Nanomicelles empower natamycin in treating fungal keratitis: An in vitro, ex vivo and in vivo study

Fungal infections of cornea are important causes of blindness especially in developing nations with tropical climate. However, the challenges associated with current treatments are responsible for poor outcome. Natamycin is the only FDA-approved antifungal drug to treat fungal keratitis, but unfortunately due to its poor water solubility, it is available as suspension. The marketed suspension (5% Natamycin) has rapid precorneal clearance, poor corneal permeability, a higher frequency of administration, and corneal irritation due to undissolved suspended drug particles. In our study, we developed clear and stable natamycin-loaded nanomicelles (1% Natcel) to overcome the above challenges. We demonstrated that 1% Natcel could permeate the cornea better than 5% suspension. The developed 1% Natcel was able to provide sustained release for up to 24 h. Further, it was found to be biocompatible and also improved the mean residence time (MRT) than 5% suspension in tears. Therefore, the developed 1% Natcel could be a potential alternative treatment for fungal keratitis.

Lane-Hamilton syndrome - Is it really a needle in a haystack?

Introduction

The association of pulmonary hemosiderosis with celiac disease (Lane-Hamilton syndrome) is extremely rare.

Case Details

A five-year-old female child presented with fever, cough, breathlessness, and pallor for 20 days, without any previous history of recurrent lower respiratory tract infections, tuberculosis, or cardiac disease. There was no history of pica, chronic diarrhea, bleeding, or personal or family history of repeated blood transfusions. She had tachycardia, tachypnea, severe pallor, stunting, rickets, and bilateral fine lung crepitations. Peripheral smear and blood indices revealed dimorphic anemia. Anti-tissue transglutaminase IgA antibody levels were high (>200 U/mL) and the upper gastrointestinal endoscopy with duodenal biopsy confirmed the diagnosis of celiac disease. The child was discharged on a gluten-free diet (GFD) and oral hematinic, but her dietary compliance was poor. Interestingly, the child had persistent bilateral pulmonary infiltrates, which was initially attributed to congestive cardiac failure (CCF), which persisted even despite treatment. HRCT chest revealed interstitial thickening and bilateral alveolar shadows and bronchoalveolar lavage showed a few inflammatory cells. The child was readmitted four times with similar complaints and was given packed red cell transfusions. In the fourth admission, a lung biopsy was done, which revealed extensive pulmonary hemosiderosis. The patient was given a course of oral steroids for 6 weeks, with a gluten-free diet, following which both the anemia and the pulmonary infiltrates resolved.

Conclusion

Pulmonary hemosiderosis is an important cause of anemia in cases of celiac disease and may be misdiagnosed as CCF due to severe anemia. A strict GFD, with or without corticosteroids, can reverse the clinical and radiological picture.

Dithranol-loaded nanostructured lipid carrier-based gel ameliorate psoriasis in imiquimod-induced mice psoriatic plaque model

OBJECTIVE

The aim of this study was to formulate nanostructured lipid carriers (NLCs) of dithranol-loaded in gel for ease of application and to evaluate its anti-psoriatic efficacy vis-a-vis conventional ointment formulation.

SIGNIFICANCE

This study will provide an insight about the use of nanocarriers, esp. NLCs loaded with dithranol for the effective treatment of psoriasis.

METHODS

Dithranol-loaded NLCs were prepared by hot melt homogenization method and characterized for particle size and percentage entrapment efficiency. The optimized NLCs were loaded into gel and evaluated for drug release, spreadability, rheological behavior, and staining. Anti-psoriatic efficacy of the NLC gel was evaluated in imiquimod (IMQ) induced psoriatic plaque model in comparison with prepared conventional ointment formulation (1.15% w/w dithranol).

RESULTS

NLCs were prepared with particle size below 300 nm, polydispersity index (PDI) below 0.3 and percentage entrapment efficiency of ∼100%. The prepared NLC gel was then compared with the ointment for drug release, staining property, and efficacy. Topical application of dithranol-loaded NLC gel on IMQ-induced psoriatic plaque model reduced the symptoms of psoriasis assessed by both Psoriasis area severity index (PASI) scoring and enzyme-linked immunosorbent assay. There was a significant reduction in disease severity and cytokines like Interleukins-17, 22, 23 and Tumor necrosis factor-α by the developed system in comparison to the negative control.

CONCLUSIONS

To conclude dithranol-loaded NLCs in gel base was efficacious in management of psoriasis at the same drug concentration and also offer less cloth staining to that of the ointment product.

The steady-state development of splenic dendritic cells

Dendritic cells (DCs) are a heterogenous population of cells that can be grouped into the conventional DCs (cDCs) and plasmacytoid DCs (pDCs), or interferon-producing cells. pDCs are thought to develop in the bone marrow and migrate to the periphery as mature cells. In contrast, cDC precursors are thought to migrate to the periphery, where they further differentiate into cDCs. In the case of migratory cDCs, these precursors are thought to be monocytes, whereas resident cDCs derive from a different precursor. Recent activity on this subject has shed some light on the precursors that differentiate into resident cDCs and pDCs, but often with conflicting findings. Here, we review some of these findings and discuss some of the outstanding issues in the field.

Evaluation of truncated areas in the assessment of bioequivalence of immediate release formulations of drugs with long half-lives and of Cmax with different dissolution rates

PURPOSE

To Evaluate truncated AUC in place of AUCt or extrapolated AUCinf, for drugs with long half-lives and to study the relationship between Cmax and in vitro dissolution rates.

METHODS

Monte-Carlo simulations were conducted using actual mean plasma concentrations of five long half-life drug products. The simulations were based on a catenary pharmacokinetic system in which the drug disposition in the body was represented by a one-or two-compartment model, characterizing the observed mean profiles. The influence of dramatic changes in the in vitro dissolution rate constant 'kd', was simulated in scenarios consisting of 20 crossover trials with 24 subjects per trial, comparing a fast dissolving reference and a hypothetical, slow dissolving test formulation.

RESULTS

The AUC's truncated after the completion of distribution phase were found surrogate to the AUCt or AUCinf measures. Except for Phenylbutazone, the Cmax measure was insensitive to the changes in the in vitro dissolution rate. The Cmax measure was found to be useful in the bioequivalence assessment since it reflected both the rate and extent of absorption. (Cmax/AUCt) measure was specific to absorption rate.

CONCLUSIONS

For the bioequivalence determination of long half-life drug products, (1) the use of truncated AUC's after completion of the distribution phase instead of AUCinf, appears feasible. (2) Cmax measure may be insensitive to input rate changes, if the absorption rate is not constrained by the input rate in relation to the distribution or elimination rate. (3) (Cmax/AUCt) may be more specific to 'ka' differences, but Cmax reflects differences in both rate and extent of absorption.

In vitro dissolution profile comparison--statistics and analysis of the similarity factor, f2

PURPOSE

To describe the properties of the similarity factor (f2) as a measure for assessing the similarity of two dissolution profiles. Discuss the statistical properties of the estimate based on sample means.

METHODS

The f2 metrics and the decision rule is evaluated using examples of dissolution profiles. The confidence interval is calculated using bootstrapping method. The bias of the estimate using sample mean dissolution is evaluated.

RESULTS

1. f2 values were found to be sensitive to number of sample points, after the dissolution plateau has been reached. 2. The statistical evaluation of f2 could be made using 90% confidence interval approach. 3. The statistical distribution of f2 metrics could be simulated using 'Bootstrap' method. A relatively robust distribution could be obtained after more than 500 'Bootstraps'. 4. A statistical 'bias correction' was found to reduce the bias.

CONCLUSIONS

The similarity factor f2 is a simple measure for the comparison of two dissolution profiles. But the commonly used similarity factor estimate f2 is a biased and conservative estimate of f2. The bootstrap approach is a useful tool to simulate the confidence interval.

In vitro dissolution profile comparison and IVIVR. Carbamazepine case

Dissolution data for the immediate or modified release drug products are usually collected as percent dissolved at multiple time points. Once an in-vitro/in-vivo relationship is established on a drug product, the dissolution profile becomes meaningful and important. In that context, if a firm desires to modify its formulation on which the in-vitro/in-vivo association has been established, a meaningful insight into the pharmacokinetics may be obtained by comparing the dissolution profiles of the two lots. In this presentation, we demonstrated a model dependent dissolution profile comparison approach using example of carbamazepine tablet dissolution data. Once a mathematical function was selected to describe the dissolution data coming from various standard lots, a similarity region could be constructed using the model parameter variances. To compare the test and reference lot dissolution profiles, a statistical distance was calculated between the mean parameters. A confidence region generated around the normalized mean statistical distance could then be compared with the similarity region to assess the similarity or dissimilarity of the dissolution profiles.

Acute tolerance to the cardiovascular effects of volatilized cocaine free base in rats

The cardiovascular effects elicited by volatilized cocaine were compared to those produced by i.v. drug administration. All of the subjects exposed to volatilized cocaine exhibited an initial increase in mean arterial pressure (MAP), profound bradycardia, and heart blocks. Intravenous administration of cocaine (1.5 mg/kg i.v.), a dose equivalent to the amount of drug subjects received from inhalation exposure, led to a transient increase in MAP but failed to produce any obvious ECG abnormalities or bradycardia; however, increasing the dose to 4.5 mg/kg resulted in considerable toxicity. Finally, the hemodynamic effects elicited by inhalation cocaine were found to undergo rapid tolerance during the first 5-min exposure period and the three subsequent drug exposures.