Multiple emulsions: an overview

Multiple emulsions are complex polydispersed systems where both oil in water and water in oil emulsion exists simultaneously which are stabilized by lipophillic and hydrophilic surfactants respectively. The ratio of these surfactants is important in achieving stable multiple emulsions. Among water-in-oil-in-water (w/o/w) and oil-in-water-in-oil (o/w/o) type multiple emulsions, the former has wider areas of application and hence are studied in great detail. Formulation, preparation techniques and in vitro characterization methods for multiple emulsions are reviewed. Various factors affecting the stability of multiple emulsions and the stabilization approaches with specific reference to w/o/w type multiple emulsions are discussed in detail. Favorable drug release mechanisms and/or rate along with in vivo fate of multiple emulsions make them a versatile carrier. It finds wide range of applications in controlled or sustained drug delivery, targeted delivery, taste masking, bioavailability enhancement, enzyme immobilization, etc. Multiple emulsions have also been employed as intermediate step in the microencapsulation process and are the systems of increasing interest for the oral delivery of hydrophilic drugs, which are unstable in gastrointestinal tract like proteins and peptides. With the advancement in techniques for preparation, stabilization and rheological characterization of multiple emulsions, it will be able to provide a novel carrier system for drugs, cosmetics and pharmaceutical agents. In this review, emphasis is laid down on formulation, stabilization techniques and potential applications of multiple emulsion system.     

Challenges in containing the burden of hepatitis B infection in dialysis and transplant patients in India

Aim: Whether or not completing the hepatitis B vaccination in patients who have undergone kidney transplantation in the middle of incomplete vaccination schedule leads to development of protective antibody titres is not known. This study was designed to determine whether the strategy of completing hepatitis B virus (HBV) vaccination after transplantation is efficacious. Methods: Sixty‐four end‐stage renal disease (ESRD) patients were screened for hepatitis B surface antigen (HBsAg), antibodies to hepatitis B surface antigen (anti‐HBs), hepatitis B e‐antigen (HBeAg) and HBV DNA. HBsAg negative patients received four doses of 40 µg recombinant HBV vaccine. Schedule was continued in after transplantation period if it was incomplete before transplant. Anti‐Hbs titres were evaluated at 1, 3, 6, 9 and 12 months. Results: Past HBV infection was noted in 12 patients: 10 by serology plus viraemia and two by viraemia alone. Of the 46 patients without current or past HBV infection who had received at least two doses of the vaccine before transplant, 17 each had received two and three doses and 12 had completed the schedule. Seventeen (37%) exhibited protective titres. Patients who had completed vaccination were more likely to have protective titres than those incompletely vaccinated (P = 0.02). Five patients responded to post‐transplant vaccination. Conclusion: Partially vaccinated patients do not mount an adequate antibody response despite continued vaccination in the post‐transplant period, whereas complete vaccination provides protection in 60%. The present study data highlights the need of administration of a full schedule of HBV vaccination before kidney transplantation. Nucleic acid‐based tests can identify occult HBV infection.     

Chemical constituents from the leaves of Boehmeria rugulosa with antidiabetic and antimicrobial activities

Three new flavonoid glycosides, named chalcone-6′-hydroxy-2′,3,4-trimethoxy-4′-O-β-d-glucopyranoside (1), isoflavone-3′,4′,5,6-tetrahydroxy-7-O-{β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside} (2), and isoflavone-3′,4′,5,6-tetrahydroxy-7-O-{β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl-(1 → 3)-α-l-rhamnopyranoside} (3), were isolated from the leaves of Boehmeria rugulosa, together with five known compounds, β-sitosterol, quercetin, 3,4-dimethoxy-ω-(2′-piperidyl)-acetophenone (4), boehmeriasin A (5), and quercetin-7-O-β-d-glucopyranoside. The structures of the isolated compounds were determined by means of chemical and spectral data including 2D NMR experiments. The ethanolic extract of leaves showed significant hypoglycemic activity on alloxan-induced diabetic mice. Glibenclamide, an oral hypoglycemic agent (5 mg/kg, p.o.), was used as a positive control. The ethanolic extract of the plant as well as the isolated compounds 1–3 (25 μg/ml) showed potent antimicrobial activity against two bacterial species (Staphylococcus aureus and Streptococcus mutans) and three fungus pathogens (Microsporum gypseum, Microsporum canis, and Trichophyton rubrum). The activities of the isolated compounds 1–3 have been compared with positive controls, novobiocin, and erythromycin (15 μg/ml).     

The medical student as a patient: attitudes towards involvement in the quality and safety of health care

Background In recent years, factors that affect patients' willingness and ability to participate in safety‐relevant behaviours have been investigated. However, how trained healthcare professionals or medical students would feel participating in safety‐relevant behaviours as a patient in hospital remains largely unexplored. Objectives To investigate medical students' willingness to participate in behaviours related to the quality and safety of their health care. Design A cross‐sectional exploratory study using a survey that addressed willingness to participate in different behaviours recommended by current patient safety initiatives. Three types of interactional behaviours (asking factual or challenging questions, notifying doctors or nurses of errors/problems) and three non‐interactional behaviours (choosing a hospital based on the safety record, bringing medicines and a list of allergies into hospital, and reporting an error to a national reporting system) were assessed. Participants One hundred and seventy‐nine medical students from an inner city London teaching hospital participated in the study. Findings Students' willingness to participate was affected (P < 0.05) by the action required by the patient and (for interactional behaviours) whether the patient was engaging in the specific action with a doctor or nurse. Students were least willing to ask ‘challenging’ questions to doctors and nurses and to report errors to a national reporting system. Doctors' and nurses' encouragement appeared to increase self‐reported willingness to participate in behaviours where baseline willingness was low. Conclusion Similar to research on lay patient populations; medical students do not view involvement in safety‐related behaviours equally. Interventions should be tailored at encouraging students to participate in behaviours they are less inclined to take on an active role in. Future research is required to examine students' motivations for participation in this important but heavily under‐researched area.     

Platelet counts and outcome in the pediatric intensive care unit

Objectives:

Thrombocytopenia is commonly observed in critically ill patients. This study was undertaken to evaluate the variation in platelet counts and the risk factors associated with thrombocytopenia and mortality in pediatric intensive care patients. In addition, prognostic value of platelet counts for outcome in pediatric intensive care unit was studied.

Study Design:

Prospective, observational cohort analysis.

Setting:

8- bedded pediatric intensive care unit of a tertiary care teaching hospital.

Patients:

All consecutively admitted patients (n=138) staying in the pediatric intensive care unit (PICU) for at least 48h over a 7 months period were studied.

Measurements and Main Results:

Thrombocytopenia was defined as platelet counts <150.0/nL. Median 1^st day Pediatric Risk of Mortality Score (PRISM) was 5 (range 0-30) and median ICU stay was 4 days (range 2-98 days). Twenty five percent patients had at least one episode of thrombocytopenia during the stay. Twenty percent of these patients had thrombocytopenia on admission and rest (80%) developed it during the PICU stay. Seventy one percent (19) of the patients developed thrombocytopenia by fourth day of admission. Patients with PICU acquired thrombocytopenia had statistically significant lower baseline, nadir and 4th day platelet counts and a significantly higher drop in platelet counts (56% vs. 6% P<0.001) as compared to non thrombocytopenic patients. PRISM score, long PICU stay, sepsis, coagulopathy, and creatinine levels were significantly associated with occurrence of thrombocytopenia. Patients with thrombocytopenia had higher probability of bleeding (34% vs. 15%, P=0.01). Higher platelet counts on admission were associated with significantly reduced risk of thrombocytopenia (P=0.00) Baseline, nadir and day-4 platelet counts, presence of thrombocytopenia on admission, sepsis, coagulopathy and a higher mean PRISM score on univariate analysis were significantly associated with mortality. Leucopenia or leucocytosis, thrombocytopenia and coagulopathy were found to significantly affect outcome. Drop in platelet counts was found to have slightly higher discriminative value for mortality prediction than PRISM on the ROC curve. The survivors had higher platelet counts throughout the PICU stay and after an initial fall in platelet counts in the PICU showed a significantly higher rise in the platelet counts in the following days than the non-survivors.

Conclusions:

Thrombocytopenia is common in PICU. Patients requiring cardiopulmonary resuscitation or with circulatory shock, coagulopathy, sepsis and with more severe disease have higher risk of developing thrombocytopenia. Thrombocytopenic patients have a higher risk of bleeding. Drop in platelet counts >27% and thrombocytopenia were independently related to mortality. Serial measurements of platelet counts are better predictors of pediatric intensive care outcome than one-time values. Any drop in platelet counts even without thrombocytopenia needs an urgent and extensive evaluation.