Development and optimization of a one step process for the production and sterilization of liposomes using supercritical CO2

Liposomes are very interesting drug delivery systems for pharmaceutical and therapeutic purposes. However, liposome sterilization as well as their industrial manufacturing remain challenging. Supercritical carbon dioxide is an innovative technology that can potentially overcome these limitations. The aim of this study was to optimize a one-step process for producing and sterilizing liposomes using supercritical CO2. For this purpose, a design of experiment was conducted. The analysis of the experimental design showed that the temperature is the most influential parameter to achieve the sterility assurance level (SAL) required for liposomes (≤10-6). Optimal conditions (80 °C, 240 bar, 30 min) were identified to obtain the fixed critical quality attributes of liposomes. The conditions for preparing and sterilizing empty liposomes of various compositions, as well as liposomes containing the poorly water-soluble drug budesonide, were validated. The results indicate that the liposomes have appropriate physicochemical characteristics for drug delivery, with a size of 200 nm or less and a PdI of 0.35 or less. Additionally, all liposome formulations demonstrated the required SAL and sterility at concentrations of 5 and 45 mM, with high encapsulation efficiency.

Entomotherapy as an alternative treatment for diseases due to Gram-negative bacteria in Burkina Faso

Insects are known for their harmful effects. However, they also benefit humans, animals, plants, and ecosystems. Its beneficial uses include entomophagy and entomotherapy. This study aimed to evaluate the antibacterial activity of insect extracts against Gram-negative bacteria. Antibacterial activities of thirteen crude extracts of medicinal insects were tested against twelve Gram-negative bacteria by diffusion on agar. Imipenem was used as an antibiotic for positive control. The thirteen extracts acted differently against certain Gram-negative bacteria. The largest inhibition diameter was for extracts of Cirina butyrospermi and Mylabris variabilis against Pseudomonas aeruginosa ATCC27853 and Salmonella enteritidis ATCC13076, respectively. The diameters of inhibition obtained using imipenem against these same bacterial strains were 13.0 ± 0.0 mm and 22 ± 1.0 mm, respectively. The lowest inhibition diameter (7.5 ± 0.0 mm) was obtained using Anopheles gambiae extract against Salmonella Typhimurium ATCC14028. Imipenem was active on all strains tested. The highest values of the index multi-resistance to insect's extracts were reported for Pseudomonas aeruginosa ATCC9027 and Serratia odorifera 652411. Overall, the results of this study confirmed the antibacterial activities of insects used by traditional health practitioners to treat different pathologies. Entomotherapy could be an alternative treatment for certain infectious pathologies caused by gram-negative bacteria.

Phytopharmaceutical practices of traditional health practitioners in Burkina Faso: a cross-sectional study

BACKGROUND

Traditional health practitioners constitute an important part of the health care system in Burkina Faso, particularly in the supply of traditional herbal medicines. Quality and safety of these medicines rely heavily on practices employed during their traditional development. However, traditional phytopharmaceutical practices are poorly described in Burkina Faso. This study aimed to describe the phytopharmaceutical practices of traditional medicine practitioners in Burkina Faso.

METHODS

This was a cross-sectional descriptive ethno-pharmaceutical study, conducted from October 1 to November 30, 2020, among traditional practitioners in four randomly selected health districts: Nongr-Massom (Centre region), Tenkodogo (Centre-East region), Diapaga (East region) and Dafra (Hauts-Bassins region). An anonymous semi-structured face-to-face questionnaire was used to collect socio-demographic data and data on raw materials and finished products.

RESULTS

Sixty-seven (67) traditional health practitioners, aged 56 years on average, including a majority of men (72%), participated in the study. Gathering of wild medicinal plants was the main source of raw materials acquisition (51.5%), which were usually leaves (32.3%). These raw materials were usually sun-dried (43.9%) and packaged mostly in plastic bags (37.2%). They were derived from 60 plant species belonging to 33 botanical families. Fabaceae was the most represented family (18.7%) and Khaya senegalensis Juss. (Meliaceae) the most cited plant species (5.2%). The finished products had an average shelf life of 17 months and were usually prepared as a decoction (31.7%) and administered most often orally (71.4%). Gastrointestinal disorders were the main predictable adverse events of the finished products (54%).

CONCLUSION

This study showed that THPs have important knowledge in the use of medicinal plants, but several shortcomings are observed in their phytopharmaceutical and plant protection practices. Continuous improvement of these practices, through education and training of traditional health practitioners, is essential for the conservation of plant biodiversity and quality assurance of traditional herbal medicines.

Current Status and Challenges of Pharmacovigilance of Traditional Medicines in French-Speaking West African (UEMOA) Countries

BACKGROUND

West African Economic and Monetary Union (UEMOA) countries are characterised by a high prevalence of informal use of medicinal plants and traditional medicines by their population for health care, requiring the establishment of pharmacovigilance, in order to monitor the associated health risks. However, the state of implementation of pharmacovigilance for traditional medicines in UEMOA countries is not known.

OBJECTIVE

This study aimed to assess the state of implementation of pharmacovigilance for traditional medicines in the eight UEMOA countries, describing the relevant community provisions, assessing the integration of traditional medicines monitoring into national pharmacovigilance systems and identifying related national challenges.

METHODS

This was a cross-sectional study using questionnaires, conducted between 1 May and 31 August 2022. A face-to-face questionnaire was administered to officials responsible for the issue within UEMOA and the West African Health Organisation (WAHO). A second online questionnaire was specifically sent to the pharmacovigilance focal points of the eight UEMOA countries. Questionnaires were designed using the WHO indicators for pharmacovigilance. The face-to-face questionnaire collected two types of data, namely community policies and regulations on pharmacovigilance and technical and financial support from sub-regional organisations to countries. The online questionnaire sent to countries collected four categories of data on the study issue: structural data, process data, impact data and data on national challenges.

RESULTS

As a community provision, WAHO has a harmonised regulatory framework for phytovigilance. The monitoring of traditional medicines is not effectively implemented in the pharmacovigilance systems of UEMOA countries. Only two reports of adverse events due to traditional medicines have so far been recorded in the Union. The countries have neither funding nor sufficient human resources for pharmacovigilance in general. Monitoring of traditional medicines in the unregulated market, training of stakeholders, risk communication, and integration of traditional health practitioners in reporting systems are the main challenges of countries for the development of pharmacovigilance for traditional medicines.

CONCLUSION

The effective compliance of WAHO's harmonised phytovigilance regulatory framework by UEMOA countries and addressing the challenges identified by the countries constitute the basis for the development of pharmacovigilance for traditional medicines within UEMOA.

Use of supercritical CO2 for the sterilization of liposomes: Study of the influence of sterilization conditions on the chemical and physical stability of phospholipids and liposomes

The effects of four potential supercritical carbon dioxide (ScCO₂) sterilization conditions on the chemical stability of 9 phospholipids and on the physicochemical characteristics of liposomes consisting of stable phospholipids, as well as their sterilization efficiency were evaluated. These conditions were : C1 (ScCO₂/70 °C/150 bar/240 min), C2 (ScCO₂/0.25 % water/ 0.15% H₂O₂/ 0.5% acetic anhydride/38° C/85 bar/45 min), C3 (ScCO₂/0.08 % peracetic acid/35° C/104 bar/180 min) and C4 (ScCO₂/200 ppm H₂O₂/40 °C/270 bar/90 min). The results showed for phospholipids, a significant increase in hydrolysis products of 3.77 to 14.50 % and an increase in oxidation index of 6.10 to 430.50 % with unsaturated phospholipids for all tested conditions while with saturated phospholipids, no significant degradation was observed. Concerning the liposome formulation, no change in dispersion color and no phospholipid degradation were observed. However, a decrease in liposome size from 126.90 nm to 111.80 nm, 96.27 nm, 99.60 nm and 109.13 nm and an increase in the PdI from 0.208 to 0.271, 0.233, 0.285, and 0.298 were found with conditions C1, C2, C3 and C4 respectively. For the sterilization efficiency, conditions C1, C2 and C3 achieved the required sterility assurance level (SAL) of 10^-6 for liposomes.

Use of traditional medicines among conventional medicine practitioners in Burkina Faso

INTRODUCTION

The integration of traditional medicine into biomedical health care practice is highly dependent on its acceptability by conventional medical practitioners. Its use by conventional practitioners was previously unknown in Burkina Faso.

PURPOSE OF RESEARCH

The purpose of this study was to estimate the prevalence of traditional medicine use and the frequency of occurrence of adverse events associated with this use among conventional medical practitioners in Burkina Faso.

RESULTS

The majority of the practitioners surveyed were women (56.1%) and the average age was 39.7±7 years. Nurses (56.1%), midwives (31.4%) and physicians (8.2%) were the most represented professions. The prevalence of the use of traditional medicines in the 12 months preceding the survey was 75.6%. Malaria was the main medical reason for using traditional medicines (28%). The frequency of reported adverse events was 10% and mainly concerned gastrointestinal disorders (78.3%).

CONCLUSIONS

The majority of conventional medical practitioners in Burkina Faso use traditional medicines for their health problems. This finding suggests the effective integration of traditional medicine into biomedical health care practice which could benefit from good acceptability by these professionals.

Port des équipements de protection individuelle dans le contexte de la COVID-19 dans un centre hospitalier du Burkina Faso

INTRODUCTION

Personal protective equipment (PPE) is used by health care workers to protect themselves and patients from various exposures such as infectious agents. However, the wearing of this equipment is not always optimal, especially in an epidemic context of COVID-19 transmission.

AIM OF THE STUDY

The aim of this study, in the specific context of COVID-19, is to contribute to the improvement of PPE wearing practices by health workers.

METHODS

This is a descriptive cross-sectional study conducted in 2020 at the Charles De Gaulle Pediatric University Hospital in Burkina Faso. All health workers in the care units and the laboratory were included. Data were collected using an observation grid during the first situation indicating the wearing of PPE. The assessment of the indications for wearing PPE was based on the recommendations of the French Society of Hospital Hygiene and on the technical guide for the prevention and control of healthcare-associated infections in Burkina Faso.

RESULTS

Out of 350 targeted agents, 296 were observed. Gowns, masks and gloves were worn in 95.60%, 96.58% and 97.63% of cases respectively. However, PPE such as goggles (1.56%), apron (11.54%), and tunic and pants (46.28%) were poorly used during medical care.

CONCLUSION

The practices of health workers with regard to the wearing of certain PPE are still insufficient. A training and awareness program on PPE should be considered to improve patient and staff safety.

Factors limiting traditional medicine integration into modern health systems in Africa: protocol for a systematic review of qualitative studies

OBJECTIVES

It was recognised in the 1978 Alma-Ata Declaration that the integration of traditional medicine into modern health systems is a major lever for achieving universal health coverage. In several African countries, the integration of traditional medicine still faces constraints, despite the development of policies and regulations in favour of this integration. The objective of this study is to conduct a systematic review of the limitations of integrating traditional medicine in Africa.

STUDY DESIGN

This is a systematic review protocol for qualitative studies.

METHODS

The aim will be to conduct a systematic review of qualitative studies according to PRISMA guidelines. Given the qualitative nature of the primary studies, the COREQ guidelines will also be used to complement PRISMA. The search for primary studies will be conducted in Medline, Science Direct, Hinari and Google Scholar databases, using search equations designed based on the keywords constituting the thesauri of the search question. This will be done independently by two authors. The screening steps of the identified articles will be presented in PRISMA 2009 flowchart. The assessment of the risk of bias of the primary studies and the strength of the conclusions or recommendations will be performed by the GRADE tool.

RESULTS

The results of this systematic review will consist of the primary qualitative studies on the limitations of integrating traditional medicine into conventional health systems in African countries. These will be categorised into policy, legal, organisational and sociocultural limitations. They will be reported in accordance with the PRISMA and COREQ guidelines.

CONCLUSION

A systematic qualitative study of the limitations of effective integration of traditional medicine into conventional health systems in Africa is needed to guide national policies and regulations on traditional medicine. The application of PRISMA and COREQ standards to this review will ensure its quality and reproducibility.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO ID: CRD42022318699.

In Vitro Antioxidant and Anticancer Properties of Various E. senegalensis Extracts

Although Erythrina senegalensis is a plant widely used in traditional medicine in sub-Saharan Africa, its biological properties have been poorly investigated to date. We first characterized by conventional reactions the composition of several stem bark extracts and evaluated in acellular and cellular assays their pro- or antioxidant properties supported by their high phenolic and flavonoid content, particularly with the methanolic extract. The pro- or antioxidant effects observed did not correlate with their IC₅₀ concentrations against five cancer cell lines determined by MTT assay. Indeed, the CH₂Cl₂ extract and its ethyl acetate (EtOAc) subfraction appeared more potent although they harbored lower pro- or antioxidant effects. Nevertheless, at equipotent concentration, both extracts induced ER- and mitochondria-derived vacuoles observed by fluorescent microscopy that further led to non-apoptotic cell death. LC coupled to high resolution MS investigations have been performed to identify chemical compounds of the extracts. These investigations highlighted the presence of compounds formerly isolated from E. senegalensis including senegalensein that could be retrieved only in the EtOAc subfraction but also thirteen other compounds, such as 16:3-Glc-stigmasterol and hexadecanoic acid, whose anticancer properties have been previously reported. Nineteen other compounds remain to be identified. In conclusion, E. senegalensis appeared rich in compounds with antioxidant and anticancer properties, supporting its use in traditional practice and its status as a species of interest for further investigations in anticancer drug research.

Hospital preparations of ethanol-free furosemide oral solutions: Formulation and stability study

Furosemide is a diuretic frequently used in the therapeutic management of edema associated with cardiac, renal, and hepatic failure and hypertension. However, there are a very low number of pharmaceutical dosage forms containing furosemide that are suitable for children under 6- years old. Therefore, there is a real need to develop hospital preparations, especially in the hospital. Four oral pediatric solutions of furosemide (2 mg/Ml) were formulated. Two of those solutions did not contain ethanol. For each formulation, 12 batches of 1600.0 Ml were prepared and packaged in 250.0 Ml brown glass bottles with polypropylene screw caps. The physicochemical properties (visual appearance, pH, osmolarity, drug content) and microbiological quality of the finished product were determined on the freshly prepared solutions and after 90 days of storage at 30°C/65% RH. The physicochemical and microbiological characteristics of the freshly prepared solutions were within the prescribed specifications. After 90 days of storage at 30°C/65% RH, the solutions containing sucrose and those without ethanol showed a slight decrease in pH and furosemide content of about 2.5%–4.5% (w/w). Despite this slight decrease, the characteristics remained within the prescribed specifications. Based on the stability profile of the ethanol-free solution containing sorbitol, it could be implemented in hospitals for the care of pediatric patients.

[State of play of the regulation of clinical trials in Mali]

OBJECTIVE

The objective was to take stock of the regulation of clinical trials in Mali.

MATERIAL AND METHODS

This was a descriptive cross-sectional study carried out of the September 1 to December 15, 2019. It consisted of a literature search and a survey in research centers, ethics committees and regulatory structures in Mali.

RESULTS

In 2019, there were 15 clinical trials authorized and conducted by three research centers, including 12 vaccines and 3 drugs trials all approved by an ethics committee. The legal framework for clinical trials is governed in Mali by two texts, one legislative and the other regulatory. They provide for the authorization, suspension or prohibition of biomedical research by the minister in charge of Health. The shortcomings identified relate to the low recovery and lack of evaluation of pharmacovigilance data, the scarcity of site inspections and especially the absence of a technical committee for regulatory evaluation of files at the Pharmacy and Medicines Department (DPM).

CONCLUSION

The strengthening of the legal framework is, more than ever, necessary to ensure the protection of the rights, safety and well-being of research subjects in a context of increasing relocation of clinical trials to our countries.

Sterilization methods of liposomes: Drawbacks of conventional methods and perspectives

Liposomes are targeted drug delivery systems that are of great pharmaceutical and therapeutic interest. Parenteral route is the main way used for liposome administration. In this case, their sterility is a requirement. However, due to the particular sensitivity of liposomes and their tendency to physicochemical alterations, their sterilization remains a real challenge. Conventional sterilization methods such as heat, ethylene oxide, ultraviolet and gamma irradiations are considered as unsuitable for liposome sterilization and the recommended methods for obtaining sterility of liposomes are filtration and aseptic manufacturing. Unfortunately, these recommended methods are not without limitations. This review outlines the difficulties associated with the use of these different classical methods for obtaining liposome sterility. The effects on liposome physicochemical and biopharmaceutical characteristics as well as efficacy, toxicity and practical problems of these sterilization techniques have been discussed. The search for an alternative method being therefore necessary, the applicability of supercritical carbon dioxide (ScCO₂) technology, which is nowadays a promising strategy for the sterilization of sensitive products such as liposomes, is also examined. It appears from this analysis that ScCO₂ could effectively be an interesting alternative to achieve sterility of liposomes, but for this, sterilization assays including challenge tests and optimization studies are needed.

[Wholesale distribution and delivery of plant-based medicinal products through the pharmaceutical system of Burkina Faso]

OBJECTIVE

In order to improve the contribution of medicines from traditional pharmacopoeia to health care, African countries like Burkina Faso have adopted for several years, policies and regulations organizing their distribution. This study aims to analyze the situation of the wholesale and retail sale of herbal medicines imported by the official pharmaceutical facilities.

METHOD

This is a retrospective study involving all 18 drug wholesalers and 115 pharmacies in the city of Ouagadougou (Burkina Faso). It consisted of a collection of sales data of herbal medicines from 2013 to 2016 and interviews of the pharmacists responsible for the facilities surveyed.

RESULTS

All the pharmacies surveyed obtain their supplies from national wholesalers, but eleven of them do so directly from manufacturers or non-wholesalers. Only 40% (44/111) of herbal medicines distributed by wholesalers and pharmacies had valid marketing authorizations. Also, although the average growth rates of annual sales by wholesalers and private pharmacies, respectively 23.67% and 11.94%, are significant, the turnover generated from their sale remains low.

CONCLUSION

Supporting local producers with appropriate funding and adequate promotion of herbal medicines is still needed to boost the share of the national herbal medicines market.

Plaidoyer pour un renforcement du système de pharmacovigilance au Burkina Faso

Large-scale deployment of new medicines has been observed over the last two decades in many Sub-Saharan Africa countries faced with major public health issues such as malaria and HIV/AIDS. However, some of these medicines may be responsible for varying degrees of toxicity, with adverse drug reactions leading to decreased compliance or even discontinuation of treatment. Pharmacovigilance systems therefore had to be set up in these countries, such as in Burkina Faso, West Africa, which initiated the organization of pharmacovigilance activities in 2008. Despite this progress, the systems in place have not yet achieved a sufficient level of performance to deal with drug-related health issues, highlighting the need for further actions. Pharmacovigilance in Burkina Faso can be strengthened at multiple levels: pre-service and in-service training of health workers; the establishment of active surveillance based on sentinel sites; informing the public and raising awareness; and strengthening national coordination.

Ciprofloxacin monoolein water gels as implants for the treatment of chronic osteomyelitis: In vitro characterization

This work investigated the possibility of using the biodegradable gentamicin-monoolein-water gels as models, in order to obtain a similar sustained release of ciprofloxacin hydrochloride. Four gels containing antibiotics were prepared and were examined with regard to their physicochemical properties and in vitro drug release characteristics. Ciprofloxacin, unlike gentamicin, which was dissolved in the matrix, was in dispersed form. However, despite its insolubility, microscopic observation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and X-ray diffraction showed that the developed gel was in the cubic liquid crystalline structure and have maintained their ability to progressively release ciprofloxacin. ciprofloxacin-monoolein-water (5:80:15% w/w), which released in vitro approximately 85% of ciprofloxacin after 16 days could possibly be considered as an alternative to a gentamicin-monoolein-water gel for the treatment of chronic osteomyelitis.

Effect of hydroxyapatite on the physicochemical characteristics of a gentamicin-loaded monoolein gel intended to treat chronic osteomyelitis

Many works have demonstrated the real potential of gentamicin-monoolein-water formulations as bioresorbable and sustained-release implants for the local treatment of the chronic osteomyelitis. In order to improve the efficacy of this type of implant, the incorporation of hydroxyapatite, a well-known osteointegrator material, is thought to be an interesting approach. Five formulations incorporating 0, 2.5, 5, 10, and 20% of hydroxyapatite were examined with regard to their physicochemical and in vitro drug release characteristics. The rheological, thermal (differential scanning calorimetric and thermogravimetric diffraction analysis), X-ray diffraction, and dissolution studies have showed that the presence of hydroxyapatite does not dramatically disturb the cubic liquid crystalline structure of the monoolein-water gel and their ability to progressively release the antibiotic. Implant 20% that was capable to release gentamicin sulfate over a period of four weeks without marked burst effect could be used as a more suitable biodegradable delivery system for the local management of chronic osteomyelitis.

Monoolein-water liquid crystalline gels of gentamicin as bioresorbable implants for the local treatment of chronic osteomyelitis: in vitro characterization

To maximize the efficacy of chronic osteomyelitis antibiotherapy while reducing antibiotic systemic toxicity, as well as time and costs of hospitalizations, it has been thought that monoolein-water gels incorporating gentamicin sulfate could be used as local, bioresorbable,and sustained-release implants. For this purpose, four formulations were examined with regard to their physicochemical and in vitro drug release characteristics. Hot stage microscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA),and X-ray diffraction showed cubic liquid crystalline and eutectic structures. The more suitable formulation consisting of 80-15-5%wt/wt monoolein-water-gentamicin sulfate progressively released the antibiotic for a period of 3 weeks without burst effect. Moreover, the content and the release profile of gentamicin sulfate were not significantly changed after storage at 2-6 degrees C for a period of 10 months.

[Bioequivalence in vitro evaluation of some antibacterial generic dosage forms]

In this work, bioequivalence between generic and corresponding original brand-name dosage forms of some antibacterial drugs, frequently prescribed in developing countries, have been examined using in vitro dissolution testing. For this purpose, tablet or hard capsule formulations of five active substances (amoxycillin, ampicillin, co-trimoxazole (sulphamethoxazole/trimethoprim), metronidazole and penicillin V) have been retained. For each active substance, batch samples of three generic and one test formulations have been submitted to the pharmaceutical quality control and dissolution testing. Results obtained have shown that all samples examined met the specifications of quality edited by the pharmacopeias. On the other hand, interchangeability between generic and corresponding test formulations should be possible since their dissolution profiles are superposables enough.

Synthesis and enzymatic degradation of epichlorohydrin cross-linked pectins

The water solubility of pectin was successfully decreased by cross-linking with increasing amounts of epichlorohydrin in the reaction media. The initial molar ratios of epichlorohydrin/ galacturonic acid monomer in the reaction mixtures were 0, 0.37, 0.56, 0.74, 1.00, 1.47, and 2.44. The resulting epichlorohydrin cross-linked pectins were thus referred to as C-LP0, C-LP37, C-LP56, C-LP75, C-LP100, C-LP150, and C-LP250, respectively. Methoxylation degrees ranged from 60.5 +/- 0.9% to 68.0 +/- 0.6%, and the effective cross-linking degrees, determined by quantification of the hydroxyl anions consumed during the reaction, were 0, 17.8, 26.0, 38.3, 46.5, 53.5, and 58.7%. respectively. After incubating the different cross-linked pectins (0.5% w/v) in 25 mL of 0.05 M acetate-phosphate buffer (pH 4.5), containing 50 microL of Pectinex Ultra SP-L (pectinolytic enzymes), between 60 and 80% of the pectin osidic bounds were broken in less than 1 hr. Moreover, increasing the cross-linking degree only resulted in a weak slowing on the enzymatic degradation velocity.

Effect of pectinolytic enzymes on the theophylline release from pellets coated with water insoluble polymers containing pectin HM or calcium pectinate

Theophylline pellets were coated with cellulosic (Aquacoat ECD 30, Surelease clear) or acrylic (Eudragit NE30D, RS30D) polymer aqueous dispersions, containing 10% (related to the insoluble polymer content) of pectin HM or calcium pectinate, using a Uni-Glatt fluidized-bed coating apparatus. When commercial pectinolytic enzymes were added to the dissolution media (0.05 M acetate - phosphate buffer, pH 6.0), the release of theophylline from the coated pellets was generally slower than that observed in the media without enzymes. The enzymatic slowing down of the drug release, depending on the type of the aqueous polymer dispersion used, is more important with mixed Eudragit NE/calcium pectinate coated pellets. The results obtained have been examined with regard to the validity of the approach based on the combination of pectins and the insoluble polymer aqueous dispersions intended for specific-delivery of drugs to the colon. The mechanism of the hydrophilic drug release from pellets coated with insoluble polymer aqueous dispersions containing an aqueous gel-forming polymer has been also discussed.

Studies of pectin HM/Eudragit RL/Eudragit NE film-coating formulations intended for colonic drug delivery

Theophylline pellets were coated with Eudragit NE30D aqueous dispersions, containing various pectin HM/Eudragit RL30D ionic complexes, using an Uni-Glatt fluidized-bed apparatus. Dissolution studies were then carried out on the coated pellets at pH 6.0, in absence and in presence of commercial pectinolytic enzymes. The theophylline release from the coated pellets, after an initial latency phase, occurred linearly as a function of time. The theophylline release rate was dependent on the pectin HM content of the complexes incorporated in the coatings. The lowest theophylline release from the coated pellets was obtained when the pectin HM content of the complexes was 20.0% w/w (related to Eudragit RL), i.e. when the complexation between pectin HM and Eudragit RL is optimal. The theophylline release from the coated pellets was slower in presence of the pectinolytic enzymes when the pectin content of complexes is higher than 20% w/w. On the other hand, the effect of the enzymes induced an increase of the theophylline release when the pectin HM content of the coatings ranged between 10.0 and 15.0% w/w (related to Eudragit RL).