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Pharmaceutics, Volume 5, Issue 4 (December 2013), Pages 508-651

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Research

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Open AccessArticle Influence of Sodium Lauryl Sulfate and Tween 80 on Carbamazepine–Nicotinamide Cocrystal Solubility and Dissolution Behaviour
Pharmaceutics 2013, 5(4), 508-524; doi:10.3390/pharmaceutics5040508
Received: 6 August 2013 / Revised: 5 September 2013 / Accepted: 29 September 2013 / Published: 11 October 2013
Cited by 13 | PDF Full-text (804 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The influence of the surfactants of sodium lauryl sulfate (SLS) and Tween 80 on carbamazepine–nicotinamide (CBZ–NIC) cocrystal solubility and dissolution behaviour has been studied in this work. The solubility of the CBZ–NIC cocrystal was determined by measuring the eutectic concentrations of the [...] Read more.
The influence of the surfactants of sodium lauryl sulfate (SLS) and Tween 80 on carbamazepine–nicotinamide (CBZ–NIC) cocrystal solubility and dissolution behaviour has been studied in this work. The solubility of the CBZ–NIC cocrystal was determined by measuring the eutectic concentrations of the drug and the coformer. Evolution of the intrinsic dissolution rate (IDR) of the CBZ–NIC cocrystal was monitored by the UV imaging dissolution system during dissolution. Experimental results indicated that SLS and Tween 80 had little influence upon the solubility of the CBZ–NIC cocrystal but they had totally opposite effects on the IDR of the CBZ–NIC cocrystal during dissolution. SLS significantly increased the IDR of the CBZ–NIC cocrystal while Tween 80 decreased its IDR. Full article
(This article belongs to the Special Issue Solid State Chemistry of Drugs)
Open AccessArticle Design of Olanzapine/Lutrol Solid Dispersions of Improved Stability and Performances
Pharmaceutics 2013, 5(4), 570-590; doi:10.3390/pharmaceutics5040570
Received: 3 September 2013 / Revised: 11 October 2013 / Accepted: 14 October 2013 / Published: 25 October 2013
Cited by 2 | PDF Full-text (1484 KB) | HTML Full-text | XML Full-text
Abstract
Eleven solid dispersions containing olanzapine, with carriers of different composition (Lutrol® F68, Lutrol® F127, Gelucire® 44/14), were prepared and examined by thermal (differential scanning calorimetry (DSC); thermomicroscopy (HSM)) and X-ray diffraction (XRD) analysis, both as fresh or aged (one [...] Read more.
Eleven solid dispersions containing olanzapine, with carriers of different composition (Lutrol® F68, Lutrol® F127, Gelucire® 44/14), were prepared and examined by thermal (differential scanning calorimetry (DSC); thermomicroscopy (HSM)) and X-ray diffraction (XRD) analysis, both as fresh or aged (one year) samples. Drug and carriers were preliminarily selected in order to avoid problems related to the aging of the formulation, according to the solubility parameters of carriers and drug. These parameters make it possible to predict the low solubility of olanzapine in the carriers (alone or in mixtures). Systems containing only Lutrol (also in the presence of Transcutol®) contain the drug in the form of particles of reduced size and in a crystalline form. Gelucire® 44/14 apparently increases the amount of olanzapine dissolved in the solid carrier, but this is presumed to be a metastable state, probably related to the heterogeneous nature of the carrier that delays crystallization of the drug. The high hydrophilicity of the carriers proves suitable to an accelerated and quick release of the drug regardless of aging. Differences in the release profiles between Lutrol- and Gelucire-containing systems were interpreted in terms of the formation of polymer micelles by the Lutrols when in aqueous solution. Full article
(This article belongs to the Special Issue Solid State Chemistry of Drugs)
Open AccessArticle Terahertz Pulsed Imaging and Magnetic Resonance Imaging as Tools to Probe Formulation Stability
Pharmaceutics 2013, 5(4), 591-608; doi:10.3390/pharmaceutics5040591
Received: 3 August 2013 / Accepted: 21 September 2013 / Published: 25 October 2013
Cited by 2 | PDF Full-text (1687 KB) | HTML Full-text | XML Full-text
Abstract
Dissolution stability over the entire shelf life duration is of critical importance to ensure the quality of solid dosage forms. Changes in the drug release profile during storage may affect the bioavailability of drug products. This study investigated the stability of a [...] Read more.
Dissolution stability over the entire shelf life duration is of critical importance to ensure the quality of solid dosage forms. Changes in the drug release profile during storage may affect the bioavailability of drug products. This study investigated the stability of a commercial tablet (Lescolr XL) when stored under accelerated conditions (40 oC/75% r.h.). Terahertz pulsed imaging (TPI) was used to investigate the structure of the tablet coating before and after the accelerated aging process. The results indicate that the coating was reduced in thickness and exhibited a higher density after being stored under accelerated conditions for four weeks. In situ magnetic resonance imaging (MRI) of the water penetration processes during tablet dissolution in a USP-IV dissolution cell equipped with an in-line UV-vis analyzer was carried out to study local differences in water uptake into the tablet matrix between the stressed and unstressed state. The drug release profiles of the Lescolr XL tablet before and after the accelerated storage stability testing were compared using a “difference” factor ∫1 and a “similarity” factor ∫2. The results reveal that even though the physical properties of the coating layers changed significantly during the stress testing, the coating protected the tablet matrix and the densification of the coating polymer had no adverse effect on the drug release performance. Full article
(This article belongs to the Special Issue Solid State Chemistry of Drugs)
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Open AccessArticle Preparation of Microcapsules Containing β-Carotene with Thermo Sensitive Curdlan by Utilizing Reverse Dispersion
Pharmaceutics 2013, 5(4), 609-620; doi:10.3390/pharmaceutics5040609
Received: 26 September 2013 / Revised: 30 October 2013 / Accepted: 12 November 2013 / Published: 21 November 2013
Cited by 1 | PDF Full-text (469 KB) | HTML Full-text | XML Full-text
Abstract
We have tried to microencapsulate β-carotene with curdlan of a thermogelation type polysaccharide. Microcapsules were prepared by utilizing reverse dispersion, in which salada oil was the continuous phase (O’) and the curdlan water slurry (W) was the dispersed phase. β-carotene (O) as [...] Read more.
We have tried to microencapsulate β-carotene with curdlan of a thermogelation type polysaccharide. Microcapsules were prepared by utilizing reverse dispersion, in which salada oil was the continuous phase (O’) and the curdlan water slurry (W) was the dispersed phase. β-carotene (O) as a core material was broken into fine oil droplets in the dispersed phase to form the (O/W) dispersion. The (O/W) dispersion was poured in the continuous phase (O’) and stirred to form the (O/W)/O’ dispersion at room temperature and then, temperature of the dispersion was raised to 80 °C to prepare curdlan-microcapusles containing β-carotene. In this microencapsulation process, the concentrations of curdlan and oil soluble surfactant and the impeller speed to form the (O/W)/O’ dispersion were mainly changed stepwise. We were able to prepare microcapsules by the microencapsulation method adopted here. The content of core material was increased with the curdlan concentration and decreased with the impeller speed and the oil soluble surfactant concentration. With the curdlan concentration, the drying rate of microcapsules was decreased and the retention ability for water was increased due to the stable preservation of β-carotene. Full article
(This article belongs to the Special Issue Microencapsulation Technology Applied to Pharmaceutics 2014)
Open AccessArticle Oral Liquid Formulation of Levothyroxine Is Stable in Breakfast Beverages and May Improve Thyroid Patient Compliance
Pharmaceutics 2013, 5(4), 621-633; doi:10.3390/pharmaceutics5040621
Received: 15 November 2013 / Revised: 29 November 2013 / Accepted: 4 December 2013 / Published: 13 December 2013
Cited by 8 | PDF Full-text (273 KB) | HTML Full-text | XML Full-text
Abstract
Patients on treatment with levothyroxine (T4) are informed to take this drug in the morning, at least 30 min before having breakfast. A significant decrease of T4 absorption was reported, in fact, when T4 solid formulations are taken with food or coffee. [...] Read more.
Patients on treatment with levothyroxine (T4) are informed to take this drug in the morning, at least 30 min before having breakfast. A significant decrease of T4 absorption was reported, in fact, when T4 solid formulations are taken with food or coffee. According to preliminary clinical study reports, administration of T4 oral solution appears to be less sensitive to the effect of breakfast beverages on oral bioavailability. In the present study, stability of T4 oral solution added to breakfast beverages was investigated. A 1 mL ampoule of single-dose Tirosint® oral solution (IBSA Farmaceutici Italia, Lodi, Italy) was poured into defined volumes of milk, tea, coffee, and coffee with milk warmed at 50 °C, as well as in orange juice at room temperature. Samples were sequentially collected up to 20 min and analyzed by validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. The results of the study demonstrated that T4 is stable in all beverages after 20 min incubation. Demonstration of T4 stability is a prerequisite for a thorough evaluation of the effect of breakfast beverages on the bioavailability of T4 given as oral solution and for a better understanding of the reasons underlying a decreased T4 bioavailability administered as solid formulations. Full article
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Review

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Open AccessReview Liposome Formulation of Fullerene-Based Molecular Diagnostic and Therapeutic Agents
Pharmaceutics 2013, 5(4), 525-541; doi:10.3390/pharmaceutics5040525
Received: 19 August 2013 / Revised: 26 September 2013 / Accepted: 27 September 2013 / Published: 18 October 2013
Cited by 5 | PDF Full-text (689 KB) | HTML Full-text | XML Full-text
Abstract
Fullerene medicine is a new but rapidly growing research subject. Fullerene has a number of desired structural, physical and chemical properties to be adapted for biological use including antioxidants, anti-aging, anti-inflammation, photodynamic therapy, drug delivery, and magnetic resonance imaging contrast agents. Chemical [...] Read more.
Fullerene medicine is a new but rapidly growing research subject. Fullerene has a number of desired structural, physical and chemical properties to be adapted for biological use including antioxidants, anti-aging, anti-inflammation, photodynamic therapy, drug delivery, and magnetic resonance imaging contrast agents. Chemical functionalization of fullerenes has led to several interesting compounds with very promising preclinical efficacy, pharmacokinetic and safety data. However, there is no clinical evaluation or human use except in fullerene-based cosmetic products for human skincare. This article summarizes recent advances in liposome formulation of fullerenes for the use in therapeutics and molecular imaging. Full article
(This article belongs to the Special Issue Liposome Technologies)
Open AccessReview Surface Engineering of Liposomes for Stealth Behavior
Pharmaceutics 2013, 5(4), 542-569; doi:10.3390/pharmaceutics5040542
Received: 2 September 2013 / Revised: 10 October 2013 / Accepted: 14 October 2013 / Published: 25 October 2013
Cited by 34 | PDF Full-text (692 KB) | HTML Full-text | XML Full-text
Abstract
Liposomes are used as a delivery vehicle for drug molecules and imaging agents. The major impetus in their biomedical applications comes from the ability to prolong their circulation half-life after administration. Conventional liposomes are easily recognized by the mononuclear phagocyte system and [...] Read more.
Liposomes are used as a delivery vehicle for drug molecules and imaging agents. The major impetus in their biomedical applications comes from the ability to prolong their circulation half-life after administration. Conventional liposomes are easily recognized by the mononuclear phagocyte system and are rapidly cleared from the blood stream. Modification of the liposomal surface with hydrophilic polymers delays the elimination process by endowing them with stealth properties. In recent times, the development of various materials for surface engineering of liposomes and other nanomaterials has made remarkable progress. Poly(ethylene glycol)-linked phospholipids (PEG-PLs) are the best representatives of such materials. Although PEG-PLs have served the formulation scientists amazingly well, closer scrutiny has uncovered a few shortcomings, especially pertaining to immunogenicity and pharmaceutical characteristics (drug loading, targeting, etc.) of PEG. On the other hand, researchers have also begun questioning the biological behavior of the phospholipid portion in PEG-PLs. Consequently, stealth lipopolymers consisting of non-phospholipids and PEG-alternatives are being developed. These novel lipopolymers offer the potential advantages of structural versatility, reduced complement activation, greater stability, flexible handling and storage procedures and low cost. In this article, we review the materials available as alternatives to PEG and PEG-lipopolymers for effective surface modification of liposomes. Full article
(This article belongs to the Special Issue Liposome Technologies)
Open AccessReview Mathematical Model to Predict Skin Concentration after Topical Application of Drugs
Pharmaceutics 2013, 5(4), 634-651; doi:10.3390/pharmaceutics5040634
Received: 17 October 2013 / Revised: 7 December 2013 / Accepted: 10 December 2013 / Published: 16 December 2013
Cited by 1 | PDF Full-text (405 KB) | HTML Full-text | XML Full-text
Abstract
Skin permeation experiments have been broadly done since 1970s to 1980s as an evaluation method for transdermal drug delivery systems. In topically applied drug and cosmetic formulations, skin concentration of chemical compounds is more important than their skin permeations, because primary target [...] Read more.
Skin permeation experiments have been broadly done since 1970s to 1980s as an evaluation method for transdermal drug delivery systems. In topically applied drug and cosmetic formulations, skin concentration of chemical compounds is more important than their skin permeations, because primary target site of the chemical compounds is skin surface or skin tissues. Furthermore, the direct pharmacological reaction of a metabolically stable drug that binds with specific receptors of known expression levels in an organ can be determined by Hill’s equation. Nevertheless, little investigation was carried out on the test method of skin concentration after topically application of chemical compounds. Recently we investigated an estimating method of skin concentration of the chemical compounds from their skin permeation profiles. In the study, we took care of “3Rs” issues for animal experiments. We have proposed an equation which was capable to estimate animal skin concentration from permeation profile through the artificial membrane (silicone membrane) and animal skin. This new approach may allow the skin concentration of a drug to be predicted using Fick’s second law of diffusion. The silicone membrane was found to be useful as an alternative membrane to animal skin for predicting skin concentration of chemical compounds, because an extremely excellent extrapolation to animal skin concentration was attained by calculation using the silicone membrane permeation data. In this chapter, we aimed to establish an accurate and convenient method for predicting the concentration profiles of drugs in the skin based on the skin permeation parameters of topically active drugs derived from steady-state skin permeation experiments. Full article
(This article belongs to the Special Issue Advanced Transdermal Drug Delivery)
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