Prevalence of cardiovascular risk factors in Indian patients undergoing coronary artery bypass surgery

BACKGROUND

Conventional cardiovascular risk factors (CVRFs) are known to influence short-term and long-term outcome following coronary artery bypass graft surgery (CABG). There has been recent increase in prevalence of CVRFs in general population in India. However no information is available regarding the prevalence of same in patients undergoing CABG.

METHODS AND RESULTS

In this cross-sectional study, one thousand consecutive patients undergoing elective CABG were included and data on major CVRFs was obtained in them. Mean age of the patients was 59.73 +/- 9.5 years and 884/1000 (88.4%) patients were males. 505/994 (50.8%) patients had BMI > or = 25.0 kg/m2 and 747/994 (75.2%) had BMI > or = 23.0 kg/m2. Diabetes mellitus was present in 475/1000 (47.5%) patients (46.5% men and 55.2% women), hypertension in 709/1000 (70.9% overall; 70.8% men and 71.6% women) and dyslipidemia in 781/913 patients (85.6% overall; 84.5% men and 93.9% women). 213/913 (23.3%) patients had LDL > or = 100mg/dl, 662/913 (72.5%) patients had low HDL and 338/913 (37.0%) patients had elevated triglycerides. 199/1000 (19.9%) patients (18.7% men and 29.3% women) had family history of premature CAD and 545/1000 (54.5%) patients (53.4% men and 62.9% women) had at least one family member having CAD (irrespective of the age of onset). 94/1000 (9.4%) patients (10.4% men and 1.7% women) were current smokers and another 302/1000 (30.2% overall; 33.7% men and 3.4% women) had history of smoking in the preceding one year. 876/913 (95.9%) of all the patients had at least one of the five major CVRFs and only 37/ 913 (4.1%) patients (4.1% men and 4.3% women) were free of all these risk factors. Sixty-one of the 1000 patients (6.1%) were younger than 45.0 years of age. As compared to older patients, dyslipidemia, family history of premature CAD and smoking were commoner in patients less than 45 years of age. In contrast, diabetes and hypertension were more prevalent in the older individuals.

CONCLUSIONS

The present study showed high prevalence of most of the conventional CVRFs, esp. diabetes, hypertension and dyslipidemia in Indian population undergoing CABG.

SCH 503034, a mechanism-based inhibitor of hepatitis C virus NS3 protease, suppresses polyprotein maturation and enhances the antiviral activity of alpha interferon in replicon cells

Cleavage of the hepatitis C virus (HCV) polyprotein by the viral NS3 protease releases functional viral proteins essential for viral replication. Recent studies by Foy and coworkers strongly suggest that NS3-mediated cleavage of host factors may abrogate cellular response to alpha interferon (IFN-alpha) (E. Foy, K. Li, R. Sumpter, Jr., Y.-M. Loo, C. L. Johnson, C. Wang, P. M. Fish, M. Yoneyama, T. Fujita, S. M. Lemon, and M. Gale, Jr., Proc. Natl. Acad. Sci. USA 102:2986-2991, 2005, and E. Foy, K. Li, C. Wang, R. Sumpter, Jr., M. Ikeda, S. M. Lemon, and M. Gale, Jr., Science 300:1145-1148, 2003). Blockage of NS3 protease activity therefore is expected to inhibit HCV replication by both direct suppression of viral protein production as well as by restoring host responsiveness to IFN. Using structure-assisted design, a ketoamide inhibitor, SCH 503034, was generated which demonstrated potent (overall inhibition constant, 14 nM) time-dependent inhibition of the NS3 protease in cell-free enzyme assays as well as robust in vitro activity in the HCV replicon system, as monitored by immunofluorescence and real-time PCR analysis. Continuous exposure of replicon-bearing cell lines to six times the 90% effective concentration of SCH 503034 for 15 days resulted in a greater than 4-log reduction in replicon RNA. The combination of SCH 503034 with IFN was more effective in suppressing replicon synthesis than either compound alone, supporting the suggestion of Foy and coworkers that combinations of IFN with protease inhibitors would lead to enhanced therapeutic efficacy.

HLA-E and immunobiology of pregnancy

Recently, it has been suggested that non-classical antigens such as human leukocyte antigen (HLA)-G and HLA-E may interact with KIR receptors of NK cells which results into downregulation of immune response and helps in the maintenance of pregnancy. In the present study, we have investigated HLA-E polymorphism in normal fertile women and recurrent spontaneous aborters to assess the effect of HLA-E alleles on the success of pregnancy. Allele E*0101 was found to be significantly higher in patients with recurrent spontaneous abortion (chi(2) = 4.097 and P = 0.0430). Differential expression, peptide affinity, and stability of E*0101 may be one of the reasons.

Carotid Intima-Media Thickness and Brachial Artery Flow-Mediated Dilatation in Patients with and without Metabolic Syndrome

BACKGROUND, Metabolic syndrome has recently emerged as a marker of future cardiovascular risk. However its incremental value for this purpose, over conventional cardiovascular risk factors and diabetes mellitus in particular, is debated. The present study was conducted to determine the extent of subclinical atherosclerosis in patients with metabolic syndrome, and compare it with the same in individuals with cardiovascular risk factors not having metabolic syndrome. METHODS, A total of 156 individuals seeking outpatient cardiac consultation for various indications were included in the study and were divided into four groups - group 1: cardiovascular risk factors present but not metabolic syndrome (n = 60) : group 2 : metabolic syndrome without diabetes mellitus or coronary artery disease (n = 21) ;group 3: metabolic syndrome with diabetes mellitus without coronary artery disease ( n = 27) ;and group 4:patients with documented coronary artery disease (n = 48). Metabolic syndrome was diagnosed on the basis of Adult Treatment Panel III (ATPIII) criteria. All patients underwent assessment of carotid intima-media thickness and brachial artery flow-mediated vasodilatation. RESULTS, Both carotid intima-media thickness and brachial artery flow-mediated vasodilatation were similar in groups 1 and 2 (carotid intima-media thickness: 0.687 -/+ 0.13mm and 0.706 -/+0.23mm, p = 0.963; brachial artery flow-mediated vasodilatation: 11.80 -/+ 5.16% and 12.87 -/+ 7.04%, respectively, p =0.883) , but group 3 patients had significantly higher carotid intima-media thickness (0.774 +/- 0.15mm, p = 0.047) and significantly lower brachial artery flow-mediated vasodilatation (7.37 -/+ 6.12%, p -/+ 0.007) as compared to group 1 patients. There was no significant difference in the two parameters between groups 3 and 4 (carotid intima-media thickness in group 4:0.789 -/+ 0.16mm,p = 0.976 and brachial artery flow-mediated vasodilatation:5.86 -/+ 3.85%, p -/+ 0.709). CONCLUSIONS, In absence of diabetes mellitus, metabolic syndrome was not associated with greater extent of subclinical atherosclerosis compared to individual cardiovascular risk factors. Presence of diabetes mellitus, however, resulted in significant endothelial dysfunction and evidence of subclinical atherosclerosis, similar to that seen in patients with already established coronary artery disease.

Angiotensin converting enzyme gene polymorphism in Indian children with steroid sensitive nephrotic syndrome

CONTEXT

Nephrotic syndrome is one of the commonest renal problem encountered in children. It is difficult to predict at onset, the clinical course in terms of steroid responsiveness or resistance. Angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been studied as a predictor of clinical course in common multi-factorial diseases including focal segmental glomerulosclerosis. There is no study available from our country till date to find out any correlation of the steroid response in idiopathic nephrotic syndrome and ACE gene polymorphism.

AIM

To study distribution and correlation of ACE gene I/D polymorphism in idiopathic steroid sensitive nephrotic syndrome.

SETTINGS & DESIGN

Case-control retrospective study.

SUBJECTS & METHODS

We studied ACE gene polymorphism in 90 consecutive patients (82% males, 18% females) with steroid sensitive idiopathic nephrotic syndrome and 300 normal controls (NC).

STATISTICAL ANALYSIS

Chi-square test and Fisher's exact test (for cases with insufficient expected cell frequencies).

RESULTS

The mean age of onset was 5.3 +/- 4 years. Steroid sensitive (SS) patients showed II (SS-48%, NC-26%) genotype was more frequent than normal controls (p=0.002). There was no significant difference in genotype frequencies among steroid SS subgroups.

CONCLUSIONS

In our study II genotype was more frequent in steroid sensitive nephrotic syndrome children in comparison to normal controls. Further functional studies with large number of children are required to investigate the role of II genotype in steroid sensitive nephrotic syndrome. Comparison of the genotypic frequency with steroid resistant patients may provide information, which might be useful in clinical practice.

MUC 1 core protein as a marker of gallbladder malignancy

AIM

The significance of MUC 1 expression in the gallbladder tissues in relation to cancer and non-cancer disease is not well understood. The aim of this study was to clarify the significance of MUC 1 expression.

MATERIALS AND METHODS

A monoclonal antibody (CA 15--3; DF 3) was applied to stain MUC 1 core protein in surgical specimens.

RESULTS

MUC 1 expression is significantly higher (p<0.0001) in gallbladder cancer (69/88) compare to non-cancerous tissue, while, very trace in normal and inflammatory tissues. The expression rate was significantly lower (p<0.0001) when the cancer did not penetrate the mucosal layer than when cancers did penetrate this layer. The MUC 1 expression rate was (4/14) in T1 tumours, (11/14) in T4, (40/45) in T3, and (14/15) in T2, respectively. Every cell of normal and inflammatory mucosa, and T1 cancers had the polarized pattern. The depolarized pattern was dominant in cancer cells from the advanced tumours of T2, T3 and T4. That is, (45/74) of cancer cells from the mucosal layer and (58/74) of penetrating cancer cells in submucosal layer had the depolarized pattern. There was no significant correlation of MUC 1 expression rate and staining pattern with cancer differentiation and microscopic venous invasion. On the other hand, lymphatic vessel invasion was significantly correlated with the staining pattern but not with expression rate.

CONCLUSION

MUC 1 core protein expression rate and pattern are suggesting that MUC 1 core protein would be a marker of malignant transformation of gallbladder epithelium and its depolarized expression would also be a marker of invasion of gallbladder cancer.

Minimum sample size and sampling time requirements for assessment of rifampicin bioequivalence from FDC formulations

SETTING

The WHO- and IUATLD-recommended protocol for rifampicin (RMP) bioequivalence utilises 20-22 volunteers and 8 h, whereas the requirement of other regulatory authorities is 12 volunteers with a 24 h sampling schedule. Differing sampling size and time requirements may change the outcome of RMP bioequivalence.

OBJECTIVE

To determine the minimal sample size and time required to assess RMP bioequivalence from FDC formulations.

DESIGN

Bioequivalence studies were conducted that fulfilled the criteria of the WHO and Indian regulatory protocols. From earlier studies, retrospective pharmacokinetic evaluation, power of the test and bioequivalence limits were also calculated using 8-22 volunteers and sampling points of 8-24 h. Pharmacokinetic and statistical evaluations from three representative studies showing low, moderate and high intra-subject variability are given to determine minimum requirements for RMP bioequivalence.

RESULT

It was found that a sampling schedule up to 8 h was sufficient to compare the absorption process of RMP. There was no influence of reduced sample size on bioequivalence estimates of RMP that showed low or moderate variability. However, in a study showing higher variation, a sample size of 14-16 subjects was found to be optimal.

CONCLUSION

It is possible to reduce the sample size requirement for determination of RMP bioequivalence using the WHO protocol.

Angiotensin converting enzyme gene polymorphism in Indian children with steroid sensitive nephrotic syndrome

CONTEXT

Nephrotic syndrome is one of the commonest renal problem encountered in children. It is difficult to predict at onset, the clinical course in terms of steroid responsiveness or resistance. Angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been studied as a predictor of clinical course in common multi-factorial diseases including focal segmental glomerulosclerosis. There is no study available from our country till date to find out any correlation of the steroid response in idiopathic nephrotic syndrome and ACE gene polymorphism.

AIM

To study distribution and correlation of ACE gene I/D polymorphism in idiopathic steroid sensitive nephrotic syndrome.

SETTINGS & DESIGN

Case-control retrospective study.

SUBJECTS & METHODS

We studied ACE gene polymorphism in 90 consecutive patients (82% males, 18% females) with steroid sensitive idiopathic nephrotic syndrome and 300 normal controls (NC).

STATISTICAL ANALYSIS

Chi-square test and Fisher's exact test (for cases with insufficient expected cell frequencies).

RESULTS

The mean age of onset was 5.3 +/- 4 years. Steroid sensitive (SS) patients showed II (SS-48%, NC-26%) genotype was more frequent than normal controls (p=0.002). There was no significant difference in genotype frequencies among steroid SS subgroups.

CONCLUSIONS

In our study II genotype was more frequent in steroid sensitive nephrotic syndrome children in comparison to normal controls. Further functional studies with large number of children are required to investigate the role of II genotype in steroid sensitive nephrotic syndrome. Comparison of the genotypic frequency with steroid resistant patients may provide information, which might be useful in clinical practice.

Variation of intraocular pressure in patients with leprosy

INTRODUCTION

There are various controversial reports on intraocular pressure (IOP) in patients with leprosy.

PURPOSE

The current study was undertaken to study the level of intraocular pressure in leprosy patients and its association with the risk factors.

MATERIALS AND METHODS

This was a prospective cross sectional comparative study. An ophthalmologist and a dermatologist evaluated consecutive 93 patients with leprosy. The risk factors studied were age, gender, bacillary index, clinical diagnosis, duration of disease and treatment; and ocular complications. The IOP in these patients was compared with healthy age and sex matched controls.

RESULTS

A total of 186 leprosy patients (93) and healthy controls (93) were studied. The mean applanation IOP for the right and left eyes in leprosy patients was 12.87 1.20 mm of Hg and 13.222.70 mm of Hg respectively. This was found to be significantly lesser (p<0.001) than in the controls (RE=15.142.58 and LE=15.412.36 mmHg). The untreated leprosy patients had significantly lower IOP than those with treatment (p<0.001). None of the risk factors were found to be independently associated with the decrease in IOP. The duration of treatment, however, showed a trend towards having a significant association (p=0.057) with the lower level of IOP.

CONCLUSION

The level of IOP is lower in leprosy patients than in the healthy controls. Age, gender, bacillary index and presence of ocular complications due to leprosy are not independently associated with the decrease in IOP. The untreated leprosy patient tends to have a lower IOP. This finding can be used to monitor effectiveness of treatment of leprosy.

The association between narcolepsy and REM behavior disorder (RBD)

BACKGROUND AND PURPOSE

Rapid eye movement (REM) sleep Behavior Disorder (RBD) is a movement disorder associated with loss of REM-related muscle atonia and is characterized by complex, vigorous and frequently violent dream-enacting behavior during REM sleep. RBD is usually idiopathic or secondary to neurological problems such as Parkinson's disease. This study looked at the association of RBD with another sleep disorder, narcolepsy.

PATIENTS AND METHODS

Seventy-eight questionnaires were sent to known narcoleptics chosen at random from those with contact details available at the center. The questionnaire addressed current narcolepsy symptoms, medication use and symptoms of RBD. Positive questionnaire results were followed up with a telephone interview. Limited polysomnography (PSG) data was also analyzed.

RESULTS

Fifty-five patients responded (response rate 71%). Of these, 20 (36%) had symptoms suggestive of RBD. The typical RBD patient is an older male (mean age of onset 60.9 years, 87% male); however, in this study, females were as likely to have RBD as males, and the mean age was 41 years. Sixty-eight percent of patients who regularly experienced cataplexy and the associated symptoms of narcolepsy (sleep paralysis, hypnogogic hallucinations and automatic behavior) had RBD, compared to 14% of those who never or rarely experienced these symptoms.

CONCLUSION

This study implies a stronger relationship between these disorders than a previously published figure of 7-12% This is clinically significant as RBD is a potentially distressing but readily treatable disorder. It follows that narcoleptics, especially those with cataplexy and other associated symptoms, should be questioned about symptoms of RBD and treated accordingly. Similarly, anyone presenting with RBD should be assessed for symptoms of narcolepsy, particularly if female or of a younger age group than would otherwise be expected.

Ab-initio study of the structural and electronic properties of very thin silver nanowires

An ab initio study of the energetics, structural, and electronic properties of thin silver nanowires of Ag(n) with n = 1 to 6 has been made in density functional theory in local density approximation. The present study reveals that all of the wires are stable except the wire with 3 silver atoms per unit cell. The linear chain is comparatively less stable. The binding energies of the most stable wires lie in the range 2.60-3.18 eV/atom with maximum values for the 5-Ag pentagonal and the two 6-Ag (hexagonal and pyramidal) nanowires. The nearest neighbor Ag-Ag separations in all of the most stable wires up to n=6 is quite the same and is equal to 2.634 +/- 0.03 A. For the most stable 6-Ag pyramidal wire, the bond length increases to 2.75 or 2.81 A. The cross-sectional dimension of these wires are around 5.0 A. All of the studied silver wires are metallic. A majority of the sd mixed states cross the Fermi level. The density of state is maximum for the 5-Ag pentagonal and 6-Ag pyramidal nanowires, and so is the number of channels (5 or 6) crossing the E(F) which would be available for high electrical conduction.

Analysis of human leukocyte antigen (HLA)-G polymorphism in normal women and in women with recurrent spontaneous abortions

Human leukocyte antigen (HLA)-G is a non-classical class I antigen. It has limited expression, but is high at the foetomaternal interface. This unique expression pattern of HLA-G suggests that it might be important for survival of the foetus during pregnancy. In the present study, 120 women with recurrent spontaneous abortions (RSA) and 120 fertile control women were genotyped for the HLA-G locus. This is the first report describing HLA-G polymorphism in normal fertile and RSA women from India. The allele HLA-G*010103 was higher in women with recurrent foetal losses. Interestingly, the HLA-G*010105 and G*010108 alleles were totally absent in normal fertile women but present in RSA women with frequencies of 1.7% and 0.4%, respectively. Allele G*010107 was absent in both the groups. The frequency of the null allele G*0105N was high (13.8%) in our population as compared to other world populations. Our data support the hypothesis that HLA-G polymorphism may contribute to recurrent foetal loss.

Structural and vibrational properties of small carbon clusters

An ab-initio comprehensive study of the stability and structural and vibrational properties of small carbon clusters, CN for N = 1-10, has been made. We use a self-consistent pseudopotential method within density functional theory in the generalized gradient approximation considering spin polarization. The estimated values of binding energies for the various clusters are overestimated in the non-spin-polarized calculations. On the other hand, for the spin-polarized case, the computed binding energies are in very good agreement with the available experimental data. Also, the calculated vibrational frequencies for CN, N = 2-5, are in reasonable agreement with the available experimental values.

Chitosan hydrochloride based microspheres of albendazole for colonic drug delivery

Microspheres of chitosan hydrochloride (CH) were prepared in order to deliver albendazole specifically into the colon. Microspheres were prepared by an emulsion method using different ratios of drug and CH (1:1 to 1:5), agitation speeds (500 to 1500 rpm) and concentrations of glutaraldehyde in toluene as the cross-linking agent (0.25 to 1.0% w/v). The effect of polymer concentration, stirring rate and concentration of cross-linking agent on the particle size and drug loading was studied. With an increase in CH concentration, the average particle size was increased. Increased agitation speed reduced the size of the microspheres but higher agitation speed resulted in irregularly shaped microspheres. Increasing the concentration of cross-linking agent produced more regularly shaped microspheres of smaller size. The drug loading was highest at a drug: CH ratio of 1:3, stirring speed 1000 rpm and 0.75% w/v concentration of cross-linking agent. The effect of CH concentration on in vitro drug release from the microspheres was evaluated in simulated g.i.t fluids. A comparative in vitro drug release study of the optimized formulation was carried out in simulated colonic fluid, with and without 2% rat caecal content. The drug release in 24 h was 48.9% in colonic fluid without rat caecal content, and 76.5% in colonic fluid with rat caecal contents.

Determination of rifampicin bioequivalence in a three-drug FDC by WHO and indian protocols: effect of sampling schedule and size

SETTING

To promote the quality assurance of fixed-dose combination (FDC) formulations, the World Health Organization (WHO) has prepared a convenient simplified protocol for the determination of rifampicin (RMP) bioequivalence. During the development of this protocol, it was proved that sampling time up to 8 h can determine the rate and extent of RMP absorption. However, this protocol utilises 20 volunteers in contrast to other local regulatory requirements of a minimum of 12 volunteers. The different sample sizes utilised in these protocols may affect the sensitivity of the bioequivalence outcome.

OBJECTIVE

To determine the effect of sampling size and schedule on RMP bioequivalence when two different protocols are used.

DESIGN

A bioequivalence trial was conducted with a study design of 20 volunteers and 24 h sampling time, which fulfils the requirements of both the WHO and Indian regulatory protocols. Pharmacokinetic and statistical analysis was done by stepwise reduction in sample size and schedule.

RESULT

Bioequivalence limits of RMP were unaffected by a reduced sample size of 12 volunteers and 8 h sampling time.

CONCLUSION

Minimising sample size after validation for borderline and poor quality FDC formulations can further reduce the cost of conducting bioequivalence trials.

Management of visceral leishmaniasis: Indian perspective

Diagnosis and treatment of Indian visceral leishmaniasis (VL) is extremely unsatisfactory. For diagnosis, demonstration of parasites in splenic/marrow smears remains the gold standard, though k39 rapid strip test is a useful method in regions where access to parasite demonstration is difficult. pentavalent antimony remains the mainstay for the treatment of all forms of leishmaniasis globally; however, development of large-scale antimony resistance in Bihar has necessitated search for alternative drugs. Amphotericin B is the most effective, though toxic, drug for patients with refractory VL. Lipid formulations of amphotericin B, though safe and effective, are too expensive to be useful for poor patients of this region. These hold advantage as large quantity of the drug can safely be given over a short period of time, thus leading to a decrease in the hospital stay to a few days instead of several weeks. Oral miltefosine, an alkyl phospholipid, has recently been approved and marketed in India for the treatment of VL. Miltefosine cures 94% patients with VL if given in a daily dose of 50-100 mg for 28 days. Most common adverse events are mild vomiting and diarrhea. Paromomycin, an amino glycoside, is undergoing a pivotal phase-III clinical trial, and is likely to be approved and available to patients with VL at an affordable cost. To protect the already scarce inventory of antileishmanial drugs, it is time that combination chemotherapy is introduced for the treatment of VL in India.

T1 and M1 polymorphism in glutathione S-transferase gene and coronary artery disease in North Indian population

BACKGROUND

DNA damage has been found to play an important role in atherosclerosis and coronary artery disease. Genetic polymorphisms of the genes coding for enzymes involved in the metabolism of genotoxins result in different phenotypes with respect to their ability to detoxify these agents. In the present study the contribution of the polymorphism in the glutathione S-transferase gene to the development of coronary artery disease has been investigated.

METHODS

One hundred and ninety seven angiographically proven patients with coronary artery disease and one hundred and ninety eight age-matched controls were genotyped for glutathione S- transferase polymorphism by polymerase chain reaction. Genotype frequencies were compared in patients and controls by Chi-square test. Binary logistic regression was used to examine the relationship between genotype and disease, incorporating other variables into the model.

RESULTS

GSTT1 null genotype was significantly decreased in patients with coronary artery disease. No significant association was found with GSTM1 genotypes. No such association was seen with smokers.

CONCLUSION

Null genotype of GSTT1 is protective against coronary artery disease in our population.

Role of 14-bp deletion in theHLA-Ggene in the maintenance of pregnancy

Differential expression of human leukocyte antigens (HLAs) on trophoblast has been the focus of many studies, specially on extravillous cytotrophoblast cells, which migrates into the maternal uterine tissues. These invading cells do not express classical major histocompatibility complex class I (-A and -B) and class II molecules, along with low expression of HLA-C. HLA-G is the predominantly expressed antigen along with HLA-E. Hence, it is believed that expressed antigens may be involved in materno-fetal tolerance. In the present study, we have studied 14-bp deletion polymorphism in the exon-8 of the non-classical HLA-G antigen. There was no difference in the frequency of deletion/insertion polymorphism in fertile normal women and recurrent spontaneous abortion (RSA) women. However, the number of heterozygotes (-14b/+14b) were increased in RSA women. The probable mechanism for the increase of heterozygotes in recurrent fetal loss is discussed in light of soluble HLA-G.

In vitro analysis of rifampicin and its effect on quality control tests of rifampicin containing dosage forms

The chemical stability of rifampicin both in solid state and various media has widely been investigated. While rifampicin is appreciably stable in solid-state, its decomposition rate is very high in acidic as well as in alkaline medium and a variety of decomposition products were identified. The literature reports on highly variable rifampicin decomposition in acidic medium. Hence, the objective of this investigation was to study possible reasons responsible for this variability. For this purpose, filter validation and correlation between rifampicin and its degradation products were developed to account for the loss of rifampicin in acidic media. For analysis of rifampicin with or without the presence of isoniazid, a simple and accurate method was developed using high performance chromatography recommended in FDC monographs of the United States Pharmacopoeia. Using the equations developed in this investigation, the amount of rifampicin degraded in the acidic media was calculated from the area under curve of the degradation products. Further, it was proved that in a dissolution study, the colorimetric method of analysis recommended in the United States Pharmacopoeia provides accurate results regarding rifampicin release. Filter type, time of injection as well as interpretation of data are important factors that affect analysis results of rifampicin in in vitro studies and quality control.