Scientia Pharmaceutica

249 KiB

Open AccessArticle

Formulation and In Vitro Evaluation of Sunflower Oil Entrapped within Buoyant Beads of Furosemide

by Rammohan BERA, Bivash MANDAL, Manas BHOWMIK, Hriday BERA, Sanjoy K. DEY, Gouranga NANDI and Lakshmi K. GHOSH

Sci. Pharm. 2009, 77(3), 669-678; https://doi.org/10.3797/scipharm.0811-02 - 12 Aug 2009

Cited by 31 | Viewed by 1673

Abstract

The purpose of the present study was to develop buoyant beads for the intragastric delivery of furosemide in order to evaluate the effect of incorporated sunflower oil on physiochemical properties of alginate beads. Sunflower oil entrapped buoyant alginate beads of furosemide were prepared [...] Read more.

The purpose of the present study was to develop buoyant beads for the intragastric delivery of furosemide in order to evaluate the effect of incorporated sunflower oil on physiochemical properties of alginate beads. Sunflower oil entrapped buoyant alginate beads of furosemide were prepared by the emulsion-gelation technique. During the preparation of various batches of beads, the ratio of sunflower oil to water (v/v), the ratio of drug to polymer (w/w), were kept as variables at two levels; either high or low. Smooth, spherical beads with nominal weight variation were obtained. All batches of beads floated for 24 hours with a lag time of 5–10 min. The release of drug followed for 5 hours. Higuchi and first order kinetic modeling indicated a diffusion-controlled release of drug from the beads. The study also demonstrated the influence of sunflower oil on drug entrapment (81–95%) and in vitro release. A higher level of oil increased drug entrapment efficiency but retarded drug release rate as compared to a lower level of oil containing beads. Full article

298 KiB

Open AccessReview

Synthetic Nitroimidazoles: Biological Activities and Mutagenicity Relationships

by Alka MITAL

Sci. Pharm. 2009, 77(3), 497-520; https://doi.org/10.3797/scipharm.0907-14 - 12 Aug 2009

Cited by 93 | Viewed by 4892

Abstract

Parasitic and bacterial infections affecting the gastrointestinal tract represent a significant cause of morbidity and mortality worldwide. Nitroheterocyclic drugs have been available since the early 1960s for the treatment of anaerobic protozoa. The application of these drugs has widened and they are presently [...] Read more.

Parasitic and bacterial infections affecting the gastrointestinal tract represent a significant cause of morbidity and mortality worldwide. Nitroheterocyclic drugs have been available since the early 1960s for the treatment of anaerobic protozoa. The application of these drugs has widened and they are presently used to treat anaerobic pathogenic bacteria and protozoa. 5-nitroimidazoles are a well-established group of antiprotozoal and antibacterial agents that inhibit the growth of both anaerobic bacteria and certain anaerobic protozoa, such as Trichomonas vaginalis, Entamoeba histolytica and Giardia lamblia. The important antibacterial and antiprotozoal activities of nitroimidazoles are associated with reductive metabolism that has led to considerable interest in nitroimidazole reduction chemistry and the synthesis of new, highly effective drugs. The present review provides a brief account of various biological activities exhibited by synthetic nitroimidazole derivatives as well as their structure–mutagenicity relationships. Full article

250 KiB

Open AccessArticle

Comparative Study on Inhibitory Activity of Zerumbone and Zerumbone 2,3-Epoxide on NF-κB Activation and NO Production

by Phan M. GIANG, Phan T. SON, Hui Z. JIN, Jeong H. LEE and Jung J. LEE

Sci. Pharm. 2009, 77(3), 589-596; https://doi.org/10.3797/scipharm.0907-16 - 6 Aug 2009

Cited by 18 | Viewed by 1940

Abstract

In the present study the significant role of the α,β-unsaturated carbonyl structure in the anti-inflammatory activity of the natural humulane sesquiterpenoids zerumbone and zerumbone 2,3-epoxide was evidenced from a comparative study of the ability of zerumbone and zerumbone 2,3-epoxide to inhibit NF-κB activation [...] Read more.

In the present study the significant role of the α,β-unsaturated carbonyl structure in the anti-inflammatory activity of the natural humulane sesquiterpenoids zerumbone and zerumbone 2,3-epoxide was evidenced from a comparative study of the ability of zerumbone and zerumbone 2,3-epoxide to inhibit NF-κB activation and NO production in LPS (lipopolysaccharide)- stimulated RAW 264.7 cells. The IC50 of these compounds were 1.97 μM ± 0.18 and 30.11 μM ± 4.10 in the NF-κB activation assay and 3.58 μM ± 0.46 and 34.7 μM ± 3.72 in the nitric oxide production assay, respectively. Full article

313 KiB

Open AccessArticle

Preparation and Biological Evaluation of a [⁵⁵Co]-2-Acetylpyridine Thiosemicarbazone

by Amir R. JALILIAN, Pejman ROWSHANFARZAD, Mehdi AKHLAGHI, Mahsheed SABET, Mohsen KAMALI-DEHGHAN and Mehrban POULADI

Sci. Pharm. 2009, 77(3), 567-578; https://doi.org/10.3797/scipharm.0907-04 - 5 Aug 2009

Cited by 3 | Viewed by 1414

Abstract

Due to the anti-proliferative properties of cobalt-thiosemicarbazone complexes, the production of [⁵⁵Co](III)-bis-(2-acetylpyridine thiosemicarbazone) ([⁵⁵Co](III)[APTS]₂) was investigated. Co-55 (T_1/2=17.53 h) was produced by 150 μA irradiation of a natural nickel target by 15 MeV protons. The [...] Read more.

Due to the anti-proliferative properties of cobalt-thiosemicarbazone complexes, the production of [⁵⁵Co](III)-bis-(2-acetylpyridine thiosemicarbazone) ([⁵⁵Co](III)[APTS]₂) was investigated. Co-55 (T_1/2=17.53 h) was produced by 150 μA irradiation of a natural nickel target by 15 MeV protons. The ⁵⁵Co was separated from the irradiated target material using a two-step method with a radiochemical yield of >95% followed by radionuclidic and chemical purity control. [⁵⁵Co](III)chloride was mixed with 2-acetylpyridine thiosemicarbazone for 30 min at room temperature to yield [⁵⁵Co](III)[APTS]2 (radiochemical purity > 98% shown by RTLC/HPLC). A specific activity of about 10–20 Ci/mmol was obtained. The final solution was diluted in normal saline to 5% ethanolic solution for biological evaluation. The stability of the final product was checked in the absence and presence of human serum at 37°C to 24 h. The partition co-efficient of the final complex at the pH of 7 was 1.00±0.08. A significant tumor accumulation (%ID/g; 3.5%) was observed in tumoral tissue 21 h post injection in fibrosarcoma-bearing mice by biodistribution studies. Co-incidence imaging also demonstrated tumor uptake from 21–35 h however at 35 h tumor uptake is more specific and significant. Full article

266 KiB

Open AccessArticle

Antiarrhythmic Activities of Some Newly Synthesized Tricyclic and Tetracyclic Thienopyridine Derivatives

by Naglaa A. ABDEL-HAFEZ, Ashraf, M. MOHAMED, Abd El-Galil E. AMR and Mohamed M. ABDALLA

Sci. Pharm. 2009, 77(3), 539-554; https://doi.org/10.3797/scipharm.0905-06 - 5 Aug 2009

Cited by 15 | Viewed by 1507

Abstract

3,5-Bis(4-chlorobenzylidene)-1-ethylpiperidin-4-one (1b) was condensed with malononitrile or cyanothioacetamide to yield pyranopyridine 2 and thiopyridopyridine 3b, respectively. Treatment of compound 3b with methyl iodide or ethyl chloroacetate in the presence of a base catalyst gave the corresponding compounds 4 and 5 [...] Read more.

3,5-Bis(4-chlorobenzylidene)-1-ethylpiperidin-4-one (1b) was condensed with malononitrile or cyanothioacetamide to yield pyranopyridine 2 and thiopyridopyridine 3b, respectively. Treatment of compound 3b with methyl iodide or ethyl chloroacetate in the presence of a base catalyst gave the corresponding compounds 4 and 5. Compound 3b was reacted with 2-chloro-N-arylacetamide derivatives to yield compounds 7a,b, which were reacted with benzoyl chloride or sodium nitrite to give the corresponding tetracyclic compounds 8a,b and 9a,b, respectively. Compound 2 was treated with acetic anhydride or formic acid to yield the corresponding N-acetylpyranopyridine 10 and pyranopyrimidine 11. Treatment of compound 2 with triethyl ortho-formate gave compound 12, which was cyclized with hydrazine hydrate to give N-aminopyrimidine 13. Some of the synthesized compounds showed high antiarrhythmic activities comparable with Procaine amide and Lidocaine as positive controls. Full article

265 KiB

Open AccessArticle

HPLC Analysis and Standardization of Arjunarishta – An Ayurvedic Cardioprotective Formulation

by Uma R. LAL, Shailendra M. TRIPATHI, Sanjay M. JACHAK, Kamlesh K. BHUTANI and Inder P. SINGH

Sci. Pharm. 2009, 77(3), 605-616; https://doi.org/10.3797/scipharm.0906-03 - 30 Jul 2009

Cited by 31 | Viewed by 2408

Abstract

Arjunarishta (Parthadyarishta) is an important Ayurvedic formulation used for cardiovascular disorders and is prepared by fermenting the decoction of specified plant materials using flowers of Woodfordia fruticosa. In present communication, an HPLC-PDA method was developed for the standardization of Arjunarishta [...] Read more.

Arjunarishta (Parthadyarishta) is an important Ayurvedic formulation used for cardiovascular disorders and is prepared by fermenting the decoction of specified plant materials using flowers of Woodfordia fruticosa. In present communication, an HPLC-PDA method was developed for the standardization of Arjunarishta by quantitative estimation of major antioxidant compounds, ellagic acid, gallic acid, ethyl gallate, quercetin and kaempferol as markers. The developed method was validated with respect to linearity, precision, accuracy, and robustness. The HPLC analysis showed an increase in amount of ellagic acid and gallic acid during preparation, i.e. decoction vs formulation. A similar increase in free radical scavenging activity of formulation vs decoction was also observed. Arjunolic acid and arjunic acid were not detected in the formulation. Full article

360 KiB

Open AccessArticle

Design and Development of a Self Correcting Monolithic Gastroretentive Tablet of Baclofen

by Rishad R. JIVANI, Chhagan N. PATEL and Nuruddin P. JIVANI

Sci. Pharm. 2009, 77(3), 651-668; https://doi.org/10.3797/scipharm.0905-11 - 24 Jul 2009

Cited by 11 | Viewed by 1386

Abstract

The present investigation describes the design and development of selfcorrecting monolithic Gastroretentive system of baclofen. Tablets were prepared by direct compression method. Optimization was carried out using simplex lattice design. Drug released at 2h, 4h, 8h, and floating lag time were considered as [...] Read more.

The present investigation describes the design and development of selfcorrecting monolithic Gastroretentive system of baclofen. Tablets were prepared by direct compression method. Optimization was carried out using simplex lattice design. Drug released at 2h, 4h, 8h, and floating lag time were considered as response variables related to percentages of diluent (MCC), Polyethylene oxide (PEO) and sodium bicarbonate. Tablets were evaluated for in-vitro buoyancy, in-vitro drug release, swelling index and ex-vivo bioadhesion studies. The similarity factor (f₂) was used as a base to compare dissolution profiles. Drug release data was fitted into different kinetic models. The floating lag time and floating time were found to be 2min and 12h respectively. Increasing trend in bioadhesive strength was observed with an increase in the amount of PEO. The experimental values of Q2, Q4 and Q8 for check point batch were found to be 30.8%, 44.1% and 69.9% respectively. Similarity factor (f₂) for check point batch was 78.08. Kinetics of drug release from tablet followed Korsmeyer–Peppas model by anamolous non-fickian diffusion. It was concluded that gastroretentive tablet of baclofen can be prepared via floating and bioadhesion mechanism to increase residence time of drug in stomach and there by increases absorption. Full article

286 KiB

Open AccessArticle

Development and Validation of a Dissolution Test for 6 mg Deflazacort Tablets

by Norma R. SPERANDEO and Diego E. KASSUHA

Sci. Pharm. 2009, 77(3), 679-694; https://doi.org/10.3797/scipharm.090405 - 16 Jul 2009

Cited by 3 | Viewed by 2886

Abstract

The aim of this study was to develop and validate a dissolution test for the quality control of deflazacort (DEF) tablets, a drug mainly used for the prevention of organ transplantation rejection, labeled as containing 6 mg of active pharmaceutical ingredient (API), using [...] Read more.

The aim of this study was to develop and validate a dissolution test for the quality control of deflazacort (DEF) tablets, a drug mainly used for the prevention of organ transplantation rejection, labeled as containing 6 mg of active pharmaceutical ingredient (API), using an RP-HPLC method. After testing sink conditions and stability at 37°C, DEF was found to be unstable, and decomposed as a function of the dissolution media. However, in water the decomposition was not significant enough to interfere with the determination of dissolution for DEF. The best conditions to carry out the dissolution test were paddle at 50 rpm, with 500 mL of deaerated water at 37°C. Under these conditions, the in vitro release profiles of 6 mg DEF tablets produced by two different laboratories, representing all approved products in the national market, shown to be dissimilar. A correlation between disintegration and in vitro dissolution was found for the two investigated formulations. The developed dissolution test was adequate for its purpose and can be applied for the quality control of 6 mg DEF tablets. Full article

967 KiB

Open AccessArticle

Defensive Agents of Blaps femoralis, a Traditional Mongolian Medicinal Insect

by Disan GUNBILIG and Wilhelm BOLAND

Sci. Pharm. 2009, 77(3), 597-604; https://doi.org/10.3797/scipharm.0905-18 - 6 Jul 2009

Cited by 8 | Viewed by 1556

Abstract

Knowledge about therapy with insects in Mongolian traditional medicine is less studied even they have been used broadly since ancient time. Several orthodox practitioners have surveyed the therapeutic potentials of defensive agents in Blaps femoralis known as “stink beetle” in the [...] Read more.

Knowledge about therapy with insects in Mongolian traditional medicine is less studied even they have been used broadly since ancient time. Several orthodox practitioners have surveyed the therapeutic potentials of defensive agents in Blaps femoralis known as “stink beetle” in the past. We present results about content of defensive secretion and surface lipids, both a biologically active principle in insect, used in traditional Mongolian medicine. A combination of gas chromatography and mass spectroscopy was used for the identification of several p-benzoquinone derivatives accompanied by straight chain hydrocarbons and fatty acids. None of these compounds has been reported previously from this species. An IR imaging of insect cuticle surface shows the possibility for the analytical characterization of fatty acids in tissue at high lateral resolution of few microns. Full article

221 KiB

Open AccessArticle

Antipyretic Potential of Swertia chirata Buch Ham. Root Extract

by Sushil BHARGAVA, Prakash S. RAO, Paridhi BHARGAVA and Shivshankar SHUKLA

Sci. Pharm. 2009, 77(3), 617-624; https://doi.org/10.3797/scipharm.0812-10 - 4 Jul 2009

Cited by 32 | Viewed by 3333

Abstract

The aqueous extract of Swertia chirata Buch Ham. Root (ASC) (Family: Gentianaceae) was evaluated for its antipyretic potential on Brewer’s yeastinduced pyrexia in albino rats and Typhoid-Paratyphoid A, B vaccine induced Hyperexia in rabbits. In both models, the extract, at dose of 200 [...] Read more.

The aqueous extract of Swertia chirata Buch Ham. Root (ASC) (Family: Gentianaceae) was evaluated for its antipyretic potential on Brewer’s yeastinduced pyrexia in albino rats and Typhoid-Paratyphoid A, B vaccine induced Hyperexia in rabbits. In both models, the extract, at dose of 200 mg kg⁻¹ body wt. and 400 mg kg⁻¹ body weight, produced significant (p<0.001) reduction in elevated body temperature in a dose dependent manner. The antipyretic effect of the extract was comparable to that of paracetamol (150 mg kg⁻¹ body weight, p.o.), a standard antipyretic agent. Full article

310 KiB

Open AccessArticle

Isolation and Characterization of a Trace Level Unknown Impurity of Salmeterol by Chromatographic and Spectroscopic Methods

by Bandaru VENKATASUBBAIAH, Lakki Reddy PRAKASH, Rudraraju Vasu DEV, Vakamudi VARAPRASAD and Kalluru SUBRAMANYAM REDDY

Sci. Pharm. 2009, 77(3), 579-588; https://doi.org/10.3797/scipharm.0906-01 - 4 Jul 2009

Cited by 2 | Viewed by 1908

Abstract

During the process development of Salmeterol, an unknown impurity was detected at 2.08 Relative Retention Time (RRT) at a level of 0.11% by a gradient Reverse Phase-High Performance Liquid Chromatography (RP-HPLC). The impurity was isolated from the salmeterol drug substance using preparative HPLC. [...] Read more.

During the process development of Salmeterol, an unknown impurity was detected at 2.08 Relative Retention Time (RRT) at a level of 0.11% by a gradient Reverse Phase-High Performance Liquid Chromatography (RP-HPLC). The impurity was isolated from the salmeterol drug substance using preparative HPLC. The separation was achieved with an Inertsil C8 column, using acetonitrile–trifluroacetic acid buffer pH 2.7 as mobile phase. The isolated impurity was characterized by NMR and MS techniques. The impurity has been characterized as 4-(2-{[6-(4-cyclohexylbutoxy)hexyl]amino}-1-hydroxyethyl)- 2-(hydroxymethyl)phenol. The synthesis of the impurity and its formation was also discussed. Full article

252 KiB

Open AccessArticle

QSAR Study on 6-Substituted Benzimidazoles: An Insight into the Structural Requirement for the Angiotensin II AT1 Receptor Antagonist

by Anurekha JAIN and Subhash C. CHATURVEDI

Sci. Pharm. 2009, 77(3), 555-566; https://doi.org/10.3797/scipharm.0901-30 - 6 Jun 2009

Cited by 4 | Viewed by 1168

Abstract

With an aim to identify the structural requirements for selective AT1 angiotensin antagonistic activity, a quantitative structure activity relationship (QSAR) analysis was carried out on a series of 6-substituted benzimidazole derivatives. The QSAR expressions were generated using 28 compounds and the predictive ability [...] Read more.

With an aim to identify the structural requirements for selective AT1 angiotensin antagonistic activity, a quantitative structure activity relationship (QSAR) analysis was carried out on a series of 6-substituted benzimidazole derivatives. The QSAR expressions were generated using 28 compounds and the predictive ability of the resulting model was evaluated against a test set of 12 compounds. The internal (cross validated squared correlation coefficient) and external consistency (predictive correlation coefficient) of the QSAR model was 0.78 and 0.40 respectively. In the present work QSAR analysis reveals that geometrical, structural, and shape descriptors govern the angiotensin II AT1 antagonistic activity. Full article

412 KiB

Open AccessArticle

Development of a w/o/w-Emulsion Containing N-Acetylcysteine for Cosmetic Use

by Gülgün YENER and Tuba İncegülKE

Sci. Pharm. 2009, 77(3), 639-650; https://doi.org/10.3797/scipharm.0902-05 - 4 Jun 2009

Cited by 1 | Viewed by 1366

Abstract

N-Acetylcysteine was known to be used as a mucolytic agent having significant antioxidant activity. It has been reported to be used to alleviate or improve various cosmetic conditions and dermatological disorders including changes or damage to skin associated with intrinsic or extrinsic [...] Read more.

N-Acetylcysteine was known to be used as a mucolytic agent having significant antioxidant activity. It has been reported to be used to alleviate or improve various cosmetic conditions and dermatological disorders including changes or damage to skin associated with intrinsic or extrinsic aging recently. However many benefits regarding to its antioxidant effects were reported, its probable potential moisturizing effects have not been stated yet. Since N-acetylcysteine has similar effects as vitamin C, it might be assumed that it could also increase skin hydration by its antioxidant capacity. The aim of this work was to investigate the feasibility of a topical delivery system as a multiple emulsion containing N-acteylcysteine and compare the moisturizing potential of this formulation with a base multiple emulsion and vitamin E which was chosen as a popular moisturizer. Full article

302 KiB

Open AccessArticle

Physicochemical Properties and Excipient Compatibility studies of Probiotic Bacillus coagulans Spores

by Pushpak S. BORA, Vibha PURI and Arvind K. BANSAL

Sci. Pharm. 2009, 77(3), 625-638; https://doi.org/10.3797/scipharm.0904-01 - 26 May 2009

Cited by 21 | Viewed by 3139

Abstract

The probiotic formulations are susceptible to loss in viability due to formulation, processing, storage and in vivo environment. The aim of the present study was to perform preformulation studies of probiotic Bacillus coagulans spores to aid designing of stable formulations. Bacillus coagulans spores [...] Read more.

The probiotic formulations are susceptible to loss in viability due to formulation, processing, storage and in vivo environment. The aim of the present study was to perform preformulation studies of probiotic Bacillus coagulans spores to aid designing of stable formulations. Bacillus coagulans spores were studied for hygroscopicity, resistance to compaction force, aqueous pH stability, and excipient compatibility. The spores were found to be moderately hygroscopic with a significant loss of microbiological assay at water activity value of more than 0.5. Progressive loss of viability from 95% to 58% was observed with increase in compaction force from 1000 to 4000 psi. Aqueous suspension of Bacillus coagulans spores in buffer solutions of pH 1.2 to 8 showed rapid degradation with maximal stablility in pH 6.8. Excipient compatibility studies showed reduced assay with citric acid monohydrate, meglumine and sodium starch glycolate. The loss of activity seemed to be related to the moisture uptake, free and bound water present in the bulk. Full article

307 KiB

Open AccessArticle

Superaugmented Pendentic Indices: Novel Topological Descriptors for QSAR/QSPR

by Harish DUREJA, Kinkar C. DAS and Anil Kumar MADAN

Sci. Pharm. 2009, 77(3), 521-538; https://doi.org/10.3797/scipharm.0903-07 - 26 May 2009

Cited by 4 | Viewed by 1471

Abstract

Four pendenticity based topological descriptors termed as superaugmented pendentic indices have been conceptualized in the present study. An in-house computer program was utilized to compute index values of all the possible structures (with at least one pendent vertex) containing four, five and six [...] Read more.

Four pendenticity based topological descriptors termed as superaugmented pendentic indices have been conceptualized in the present study. An in-house computer program was utilized to compute index values of all the possible structures (with at least one pendent vertex) containing four, five and six vertices. The sensitivity towards branching, discriminating power, degeneracy and mathematical properties of the proposed superaugmented pendentic indices were investigated. All the four proposed indices exhibited exceptionally high sensitivity towards branching, high discriminating power and extremely low degeneracy. Superaugmented pendentic index-4 (^SA∫^P-4) exhibited exceptionally high discriminating power of 114 in structures containing only six vertices. Statistical significance of the proposed indices was investigated using intercorrelation analysis with Wiener’s index, Balaban’s mean square distance index, molecular connectivity index, Zagreb indices (M₁ and M₂), superpendentic index and eccentric connectivity index. The exceptionally high sensitivity towards branching, high discriminating power amalgamated with extremely low degeneracy offer proposed indices a vast potential for isomer discrimination, similarity/dissimilarity, drug design, quantitative structureactivity/ structure-property relationships, lead optimization and combinatorial library design. Full article

245 KiB

Open AccessEditorial

Scientia Pharmaceutica, Autorenhinweise 2009

by Scientia Pharmaceutica Editorial Office

Sci. Pharm. 2009, 77(3), 711-724; https://doi.org/10.3797/scipharm.aut-09-03 - 5 May 2009

Viewed by 1128

Abstract

n/a Full article

528 KiB

Open AccessArticle

Molecular Mobility and Physical Stability of Amorphous Irbesartan

by Garima CHAWLA and Arvind K. BANSAL

Sci. Pharm. 2009, 77(3), 695-710; https://doi.org/10.3797/scipharm.0806-09 - 18 Jul 2008

Cited by 14 | Viewed by 2074

Abstract

Amorphous systems have attracted considerable attention due to their favorable properties; however, their stability issues still pose a major challenge. The purpose of the present work was to investigate the role of molecular mobility and moisture in the physical stability of a selected [...] Read more.

Amorphous systems have attracted considerable attention due to their favorable properties; however, their stability issues still pose a major challenge. The purpose of the present work was to investigate the role of molecular mobility and moisture in the physical stability of a selected pharmaceutical amorphous system. Irbesartan (IBS), a relatively stable glass, was chosen as the model drug, as it exhibits a good physical stability (resistance to crystallization) at temperatures below the glass transition (Tg-50 K). The amorphous system was annealed at temperatures 298 K (25 °C) and 313 K (40 °C) at 0 and 75 % RH to study the effect of temperature and moisture on its relaxation behavior. Differential scanning calorimetry (DSC) was used to characterize both the crystalline and the freshly prepared glass, and to monitor the extent of relaxation at temperatures below glass transition (Tg) as well as heat capacity changes as a function of temperature. Molecular relaxation time constant (τ) decreased drastically from 302 years to 68 hours with the increase in annealing temperature as determined by Kohlrausch-William-Watts (KWW) equation. IBS was found to be ‘relatively’ stable in the amorphous state and presented a challenge for temporal measurements. Hence, at low annealing temperatures, (T_g-50 K or below) initial relaxation time (τ⁰) was estimated using the calorimetric based approach. Amorphous IBS was non-hygroscopic and retained its glassy nature under the accelerated stability conditions. The extent of relaxation in the amorphous drug in the presence of moisture was also estimated. Full article

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Sci. Pharm., Volume 77, Issue 3 (September 2009) – 17 articles , Pages 497-724

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