New conformational polymorph of hydrochlorothiazide with improved solubility.

CONTEXT: To characterize a new conformation of hydrochlorothiazide (HCT) with better solubility and establishing its relationship with previously reported form I, obtained during attempted crystallization experiments. OBJECTIVE: The aim of present investigation is to unveil a new conformational polymorph (form IA) having a higher solubility compared to commercially available form I. MATERIALS AND METHODS: New form (IA) was obtained from slow evaporation as well as by solvent-antisolvent method and was then characterized by DSC, FTIR, PXRD and SCXRD. Equilibrium solubility profile shows that it is more soluble than form I. RESULTS: Appearance of phase transition endotherm at 215.87 °C in DSC spectra indicated the existence of new polymorph which was further confirmed by FTIR and PXRD. Single crystal study showed significant difference in various bond angles and torsion angles of the two forms. The solubility exhibited by form IA was (938 µg/mL) compared to form I (791 µg/mL) in water. DISCUSSION: Complete structural analysis and molecular arrangements in the unit cell along with the DSC and FTIR data confirm the existence of new conformer of HCT. CONCLUSION: This study reveals the existence of a new conformational polymorph of HCT molecule having higher solubility could prove to be promising in pre-formulation.

Characterization and evaluation of multi-component crystals of hydrochlorothiazide.

PURPOSE: The present work aims at improving the physicochemical properties of hydrochlorothiazide, a poorly water soluble antihypertensive drug by preparing its multi-component crystals with nicotinic acid (HCT-NA) and 2-picolinic acid (HCT-PIC). METHODS: The crystals prepared by solution crystallization were investigated by thermoanalytical techniques. The crystal structures of HCT-NA (1) and HCT-PIC (2) were determined by the single crystal X-ray diffraction and were assessed for their aqueous solubility, antihypertensive activity and acute toxicity in rats. RESULTS: Both 1 and 2 crystallized in the orthorhombic space group P212121 and formation of salts were confirmed. The solubility profiles of 1 and 2 in basic media showed a maximum release of 2.5 mg/ml and 1.9 mg/ml, respectively, in comparison to the drug (0.82 mg/ml). The in-vivo antihypertensive activity of 1 in deoxycorticosterone acetate salt induced hypertensive rats showed 1.5 fold improvement. No increase in the signs of toxicity were revealed in rats during the acute toxicity studies even at doses of 2,000 mg/kg by body weight in comparison to the free drug. Histopathological findings supported the safety of these multi-component crystals. CONCLUSIONS: The new solid phases exhibit potential to be explored for the oral drug delivery of HCT with improved solubility and therapeutic outcome.

Characterization, quantification and stability of differently prepared amorphous forms of some oral hypoglycaemic agents.

The study deals with the investigation of possible differences induced in the physicochemical properties within the amorphous forms prepared by different methods. Enthalpy of solution measured by solution calorimetry was utilized to highlight the differences prevailing within the amorphous forms and to determine the percentage of amorphous content. Emphasis is laid on the quantification and physical stability of these forms. Amorphization was induced in poorly water-soluble oral hypoglycaemic agents (repaglinide, gliclazide and glipizide), by quench cooling, vaporization under reduced pressure and lyophilization. The amorphous nature was evident from a halo pattern in powder X-ray diffraction. A glass transition event is evident in differential scanning calorimetry thermograms of the amorphous forms of the three drugs. As expected, the amorphous forms show improvement in solubility and dissolution profiles. On subjecting these amorphous forms to different relative humidities at 25°C for three months and subsequent analysis showed that amorphous form of repaglinide prepared by quench cooling is most stable and has the potential to be formulated without any additive while amorphous form of gliclazide tends to devitrify pointing towards its unstable nature.

Validation and meaningful within-patient change in work productivity and activity impairment questionnaire (WPAI) for episodic or chronic migraine.

BACKGROUND: No available studies demonstrate validity and meaningful change thresholds of Work Productivity and Activity Impairment (WPAI) questionnaire in patients with migraine. In this post-hoc analysis, we assessed reliability, validity, responsiveness, and meaningful within-patient change from baseline to Month 3 for Work Productivity and Activity Impairment (WPAI) domain scores in patients with episodic migraine (EM) or chronic migraine (CM). METHOD: The Phase 3, multicenter, randomized, double-blind, placebo-controlled CONQUER study (NCT03559257, N = 462) enrolled patients with EM or CM who failed two to four categories of prior preventive medication in past ten years. The analyses were performed for WPAI domain scores (absenteeism, presenteeism, overall work productivity, and non-work-related activity impairment). Migraine Specific Quality of Life Questionnaire version 2.1 (MSQv2.1) domain scores (Role Function-Restrictive [RFR] and Role Function-Preventive [RFP]), and monthly migraine headache days were used as anchors. Responder criteria were changes from baseline to Month 3 for each of these anchors and were defined as: increase in MSQ-RFR by ≥ 25.71 points and MSQ-RFP by ≥ 20.00 points and a 50% reduction in monthly migraine headache days. Assessments were performed for overall population, and patients with EM or CM. The meaningful change threshold was determined based on Youden index, Phi coefficient and sensitivity. RESULTS: Of 462 randomized patients, 444 who completed WPAI questionnaire were included in post-hoc analysis. Test-retest reliability over 3 months in a stable subgroup revealed moderate correlations for non-work-related Activity Impairment (ICC = 0.446) presenteeism (ICC = 0.438) and a fair correlation for overall work productivity loss (ICC = 0.360). At baseline, all correlations between WPAI domain scores and continuous anchor variables exceeded recommended threshold of ≥ 0.30, except for WPAI domain scores with number of monthly migraine headache days. Patients achieving pre-specified responsiveness thresholds for monthly migraine headache days, and MSQ-RFP, MSQ-RFR from baseline to Month 3 (responders) showed significant improvements in WPAI domain scores compared with non-responders (P < 0.001). The meaningful change thresholds of -20 (% unit) were identified for WPAI domain scores. CONCLUSION: In conclusion, WPAI has sufficient validity, reliability, responsiveness, and appropriate interpretation standards to assess the impact of EM or CM on presenteeism and overall work productivity loss and non-work-related activity impairment. TRIAL REGISTRATION: NCT number of CONQUER study, NCT03559257.

Exploring the potential of lecithin/chitosan nanoparticles in enhancement of antihypertensive efficacy of hydrochlorothiazide.

The present study involves the preparation of lecithin/chitosan nanoparticles loaded with hydrochlorothiazide (HCT) (a poorly water soluble antihypertensive) and hydrochlorothiazide complexed with ß-cyclodextrin (HCT-ß-CD) with a view to improve its biopharmaceutical properties. Nanoparticles prepared using modified solvent evaporation method showed a particle size in the range of 126-139 and 152-181 nm (polydispersity index, PDI = 0.2) for HCT and HCT-ß-CD loaded nanoparticles respectively. TEM images revealed their spherical nature. The stable nature of the prepared formulations was evident from the high positive value of zeta potential (>20 mV). HCT and HCT-ß-CD loaded nanoparticles with 150 mg of drug have shown a maximum entrapment efficiency of 81.8 ± 1.7% and 91.1 ± 1.5% respectively. In vitro studies have shown an improved and a sustained release pattern. In vivo activity in DOCA induced hypertensive rats demonstrates 1.5-fold percentage decrease in systolic blood pressure and a prolonged duration of action.

Drug-excipient compatibility screening--role of thermoanalytical and spectroscopic techniques.

Estimation of drug-excipient interactions is a crucial step in preformulation studies of drug development to achieve consistent stability, bioavailability and manufacturability of solid dosage forms. The advent of thermoanalytical and spectroscopic methods like DSC, isothermal microcalorimetry, HSM, SEM, FT-IR, solid state NMR and PXRD into pre-formulation studies have contributed significantly to early prediction, monitoring and characterization of the active pharmaceutical ingredient incompatibility with pharmaceutical excipients to avoid expensive material wastage and considerably reduce the time required to arrive at an appropriate formulation. Concomitant use of several thermal and spectroscopic techniques allows an in-depth understanding of physical or chemical drug-excipient interactions and aids in selection of the most appropriate excipients in dosage form design. The present review focuses on the techniques for compatibility screening of active pharmaceutical ingredient with their potential merits and demerits. Further, the review highlights the applicability of these techniques using specific drug-excipient compatibility case studies.

Anti-kindling Effect of Bezafibrate, a Peroxisome Proliferator-activated Receptors Alpha Agonist, in Pentylenetetrazole Induced Kindling Seizure Model.

BACKGROUND AND PURPOSE: Studies in the animals suggested that Peroxisome proliferators activated receptors (PPARs) may be involved in seizure control and selective agonists of PPAR α or PPAR γ raise seizure thresholds. The present study was contemplated with the aim of evaluating the anti kindling effects and the mechanism of bezafibrate, a Peroxisome proliferator-activated receptors α (PPAR-α) agonist in pentylenetetrazole (PTZ) induced kindling model of seizures in rats. METHODS: In a PTZ kindled Wistar rat model, different doses of bezafibrate (100 mg/kg, 200 mg/kg and 300 mg/kg) were administered intraperitoneally 30 minutes before the PTZ injection. The PTZ injection was given on alternate day till the animal became fully kindled or till 10 weeks. The parameters measured were the latency to develop kindling and incidence of kindling, histopathological study of hippocampus, hippocampal lipid peroxidation studies, serum neuron specific enolase, and hippocampal DNA fragmentation study. RESULTS: In this study, bezafibrate significantly reduced the incidence of kindling in PTZ treated rats and exhibited a marked prolongation in the latencies to seizures. In the present study bezafibrate decreased the thiobarbituric acid-reactive substance i.e. Malondialdehyde levels, increased the reduced glutathione levels, catalase and superoxide dismutase activity in the brain. This added to its additional neuroprotective effects. Bezafibrate also reduced the neuronal damage and apoptosis in hippocampal area of the brain. Therefore bezafibrate exerted anticonvulsant properties in PTZ induced kindling model in rats. CONCLUSIONS: These findings may provide insights into the understanding of the mechanism of bezafibrate as an anti kindling agent and could offer a useful support to the basic antiepileptic therapy in preventing the development of PTZ induced seizures, suggesting its potential for therapeutic applications in temporal lobe epilepsy.

Pharmaceutical cocrystals: a novel approach for oral bioavailability enhancement of drugs.

Solid dosage forms are by far the preferred drug delivery systems. However, these often face the problem of poor and erratic bioavailability during the drug development process. Numerous formulation strategies for drug delivery are currently under development, among which the solid forms such as polymorphs, solvates, salts, and cocrystals have been considered to be the most important for improving dissolution rate and bioavailability. Cocrystallization is a fairly new approach in pharmaceutical industry that can improve the solubility and, consequently, the bioactivity of the active pharmaceutical ingredient (API) without compromising its structural integrity. Pharmaceutical cocrystals have found their place in drug delivery, primarily due to their ability to produce alternative, viable solid forms when a more standard approach of salt and polymorph formation fails to deliver the desired objectives. Over the past few years, a number of papers have been published focusing on a broad range of subjects, from traditional crystal engineering to structure-property relationships of cocrystals. The present review, however, illustrates how the cocrystalline forms of APIs have improved their in vitro dissolution rate and in vivo bioavailability, often correlating well with their improved solubility as well.

Potential of solid lipid nanoparticles in brain targeting.

Brain is a delicate organ, isolated from general circulation and characterized by the presence of relatively impermeable endothelial cells with tight junctions, enzymatic activity and the presence of active efflux transporter mechanisms (like P-gp efflux). These formidable obstacles often impede drug delivery to the brain. As a result several promising molecules (showing a good potential in in vitro evaluation) are lost from the market for a mere consequence of lack of in vivo response probably because the molecule cannot reach the brain in a sufficient concentration. The options to tailor make molecules for brain, though open to the medical chemist, are a costly proposition in terms of money, manpower and time (almost 50 years). The premedial existing approaches for brain delivery like superficial and ventricular application of chemical or the application of chemicals to brain parenchyma are invasive and hence are less patient friendly, more laborious and require skill and could also damage the brain permanently. In view of these considerations novel drug delivery systems such as the nanoparticles are presently being explored for their suitability for targeted brain delivery. Nanoparticles are solid colloidal particles ranging in size from 1 to 1000 nm (<1 microm) and composed of macromolecular material. Nanoparticles could be polymeric or lipidic (SLNs). SLNs are taken up readily by the brain because of their lipidic nature. The bioacceptable and biodegradable nature of SLNs makes them less toxic as compared to polymeric nanoparticles. Supplemented with small size which prolongs the circulation time in blood, feasible scale up for large scale production and absence of burst effect makes them interesting candidates for study. In the present review we will discuss about the barriers to CNS drug delivery, strategies to bypass the blood-brain barrier and characterization methods of SLNs and their usefulness. The proposed mechanism of uptake, methods of prolonging the plasma retention and the in vivo and in vitro methods for assessment will also be discussed in some details.