycin, evenly distributed through the wound layers based on a 70 kg weight cutoff. Intraoperative institutional standards of infection prophylaxis were unchanged throughout the study period. Infection rate of baclofen pump placement prior to the use of vancomycin powder from 2001-2009 at the same institution was monitored. Wound infection rate was tracked for a 12 month postoperative period. Six patients out of 26 baclofen pump implantations (23%) in this cohort were identified to have seven infections despite vancomycin powder placement in the lumbar and catheter wounds. Prior infection rates have been investigated for intrathecal drug delivery systems from 2001 to 2009 at the same institution with an overall infection rate of 3% (8/274). The use of vancomycin powder in patients with implants in this series did not reduce infection rates compared to published historical controls, and was elevated compared to institutional controls. Further prospective study of this high risk patient population is warranted.

Microsurgical clipping of large and giant cerebral aneurysms: a single-center contemporary experience

Several treatment strategies are available to manage large and giant cerebral aneurysms, including surgical, endovascular and combined approaches. We present our experience with microsurgical clipping of large and giant aneurysms. A total of 138 patients with 139 aneurysms of which 128 were large (≥10mm) and 11 were giant (≥25mm) were treated at our institution between 2004 and 2011. Data were collected from a prospectively maintained neurovascular database. Of 138 patients, 53 (38.4%) patients presented with subarachnoid hemorrhage (SAH). Peri-operative complications occurred in 16.7% of patients causing permanent morbidity in 4.4% and death in 0.7%. Complete occlusion, as evident on intra-operative angiography, was achieved in all clipped aneurysms (100%). Long-term follow-up angiography showed no recurrence (mean follow-up time, 43.9 months; range: 1-72 months). Favorable outcomes at discharge (Glasgow Outcome Scale score 4 or 5) were noted in 64.1% of SAH patients and 93% of non-SAH patients. Favorable outcomes at follow-up (mean follow up time, 42.5 months) were seen in 96% of patients. In our experience, microsurgical clipping of large and giant aneurysms carries low rates of morbidity and mortality with high rates of favorable outcomes. The excellent durability of surgical treatment stands in stark contrast with the high recurrence rates observed with coiling for this subset of aneurysms. These data suggest that microsurgical clipping continues to be a viable option that can be offered for patients with large and giant aneurysms.

The angiotensin-converting enzyme gene insertion/deletion polymorphism in Indian patients with vitiligo: a case-control study and meta-analysis

BACKGROUND

Vitiligo is a common, acquired, idiopathic depigmenting skin disorder. Although the exact pathogenesis remains unknown, genetic susceptibility and autoimmune responses play a role in vitiligo development. Previous studies have suggested that the D allele of the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene is associated with vitiligo in Indians and Koreans. Furthermore, significantly higher serum ACE levels have been demonstrated in patients with some autoimmune and autoinflammatory disorders.

OBJECTIVES

The objectives were to investigate any association between the ACE I/D polymorphism and vitiligo susceptibility in an Indian population, and to compare serum ACE levels in patients with vitiligo and healthy subjects.

METHODS

The ACE I/D genotypes of 79 patients with vitiligo and 100 normal individuals were determined by polymerase chain reaction amplification. A meta-analysis was done to compare the distribution of the ACE I/D alleles and genotypes in the current and three previous studies. Serum ACE levels were evaluated by enzyme-linked immunosorbent assay.

RESULTS

A significant increase in the frequency of the ACE I/D D allele was evident in patients with vitiligo in both the case-control study [P=0·005; odds ratio (OR) 1·87; 95% confidence intervals (CI) 1·22-2·85] and the meta-analysis (P=0·044; OR 1·44; 95% CI 1·01-2·06). Serum ACE levels were significantly increased in patients with vitiligo compared with healthy subjects (P<0·0001).

CONCLUSIONS

In agreement with earlier reports, the ACE I/D D allele is associated with vitiligo susceptibility in the Indian population. The significantly elevated serum ACE levels in our cohort of patients with vitiligo concur with those previously found in patients with some other autoimmune diseases.

Endovascular management of cerebral vasospasm following aneurysm rupture: outcomes and predictors in 116 patients

OBJECTIVE

To retrospectively assess the safety and efficacy of endovascular treatment of cerebral vasospasm with different modalities and assess predictors of outcome.

METHODS

Endovascular treatment was indicated in the event of neurological deterioration refractory to medical therapy. Data were collected for 116 patients treated at our institution.

RESULTS

Vasospasm was treated with balloon angioplasty in 52.6%, intra-arterial nicardipine infusion in 19.8%, or both in 27.6%. Angiographic vasospasm was reversed in all but 4 (96.6%) patients. The complication rate was 0.9%. Twenty patients (17.2%) had incipient pre-procedure hypodensities; 3 (15%) hypodensities were reversed and neurological improvement occurred in 60% of these patients. Retreatment was required in 22 (19%) patients. Higher Hunt and Hess grades and treatment with nicardipine alone predicted retreatment. Neurological improvement was noted in 82%. Male gender, pre-procedure hypodensities, and posterior communicating artery aneurysm location negatively predicted neurological recovery. Favorable outcomes were noted in 73%. Higher Hunt and Hess grades, pre-procedure hypodensities, posterior circulation aneurysms, and no neurological recovery predicted poor outcome.

CONCLUSION

Endovascular therapy for vasospasm has an excellent safety-efficacy profile. Balloon angioplasty and nicardipine are equally effective but effects of nicardipine are less durable. Patients with incipient pre-procedure hypodensities benefit from endovascular intervention and should probably not be excluded from treatment.

Subarachnoid hemorrhage with negative initial catheter angiography: a review of 254 cases evaluating patient clinical outcome and efficacy of short- and long-term repeat angiography

BACKGROUND

Subarachnoid hemorrhage (SAH) is found to have no vascular origin by initial catheter angiography in approximately 15% of cases. The most appropriate course for the type and frequency of additional diagnostic workup remains controversial.

OBJECTIVE

To retrospectively assess the diagnostic yield of short-term and long-term repeat catheter angiography in the era of advanced imaging.

METHODS

Between 2003 and 2011, 254 consecutive patients diagnosed with SAH had negative initial angiography. SAH was perimesencephalic (PM) in 46.5% and nonperimesencephalic (NPM) in 53.5%. Angiography was repeated at 1-week (short-term) and 6-week (long-term) intervals from the initial negative angiogram.

RESULTS

Ten of 254 patients had a vascular source of hemorrhage on short-term follow-up angiography with a diagnostic yield of 3.9%. One hundred seventy-four patients with negative findings on the first 2 angiograms received a third angiogram, and 7 of these patients were found to have a vascular abnormality. The estimated yield of this third angiogram was 4.0%. The overall diagnostic yield of repeat angiography was 0% in the PM group and 12.5% in the NPM group. The diagnostic yield of short-term and long-term follow-up angiography in patients with NPM SAH was 7.3% and 7.8%, respectively. NPM patients were more likely to experience vasospasm and hydrocephalus requiring external ventricular drainage or cerebrospinal fluid diversion than PM patients.

CONCLUSION

Our results support a protocol of short-term and long-term angiographic follow-up in patients with NPM SAH and negative initial angiography. Aggressive protocols of follow-up angiography may not be necessary in patients with PM SAH.

Effects of spray drying conditions on the physicochemical properties of the Tramadol-Hcl microparticles containing Eudragit(®) RS and RL

The preparation of Tramadol-HCL spray-dried microspheres can be affected by the long drug recrystallization time. Polymer type and drug–polymer ratio as well as manufacturing parameters affect the preparation. The purpose of this work was to evaluate the possibility to obtain tramadol spray-dried microspheres using the Eudragit^® RS and RL; the influence of the spray-drying parameters on morphology, dimension, and physical stability of microspheres was studied. The effects of matrix composition on microparticle properties were characterized by Laser Light scattering, differential scanning calorimetry (DSC), X-ray diffraction study, FT-infrared and UV-visible spectroscopy. The spray-dried microparticles were evaluated in terms of shape (SEM), size distribution (Laser light scattering method), production yield, drug content, initial drug loding and encapsulation efficiency. The results of X-ray diffraction and thermal analysis reveals the conversion of crystalline drug to amorphous. FTIR analysis confirmed the absence of any drug polymer interaction. The results indicated that the entrapment efficiency (EE), and product yield were depended on polymeric composition and polymeric ratios of the microspheres prepared. Tramadol microspheres based on Eudragit^® blend can be prepared by spray-drying and the nebulization parameters do not influence significantly on particle properties.

Development and characterisation of thermo reversible mucoadhesive moxifloxacin hydrochloride in situ ophthalmic gel

A sustain release thermo reversible in situ gel of Moxifloxacin Hydrochloride using mucoadhesive polymer was prepared. Mucoadhesive polymer was used to obtain an ophthalmic delivery system with improved mechanical and mucoadhesive properties that will provide prolong retention time for treatment of ocular diseases. Developed formulations were evaluated for drug-excipient compatibility study, pH, Clarity, Gelation temperature study, Mucoadhesion properties and in-vitro release studies. Drug-excipient compatibility study was performed by FTIR technique. The individual IR spectra of the pure drug and polymers as well as the combination spectra of the drug and polymer were taken, which indicate no interaction between Moxifloxacin and polymers when compared with infrared spectrum of pure drug as all functional group frequencies were present. The values of other parameters obtained were in acceptable range. In vitro release tests revealed that 98% drug was released from the in situ gel containing 0.5% and 1.00% HPMC in 12 hr. provides prolonged release.

Vitiligo patients from India (Mumbai) show differences in clinical, demographic and autoantibody profiles compared to patients in western countries

BACKGROUND

Vitiligo is a common, idiopathic skin disorder characterized by depigmented skin due to the loss of cutaneous melanocytes. Several studies have reported the clinical and demographic characteristics of Indian vitiligo patients, however, none has characterized their antibody profiles.

OBJECTIVE

To establish the clinical, demographic and serological details of a population of vitiligo patients from Mumbai, India, and to evaluate the data for any associations between clinical presentations and the occurrence of antibody responses.

METHODS

Vitiligo patients (n = 79) were recruited to the study and their clinical and demographic details recorded. Serum antibodies, including those against melanocyte-specific antigens, thyroid antigens and keratinocytes, were evaluated.

RESULTS

The prevalence of vitiligo was independent of sex, and non-segmental vitiligo was the most common form of the disease occurring in 65% of the patients. Patients with segmental vitiligo (mean age = 14.4 ± 4.6 years) presented at a younger age than those with non-segmental disease (mean age = 32.5 ± 17.8 years). Personal and family histories of other autoimmune diseases occurred in 3% and 8% of patients, respectively. Antibodies were detected against tyrosinase, tyrosine hydroxylase, thyroid peroxidase, thyroglobulin and keratinocytes at frequencies of 11%, 22%, 18%, 24% and 27%, respectively. Overall, antibodies were more common in patients with non-segmental vitiligo (50-67%) than in those with segmental disease (0-17%), and were detected more frequently in patients with shorter disease durations (<10 years).

CONCLUSION

Our study provides novel information relative to the clinical details, demographic features and serological parameters of a population of vitiligo patients from Mumbai, India. Important distinctions from similar surveys conducted in European patients were evident such as an infrequency of family history, a low prevalence of clinical autoimmune disease, and an absence of particular antibody specificities. These differences may have a bearing on the pathogenesis and course of the disease in Indian patients.

Evaluation of bioequivalence of two oral formulations of olanzapine

Olanzapine is an atypical antipsychotic drug, used for the management of schizophrenia and for the treatment of moderate to severe mania associated with bipolar disorder. The objective of the present randomised, crossover study was to compare the bioavailability of olanzapine 10 mg/5 ml powder for oral suspension with olanzapine 10 mg orally disintegrating tablet. Eighteen healthy male volunteers were randomly assigned to crossover, single-dose treatment regimens. Serial blood samples were collected, and plasma concentrations of olanzapine were analysed using the LC-MS/MS technique. Pharmacokinetic parameters and bioequivalence limits were calculated using non-compartmental methods. Average C(max) following administration of the single 10 mg disintegrating tablet formulation and 10 mg/5 ml suspension were 14.47±4.25 ng/ml and 13.56±3.99 ng/ml respectively. Corresponding median T(max) were 5.0 h and 6.0 h, respectively. The average AUC(0-t) values and AUC(0-inf) values were similar following each of the olanzapine preparations. Overall, the 90% Confidence Interval for the intra-individual ratios of the log-transformed C(max) and AUC values of the two formulations were within the bioequivalence interval of 80-125%. The study has demonstrated the bioequivalence of the 10 mg tablet and the 10 mg/5 ml oral suspension of olanzapine.

Perceiving individuals and groups: expectancies, dispositional inferences, and causal attributions

Two experiments investigated differences in forming impressions of individual and group targets. Experiment 1 showed that when forming an impression of an individual, perceivers made more extreme trait judgments, made those judgments more quickly and with greater confidence, and recalled more information than when the impression target was a group. Experiment 2 showed that when participants were forming an impression of an individual, expectancy-inconsistent behaviors spontaneously triggered causal attributions to resolve the inconsistency; this was not the case when the impression target was a group. Results are interpreted as reflecting perceivers' a priori assumptions of unity and coherence in individual versus group targets.