A pharmacometrics approach to assess the feasibility of capillary microsampling to replace venous sampling in clinical studies: Tafenoquine case study.

AIM: Microsampling has the advantage of smaller blood sampling volume and suitability in vulnerable populations compared to venous sampling in clinical pharmacokinetics studies. Current regulatory guidance requires correlative studies to enable microsampling as a technique. A post hoc population pharmacokinetic (POPPK) approach was utilized to investigate blood capillary microsampling as an alternative to venous sampling. METHODS: Pharmacokinetic data from microsampling and venous sampling techniques during a paediatric study evaluating tafenoquine, a single-dose antimalarial for P. vivax, were used. Separate POPPK models were developed and validated based on goodness of fit and visual predictive checks, with pharmacokinetic data obtained via each sampling technique. RESULTS: Each POPPK model adequately described tafenoquine pharmacokinetics using a two-compartment model with body weight based on allometric scaling of clearance and volume of distribution. Tafenoquine pharmacokinetic parameter estimates including clearance (3.4 vs 3.7 L/h) were comparable across models with slightly higher interindividual variability (38.3% vs 27%) in capillary microsampling-based data. A bioavailability/bioequivalence comparison demonstrated that the point estimate (90% CI) of capillary microsample versus venous sample model-based individual post hoc estimates for area under the concentration-time curve from time zero to infinity (AUC0-inf ) (100.7%, 98.0-103.5%) and Cmax (79.7%, 76.9-82.5%) met the 80-125% and 70-143% criteria, respectively. Overall, both POPPK models led to the same dose regimen recommendations across weight bins based on achieving target AUC. CONCLUSIONS: This analysis demonstrated that a POPPK approach can be employed to assess the performance of alternative pharmacokinetic sampling techniques. This approach provides a robust solution in scenarios where variability in pharmacokinetic data collected via venous sampling and microsampling may not result in a strong linear relationship. The findings also established that microsampling techniques may replace conventional venous sampling methods.

Systematic Evaluation of the Effect of Formulation Variables on In Vitro Performance of Mometasone Furoate Suspension-Metered Dose Inhalers.

The therapeutic benefits of metered dose inhalers (MDIs) in pulmonary disorders are mainly driven by aerosol performance, which depends on formulation variables (drug and excipients), device design, and patient interactions. The present study provides a comprehensive investigation to better understand the effect of formulation variables on mometasone furoate (MF) suspension-based MDI product performance. The effects of MF particle size (volume median diameter; X50) and excipient concentration (ethanol and oleic acid, cosolvent, and surfactant, respectively) on selected critical quality attributes (delivered dose (DD), fine particle dose of particles lesser than 5 µm (FPD < 5), ex-throat dose and median dissolution time (MDT)) were studied. Eight MF-MDI formulations (one per batch) were manufactured based on a reduced factorial design of experiment (DOE) approach, which included relevant formulation levels with varying X50 (1.1 and 2 µm), concentration of ethanol (0.45, 0.9, 1.8, and 3.6%w/w), and oleic acid (0.001 and 0.025%w/w). The in vitro evaluation of these MF-MDI formulations indicated the importance of drug particle's X50, oleic acid, and ethanol canister concentration as critical formulation variables governing the performance of MF suspension-based MDI products. The effect of these formulation variables on DD, FPD < 5, ex-throat dose, and MDT was subsequently utilized to develop empirical relationships linking formulation factors with effects on in vitro performance measures. The developed strategy could be useful for predicting MF-MDI product performance during MDI product development and manufacturing. The systematic DOE approach utilized in this study may provide insights into the understanding of the formulation variables governing the MF-MDI product performance.

Nose-to-Brain Delivery of Diazepam from an Intranasal Aqua-Triggered In-Situ (ATIS) Gelling Microemulsion: Monitoring Brain Uptake by Microdialysis.

BACKGROUND AND OBJECTIVES: An innovative intranasal aqua-triggered in-situ (ATIS) gel is a polymer-free in-situ gelling microemulsion which gels instantaneously on contact with minute quantities of water to form a mucoadhesive gel. The objective of the study was to develop ATIS diazepam (ATIS-diazepam) as an alternative to the injection for epileptic emergencies and evaluate its brain uptake and nose-to-brain targeting efficiency in rats. METHODS: ATIS-diazepam (1 mg/100 µL) was prepared and characterized for in vitro formulation characteristics. An LC-MS/MS method was developed and validated for the bioanalysis of diazepam. In vivo studies for pharmacokinetics, brain uptake and nasal irritation of intranasal ATIS-diazepam were conducted in rats. Brain uptake was investigated with brain microdialysis, a highly sensitive technique enabling quantification of free drug, which correlates to efficacy. RESULTS: ATIS-diazepam exhibited globule size < 200 nm, low viscosity, negative zeta potential and good stability. A significant increase in mucoadhesion was exhibited by ATIS-diazepam following the addition of a small quantity of water. ATIS-diazepam showed burst release in pH 6.4 with 50% diazepam release in ~ 10 min, which was sustained over 1 h. The absolute bioavailability was ~ 50% with both intranasal free-diazepam and ATIS-diazepam. Intranasal administration of ATIS-diazepam revealed immediate absorption with rapid and high brain extracellular fluid concentration compared to intravenous free-diazepam solution. The estimated direct transport potential and drug targeting efficiency of intranasal ATIS-diazepam was significantly higher (2-fold) than intranasal free-diazepam solution, which was attributed to the mucoadhesive and microemulsion properties of ATIS-diazepam. The nasal irritation study revealed the safety of ATIS-diazepam compared to free-diazepam solution. CONCLUSION: Intranasal ATIS-diazepam showed promise of higher direct nose-to-brain targeting, better safety and hence has an immense implication in the treatment of epileptic emergencies.

Exploring Peyer's Patch Uptake as a Strategy for Targeted Lung Delivery of Polymeric Rifampicin Nanoparticles.

Uptake of nanoparticles through Peyer's Patches following oral administration could enable translocation through lymph to lymphatic organs like the lungs. An important consideration, however, is nanosize and particle hydrophobicity. Furthermore, as delivering the nanoparticles to the intestine where the Peyer's Patches are localized is important, their intact and rapid transit through the stomach into the intestine is highly desirable. We report hydrophobization of mucoadhesive Rifampicin-GantrezAN-119 nanoparticles (GzNP) using a hydrophobic polymer, ethyl cellulose (EC), with the objectives of augmenting Peyer's Patch uptake due to enhanced hydrophobicity and increased intestinal localization as a result of decreased mucoadhesion. RIF-Gantrez-EC nanoparticles (ECGzNP2) exhibited >13% RIF loading and an average particle size of 400-450 nm, which is appropriate for translation through lymph following Peyer's Patch uptake. Higher contact angle (67.3 ± 3.5° vs 30.3 ± 2.1°) and lower mucoadhesion (30.7 ± 4.8 g vs 87.0 ± 3.0 g) of ECGzNP2 over GzNP confirmed hydrophobization and lower mucoadhesion. Fluorescence photomicrographs of intraduodenally administered coumarin-labeled RIF-NP in rats demonstrated higher Peyer's Patch uptake with ECGzNP2, while the increased lung/plasma RIF ratio signified lymph mediated lung targeting. The gastrointestinal transit study in rats, which revealed a significantly higher intestine-to-stomach accumulation ratio with ECGzNP2 (3.4) compared to GzNP (1.0) [ p < 0.05], confirmed availability of the NP in the intestine for Peyer's Patch uptake. Such uptake enabled 182.4 ± 22.6% increase in relative bioavailability, a ∼2-fold higher plasma AUC/MIC ratio and significantly higher lung concentration with ECGzNP2, thereby proposing better efficacy. A significantly higher lung/liver ratio with ECGzNP2 also suggested lower hepatic exposure. The repeated dose 28-day oral toxicity study demonstrated the safety of the nanocarrier and reduced hepatotoxicity with ECGzNP2 compared to RIF. We hereby demonstrate uptake of orally administered NP through Peyer's Patches as a feasible strategy for lung targeting.

Rifampicin Lipid-Polymer hybrid nanoparticles (LIPOMER) for enhanced Peyer's patch uptake.

The oral uptake of intact nanocarriers through Peyer's patches is an important uptake pathway. We report Rifampicin Lipid-Polymer hybrid nanoparticles (RIF-LIPOMER) using glyceryl monostearate as lipid and the mucoadhesive polymer, Gantrez, with the objective of balancing hydrophobicity and mucoadhesion for enhanced Peyer's patch uptake. RIF-LIPOMER was optimized for size, hydrophobicity, and mucoadhesion using Box-Behnken. Designed RIF-LIPOMER (RIF-LIPO-120) exhibited average particle size in the range 300-400nm with drug loading >12%. DSC and XRD confirmed complete amorphization. Contact angle and mucoadhesion force revealed that RIF-LIPO-120 exhibited greater hydrophobicity and lower mucoadhesion compared to Gantrez nanoparticles (RIF-GzNP). Comparative uptake of fluorescent labelled RIF-LIPO-120 and RIF-GzNP, through Peyer's patch following intraduodenal administration in rats, revealed the high accumulation of RIF-GzNP at the villi border, and high Peyer's patch uptake of RIF-LIPO-120. Furthermore, lower accumulation of RIF-LIPO-120 in the liver, compared to RIF-GzNP, suggested bypass of the portal circulation and lymphatic uptake through Peyer's patches. Significantly higher lung: plasma concentration ratio exhibited by RIF-LIPO-120 compared to RIF-GzNP confirmed the same (p<0.05). Our study demonstrated that optimization of hydrophobicity and mucoadhesion of nanoparticles could favor Peyer's patch uptake, which in turn could enable enhanced drug accumulation in the lungs with advantage in the therapy of pulmonary afflictions.

In situ hybrid nano drug delivery system (IHN-DDS) of antiretroviral drug for simultaneous targeting to multiple viral reservoirs: An in vivo proof of concept.

We report In situ hybrid nano drug delivery system (IHN-DDS) of nevirapine (NVP) for simultaneous targeting to multiple viral reservoirs. The IHN-DDS system was comprised of a preconcentrate containing NVP, lipid, and a surfactant which when diluted with water resulted in the formation of nanoparticles of size range varied from 70 to 1100nm. Transmission electron microscopy and small angle neutron scattering studies of pellet and supernatant obtained after centrifugation of the IHN-DDS revealed spherical shaped nanoparticles and assembled structures, respectively. Uniform distribution of the NVP in lipid nanoparticles was confirmed by fourier transform infrared spectroscopy. Biodistribution studies in rats showed significant enhancement of NVP concentration of about 6.1, 5.8 and 3.7 fold in the liver, spleen, and brain, respectively after intravenous administration of IHN-DDS systems compared to plain NVP solution. In conclusion, IHN-DDS systems could be a promising approach for simultaneous multisite targeting and could provide therapeutic benefits in complete eradication of HIV infections.

Bioenhanced advanced third generation solid dispersion of tadalafil: Repurposing with improved therapy in pyelonephritis.

Tadalafil (TDL) a BCS-II drug is recently reported for repurposing nephroprotective effect in Pyelonephritis (PN). However, poor water solubility and dissolution rate limited oral bioavailability pose serious challenges in its therapeutic applications. We present an advanced third generation Solid Dispersion (SD) of TDL comprising a polymer in combination with a Self Micro-emulsifying Composition (SMEC) to achieve high drug loading, improved stability and rapid dissolution of TDL for enhancing bioavailability and efficacy in PN. TDL-SMEC-SD was coated onto rapidly disintegrating inert tablet cores which disintegrated rapidly in water to release SD as a film. TDL-SMEC-SD was evaluated for in-vivo oral bioavailability and in-vivo efficacy in lipopolysaccharide-induced PN in rats. TDL exhibited high solubility (45.6 mg/ml) in the SMEC. TDL-SMEC-SD exhibited remarkably high TDL loading (45%w/w), exceptionally low contact angle (9°), rapid in-vitro release (t50 7.3 min), microemulsion formation (globule size ~100 nm) in aqueous dispersion, and stability as per ICH guidelines. SEM, DSC, and XRD confirmed high physical stability. A relative bioavailability of 350% and 150% compared to TDL and TDL-SD without SMEC respectively, established the superiority of TDL-SMEC-SD. A significant reduction in serum creatinine, blood urea nitrogen and nitric oxide levels in the lipopolysaccharide-induced PN confirmed the benefit of the TDL-SMEC-SD. The advanced third generation SMEC SDs presents the possibility of platform technology for bioenhancement of poorly water soluble drugs.

Solid Dispersion of Curcumin as Polymeric Films for Bioenhancement and Improved Therapy of Rheumatoid Arthritis.

PURPOSE: The aim of our study was development of advanced third generation Curcumin self microemulsifying composition solid dispersion (Cur SMEC-SD) with high drug loading, improved stability, rapid in-vitro dissolution and enhanced bioavailability for improved therapy of rheumatoid arthritis. METHOD: The Cur SMEC-SD comprising polymers (KollidonVA64[KVA], Eudragits, HPMC and Soluplus) and self microemulsifying composition of surfactant:co-surfactant:oil were coated onto rapidly disintegrating inert tablet core. SDs evaluated for stability, in-vitro release and bioenhancement. RESULTS: Cur SMEC-SDs exhibited high Cur loading of 45% w/w and microemulsion formation with globule size (~100 nm) irrespective of polymers. Among the polymers, SD with KVA revealed exceptionally low contact angle (7°C) and rapid in-vitro release (t50%-6.45 min). No crystallization was evident as confirmed by SEM, DSC and XRD and is attributed to SMEC aided solubilization/amorphisation, and interaction of KVA with Cur seen in the FTIR spectra. Stability was confirmed as per ICH guidelines. Remarkable bioenhancement with Cur SMEC-SD was confirmed by the > four fold and a two fold compared to Cur and Cur-SD without SMEC respectively. High efficacy ~ 80% compared to Indomethacin, seen with rheumatoid arthritis (RA) induced rats coupled with no adverse toxicity. CONCLUSION: The advanced third generation Cur SMEC-SD presents a practical technological advancement and suggests Cur SMEC-SD as promising alternative for RA therapy.

Systematic review of drug utilization studies & the use of the drug classification system in the WHO-SEARO Region.

BACKGROUND & OBJECTIVES: Information available on drug consumption is inadequate in most low and middle income countries. This systematic review was conducted to analyse published work on drug utilization research/studies (DUR) in the SEARO region of WHO for study objectives, methodology, results and recommendations and to identify the need for improving DUR and the use of the ATC/DDD system. METHODS: A literature search for DUR was carried out in biomedical databases (PubMed, Scirus, Scopus and Google Scholar) up to May 2012. Publications were selected if those were in the English language, describing DUR or prescription practices, and study conducted in the WHO-SEARO countries. RESULTS: A total of 318 publications were included in the review. Of these, 67 per cent were from India and 13 per cent were from Thailand. Majority of the publications were hospital based; only 16 per cent were community based. The ATC/DDD system was used in only 20 per cent of the publications, of which 73 per cent publications used DDD indicators. Several publications focused on antibiotics (31%). Publications that recommended the need for a policy or intervention to improve prescription practices/rational drug use amounted to 35 per cent. INTERPRETATION & CONCLUSIONS: Drug utilization studies using ATC/DDD system need to be promoted and carried out on an ongoing basis. DUR is important for rational use of drugs. Its relevance to policy making and resource allocation needs to be emphasized.

ICMR programme on Antibiotic Stewardship, Prevention of Infection & Control (ASPIC).

Antimicrobial resistance and hospital infections have increased alarmingly in India. Antibiotic stewardship and hospital infection control are two broad strategies which have been employed globally to contain the problems of resistance and infections. For this to succeed, it is important to bring on board the various stakeholders in hospitals, especially the clinical pharmacologists. The discipline of clinical pharmacology needs to be involved in themes such as antimicrobial resistance and hospital infection which truly impact patient care. Clinical pharmacologists need to collaborate with faculty in other disciplines such as microbiology to achieve good outcomes for optimal patient care in the hospital setting. The ASPIC programme was initiated by the Indian Council of Medical Research (ICMR) in response to the above need and was designed to bring together faculty from clinical pharmacology, microbiology and other disciplines to collaborate on initiating and improving antibiotic stewardship and concurrently curbing hospital infections through feasible infection control practices. This programme involves the participation of 20 centres per year throughout the country which come together for a training workshop. Topics pertaining to the above areas are discussed in addition to planning a project which helps to improve antibiotic stewardship and infection control practices in the various centres. It is hoped that this programme would empower hospitals and institutions throughout the country to improve antibiotic stewardship and infection control and ultimately contain antimicrobial resistance.

Oleanolic Acid Prevents Increase in Blood Pressure and Nephrotoxicity in Nitric Oxide Dependent Type of Hypertension in Rats.

BACKGROUND: Recently, we have reported antihypertensive activity of oleanolic acid (OA) in glucocorticoid-induced hypertension with restoration of nitric oxide (NO) level. However, the involvement of NO-releasing action of OA was unclear. OBJECTIVE: To explore antihypertensive activity of OA in N(ω)-nitro-L-arginine methyl ester (L-NAME) hypertensive rats wherein NO is completely blocked, which would allow exploring the possibility of involvement of NO-releasing action of OA. MATERIALS AND METHODS: Five groups of rats were investigated as normal control, L-NAME (40 mg/kg/day), L-NAME + enalapril (15 mg/kg/day), L-NAME + l-arginine (100 mg/kg/day), and L-NAME + OA (60 mg/kg/day) for 4 weeks. The systolic blood pressure, body weight, and heart rate were measured weekly for 4 weeks. Serum nitrate/nitrite (NOx) level, urine electrolytes concentration, cardiac mass index, and serum creatinine level were determined followed by organ histopathology. RESULTS: OA and enalapril delayed the rise in blood pleasure following L-NAME administration. Decreased serum NOx level was not significantly increased with any of the treatment. OA produced a small, though nonsignificant, increase in the NOx level. L-NAME administration did not affect cardiac mass index. There was an increase in serum creatinine upon L-NAME administration which was prevented by OA. Decreased urine volume, urine sodium and potassium were reversed by OA. CONCLUSION: These results suggest that the antihypertensive effect of OA in L-NAME hypertension is due to diuresis and nephroprotection. However, OA has nonsignificantly affected the NO levels.

Comparative regulatory performance on introduction & withdrawal of drugs in India and EU/internationally.

BACKGROUND: With globalization and signing of WTO GATT treaty, the market in India has expanded. This has necessitated important regulatory decisions. OBJECTIVE: This study aims to determine the gap in introduction and withdrawal of drugs in India and EU. METHODS: For drugs prohibited for manufacture and sale(withdrawn) in India during 1983-1998 and 1999-2012 periods, data on year of introduction and withdrawal in India and EU/internationally was extracted from Central Drugs Standard Control Organization (CDSCO), European Medical Agency (EMA) websites and Google search engine and compared. RESULTS: The gap in introduction of drug in India compared to EU/internationally during 1999-2012 period is shorter than 1983-1998 period, while the gap in withdrawal has not changed much. CONCLUSION: Regulatory authority in India has approved drugs in recent year more quickly than the past but gap in withdrawal has not shortened, indicating need for strengthening postmarketing studies and review process.

Nimesulide controversy: a comparison of EU and Indian scenario.

BACKGROUND: Regulatory decision for withdrawal of a drug from market in European Union (EU) or other developed countries poses a challenge to authorities in developing countries specially when decision varies from different countries, such as for nimesulide. OBJECTIVES: To compare and evaluate, benefit and risk data for regulatory action, of nimesulide in India and EU. METHODS: Data on Nimesulide from EU available from Report on EMA website and Indian data from published literature (SCOPUS data base), WHO Vigibase and International Medicines Statistics (IMS) was compared. RESULTS: Publications from India on Adverse drug reactions (ADRs) are case reports (10) and case series (14). Drug Utilization Research (DUR) studies (17) are mostly from tertiary centres. Data in the WHO Vigibase is meagre, data from IMS is not easily available and there is regional variation in prescriptions. Thus incidence of ADRs per sale, prescription or defined daily does (DDD) cannot be calculated, as has been done for EU. CONCLUSION: Limited and varying data in post marketing studies on ADRs and drug utilization for nimesulide from India made regulatory decision difficult. India and other similar countries could contribute to post marketing data for local and global regulatory decisions by systematically planned studies and networking within country and across countries in region.

Clinical pharmacology training in India: Status and need.

Clinical pharmacologists undertake many tasks, and this makes defining a curriculum challenging. This is especially so under the changing circumstances in developing countries, where clinical pharmacology has an expanding role. The clinical pharmacologist may be responsible for conducting ethical clinical trials, supporting the needs of the generic drug industry, providing access to safe, effective and affordable medicines, guiding their rational use, achieving millennium development goals, and supervising medicines management standards for hospital accreditation. Clinical pharmacologists, including those in developing countries, have a great opportunity to contribute to public health and the growth of pharmaceutical industry, but at present, less clinical research is undertaken and fewer clinical trials are done than might be expected. Here we review clinical pharmacology training in India, consider the needs of different professionals contributing to clinical research and medicines utilization, and suggest ways in which current programs can be modified and new programs started. The conclusions are relevant to clinical pharmacology in both the developing and the developed world.

Effect of Viscum articulatum Burm. (Loranthaceae) in Nω-nitro-L-arginine methyl ester induced hypertension and renal dysfunction.

ETHNOPHARMACOLOGICAL RELEVANCE: Viscum articulatum Burm. is used traditionally in Chinese medicine for treating hypertension. AIM OF THE STUDY: The present study was designed to evaluate the antihypertensive activity of the methanolic extract of Viscum articulatum (MVA) against N(ω)-nitro-L-arginine methyl ester (L-NAME) induced hypertension in rats. MATERIALS AND METHODS: Six groups of rats were investigated for 4 weeks as normal control, L-NAME (40 mg/kg/day), L-NAME+enalapril (15 mg/kg/day), L-NAME+L-arginine (100 mg/kg/day), L-NAME+MVA (200 mg/kg/day) and L-NAME+MVA (400 mg/kg/day) for four weeks. The systolic blood pressure (SBP) and heart rate (HR) were measured weekly throughout the experimental period. The urine electrolytes concentration, cardiac mass index, serum nitrate/nitrite (NO(x)) level, serum creatinine level and lipid profile were determined. RESULTS: Treatment with MVA (200 and 400 mg/kg) or enalapril delayed the rise in SBP produced by administration of L-NAME. None of the treatments had a significant effect on the depression of the serum NO(x) level caused by L-NAME. The serum creatinine and total cholesterol concentrations were elevated upon administration of L-NAME, and this elevation was prevented by MVA co-administration. The urine volume and urine potassium ion level were depressed by L-NAME administration and this effect being inhibited in MVA and enalapril groups. There was no cardiac hypertrophy and HR change after 28 day of L-NAME administration. CONCLUSION: We conclude that MVA may have an antihypertensive effect in the NO deficient type of hypertension, which may be attributed to its diuretic, nephroprotective and hypolipidemic actions.

Oleanolic acid prevents glucocorticoid-induced hypertension in rats.

The present study was designed to evaluate the antihypertensive activity of oleanolic acid isolated from Viscum articulatum, Burm. (Loranthaceae) in glucocorticoid (dexamethasone)-induced hypertension in rats and to propose a probable mechanism of action for this effect. Male Wistar rats (300-350 g) received dexamethasone (20 µg/kg/day s.c.) or saline (vehicle) for 10 days. In a prevention study, the rats received oleanolic acid (60 mg/kg i.p.) for 5 days, followed by dexamethasone or saline for 10 days. During this period the systolic blood pressure and body weight were evaluated on alternate days. At the end of the experiment, the weight of the thymus gland, plasma nitrate/nitrite (nitric oxide metabolites) concentration and cardiac lipid peroxidation value were determined. Oleanolic acid (60 mg/kg i.p.) significantly prevented a rise in the systolic blood pressure and cardiac lipid peroxidation level after administration of dexamethasone (p < 0.01 and p < 0.05, respectively) without showing any significant effect on the dexamethasone-induced change in body and thymus weights. The decrease in concentration of plasma nitrate/nitrite due to dexamethasone was prevented significantly in the group treated with oleanolic acid (p < 0.05). These findings suggest that oleanolic acid (60 mg/kg i.p.) prevents dexamethasone-induced hypertension in rats, which may be attributed to its antioxidant and nitric oxide releasing action.