Purification of Drug Loaded Liposomal Formulations by a Novel Stirred Cell Ultrafiltration Technique.

BACKGROUND: Presently reported methods for purification of liposomal formulations at laboratory scale have drawbacks of adversely affecting critical quality attributes (CQAs) of liposomes such as particle size, PDI, drug entrapment efficiency, etc., and are also not amenable for large scale processing. OBJECTIVE: The present study was aimed to explore stirred cell ultrafiltration technique as a novel liposome purification method for removal of unentrapped free drug and excess external aqueous fluid, maintaining the physical integrity of liposomes. METHODS: Purification of brimonidine loaded liposomes (model formulation) was performed by stirred cell ultrafiltration method, and its functional performance and impact on liposomal particle size, PDI, and entrapment efficiency were compared with two widely used laboratory scale methods, i.e., ultracentrifugation and centrifugal ultrafiltration. RESULTS: The novel stirred cell ultrafiltration method demonstrated liposomal purification within ~30 min with complete liposomal recovery showing minimal processing impact, i.e., ˂0.25 fold rise in particle size, ~0.5 fold rise in PDI, and ~4% loss in % entrapment efficiency, respectively. Whereas ultracentrifugation and centrifugal ultrafiltration methods resulted in ~4 fold and ˃2 fold rise in particle size, ˃10 fold and ˃5 fold rise in PDI, and ˃25% and ~6% loss in entrapment efficiency, respectively. CONCLUSION: The unique and product-friendly operational features of stirred cell ultrafiltration method demonstrated simple, rapid, and efficient liposomal purification without affecting CQAs of liposomal vesicles. This method was also evidently found to be product-friendly, rugged, versatile, and scalable up to large production batch processing, overcoming major drawbacks of presently used methods.

Formulation design and optimization of cationic-charged liposomes of brimonidine tartrate for effective ocular drug delivery by design of experiment (DoE) approach.

OBJECTIVE: The present study was aimed to design and optimize brimonidine tartrate (BRT) loaded cationic-charged liposome formulation with enhanced trans-corneal drug permeation, prolonged corneal residence, and sustained drug release for effective ocular delivery. METHODS: Design of experiment (DoE) based formulation optimization was done by three-factor, three-level Box-Behnken design selecting lipid, cholesterol, and drug content as independent variables and particle size (PS), polydispersity index (PDI), zeta potential (ZP), entrapment efficiency (EE%), and cumulative % drug release (CDR) as response variables. The optimized formulation consisting of 79.2 mM lipid, 36.2 mM cholesterol, and 15.8 mg/mL drug was prepared by thin film hydration-sonication method using EPCS:DOTAP (1:1) as lipid component and characterized for all desired critical quality attributes (CQAs), drug release kinetics, TEM, DSC, XRD analysis, ex vivo trans-corneal drug permeation, and physical stability studies. RESULTS: The optimized liposome formulation exhibited experimentally observed responses close to predicted values having 150.4 nm (PS), 0.203 (PDI), 30.62 mV (ZP), and 55.17% (EE). The observed CDR (%) was 36.15% at 1 h and 91.13% at 12 h exhibiting sustained drug release profile and followed Higuchi drug release kinetics. The TEM, DSC, and XRD studies revealed spherical, nanosized, small unilamellar vesicles effectively entrapping BRT in liposomes. The ex vivo permeation study across goat cornea recorded apparent permeability (Papp) 1.011 ± 0.07 cm.min-1 and steady-state flux (Jss) 17.63 ± 1.22 µg.cm-2.min-1 showing >2-fold enhanced drug permeation as compared to BRT solution. CONCLUSION: The developed liposomal formulation possessed all recommended CQAs in optimal range with enhanced trans-corneal drug permeation and remained physically stable in 3 months stability study.

Purification of Drug Loaded PLGA Nanoparticles Prepared by Emulsification Solvent Evaporation Using Stirred Cell Ultrafiltration Technique.

PURPOSE: The emulsifiers in an exceedingly higher level are used in the preparation of drug loaded polymeric nanoparticles prepared by emulsification solvent evaporation method. This creates great problem to the formulator due to their serious toxicities when it is to be administered by parenteral route. The final product is therefore required to be freed from the used surfactants by the conventional purification techniques which is a cumbersome job. METHODS: The solvent resistant stirred cell ultrafiltration unit (Millipore) was used in this study using polyethersulfone ultrafiltration membrane (Biomax®) having pore size of NMWL 300 KDa as the membrane filter. The purification efficiency of this technique was compared with the conventional centrifugation technique. RESULTS: The flow rate of ultrafiltration was optimized for removal of surfactant (polyvinyl alcohol) impurities to the acceptable levels in 1-3.5 h from the nanoparticle dispersion of tamoxifen prepared by emulsification solvent evaporation method. CONCLUSIONS: The present investigations demonstrate the application of solvent resistant stirred cell ultrafiltration technique for removal of toxic impurities of surfactant (PVA) from the polymeric drug nanoparticles (tamoxifen) prepared by emulsification solvent evaporation method. This technique offers added benefit of producing more concentrated nanoparticles dispersion without causing significant particle size growth which is observed in other purification techniques, e.g., centrifugation and ultracentrifugation.

Hydroxypropyl- ß -cyclodextrin: A Novel Transungual Permeation Enhancer for Development of Topical Drug Delivery System for Onychomycosis.

The treatment of onychomycosis is a challenging task because of unique barrier properties of the nail plate which hampers the passage of antifungal drugs in a concentration required to eradicate the deeply seated causative fungi in the nail bed. In present investigation, application of hydroxypropyl-ß-cyclodextrin (HP-ß-CD) was established as an effective and nail friendly transungual drug permeation enhancer especially for poorly water soluble drugs using terbinafine hydrochloride as a poorly soluble drug. HP-ß-CD significantly improves hydration of nail plates and increases solubility of terbinafine hydrochloride in the aqueous environment available therein, which leads to uninterrupted drug permeation through water filled pores of hydrogel-like structure of hydrated nail plates. A nail lacquer formulation was designed with an objective to deliver the drug in an effective concentration across nail plates, using HP-ß-CD as a permeation enhancer. The formulations containing HP-ß-CD showed higher flux than the control formulation in in vitro drug permeation study. The formulation containing 10% w/v of HP-ß-CD showed maximum flux of 4.586 ± 0.08 µg/mL/cm(2) as compared to the control flux of 0.868 ± 0.06 µg/mL/cm(2). This finding supports application of HP-ß-CD as an effective permeation enhancer for transungual delivery of terbinafine hydrochloride and possibly other poorly water soluble drugs where HP-ß-CD can act as a solubilizer.

Hydration of nail plate: a novel screening model for transungual drug permeation enhancers.

Drug delivery by topical route for the treatment of onychomycosis, a nail fungal infection, is challenging due to the unique barrier properties of the nail plate which imparts high resistance to the passage of antifungal drugs. Permeation enhancers are used in transungual formulations to improve the drug flux across the nail plate. Selection of the effective permeation enhancer among the available large pool of permeation enhancers is a difficult task. Screening the large number of permeation enhancers using conventional Franz diffusion cells is laborious and expensive. The objective of present study was to evolve a simple, accurate and rapid method for screening of transungual drug permeation enhancers based on the principle of hydration of nail plate. The permeation enhancer which affects the structural or physicochemical properties of nail plate would also affect their hydration capacity. Two screening procedures namely primary and secondary screenings were evolved wherein hydration and uptake of ciclopirox olamine by nail plates were measured. Hydration enhancement factor, HEF(24) and drug uptake enhancement factor, UEF(24) were determined for screening of 23 typical permeation enhancers. The Pearson's correlation coefficient between HEF(24) and UEF(24) was determined. A good agreement between the HEF(24) and UEF(24) data proved the validity of the proposed nail plate hydration model as a screening technique for permeation enhancers.

Formulation optimization of long-acting depot injection of aripiprazole by using D-optimal mixture design.

Non-adherence to medication specifications is a major cause for poor outcomes in the therapy of schizophrenia. In situ implantable preparation of aripiprazole, an atypical antipsychotic drug, was intended with the aim to improve the patient compliance and to offer an effective antipsychotic drug therapy. D-optimal mixture design was employed to design and optimize long-acting depot injection of aripiprazole using polylactide-co-glycolide (PLGA) 50:50, 75:25, 85:15, and cholesterol as release rate-retarding material. Desirability technique was used for the optimization of formulation. Predicted optimized formulation was experimentally validated, and it was found that the developed formulation releases the drug for a 14-day time period. The optimized formulation showed that the cholesterol-containing formulation exhibits a better drug release profile. The pharmacokinetic studies confirmed that the developed cholesterol-based depot formulation was capable of releasing the drug for a time period of more than 14 days. The implant formulation was sterilized by gamma radiation and ethylene oxide sterilization method. The D-optimal mixture design was proved to be an efficient technique for the formulation optimization.

Optimization of formulation variables for the development of long acting microsphere based depot injection of olanzapine.

This work was aimed to optimize the composition of microspheres of olanzapine to design long acting depot injection for the treatment of psychosis. Solvent evaporation method was used for the fabrication of microspheres. Different formulation variables for the solvent evaporation method, viz., effect of theoretical drug loading, type of surfactant and its concentration, temperature, volume of external phase and presence of salt in external aqueous phase, conditions and time of solvent evaporation and drying methodology were optimized. The microspheres were characterized for encapsulation efficiency, particle size, surface morphology, residual solvent content, drug release profile and drug release kinetics. The optimized formulation showed consistent drug release for upto 14 days time period.

Multiple enamel pearls in two siblings detected by volumetric computed tomography.

A rare case of multiple enamel pearl formation is presented involving the maxillary molars in two siblings incidentally recognized during volumetric CT examination. Although the pathogenesis of ectopic enamel formation is not known, possible mechanisms to account for this phenomenon are discussed in the context of current knowledge regarding root genesis. The radiographic presentation of enamel pearls and its clinical significance is also discussed. The observation of multiple enamel pearls in two siblings raises the possibility of a hereditary association in the formation of enamel pearls.

Formulation development and release studies of indomethacin suppositories.

Indomethacin suppositories were prepared by using water-soluble and oil soluble suppository bases, and evaluated for in vitro release by USP I and modified continuous flow through bead bed apparatus. Effect of the Tween 80 (1% and 5%) was further studied on in vitro release of the medicament. Release rate was good in water-soluble suppositories bases in comparison to oil soluble suppositories bases. Release was found to be greater in modified continuous flow through bead bed apparatus. When surfactant was used in low concentration then release rate was much greater, as compared to high concentration. When stability studies were performed on the prepared indomethacin suppositories it was found that suppositories made by water-soluble base had no significant changes while suppositories prepared by oil soluble bases, had some signs of instability.

Comparative pilot study of symptoms and quality of life in cancer patients and patients with end stage renal disease.

BACKGROUND: Patients with advanced renal failure are increasingly opting for conservative treatment, yet little is known of their palliative care needs. METHODS: We performed a cross-sectional study, examining symptom burden and quality of life in patients with advanced renal failure (estimated GFR < 17 mL/min; n = 11). A contemporary cohort with terminal malignancy acted as comparators (n = 11). Symptom burden was scored using an extended Memorial Symptom Assessment Scale Short Form questionnaire. Quality of life was assessed using the Euroqol-5Q questionnaire. Demographic and pathological data, performance status and co-morbidity were also recorded. RESULTS: Baseline characteristics were similar for the two groups. Symptom burden (renal 17; cancer 15; P =NS) and quality of life scores (renal 60; cancer 60; P =NS) were remarkably similar. Both groups reported high levels of psychological distress. CONCLUSIONS: Patients with advanced renal failure experience a symptom burden and impairment of quality of life similar to that of patients with terminal malignancy.

Influence of microencapsulation method and peptide loading on formulation of poly(lactide-co-glycolide) insulin nanoparticles.

Insulin stability during microencapsulation and subsequent release is essential for retaining its biological activity. Therefore we investigated a novel solid/oil/water anhydrous encapsulation method with a combination of stabilizers for maintaining the integrity of insulin during formulation and delivery. Two methods were used for preparation of nanoparticles, namely water/oil/water solvent evaporation and s/o/w anhydrous encapsulation to study the influence of the microencapsulation method on nanoparticle characteristics such as size and morphology, drug content, encapsulation efficiency, and in vitro and in vivo release profile. Poly (lactic-co-glycolic) acid (PLGA) with co-polymer ratio 50:50 was selected to prepare drug-loaded nanoparticles. When nanoparticles were prepared by solvent evaporation higher encapsulation efficiencies could be obtained, e.g. 74 +/- 13 with 5% target loading, whereas with 12% target loading, encapsulation efficiency was 27 +/- 8.6. The s/o/w method has a direct influence on the evaluation parameters where very poor encapsulation efficiencies 11 +/- 6.8 (max) were observed. The presence of stabilizers in the nanoparticles resulted in an increase in particle size but a reduction of encapsulation efficiency. Insulin release rate was comparatively higher for the batches prepared by the w/o/w method containing stabilizers than the s/o/w method. Also the presence of stabilizers resulted in sustained release of insulin resulting in prolonged reduction of blood glucose levels in streptozotocin induced diabetic rats. From the in vitro and in vivo studies, it can be concluded that careful selection of processing conditions and combination of stabilizers also result in beneficial effects without compromising the advantages of these delivery systems.

Giant congenital intrapericardial left atrial aneurysm diagnosed by contrast-enhanced computed tomography.

A left atrial aneurysm is a rare cardiac anomaly. The etiology is usually congenital, but it can also occur as an acquired pathology secondary to mitral valve disease or a degenerative process. We report a case which, on routine PA chest radiography, presented as cardiomegaly with a bulge on the left cardiac contour. Further evaluation by contrast-enhanced computed tomography proved it to be caused by a large left atrial aneurysm.

"Meth mouth": rampant caries in methamphetamine abusers.

Rampant dental caries is a characteristic finding in methamphetamine abusers. The popularity of methamphetamine, particularly among the gay community where it is linked to the spread of HIV, its ready availability, and rapid spread across the nation have placed methamphetamine use in an epidemic status in many communities unaccustomed to dealing with drug abuse. We present a case of a 25-year-old male "meth" abuser of unknown HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) status to promote recognition by the health care team of the association of rampant dental caries with methamphetamine abuse for appropriate intervention to ensure successful treatment and prevention of disease progression.

Pseudocyst formation: a rare complication of wandering spleen.

Wandering spleen is a rare entity, in which the spleen is abnormally mobile due to its attachment by a long vascular pedicle. This long vascular pedicle predisposes it to various complications, the most common being torsion. Here, we present a case in which a wandering spleen in a young female was complicated by pseudocyst formation, and discuss the possible aetiology, pathogenesis, diagnosis and therapeutic implications of this extremely rare complication.

Reconstructing the cosmic equation of state from supernova distances.

Observations of high-redshift supernovae indicate that the Universe is accelerating. Here we present a model-independent method for estimating the form of the potential V(phi) of the scalar field driving this acceleration, and the associated equation of state w(phi). Our method is based on a versatile analytical form for the luminosity distance D(L), optimized to fit observed distances to distant supernovae and differentiated to yield V(straight phi) and w(straight phi). Our results favor w(phi) approximately -1 at the present epoch, steadily increasing with redshift. A cosmological constant is consistent with our results.

A retrospective radiographic survey of embedded primary molar roots in Saudi adult patients.

This retrospective study reports the radiographic prevalence of embedded primary molar roots within Saudi adult dentulous patients. Embedded roots of primary molars were viewed radiographically by evaluation of the records of 300 patients. Embedded primary molar roots were detected in 7 percent of the viewed patient radiographs. Fifty-five percent of the embedded roots demonstrated the concomitant existence of partial bony ankylosis. The remaining 45 percent of the embedded roots were surrounded by an intact lamina dura and periodontal ligament space. The frequency of occurrence demonstrated an age-based relationship, showing 9 percent prevalence in the older age-group (41-50 yr.) as compared to a 45 percent occurrence seen in the younger (15-20 yr.) group. Seventy-seven percent of the embedded roots were found within the mandible as compared with a 23 percent occurrence in the maxilla.

Protective ability of acetylsalicylic acid (aspirin) to scavenge radiation induced free radicals in J774A.1 macrophage cells.

Radiation generates a variety of free radicals during the exposure of biological tissues through radiolysis of water. These free radicals are highly reactive and cause oxidative damage to biological molecules. This study examined the protective ability of aspirin against radiation induced oxidative stress. The study assessed the protective effect of aspirin (0.05 mM, 0.10 mM, 0.50 mM) on the generation of free radicals during exposure of J774A.1 macrophage cells to radiation (13.25 cGy). Approximately a 2.2-fold increase in superoxide anion formation as determined by cytochrome c reduction was observed following exposure of the cells to radiation for 20 one second exposures. Preincubation with aspirin exhibited a dose dependent decrease in free radical production as assessed by chemiluminescence and cytochrome c reduction. Aspirin also produced a concentration dependent reduction in radiation induced DNA damage in the cells. The data indicate that radiation of these cells results in production of reactive oxygen species and DNA damage, and aspirin can decrease these effects in a concentration dependent manner.

Bromocriptine in augmentation of antipsychotic response in chronic schizophrenia: a negative pilot report.

To further assess the usefulness of bromocriptine in treatment of schizophrenia seven inpatient chronic schizophrenics with acute exacerbation who had failed to respond to four weeks of antipsychotic therapy were treated with bromocriptine 2.5 mg daily for a treatment duration varying from one dose to four weeks while their antipsychotic dose was continued unchanged. Mean age of patients was 38.9 +/- 11.6 years and mean number of prior psychiatric hospitalizations was 12.0 +/- 7.2. Patients were rated with the Brief Psychiatric Rating Scale prior to the first bromocriptine dose, at 24 hours after dosage initiation, and at weekly intervals. One patient showed clinically significant improvement in both positive and negative schizophrenic symptoms. One patient showed slight improvement in unusual thought content, and four patients were clinically unchanged. One patient significantly worsened after the first dose. Factors possibly contributing to response and non-response are discussed. This is a report of an open study in 7 patients. It is the only report of bromocriptine treatment in patients previously shown unresponsive to antipsychotics and whose antipsychotics dose was held constant throughout the study. Addition of bromocriptine to the antipsychotic regimen remains an unproven treatment approach which may be considered only in patients refractory to or inadequately controlled with antipsychotics.

Multiple sclerotic masses of jaws.

Multiple sclerotic masses of jaws commonly occur in middle aged black females. There exists a plethora of terminologies to describe these entities. The phenomenon has been speculated to be due to low grade infection or the result of dysplastic changes of osseous tissue. Familial history has been noticed in some cases. Radiographically the masses appear multiple, dense and globular radiopacities with a radiolucent rim. This criterion may be used to distinguish the masses from chronic diffuse sclerosing osteomyelitis. Secondary infection leading to sequestration is a common complication.

Meswak chewing stick versus conventional toothbrush as an oral hygiene aid.

This study consisted of two trials. Trial 1 compared the meswak with the toothbrush when used twice and five times a day. Trial 2 compared habitual meswak users with toothbrush users. Under experimental conditions, a significant reduction in gingivitis was found both buccally (p less than 0.01) and lingually (p less than 0.05) after using a meswak five times a day compared with a conventional toothbrush. Twice a day brushing with a meswak produced a significant reduction in gingivitis buccally (p less than 0.005) compared with toothbrushing, but lingually the difference was insignificant. There were no significant differences in plaque scores between a meswak and a conventional toothbrush when brushing was continued five times a day. Plaque scores became significantly higher when a meswak was used only twice a day compared with toothbrushing, specifically on the lingual surfaces of the teeth (p less than 0.01). Habitual meswak users showed a significant reduction in gingival bleeding (p less than 0.05) and interproximal bone height (p less than 0.02) compared with toothbrush users. The differences in plaque scores and pocket depth measurements between the two groups were insignificant. The results imply that a meswak, used five times a day, may offer a suitable alternative to a toothbrush for reducing plaque and gingivitis. However, meswak may not be sufficient for maintaining interproximal dental health when used without the support of other oral hygiene aids.