Knowledge and compliance towards alendronate therapy among postmenopausal women with osteoporosis in Palestine.

BACKGROUND: Postmenopausal women compliance to alendronate therapy is suboptimal due to the complex dosing requirements. The poor compliance may increase their potential of fractures and the prevalence of side effects. In this study, the compliance of osteoporotic women on bisphosphonate therapy to the complex dosing instructions and their knowledge of alendronate-interactions were assessed. METHODS: This is a cross-sectional study, using self-administered questionnaire involving 224 osteoporotic women on alendronate therapy, who visited the orthopedic clinics and community pharmacies in the West Bank. Data was collected using a validated questionnaire consisting of 4 sections and analyzed by descriptive statistics. Moreover, associations between patient's socio-demographic characteristics and the extent of compliance and knowledge of alendronate interactions are established in this study. RESULTS: A total of 300 questionnaires were distributed and 224 were completed. The median compliance score to alendronate dosing instructions was 5 out of a possible maximum 7, and the median knowledge score about alendronate interactions was 7 out of a possible maximum 14. Factors found to affect either or both the knowledge and compliance to alendronate dosing instructions were, residency, and the source of instructions. CONCLUSION: This study identified the importance of compliance and knowledge gaps among postmenopausal women treated with alendronate. Therefore, appropriate knowledge about the importance of proper compliance to dosing instructions and avoidance of interactions is of a great benefit for maximizing clinical effectiveness, lowering fracture risk and prevention of adverse effects of alendronate among patients treated with alendronate in Palestine.

Extemporaneous Compounding and Physiological Modeling of Amlodipine/Valsartan Suspension.

METHOD: Amlodipine/valsartan extemporaneous suspension was prepared from available commercial tablets such as Valzadepine®. The dissolution profiles for the extemporaneous preparation and the commercial tablet were determined in different pH media. The physical, chemical, and microbial stability of the compounded formulation was evaluated over one-month period at room temperature. Moreover, in silico modeling using GastroPlus™ software was used to build absorption models for both drugs based on the in vitro dissolution data. The simulated plasma profiles for both active ingredients were compared with the in vivo plasma profiles to examine the similarity of the extemporaneous suspension and the commercial tablets. RESULTS: The amlodipine/valsartan extemporaneous suspension was successfully prepared with acceptable organoleptic properties. The suspension was stable for four-week period preserving its physical and chemical features. The release profiles of valsartan and amlodipine from the suspension were similar to those from source tablet Valzadepine®. In silico modeling predicted the similarity of the extemporaneous suspension and the commercial tablets. CONCLUSION: Amlodipine/valsartan extemporaneous suspension could be prepared from available commercial tablets. Moreover, GastroPlus™ can be applied along with the in vitro dissolution in order to affirm similarity in extemporaneous compounding situations.

Screening of Antioxidant and Antimicrobial Activity of Micromeria fruticosa serpyllifolia Volatile Oils: A Comparative Study of Plants Collected from Different Regions of West Bank, Palestine.

BACKGROUND: The investigation of volatile oils used in traditional medicine is vital to enhance the quality of healthcare. This study is aimed at screening the antioxidant and antimicrobial properties of Micromeria fruticosa serpyllifolia volatile oils from three different regions in Palestine (north, middle, and south). METHODS: Volatile oils of three samples of M. fruticosa serpyllifolia were extracted using the microwave-ultrasonic apparatus. The antioxidant activity of the volatile oils was assessed by inhibition of DPPH free radical. The antimicrobial activity was examined using the broth microdilution method. Assessment of antifungal activity was achieved using the agar dilution method. RESULTS: Screening the biological activity of plant extracts revealed that the sample from Ramallah (middle region) possessed the most potent antioxidant activity with an IC50 value of 0.45 µg/mL. The three samples exhibited broad antimicrobial activity and showed potential antifungal activity. The sample from the southern region showed the highest potency against Shigella sonnei with the lowest reported MIC; the sample from the northern region demonstrated the least potency against clinical isolate of Staphylococcus aureus and "methicillin"-resistant Staphylococcus aureus. CONCLUSIONS: The study showed that Micromeria fruticosa serpyllifolia volatile oil samples from different regions in Palestine possess different potential antioxidant and antimicrobial activities that were in line with traditional uses of the plant extracts.

Evaluation of food effect on the oral absorption of clarithromycin from immediate release tablet using physiological modelling.

BACKGROUND: Food may affect the oral absorption of drugs. PURPOSE: The aim of the present study was to investigate the influence of food on the oral absorption of clarithromycin by evaluating the effect of media parameters, such as pH, bile secretions and food composition, on the release of the drug from immediate release tablets, using in vitro and in silico assessments. METHOD: The solubility, disintegration and dissolution profiles of clarithromycin 500 mg immediate release tablets in compendial media with/without the addition of a homogenized FDA meal as well as in biorelevant simulated intestinal media mimicking fasting and fed conditions were determined. These in vitro data were input to GastroPlus™, which was used for developing a physiological absorption model capable of anticipating the effect of food on clarithromycin absorption. Level A in vitro-in vivo linear correlations were established using a mechanistic absorption modelling based deconvolution approach. RESULTS: The pH of the media has a profound effect on clarithromycin solubility, tablet disintegration and drug release. Clarithromycin has lower solubility in biorelevant media compared with other media, due to complex formation with bile salts. Clarithromycin tablets exhibited prolonged disintegration times and reduced dissolution rates in the presence of the standard FDA meal. The simulation model predicted no significant food effect on the oral bioavailability of clarithromycin. The developed IVIVC model considered SIF, acetate buffer and FaSSIF media to be the most relevant from the physiological standpoint. CONCLUSION: The intake of a standard FDA meal may have no significant effect on the oral bioavailability of clarithromycin immediate release tablet.

Evaluation of community pharmacists' knowledge and awareness of food-drug interactions in Palestine.

Background Food-drug interactions can produce undesirable outcomes during the therapy process. The pharmacist is responsible for providing patients counseling about common food-drug interactions. Knowledge of such interactions is important to avoid their occurrence. Objective This study aimed to assess the knowledge and awareness of community pharmacists about common food-drug interactions. Setting Pharmacists working in community pharmacies across Northern Palestine. Method This is a cross-sectional study, which involved a convenience sample of 259 pharmacists working in community pharmacies in Palestine. A self-administered questionnaire consisted of 29 questions (mainly yes/no questions) was used to assess pharmacists' knowledge towards the most common and clinically significant interactions between food and medicines. Main outcome measure Pharmacists' issues related to the knowledge of food drug interactions were evaluated. Results A total of 320 questionnaires were distributed of which 259 were completed providing a response rate 80.9%. One pharmacist from each community pharmacy was asked to complete the questionnaire. The overall knowledge score of food-drug interactions for the pharmacists was 17.9 (61.7%) out of a possible maximum of 29. The pharmacists surveyed in this study have demonstrated good knowledge of some interactions; but poor knowledge of others. Conclusion Pharmacists' knowledge about common food-drug interactions is inadequate. These findings support the need for training and educational courses for pharmacists regarding food-drug interactions.

Formulation and In Vitro, In Vivo Correlation Between Two Candesartan Cilexetil Tablets.

In this study, the in vitro and in vivo interchangeability between generic candesartan 16 mg and the branded formulation was assessed. The in vitro release of these products was conducted in 3 pH media (1.2, 5.0, and 6.8), and similarity factors (f2 ) were calculated. This bioequivalence study was a randomized, 2-period crossover study that included 42 healthy adult male subjects under fasting conditions with a 9-day washout. The pharmacokinetic (PK) parameters AUC0-last , AUC0-∞ , and Cmax , tmax , and the elimination half-life time were assessed based on the plasma concentrations of candesartan, using a newly developed and validated liquid chromatography-tandem mass spectrometry bioanalytical method with acceptable degrees of linearity, sensitivity, precision, and accuracy. The geometric mean (ng·h/mL) of the AUC0-∞ for the test and brand was 1595.49 and 1620.54, respectively, and the Cmax (ng/mL) was 160.91 and 160.88, respectively. The 90%CIs of geometric mean ratios (test-to-reference ratios) were 98.26%, 98.45%, and 99.86% for AUC0-last , AUC0-∞ , and Cmax respectively. These PK parameters lie within the US Food and Drug Administration- and European Medicines Agency-specified bioequivalence limit (80%-125%). Both products were well tolerated by all the subjects. The tested drug product was bioequivalent to the reference drug and had the same safety profile.

Food effect: The combined effect of media pH and viscosity on the gastrointestinal absorption of ciprofloxacin tablet.

BACKGROUND: The clinical implications of food-drug interactions may have to be taken seriously into account with oral drugs administration in order to minimize variations in drug bioavailability. Food intake may alter physiological changes in the pH and viscosity of the gastrointestinal lumen, which could affect the oral absorption of drugs. PURPOSE: The aim of the present study was to have an insight on the effect of media parameters: viscosity and pHon the oral absorption of ciprofloxacin HCl from solid formulations using a model food: Corchorus olitorius (Jute) Soup. METHODS: In vitro disintegration and dissolution rates of ciprofloxacin tablet were evaluated using compendia buffer media in the presence/absence of C. olitorius leaves. These in vitro data were then input to GastroPlus™ to predict ciprofloxacin absorption profiles under fasted and fed states. RESULTS: The present study demonstrated the significance of luminal pH and viscosity on the dissolution and disintegration of solid formulations following postprandial ingestion of the viscous soup. The tablets showed prolonged disintegration times and reduced dissolution rates in this soup, which could be attributed to the postprandial elevation in media viscosity and reduced solubility at elevated gastricpH. The predicted model under fed state showed no impact on AUC but prolonged Tmax and a decrease in Cmax. CONCLUSION: Concomitant intake of C. olitorius soup with ciprofloxacin might have negative effect on the rate of drug release from conventional immediate release tablets.

Bio-predictive tablet disintegration: effect of water diffusivity, fluid flow, food composition and test conditions.

Food intake may delay tablet disintegration. Current in vitro methods have little predictive potential to account for such effects. The effect of a variety of factors on the disintegration of immediate release tablets in the gastrointestinal tract has been identified. They include viscosity of the media, precipitation of food constituents on the surface of the tablet and reduction of water diffusivity in the media as well as changes in the hydrodynamics in the surrounding media of the solid dosage form. In order to improve the predictability of food affecting the disintegration of a dosage form, tablet disintegration in various types of a liquefied meal has been studied under static vs. dynamic (agitative) conditions. Viscosity, water diffusivity, osmolality and Reynolds numbers for the different media were characterized. A quantitative model is introduced which predicts the influence of the Reynolds number in the tablet disintegration apparatus on the disintegration time. Viscosity, water diffusivity and media flow velocity are shown to be important factors affecting dosage form disintegration. The results suggest the necessity of considering these parameters when designing a predictive model for simulating the in vivo conditions. Based on these experiments and knowledge on in vivo hydrodynamics in the GI tract, it is concluded that the disintegration tester under current pharmacopoeial conditions is operated in an unphysiological mode and no bioprediction may be derived. Recommendations regarding alternative mode of operation are made.

Mechanistic understanding of food effects: water diffusivity in gastrointestinal tract is an important parameter for the prediction of disintegration of solid oral dosage forms.

Much interest has been expressed in this work on the role of water diffusivity in the release media as a new parameter for predicting drug release. NMR was used to measure water diffusivity in different media varying in their osmolality and viscosity. Water self-diffusion coefficients in sucrose, sodium chloride, and polymeric hydroxypropyl methylcellulose (HPMC) solutions were correlated with water uptake, disintegration, and drug release rates from trospium chloride immediate release tablets. The water diffusivity in sucrose solutions was significantly reduced compared to polymeric HPMC and molecular sodium chloride solutions. Water diffusivity was found to be a function of sucrose concentration in the media. Dosage form disintegration and drug release was to be affected by water diffusivity in these systems. This observation can be explained by hydrogen bonding formation between sugar molecules, an effect which was not expressed in sodium chloride solutions of equal osmolality. Water diffusivity and not media osmolality in general need to be considered to predict the effect of disintegration and dissolution media on drug release. Understanding the relevance of water diffusivity for disintegration and dissolution will lead to better parametrization of dosage form behavior in gastrointestinal (GI) aqueous and semisolid media.

Mechanistic investigation of food effect on disintegration and dissolution of BCS class III compound solid formulations: the importance of viscosity.

A negative food effect, i.e. a decrease in bioavailability upon the co-administration of compounds together with food, has been attributed particularly with high solubility/low permeability compounds (BCS class III). Different mechanisms have been proposed including intestinal dilution leading to a lower concentration gradient across the intestinal wall as well as binding of the active pharmaceutical ingredient to food components in the intestine and thereby decreasing the fraction of the dose available for absorption. These mechanisms refer primarily to the compound and not to the dosage form. An increase in viscosity of the dissolution fluid will in particular affect the absorption of BCS type III compounds with preferential absorption in the upper small intestine if the API release is delayed from the dosage form. The present study demonstrated that the increase in viscosity of the dissolution medium, following ingestion of a solid meal, may drastically reduce disintegration and dissolution. For that purpose the viscosity of the standard FDA meal was determined and simulated by solutions of HPMC in buffer. As model formulations, three commercially available tablets containing trospium chloride, a BCS class III m-cholinoreceptor antagonist was used. Trospium chloride drug products have been described to undergo a negative food effect of more than 80% following ingestion with food. The tablets showed prolonged disintegration times and reduced dissolution rates in viscous media, which could be attributed to changes in the liquid penetration rates. The effect was particularly significant for film-coated tablets relative to uncoated dosage forms. The results show the necessity of considering media viscosity when designing in vitro models of drug release for BCS type III drug formulations.