Abstract P6-09-08: COMPliance and Arthralgia in Clinical Therapy: The COMPACT trial, assessing the incidence of arthralgia, therapy costs and compliance within the first year of adjuvant anastrozole therapy

Background: Aromatase Inhibitors (AI) are well established as adjuvant treatment for postmenopausal (PMP) women with hormone receptor positive (HR+) early breast cancer (EBC). However, phase III clinical trials have reported higher rates of arthralgia associated with AI than tamoxifen. This study aims to collect real world data on the effects of AI-associated arthralgia on patient compliance, patient outcomes and on treatment of arthralgia.

Methods: COMPACT is an open, prospective, non-interventional, non-randomized study (NCT00857012) run in Germany. PMP women with HR+ EBC who had been on adjuvant anastrozole (ANA) for 3–6 months were enrolled and stratified by initial adjuvant ANA or switch from tamoxifen. All patients received regular standardized information about breast cancer from baseline to week 20 to support treatment compliance. Data on demographics, arthralgia, related therapies, other side effects and QoL were collected at baseline, 3, 6 and 9 months. Primary endpoints are scaled data on arthralgia and compliance within the first year of ANA therapy. Secondary endpoints include incidence of arthralgia, therapy costs, reasons for non-compliance, and influence of arthralgia on clinical outcome.

Results: Between Apr 2009 and Mar 2011, 2313 patients were enrolled, 2007 on upfront ANA and 306 on switch from tamoxifen. The mean age at baseline was 64.5 years, mean BMI 27.7. Only 17.0% of patients had received HRT prior to their EBC. At baseline, 41.9% reported symptoms relating to skeleton or musculature. 12.0% reported arthralgia existing prior to ANA treatment and 13.2% stated a worsening of pre-existing arthralgia or new arthralgia after starting ANA. Predictors for non-adherence to AI therapy were former non-adherence, general symptom load on the side effect scale GASE, and low benefit expectation at treatment start. Risk of arthralgia was related to BMI (lowest for patients with BMI ≤24.1 kg/m2, highest with BMI >30.5 kg/m2 at all time points; OR>1) and upfront therapy (switch patients had a reduced risk of 68% at 6 and 61% at 9 months compared to patients with ANA upfront, p = 0.002). Patients with prior chemotherapy had lower rates of arthralgia before start of ANA (10.4% vs 13.3%, p = 0.036) but higher rates after the start of ANA and before study start (27.0% vs 22.5%, p = 0.013). Patients with arthralgia showed higher compliance rates at all time points (p < 0.001).

Conclusion: COMPACT identified arthralgia and musculoskeletal symptoms as common complaints in PMP women with EBC. ANA treatment both increased the number of women with such symptoms and aggravated these in some patients. Higher BMI and upfront AI predicted for risk of AI associated arthralgia. However, COMPACT also showed that AI-associated arthralgia did not lead to non-compliance in most patients. This data may help to better understand compliance issues with adjuvant AI treatment.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-09-08.

PD06-07: COMPliance and Arthralgias in Clinical Therapy (COMPACT): Assessment of the Incidence and Severity of Arthralgia, Treatment Costs and Compliance within the First Year of Adjuvant Anastrozole Therapy

Introduction: Aromatase inhibitors (AI) are well established as adjuvant endocrine treatment for postmenopausal (PMP) women with HR+ early breast cancer (EBC). However, according to retrospective data, compliance to adjuvant endocrine therapy for EBC may drop to below 70% after one year and to as low as 50% by year 4. In clinical trials, AI are significantly more frequently associated with arthralgia than tamoxifen. Yet, prospective real world data on the effects of AI-associated arthralgia on patient compliance, patient outcomes as well as treatment costs of arthralgia are lacking.

Methods: COMPACT is an open, prospective, non-interventional study assessing the incidence and severity of arthralgia, treatment costs, and compliance within the first year of adjuvant anastrozole therapy in PMP women with HR+ EBC. The study is sponsored by AstraZeneca Germany and supported by three major German health insurance funds [GWQ ServicePlus AG, DAK, TK]. Patients on adjuvant treatment for 3–6 months were enrolled at 620 breast centres and practices throughout Germany and stratified by, a) initial adjuvant anastrozole therapy or, b) switch from tamoxifen to anastrozole. All patients receive regular standardized information about EBC from baseline to week 20 to support treatment compliance. Data on patient demographics, occurrence of and treatment of arthralgia, and quality of life will be collected at baseline, 3, 6 and 9 months. Primary endpoints are scaled data on arthralgia, assessed with a visual analogous scale (VAS) via patient questionnaire, and compliance to anastrozole in both strata, assessed by patient and investigator questionnaire. Secondary endpoints include the incidence of arthralgia, treatment costs, reasons for non-compliance, and the influence of arthralgia on clinical outcome. For a subgroup of patients data on arthralgia treatment and compliance will be validated with corresponding data of the participating health insurance funds.

Results: Between April 2009 and February 2011, 2313 patients were recruited, 2007 receiving upfront anastrozole and 306 patients on switch therapy. Preliminary baseline data for 2313 patients show the following patient characteristics: mean age 64.5 years, mean BMI 27.7. Only 16.8% of patients had received hormone replacement therapy prior to their cancer. 41.5% of patients had concomitant symptoms relating to skeleton or musculature, and 11.9% stated arthralgias existing prior to anastrozole treatment. 13.1% reported a worsening of pre-existing arthralgias or new arthralgia after starting on anastrozole treatment.

Conclusion: COMPACT aims to provide valid real world data on the incidence and severity of AI-associated arthralgia, treatment modalities and treatment costs. Our results will help to understand and better counsel patients about AI-associated arthralgia to improve adherence to AI-treatment, breast cancer outcomes, and therapy costs.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD06-07.

Aromatase inhibitor-induced arthralgia: clinical experience and treatment recommendations

It is well documented that the aromatase inhibitors (AIs) are superior to tamoxifen as adjuvant endocrine therapy in postmenopausal women with hormone receptor-positive breast cancer. However, compared with tamoxifen, an elevated incidence of arthralgia has been observed during AI treatment. Concerns have been raised that AI-induced arthralgia may dissuade patients from completing their full AI treatment course, and may also deter physicians from prescribing an AI if they feel that patients may be at risk of permanent joint damage. Patient education about the possibility of experiencing arthralgia, and effective management of symptoms if they appear, are important in helping patients adhere to AI treatment, and consequently improving breast cancer outcomes. In this paper, we discuss the potential mechanisms behind AI-induced arthralgia, review the frequency with which arthralgia occurs, and propose for the first time an algorithm specifically for the treatment of AI-induced arthralgia. As with joint pain in non-breast cancer patients, a sequential approach to disease management is recommended, involving modifying the patient's lifestyle in addition to taking a stratified approach to pharmacological intervention with analgesia and anti-inflammatory medication. Knowing that joint symptoms can be managed in most patients may encourage patient-physician communication and treatment compliance.

Problem of the atherothrombotic potential of non-steroidal anti-inflammatory drugs

Treatment of pain in rheumatoid arthritis must take into account the gastrointestinal and cardiovascular risk of individual patients. Adequate results are not yet available, and until they are, treatment recommendations must take into account, not only the more favourable gastrointestinal risk profile of selective COX-2 inhibitors, but also the potential atherothrombotic risk of any NSAID or selective COX-2 inhibitor treatment.

[Recommendations for treatment with nonsteroidal anti-inflammatory drugs]

Recommendations for treatment with NSAIDs that take into account the latest study results must note that both the duration of treatment and the NSAID dose must be kept as small as possible. Elevated gastrointestinal risk is the rationale for the use of selective COX-2 inhibitors in place of conventional NSAIDs, or, where indicated, co-medication with a proton pump inhibitor. A manifest cardiovascular risk is aggravated by the use of coxibs, but probably also by the administration of traditional NSAIDs. Cardioprotective medication in the form of low-dose acetyl salicylic acid can probably reduce the cardiovascular risk, but at the same time increases the gastrointestinal risk. In such cases, proton pump inhibitors can offer some relief. However, the latter have no effect on the situation in the lower gastrointestinal tract. In patients with an elevated cardiovascular risk, the use of coxibs, and probably also NSAIDs for the treatment of pain, is problematical. The decision on what treatment to apply should be made on the basis of a benefit/risk assessment, and consideration should be given to alternative therapeutic strategies.

[Diagnosis, therapy and prognosis in systemic autoimmune disorders like lupus erythematosus]

Systemic lupus erythematosus (SLE) is the prototype of a systemic autoimmune disorder, in which immune complexes or cytotoxic antibodies give rise to tissue damage and organ failure, which often results in death. Due to more sensitive diagnostic tools and more sufficient therapeutic methods, the five-year survival rate in patients with systemic lupus erythematosus has improved dramatically during the past decades from less than 50% to 95%. Mortality is still 4 to 5 times higher and is mostly caused by uncontrolled disease flares, infections, and thromboses. Risk factors influencing the course of SLE and favouring the higher mortality are serum antibodies (anti-dsDNA, anticardiolipin, lupus anticoagulant), infections, hypertension, osteoporosis with fractures, cytopenia, renal involvement, higher age at onset, and genetic factors. Morbidity and social consequences are conducted by individual multisystemic disease manifestations.

[Differential analgesic treatment in arthrosis and arthritis]

The leading symptom of arthrosis and arthritis is pain. As in the case of pharmacotherapy fortumor pain, a stepped approach is also recommended for rheumatic complaints. Mild-to-moderate pain in noninflammatory arthrosis can be ameliorated by paracetamol or low-dose ibuprofen. If inflammation is present, nonsteroidal anti-inflammatory drugs (NSAIDs) must be employed. If this treatment does not suffice to manage systemic arthritis, oral short-acting corticosteroids are applied. Intra-articular corticosteroid injections can be used to individual inflamed active joints. For chronic pain, opioids may be necessary in addition to NSAID treatment. The use of NSAIDs is limited by gastrointestinal side effects. In the case of risk patients, therefore, preventive measures must be taken, and PPI or, instead of NSAIDs, coxibs employed in addition.

Temporomandibular joint function in patients with longstanding rheumatoid arthritis - I. Role of periodontal status and prosthetic care - a clinical study

PURPOSE

Temporomandibular joint (TMJ) dysfunction in rheumatoid arthritis (RA) occurs in 2 % to 86 % of RA patients. Dental factors possibly contributing to the development of TMJ dysfunction in RA patients have rarely been investigated in controlled studies. The present clinical study aimed 1) to compare patients with active, longstanding RA and healthy control subjects matched for age, sex, periodontal risk factors, dental and prosthetic status in order to obtain data on the prevalence of TMJ dysfunction in dentate RA patients and 2) to investigate a possible relationship between RA activity, general functional state and the severity of TMJ involvement.

METHODS

50 RA patients (38 F, 12 M; 54 +/- 9 years) were compared with 101 control subjects (76 F, 25 M; 54 +/- 11 years) with regard to dental, periodontal and prosthetic status and clinical TMJ findings as measured by the Helkimo indices. Clinical evaluation of RA patients included serological parameters, pain as measured by visual analog scale (VAS), a 28-joint count, a radiological destruction score, a functional status and measurement of grip strength.

RESULTS

The sum of carious, missing and filled teeth was similar in both groups. RA patients had more missing teeth (p < 0.01), more gingival bleeding, deeper pockets and more attachment loss (p < 0.0001). They showed no differences with regard to the mean number of occluding pairs of teeth, tooth support, the percentage of dentures, the grade of prosthetic support. 36 % of RA patients had a unilaterally shortened dental arch compared with 11.9 % in controls (p < 0.05). 32 % of RA patients and 27.7 % of the control subjects reported TMJ or facial pain. The mean VAS was 50 +/- 19 for RA patients and 52 +/- 21 for controls. The anamnestic data and the clinical symptoms grouped according to the Helkimo index showed no significant differences between both subject groups. However, the maximal mouth opening capacity in RA patients was significantly lower (40.6 +/- 6.5 mm) than in controls (45.8 +/- 5.5 mm; p < 0.001). Analysis of the Helkimo symptom groups revealed a significantly reduced mobility index in the RA group and impaired TM-joint function in controls (p < 0.05). Grip strength was significantly correlated with mouth opening capacity, TMJ pain with tooth support.

CONCLUSION

The prevalence of TMJ dysfunction in dentate patients with longstanding RA does not exceed that of healthy controls when structural risk factors predisposing to the development of temporomandibular dysfunction are taken into consideration. Maintaining adequate tooth support might help to prevent progressive TMJ impairment in the course of disease.

Primary prevention of diclofenac associated ulcers and dyspepsia by omeprazole or triple therapy in Helicobacter pylori positive patients: a randomised, double blind, placebo controlled, clinical trial

BACKGROUND

There is much controversy as to whether or not treatment of Helicobacter pylori reduces the occurrence of peptic ulcers during therapy with a non-steroidal anti-inflammatory drug (NSAID).

AIM

To assess the efficacy of triple therapy or omeprazole on the occurrence of diclofenac associated ulcers in H pylori positive patients.

METHODS

This was a randomised, double blind, placebo controlled, multicentre trial in H pylori positive patients requiring NSAID therapy who had no past or current peptic ulcer. They received diclofenac 50 mg twice daily for five weeks in combination with one of the four randomly assigned treatments: anti-H pylori treatment for one week (omeprazole 20 mg+clarithromycin 500 mg+amoxicillin 1 g, all twice daily) followed by placebo for four weeks (OAC-P); anti-H pylori treatment for one week followed by antisecretory treatment with omeprazole 20 mg once daily for four weeks (OAC-O); omeprazole 20 mg once daily for five weeks (O-O); or placebo for five weeks (P-P). Patients were endoscoped before and after treatment.

RESULTS

Data from 660 patients were included in an intention to treat analysis. The occurrence of peptic ulcers in the four treatment groups during the study period was: 1.2% for OAC-P, 1.2% for OAC-O, 0% for O-O, and 5.8% for P-P (p<0.05 between placebo and all active treatment groups). Patients who received active treatment developed therapy requiring dyspeptic symptoms less frequently than those who received placebo (p<0.05 between placebo and all active treatment groups).

CONCLUSIONS

In H pylori infected patients, all three active therapies reduced the occurrence of NSAID associated peptic ulcer and dyspeptic symptoms requiring therapy.

[Symptomatic therapy of rheumatic diseases. How they reduce pain and thereby safe costs]

The leading symptom of rheumatic diseases is pain. Further common symptoms are swelling, restricted mobility and joint deformation. The aim of treatment is freedom from pain and unrestricted function of the affected parts, together with improved quality of life. Amelioration of pain usually succeeds with the so-called non-steroidal antiinflammatory drugs (NSAIDs). In 10% of the cases, however, these can lead to gastric bleeding and perforation necessitating emergency hospitalization. Approximately 10% of patients with complicated ulcers die. COX-2-inhibitors have an analgesic action equal to that of conventional NSAIDs, but cause appreciably fewer gastrointestinal complications. Comedication of NSAIDs and misoprostol or omeprazole also has a gastric protective effect. Concomitant treatments, provision of aids and relevant information about the disease and its course, help to secure a good outcome. In the last resort, when conservative treatment fails, surgical intervention becomes necessary.

[Underestimated adverse effects of non-steroidal anti-inflammatory drugs on the distal intestine]

NSAID-induced adverse effects are diagnosed less frequently in the distal intestine than in the gastroduodenal area. During long-term NSAID use, however, the development of life-threatening ulcerations, perforations or fibrotic stenoses must be expected from the middle segment of the small intestine to the rectum. Although the clinical symptoms are not specific, together with careful examination, endoscopy, contrast x-ray studies, or computed tomography they can provide orientation, at least with regard to stenotic processes. Diarrhea, weight loss, anorexia, irregular bowel movements, obstruction symptoms, ocoult blood loss, hypoalbuminemia, and iron deficiency may be regarded as possible signs of gastrointestinal adverse effects associated with long-term NSAID therapy. Except in the case of NSAID suppository abuse, no risk indicators are known. The pathogenesis of NSAID-induced adverse effects in the lower gastrointestinal tract has not been elucidated. As the potential of nonselective NSAIDs to cause adverse effects in distal segments of the small intestine cannot be reliably reduced by prophylactic measures in the upper gastrointestinal tract such as comedication with prostaglandin analogs or proton pump inhibitors, the indication for the use of conventional NSAIDs, in any case, must be considered with caution.

HLA-DR/DQ interaction in patients with erosive rheumatoid arthritis presenting articular and extraarticular disease manifestations

In the present study we have analysed the effect of HLA-DRB1 and -DQB1 alleles on disease progression and genetic predisposition among 201 RA patients. We clearly confirm the association of RA with HLA class II alleles sharing the (Q)R/KRAA amino acid (AA) cassette in the third hypervariable region (HVR3) of the DR beta-chain. The HVR3 (Q)R/KRAA motif was significantly overrepresented among RA patients (79% vs. 40%, P < 0.001), with one third of the patients homozygous (28% vs. 6.7%, P < 10(-9)) and the number of rheumatoid factor positive (RF+) patients was significantly increased among HVR3 (Q)R/KRAA homozygous in comparison to HVR3 (Q)R/KRAA negative individuals. Erosive disease defined by the Larsen Score and personal disability determined using the Health Assessment Questionnaire (HAQ) was significantly increased among patients positive for the HVR3 motif with the worst outcome among HVR3 (Q)R/KRAA homozygous patients. In contrast, there was no association of the shared HVR3 AA cassette and disease severity in the majority of patients presenting systemic (extraarticular) disease. Homozygosity for the shared HVR3 motif was only marginally increased among patients presenting 'severe' extraarticular disease in comparison to patients with articular disease (33% vs. 43%, P = ns). Similarly, patients with nodular disease were not more often homozygous for the HVR3 (Q)R/KRAA motif. Furthermore, we observed no HLA-DR independent association of DQB1 alleles among HVR3 (Q)R/KRAA positive patients and controls. Our analysis supports the predominant role of HLA-DR for genetic susceptibility to RA. In the clinical setting, however, HLA-DR typing may be limited to assess the individual risk of patients for disease progression.

The role of risk factors for periodontal disease in patients with rheumatoid arthritis

There are conflicting reports whether patients with rheumatoid arthritis (RA) are at a higher risk for periodontal disease (PD). Analogous mechanisms of tissue destruction have been reported for both diseases. This cross-sectional study should quantify PD in patients with longstanding RA and examine a possible association between the two diseases. It should also be investigated whether PD in RA patients could be the result of reduced functional capacity or be amplified by concomitant medical treatment. 50 RA patients were matched for age, sex, smoking and oral hygiene with 101 healthy controls. Data on the medication over the last three years was obtained by questionnaire. Among the rheumatological parameters recorded were a 28-joint-count, C-reactive protein (CRP), grip strength testing, upper extremity function (Keitel Index) and the Larsen-score of radiological joint destruction. The oral examination included the recording of individual oral hygiene measures and sicca symptoms, a modified Approximal Plaque- and Sulcus-Bleeding-Index (SBI), probing depths and clinical attachment loss and the Community Periodontal Index of Treatment Needs. The mean duration of RA was 13 (+/- 7.9) years. RA patients under treatment with disease modifying antirheumatic drugs (DMARDs, n = 46; 92%), corticosteroids (n = 38; 76%) and non steroidal antirheumatic drugs (NSAIDs, n = 43; 86%) had a higher rate of gingival bleeding (+ 50%), probing depth (+ 26%), clinical attachment loss (+ 173%) and number of missing teeth (+ 29%) compared with controls. While no correlation between the rheumatological variables (radiological destruction, functional capacity, grip strength) and the periodontal measurements (SBI, probing depth, clinical attachment loss) could be demonstrated, a positive correlation was observed between the CRP and the periodontal attachment loss (r = 0.32; p <0.05). In spite of a strong correlation between the duration of DMARD- and cortisone-medication and the Larsen-score (r = 0.48 and 0.64; p = 0.0005 and 0.0001, rsp.), no correlation between the duration of pharmacotherapy and the periodontal parameters could be established. Patients with long-term active RA present a substantially higher degree of PD including loss of teeth compared with controls. Functional impairment of the upper extremity might amplify present PD. The longterm use of NSAIDs, corticosteroids and DMARDs shows no connection with the severe PD observed in these patients. Oral hygiene amplifies PD severity and treatment need. Intensive prophylactic measures are required to prevent or reduce the damage of the periodontal tissues in RA patients.

Scientific rationale for specific inhibition of COX-2

Cyclooxygenase (COX) is the principal enzyme involved in the production of prostaglandins. Inhibition of COX is also the primary mechanism of action of aspirin and other nonsteroidal antiinflammatory drugs (NSAID). Since prostaglandins are important regulators of cellular function, inhibition of prostaglandin production may lead to adverse effects. Two isoforms of COX have been identified, sequenced, and cloned. COX-1 is constitutively produced and is believed to be involved in regulating normal cellular processes, such as gastrointestinal (GI) cytoprotection, vascular homeostasis, and renal function. In contrast, COX-2 -- the inducible form -- is undetectable in most tissues but is present in inflamed tissue. Evidence therefore suggests that the GI toxicity associated with NSAID use is primarily the result of inhibition of COX-1, and antiinflammatory effects are largely due to inhibition of COX-2. A drug that specifically inhibits COX-2 without affecting COX-1 would, theoretically, reduce inflammation without leading to GI side effects. A variety of biologic assays have been developed to characterize the relative activities of NSAID against COX-1 and COX-2. Such in vitro testing has demonstrated that individual NSAID possess different relative inhibitory effects in various tissues. Several NSAID have been reported to show more potent inhibition of COX-2 than of COX-1 in vitro; however, the clinical relevance of differential inhibition of COX isozymes is as yet unknown. Some clinical studies indicating reduced toxicity for these NSAID may, in fact, be attributable to use of these agents at subtherapeutic doses. As yet, no clinically available NSAID has been shown to have significant in vivo effects on COX-2 while sparing COX-1 activity in humans. However, compounds that may be 100 to 300-fold more effective inhibitors of COX-2 and that therefore may have lower risks for toxicity as well as more potent antiinflammatory effects have been developed, but are not yet available for clinical use.

Risk for periodontal disease in patients with longstanding rheumatoid arthritis

OBJECTIVE

To quantify periodontal disease in rheumatoid arthritis (RA) patients and controls, and to correlate the degree of destruction from periodontal disease and from RA.

METHODS

Fifty RA patients were matched for age, sex, smoking status, and oral hygiene with 101 controls. Correlations between indices of chronic destruction in periodontal disease (gingival attachment loss) and in RA (Larsen radiographic score) were determined.

RESULTS

Patients with longstanding active RA (mean +/- SD 13 +/- 8 years) who were receiving treatment with disease-modifying antirheumatic drugs (n = 46), corticosteroids (n = 38), or nonsteroidal antiinflammatory drugs (n = 43) had a higher rate of gingival bleeding (increased by 50%), greater probing depth (increased by 26%), greater attachment loss (increased by 173%), and higher number of missing teeth (increased by 29%) compared with controls. No correlation was found between the Larsen radiographic score and gingival attachment.

CONCLUSION

Patients with longstanding active RA have a substantially increased frequency of periodontal disease, including loss of teeth, compared with controls. Antiinflammatory treatment interferes with periodontal disease and might have masked a possible correlation between the indices of chronic destruction in RA and periodontal disease.

Improved determination of sulfadiazine in human plasma and urine by high-performance liquid chromatography

A high-performance liquid chromatographic method for the determination of sulfadiazine in human plasma and human urine was developed and validated. The method involves the acid extraction of drug and internal standard from plasma with ethyl acetate followed by evaporation and reconstitution in mobile phase. Urine samples were simply diluted with purified water. Recovery, linearity, intra- and inter-day variation of sulfadiazine were tested and found appropriate. The quantitation range was 0.0299-15.2 micrograms/ml for plasma samples and 0.578-148.8 micrograms/ml for urine samples. The method is suitable for the quantitation of sulfadiazine from pharmacokinetic studies.

Improved high-performance liquid chromatographic determination of amoxicillin in human plasma by means of column switching

A highly sensitive and selective HPLC method was developed for the determination of amoxicillin in human plasma. After addition of buffer and internal standard, the sample was ultrafiltered and injected on to a precolumn to remove polar plasma interferences. Detection was effected with a UV detector set at 230 nm. The limit of quantification for amoxicillin was 50.1 ng/ml with an imprecision of 4.2% using 0.25 ml of plasma. Linearity was confirmed over the whole calibration range (25.4-0.0501 micrograms/ml) and the inter-day variation ranged from 2.0 to 4.5%. The method was validated according to GLP guidelines and its suitability was demonstrated by the analysis of several hundred samples in a bioequivalence study. The method can be used to determine pharmacokinetic parameters of amoxicillin in humans after a single oral dose of 500 mg.

Sensitive determination of nitrofurantoin in human plasma and urine by high-performance liquid chromatography

A highly sensitive and selective HPLC method was developed and validated for the determination of nitrofurantoin in human plasma and urine. The method involves the liquid-liquid extraction of drug and internal standard from plasma with ethyl acetate followed by evaporation and reconstitution in mobile phase. Urine samples were simply diluted with purified water. UV detection was done at 370 nm. The limit of quantification for nitrofurantoin in plasma was 0.010 micrograms/ml. In urine nitrofurantoin could be quantified down to 0.380 microgram/ml. Linearity was proven over the whole calibration range in plasma (2.48-0.0100 microgram/ml) as well as in urine (187 micrograms/ml-0.380 microgram/ml). The method was validated according to Good Laboratory Practice guidelines and its suitability was demonstrated by analysis of samples from a pharmacokinetic study.