X-Ray microtomography imaging of red lentil puffed snacks: Processing conditions, microstructure and texture.

Red lentils have a great potential to be used as healthy ingredients in puffed snacks due to their excellent nutritional qualities. However, these types of ingredients with relatively higher protein and fiber content when compared to ingredients that are typically used for the manufacture of puffed foods (e.g., refined cereal flours/starches) result in inferior textural quality. Extrusion processing parameters such as screw speed, moisture content and injection pressure of a blowing agent can be manipulated to optimize the microstructure of an extrudate, and as a consequence the texture of the final puffed product. In this study, X-Ray microtomography imaging is used to characterize and quantify the detailed microstructure of red lentil extrudates. The results indicate that an increase in the injected pressure of the physical blowing agent could be correlated with a decrease in mean cell size and wall thickness, as well as an increase in the number of cells. Evidence of wall rupture with an increased screw speed is also visible, and that effect can be counterbalanced by a higher moisture content during processing. A large variation of the cell wall thickness inside an extrudate (which can induce a weaker cellular structure) as well as a larger cell size and higher amount of wall rupture, significantly reduce the hardness of extrudates. This novel effort to quantitatively characterize the microstructure of red lentil extrudates using X-Ray microtomography establishes that an optimal product texture could, in principle, be achieved by manipulating extrusion parameters to achieve the perfect snack texture.

Pulse Flour Characteristics from a Wheat Flour Miller's Perspective: A Comprehensive Review.

Pulses (grain legumes) are increasingly of interest to the food industry as product formulators and consumers seek to exploit their fiber-rich and protein-rich reputation in the development of nutritionally attractive new products, particularly in the bakery, gluten-free, snack, pasta, and noodle categories. The processing of pulses into consistent high-quality ingredients starts with a well-defined and controlled milling process. However, in contrast to the extensive body of knowledge on wheat flour milling, the peer-reviewed literature on pulse flour milling is not as well defined, except for the dehulling process. This review synthesizes information on milling of leguminous commodities such as chickpea (kabuli and desi), lentil (green and red), pea, and bean (adzuki, black, cowpea, kidney, navy, pinto, and mung) from the perspective of a wheat miller to explore the extent to which pulse milling studies have addressed the objectives of wheat flour milling. These objectives are to reduce particle size (so as to facilitate ingredient miscibility), to separate components (so as to improve value and/or functionality), and to effect mechanochemical transformations (for example, to cause starch damage). Current international standards on pulse quality are examined from the perspective of their relationship to the millability of pulses (that is, grain legume properties at mill receival). The effect of pulse flour on the quality of the products they are incorporated in is examined solely from the perspective of flour quality not quantity. Finally, we identify research gaps where critical questions should be answered if pulse milling science and technology are to be established on par with their wheat flour milling counterparts.

Identification of malaria hot spots for focused intervention in tribal state of India: a GIS based approach.

BACKGROUND: In India, presently malaria shows a declining trend whereas Plasmodium falciparum (Pf) cases show an up trend. In central India, specifically, Madhya Pradesh (M.P.) a forested and tribal area, control of malaria is logistically difficult and outbreaks are frequently recorded, reasons for this being inadequate surveillance, poor reporting, a time lag in reporting to decision makers and a lack of geo referenced information to pin point the trouble spots for a timely preventive action. RESULTS: An information management system based on Geographic Information System (GIS) using district and block wise malaria data, has been constructed for Madhya Pradesh for quick retrieval of info and dynamic generation of maps to highlight hot spots of malaria for formulating prompt and focused malaria control strategy. Out of total 48 districts consisting of 313 blocks, based on certain criteria GIS identified 58 blocks falling in 25 districts as Hot Spots. Malaria flares up from these pockets whenever favourable conditions for transmission occurs. It was suggested to National Vector Borne Disease Control Programme (NVBDCP) that focused malaria control in these hot pockets may be taken up on priority during the year 2007, it was implemented by State Health Authorities, M.P. under the directive of NVBDCP. Implementation of control measures were evaluated by NVBDCP. CONCLUSION: GIS mapping would make it easy to update information instantly and to identify the trouble spots at the village level within the district which is the lowest unit equipped with computer facilities and the information can reach instantly to state and the policy makers to formulate focused and cost effective malaria control strategy. This is the first time when GIS has been used in national control programme for tribal malaria.

Pharmacodynamic and pharmacokinetic characterisation of RBx 7796: a novel 5-lipoxygenase inhibitor.

OBJECTIVE: RBx 7796, a 5-lipoxygenase inhibitor, was evaluated in in vivo efficacy models, in vitro ADME and in vivo pharmacokinetic models. METHOD: RBx 7796 was evaluated for inhibition of 5-lipoxygenase enzyme and release of LTB4 from isolated rat and human neutrophils. RBx 7796 was tested in allergic bronchoconstriction model in Balb/c mice and LPS induced airway hyperreactivity model in rats. RBx 7796 was evaluated for metabolic stability in liver microsomes and cytochrome P450 inhibition potential. Pharmacokinetic profile of RBx 7796 was also determined in rat and dog. RESULTS: RBx 7796 inhibited 5-lipoxygenase enzyme and inhibited release of LTB4 from neutrophils. RBx 7796 also inhibited early and late airway reactivity following allergen challenge in mouse model. LPS induced increase in airway reactivity was blocked by RBx 7796. Compound was found to be stable in liver microsomes and devoid of major cytochrome P450 inhibition potential. The oral bioavailability of RBx 7796 in rat and dog was 83 % and 47 %, respectively. Following repeated daily administration, compound did not exhibit any sign of accumulation and/or tendency to induce its own metabolism. CONCLUSION: The results suggest that RBx 7796 is an inhibitor of 5-lipoxygenase enzyme that is orally efficacious in two different models of airway reactivity. The molecule also demonstrated acceptable pharmacokinetic profile warranting further development.

Malaria control using indoor residual spraying and larvivorous fish: a case study in Betul, central India.

OBJECTIVES: To assess the impact of intensified malaria control interventions in an ethnic minority community in Betul using existing tools. METHODS: Two rounds of indoor residual spraying with synthetic pyrethroid insecticide were applied and larvivorous fish introduced, followed by intensive surveillance for early detection of Plasmodium falciparum with rapid diagnostic tests and prompt treatment with sulphadoxine pyrimethamine. RESULTS: Pre-intervention surveys revealed a very high fever rate in the community in all age groups with a slide positivity rate of >50% with >90%P. falciparum. The post-intervention phase showed a sharp steady decline in number of malaria cases (beta 0.972; P < 0.0001, 95% CI 0.35-0.47). Monitoring of entomological results revealed a significant decline in both Anopheles species and An. culicifacies (P < 0.0001). CONCLUSION: A combination of indoor residual spraying and early detection and prompt treatment complemented by rapid diagnostic tests and larvivorous fishes successfully brought malaria under control. These approaches could be applied in other regions of different endemicity to control malaria in India.

Validation of the LC-MS/MS method for the quantification of mevalonic acid in human plasma and determination of the matrix effect.

A simple, specific, and sufficiently sensitive liquid chromatography-tandem mass spectrometry (negative-ion electrospray ionization) methodology to determine mevalonic acid (MVA) in human plasma is described, and its application to the analysis of rat plasma MVA levels after rosuvastatin administration is demonstrated. The method was validated over the linearity range of 0.5-50.0 ng/ml (r(2) > 0.99) using deuterated MVA as an internal standard. The lower limit of quantification was 0.5 ng/ml. The assay procedure involved the isolation of MVA from plasma samples using solid-phase extraction. Chromatographic separation was achieved on a HyPurity Advance column with a mobile phase consisting of ammonium formate buffer (10 mM, pH 8.0) and acetonitrile (70:30, v/v). Excellent precision and accuracy were observed. MVA and deuterated mevalonolactone were stable in water and plasma under different storage and processing conditions. The recovery observed was low, which was attributable to a significant matrix effect. A significant decrease (30-40%; P < 0.05) was observed in rat plasma MVA levels after rosuvastatin administration.

Evaluation of interaction potential of certain concurrently administered drugs with pharmacological and pharmacokinetic profile of centchroman in rats.

Centchroman (Ormeloxifene) is a nonsteroidal, selective estrogen receptor modulator, oral contraceptive and anticancer agent, and is intended for long-term use by women. In view of its vast clinical application and the interaction of steroidal oral contraceptives with certain commonly used therapeutic agents, evaluation of interaction of certain concomitantly administered therapeutic agents (ibuprofen, rifampicin, diazepam, salbutamol, nifedipine, paracetamol, haloperidol, and tetracycline), in terms of both the postcoital contraceptive efficacy and pharmacokinetic profile, with centchroman was undertaken in female Sprague-Dawley rats. Among the representatives from each commonly used therapeutic category, interaction (pharmacokinetic) was observed with ibuprofen (60 mg/kg, twice daily), haloperidol (0.7 mg/kg, twice daily), and tetracycline (140 mg/kg, twice daily) coadministration on Days 1 through 5 postcoitum. Of these three therapeutic agents, only tetracycline interfered with the contraceptive efficacy of centchroman. It reduced the bioavailability of centchroman and its active metabolite by increasing their excretion through bile and feces. Increased metabolite excretion on tetracycline coadministration indicates the enterohepatic recirculation of the metabolite, not the parent drug. However, the effect of tetracycline was negated by the inclusion of lactic acid bacillus spores in the regimen.

Evaluation of absorbability of centpropazine in rats: in-situ and in-vivo appraoches.

Intestinal absorption of centpropazine was studied in rats by both in-situ (closed-loop method) and in-vivo (portal-venous difference) approaches. The drug was found to be well absorbed from solution in in-situ studies. However, the results obtained in-vivo suggested that very low amounts of drug reach the portal circulation after oral dosing. This could imply extensive binding to the mucosa or metabolism in the intestinal wall. The presence of higher amounts of metabolites in the portal vein compared with the inferior vena cava samples signal their formation in the gastrointestinal tract or enterohepatic recirculation. These findings will be useful in incorporating suitable structural and formulation modifications for enhancing the bioavailability of centpropazine and its analogues.

Tissue distribution and excretion of CDRI-81/470 in rats.

Methyl-N[5 [[4-(2-pyridinyl)-1-piperazinyl]carbonyl]- 1H-benzimidazol-2-yl] carbamate (CDRI-81/470) is a broad spectrum anthelmintic agent, effective against both intestinal and systemic parasitism. Tissue distribution and excretion of CDR1-81/470 were studied in rats after a single oral dose of 100 mg kg(-1) CDRI-81/470. One of the metabolites was identified in pilot studies as its N-decarboxylate derivative and characterized by synthesis. HPLC assay methods for the simultaneous estimation of CDRI-81/470 and its N-decarboxylate derivative in tissues, bile, urine, and faeces were developed and validated. The parent compound was quantitated in all major tissues and organs up to 48 h post-dose. Among the tissues other than serum, the highest concentrations of CDRI-81/470 were found in liver, whereas only trace levels were found in brain. Approximately 3% of the administered dose was excreted unchanged in urine at 120 h postdose, whereas approximately 7% was recovered in faeces. The contribution of the biliary route for the excretion of parent compound was less than 0.5%. The N-decarboxylate derivative was quantitated in faeces (1-4%) and bile ( < 0.1%) but was absent in serum, tissues, and urine. An additional metabolite was isolated from bile and characterized as the pyridinyl-5-hydroxy derivative of CDRI-81/470. CDRI-81/470 showed rapid absorption and distribution into all major organs and tissues, and underwent extensive metabolism in rats. Two metabolites in bile were identified and characterized by synthesis.

Binding of centchroman with human serum as determined by charcoal adsorption method.

Protein binding of drugs is an important factor influencing both pharmacokinetic and pharmacodynamic parameters. Thus, knowing the extent of protein binding of drugs is crucial. Centchroman is a non-steroidal once a week oral contraceptive. It has been reported to be useful for the treatment of breast cancer and osteoporosis. Ample data has been generated on pharmacokinetics of centchroman in animals and humans. The extent of protein binding of centchroman has not been established so far. Non-specific adsorption of the drug limits the use of conventional methods like ultrafiltration and equilibrium dialysis. A method of charcoal adsorption as reported by Yuan et al. (method I) was used after modification (method II) to determine its binding to human serum. The extent of protein binding (%) is estimated from decline of percent drug remaining in the supernatant after adding the charcoal. Study was carried out at 1- and 10-microg/ml concentrations in drug free human serum samples and an HPLC assay was used to determine concentration-time data. The percentage of centchroman remaining in serum versus time data was analysed using non-linear fitting programs on WinNonlin software. Method II was found to give higher estimates of protein binding than the former method by preventing the dilution effect. Using this method, the extent of protein binding of centchroman was found to be 101.83+/-1.28 and 94.87+/-3.59% at 1 and 10 microg/ml, respectively. However, it was approximately 90% in the individual serum samples showing intersubject variability in protein binding of centchroman.

Determination of antifilarial compound UMF-078 and its metabolites in plasma by high-performance liquid chromatography.

UMF-078, methyl (+/-)-[5-(alpha-amino-4-fluorobenzyl)benzimidazol-2-yl]carba mate, is a new antifilarial compound being developed by the World Health Organization. In the present study, a HPLC method for the simultaneous estimation of UMF-078 and its metabolites (flubendazole, decarbamoylated flubendazole, UMF060 and decarbamoylated UMF-060) in plasma was developed, validated and applied to pharmacokinetic studies. Linearity was observed between 20 and 1000 ng/ml for decarbamoylated UMF-060 and between 10 and 500 ng/ml for other analytes. Recoveries were consistent over the concentration ranges studied for all the analytes. Variations in intra- and inter-batch accuracy and precision were within acceptable limits of +/-20% at the lowest limit of quantitation, whereas at higher concentrations it was +/-15%. The analytes showed stability up to two freeze-thaw cycles in plasma. No degradation was observed for any of the analytes even after 72 h of storing the dry plasma extracts at -30 degrees C. The assay method was employed to study the pharmacokinetics of hydrochloride salt of UMF-078 in rats. The parent compound and its metabolites viz: decarbamoylated UMF-060, UMF-060 and flubendazole were quantitated in serum and the compounds could be monitored up to 168 h post-dose.

Evaluation of metronidazole toxicity: a prospective study.

Metronidazole is an antimicrobial, antiprotozoal agent that has been widely used in the treatment of a variety of infections. Some therapeutic indications necessitate prolonged treatment with metronidazole. Peripheral neuropathy is a potential metronidazole-induced toxicity, which has been reported in only a few isolated retrospective studies. This prospective study was designed to determine the toxic profile of metronidazole in patients undergoing long-term treatment with this drug. In the present study, 17 patients of both sexes, aged between 20 and 50 years, with body weights ranging from 46 to 62 kg and who were suffering from various medical ailments were recruited. The patients received 400 mg t.i.d. oral metronidazole in a total dose of 16.8-39.6 g for 2-4 weeks. It was found that patients usually suffered from some of the toxic symptoms of metallic taste, headache and dry mouth and to a lesser extent nausea, glossitis, urticaria, pruritus, urethral burning and dark colored urine. Symptoms were irrespective of sex and directly proportional to duration of therapy. Deep tendon ankle jerks were maximally reduced in four patients and sense of vibration at the level of olecranon and patella was affected in two patients. Distal latency and velocity of the sural and posterior tibial nerves were significantly affected (p < 0.01) compared with control values. These results indicate possible motor-sensory neurotoxicity involving the lower limbs due to long-term metronidazole therapy.

Development and validation of a new high-performance liquid chromatographic assay of centpropazine, a new antidepressant compound, in serum.

Centpropazine is a new anti-depressant compound developed by Central Drug Research Institute, Lucknow (India). We report here the development and validation of a new HPLC assay of a parent drug in the serum of humans, monkeys and rats for pharmacokinetic studies. Centpropazine was eluted on a C18 column with a mobile phase consisting acetonitrile phosphate buffer (60:40) pumped at 1.5 ml min(-1) flow rate and quantitated by UV detector at 270 nm. Considering the sample volume available from different species and to enhance the sensitivity of assay, three sample clean up methods requiring 0.05, 0.5 and 4 ml serum for a linear quantitation range of 312.5 ng ml(-1)-5 microg ml(-1), 0.04-2.5 microg ml(-1) and 2.5-80 ng ml(-1) respectively were developed. The lowest limit of quantitation of the method was 2.5 ng ml(-1) requiring 4 ml serum, 40 ng ml(-1) requiring 0.5 ml serum and 312 ng ml(-1) requiring 50 microl serum sample. All these methods were fully validated in human serum and extended to monkey and rat serum. The recovery of centpropazine at 5, 80, 625, 1280 and 2500 ng ml(-1) ranged between 92 and 105%. The within and between run variability in precision and accuracy were less than 10% and the drug in serum was stable up to three freeze-thaw cycles. Overall the method is simple, quick and robust for biopharmaceutical applications. The method was applied to analyse concentrations of centpropazine in rat serum after administering single 20 mg kg(-1) peroral and 5 mg kg(-1) i.v. dose. The chromatograms of treated rat serum exhibited three well resolved peaks of metabolites and one of them was identified as hydroxy-metabolite of centpropazine.

Choosing the calibration model in assay validation.

Data transformations and weighting schemes are normally used to obtain the best-fit of standard curves in bioanalysis and the calibration model is usually selected during prevalidation. In the present study, a comparison has been made between unweighted and weighted (1/x, 1/x2, and 1/square root of x) regression models with or without an intercept in achieving the best-fit for the standard curve of CDRI compound 81/470, a new anthelmintic agent, in cow milk. Validation samples in milk at the LLOQ, medium, and high concentrations were also analysed by each of the calibration models. An unweighted regression equation with an intercept overestimated the concentrations at the LLOQ. An unweighted equation without intercept and weighted equations with or without an intercept significantly minimized the bias at the LLOQ without distorting the results at higher concentrations. Hence, an unweighted equation for a straight line passing through the origin was found to be the best model for a standard curve of 81/470 in milk. Similar results were obtained for 81/470 and UMF-078 in serum and plasma, respectively. Bioanalysts should routinely test these models to obtain the best fit model for their calibration curves as part of their assay validation not during prevalidation.

A rapid and sensitive high performance liquid chromatographic assay of the new antimalarial compound 80/53 in serum with a novel sample clean-up method and its pharmacokinetics in rabbits.

The compound 80/53 (AM) is a new antimalarial agent synthesized by this institute as a safer and less toxic analogue of primaquine. It was found to exhibit fluorescence in acetonitrile solution and this finding was exploited to develop a selective and sensitive high performance liquid chromatographic (HPLC) assay of the AM in rabbit serum. The sample clean-up was done in a single step by simultaneous protein precipitation and extraction with acetonitrile in the presence of sodium sulfate. The lower limit of quantitation of the method was 50 ng ml-1 using 100 microliters of serum sample. The method was fully validated from 50 to 1600 ng ml-1 concentration range with a recovery ranging from 70 to 75%. The within- and between-run variability was less than 10% and the drug in serum was stable over four freeze-thaw cycles and up to 24 h in injection solvent at 4 degrees C. The method was applied to determine the pharmacokinetic parameters of AM in 5 rabbits receiving a single bolus intravenous and peroral dose in a crossover study. The concentration-time data after a 5 mg kg-1 i.v. dose in rabbits was best fitted to the two compartment body model with first order absorption and elimination rate constants. The terminal half-life and MRT of AM were 95.3 +/- 43.5 and 104 +/- 10.6 min respectively. After administering a single 20 mg kg-1 oral dose, the serum levels of AM in all the rabbits declined below the quantitation limit by 90 min and it was not possible to fit the data by the compartmental approach. The MRT and AM after oral dose was 31.1+2-8.3 min. Application of the assay has also been extended to analyze the serum samples of rats, monkeys and humans.

The mechanism of polyamine analog-induced enhancement of cisplatin cytotoxicity in the U-251 MG human malignant glioma cell line.

PURPOSE: During the last decade, several polyamine analogs have been developed as antineoplastic agents that replace intracellular polyamines but cannot mimic the biological functions of polyamines related to cell growth. It has been shown that pretreatment of several human brain tumor cell lines with some of these polyamine analogs increases the cytotoxicity of cis-diamminedichloroplatinum (CDDP). It has also been established that some of these polyamine analogs affect chromatin organization. In the study reported here we attempted to elucidate the mechanism by which polyamine analog-induced changes in DNA and chromatin structure may increase CDDP cytotoxicity. METHODS: We studied the micrococcal nuclease sensitivity of the nuclei and measured the amount of platinum incorporated into the nucleosomal and linker regions of chromatin isolated from CDDP-treated U-251 MG human malignant brain tumor cells with or without pretreatment with two cytotoxic polyamine analogs 1,11-bis(ethylamino)-4,8-diazaundecane (BE-3-3-3) and 1,19-bis(ethylamino)-5,10,15-diazanonadecane (BE-4-4-4-4). RESULTS: The pretreatment with the polyamine analogs decreased the MNase sensitivity and increased the incorporation of CDDP preferentially into the linker region of the chromatin. CONCLUSIONS: Pretreatment of cells with polyamine analogs probably alters the structure and/or the organization of the linker region such that more CDDP incorporates into the linker DNA. This is probably the reason for the observed enhancement of CDDP cytotoxicity in the polyamine analog-pretreated cells.

Synthesis and disposition of 14C-labelled 81/470, a new anthelminthic agent in rats.

CDRI compound 81/470 (AH) is a new broad-spectrum anthelminthic agent under development for clinical and veterinary application. We herewith report the synthesis of 14C-labelled AH, and a study of the tissue distribution and excretion of radioactivity after administering a single 1 mg/kg p.o. or i.v. dose in young male rats. After oral administration of the dose, percent radioactivity recovered in 24-h urine, faeces and tissues were 17.9, 59.7 and 22.9 respectively. The levels were below detection limit in brain and gonads up to 24 h. In bile-duct-cannulated rats, the majority (37.8 +/- 2.8 and 43.8 +/- 6.4) of the radioactivity was excreted in the bile within 24 h of p.o. and i.v. administration, respectively. After an oral dose (1 mg/kg), the urinary excretion of radioactivity in rats was found to be approximately one-half (21 +/- 5.7, 18.3 +/- 2.1) of that obtained by i.v. administration of an equal dose (40.2 +/- 3.1 and 35 +/- 1.3), in bile-duct-intact and cannulated rats respectively.

Tissue distribution and pharmacokinetics of centchroman. A new nonsteroidal postcoital contraceptive agent and its 7-desmethyl metabolite in female rats after a single oral dose.

This study reports assay methodology, tissue distribution, and the basic pharmacokinetic behavior of centchroman and its 7-desmethyl metabolite [7-desmethyl centchroman (DMC)] after a single 12.5 mg/kg po dose in young female rats. Plasma, liver, lung, spleen, uterus, and adipose tissue were collected at various time intervals up to 14 days after dose. Reversed-phase HPLC, coupled with fluorescence detector, was used for simultaneous determination of centchroman and DMC in biosamples. The drug and metabolite were quantitated up to 2 and 5 ng/ml in plasma and 10 and 20 ng/g in tissues, respectively. The assay method was validated in terms of accuracy, precision, interassay, and intraassay variability, and was found to be reliable and reproducible. Peak centchroman levels in all of the tissues were found between 8-12 hr, whereas DMC peaks appeared between 8 and 24 hr, except that in liver the first peak of 1.2 micrograms/g appeared in the 1-hr sample. Tissue-to-plasma concentration ratios of centchroman were > 200 times in the lung; > 100 times in the spleen, liver, and adipose tissue; and > 40 times in the uterus at maxima in each tissue. Similarly, tissue concentrations of DMC were > 350 times in the lung, > 100 times in the liver and spleen, and > 25 times in the uterus and adipose tissue than in the plasma. High tissue-to-plasma concentration ratios of metabolites than the parent drug are indicative of its greater affinity for tissues. Terminal half-life of the centchroman and DMC in plasma were 24.1 and 36.6 hr, respectively. The mean residence time of centchroman was highest in the liver (78.4 hr), followed by the uterus (72.7 hr), adipose tissue (47.5 hr), lung (46 hr), spleen (44.1 hr), and plasma (37.7 hr). The mean residence time of DMC was also highest in the liver (133.7 hr), followed by the uterus (122 hr), adipose tissue (85.2 hr), lung (62.6 hr), spleen (62.6 hr), and plasma (48.2 hr).

Centchroman: a new non-steroidal oral contraceptive in human milk.

Centchroman, a non-steroidal oral contraceptive drug, was given to 13 nursing mothers comprising two groups. Each participant in group I (n = 8) received a single 30 mg dose, and in group II (n = 5) each participant received a 30 mg twice a week dose for twelve weeks. Simultaneous blood and milk samples were collected and analyzed for the parent drug by high performance liquid chromatography. In the single dose study (group I), the mean +/- peak centchroman concentrations in milk and serum were 78.7 +/- 28.4 and 63.6 +/- 23.6 ng/ml with milk-to-serum (M/S) ratio of 1.4 +/- 0.9. There was no significant increase in centchroman concentrations in milk after multiple dosing (group II). However, serum concentrations reached up to 112.5 ng/ml at 6 h after the 13th dose. Average M/S ratios were insignificantly different at trough (prior to next dose) and at peak (4-6 h after dose) centchroman levels. Additionally, the breast milk and serum centchroman concentrations showed a significant correlation (r = 0.64, P < 0.01), indicating that the amount of centchroman excreted into breast milk is dependent on serum concentrations. The weekly dose (% of the maternal dose) of centchroman ingested by the breast-fed infant at peak maternal serum and milk levels was in the range of 0.4 to 11.5%, assuming a weekly milk uptake of 1.05 l/kg. There was no significant difference in the dose ingested by the infants between the two dosing groups. These levels of centchroman passing into breast milk and subsequent exposure to the infants are unlikely to be of any physiological consequence.