A national survey on registered products, availability, prices, and affordability of 100 essential medicines in community pharmacies across Sri Lanka.

INTRODUCTION: Availability of essential medicines that meet the expected quality standards, in appropriate dosage forms at affordable prices is a fundamental prerequisite to fulfill healthcare needs of given a population. This study assessed available products, prices and affordability of essential medicines (EM) in community pharmacies in Sri Lanka with comparison of registration status from the National Medicines Regulatory Authority(NMRA). METHODS: A cross-sectional island-wide survey of 80 pharmacies was conducted according to World Health Organization and Health Action International Manual (WHO/HAI). Hundred medicines were selected from the global core list(n = 14), regional core list(n = 16) and the Sri Lanka Essential Medicine List (SL-EML) (n = 70) based on healthcare needs. Number of registered products in 2015 and 2021 were compared. FINDINGS: Average availability was 85.4%(± 12.31) and availability was lowest in the Northern province (69.38 ± 21.18%)(p = 0.008). Availability between the state owned, franchise and privately owned pharmacies was not significantly different (p > 0.05). 89.4% medicines were affordable except for amiodarone, hydroxychloroquine, sitagliptin, soluble insulin, isophane insulin, losartan, levodopa carbidopa combination, clonazepam and ceftriaxone. The median price ratio (MPR) of 33.7% of medicines was less than 1 and MPR of 37.1% originator brands (OB) was over 3. Median number of generic brands in the market was 8(range 2-44), 9% of medicines had 20 or more products in the market and 72.7% medicines had more products available than the number registered in 2015. The average number of registered products were similar in 2015 (8.27) and 2021(7.59) (p = 0.15). CONCLUSION: The overall availability of EMs in Sri Lanka was high in all categories of community pharmacies. Medicines were largely affordable and reasonably priced in 2015, although OBs were generally more expensive. Majority of medicines had more products in the market than the number of registered products.

Pharmacokinetics and Bioequivalence of Two Amoxicillin 500 mg Products: Effect of Food on Absorption and Supporting Scientific Justification for Biowaiver.

PURPOSE: Aims of this study were to compare the bioequivalence of two formulations of amoxicillin 500 mg capsules under fasted and fed conditions in the same set of healthy volunteers, compare pharmacokinetics of amoxicillin under the two conditions and to assess the possibility of predicting in vivo bioequivalence of the two formulations using in vitro dissolution data. METHOD: The innovator product of amoxicillin was used as the reference formulation and a test product, which showed in vitro equivalence after a biowaiver study with the same reference product was used in the bioequivalence study. Altogether 16 subjects were randomized to the reference and test products in the fasted study and 12 of them participated in the fed study. Plasma concentration of amoxicillin was analyzed by a validated Liquid chromatography coupled with two mass spectrometry (LC-MS/MS) method. Noncompartmental analysis was used to determine the pharmacokinetic parameters. Average bioequivalence method was used to evaluate the bioequivalence of the two formulations and statistical significance of the pharmacokinetic parameters were tested to study the effect of food on amoxicillin absorption. RESULTS: The Geometric Mean Ratio (GMR) for the test/reference product for the maximum drug concentrations (Cmax) was 102.77% and 97.38% in fasted and fed conditions respectively which was within 80.00-125.00% range required to demonstrate bioequivalence. The GMR for test/reference products for the area under the curve (AUC0-8,) was 100.05% and 96.91% in fasted and fed conditions respectively meeting the bioequivalence criteria. For the reference product, the Cmax was 9.38 and 7.61 µg x mL-1(p =0.0224), time to reach maximum concentration (Tmax) was 1.73 and 3.02 h (p=0.0005) and AUC0-8 was 26.02 and 25.54 µg/h-1 mL-1p = 0.672) under fasted and fed conditions respectively. CONCLUSION: The test and the reference formulations were bioequivalent under both fasted and fed conditions. Although the Cmax was significantly lower and Tmax was significantly delayed under fed conditions, it did not affect the AUC. Therefore, being a time dependent antibiotic, clinically significant effect of food on efficacy of amoxicillin is unlikely. As the selected products were equivalent in vitro, these findings support scientific justification for conducting in vitro dissolution studies for solid oral amoxicillin products as a surrogate for in vivo bioequivalence studies.

Safety monitoring of treatment in bipolar disorder in a tertiary care setting in Sri Lanka and recommendations for improved monitoring in resource limited settings.

BACKGROUND: Safety monitoring of medicines is essential during therapy for bipolar disorder (BD). We determined the extent of safety monitoring performed according to the International Society for Bipolar Disorders (ISBD) guidelines in patients with BD attending the main tertiary care psychiatry clinics in Sri Lanka to give realistic recommendations for safety monitoring in resource limited settings. METHODS: Patients diagnosed with BD on mood stabilizer medications for more than 1 year were recruited. Data were collected retrospectively from clinic and patient held records and compared with the standards of care recommended by ISBD guidelines for safety monitoring of medicines. RESULTS: Out of 256 patients diagnosed with BD, 164 (64.1%) were on lithium. Only 75 (45.7%) had serum lithium measurements done in the past 6 months and 96 (58.5%) had concentrations recorded at least once in the past year. Blood urea or creatinine was measured in the last 6 months only in 30 (18.3%). Serum electrolytes and thyroid-stimulating hormone (TSH) concentrations were measured in the last year only in 34 (20.7%) and 30 (18.3%) respectively. Calcium concentrations were not recorded in any patient. None of the patients on sodium valproate (n = 119) or carbamazepine (n = 6) had blood levels recorded to establish therapeutic concentrations. Atypical antipsychotics were prescribed for 151 (59%), but only 13 (8.6%) had lipid profiles and only 31 (20.5%) had blood glucose concentration measured annually. Comorbidities experienced by patients influenced monitoring more than the medicines used. Patients with diabetes, hypothyroidism and hypercholesterolemia were more likely to get monitored for fasting blood glucose and (p < 0.001), TSH (p < 0.001) and lipid profiles (p < 0.001). Lithium therapy was associated with TSH monitoring (p < 0.05). Therapy with atypical antipsychotics was not associated with fasting blood glucose or lipid profile monitoring (p > 0.05). A limitation of the study is that although some tests were performed, the results may not have been recorded. CONCLUSIONS: Safety monitoring in BD was suboptimal compared to the ISBD guidelines. ISBD standards are difficult to achieve in resource limited settings due to a multitude of reasons. Realistic monitoring benchmarks and recommendations are proposed for methods to improve monitoring in resource limited settings based on our experience.