Effect of Supplier Selection Practices on Availability of Essential Medicines in Private Pharmacies: A Case Study of Kicukiro District, Rwanda.

Abstract Background Consistent access to essential medicines depends partly on the ability of pharmacies to select suppliers that can provide quality-assured products reliably and at adequate capacity. Evidence on these relationships in Rwanda's private pharmacy sector is limited. This study assessed the association of supplier reliability, supplier quality standards, and supplier capacity with essential medicines availability in private pharmacies in Kicukiro District. Methods A quantitative cross-sectional study was conducted among responsible pharmacists or knowledgeable pharmacy staff. Of 112 sampled pharmacies, 103 provided usable responses (91.9%). Data were collected using a structured Likert-scale questionnaire and a checklist covering 25 essential medicines. Descriptive statistics and multiple linear regression were performed using SPSS version 27. Pearson correlations were examined as preliminary diagnostics, and regression assumptions were assessed. Results Supplier reliability, quality standards, and capacity were positively correlated with medicine availability (r = 0.959, 0.973 and 0.777, respectively; all p < 0.001). The regression model was significant (F = 683.351, p < 0.001) and explained 95.3% of the variance (adjusted R²=0.953). Supplier quality standards (β = 0.879, p < 0.001) and supplier capacity (β = 0.124, p = 0.001) had positive statistically significant coefficients, whereas supplier reliability did not (β = 0.002, p = 0.984). Severe multicollinearity between reliability and quality standards limits interpretation of their individual coefficients. Conclusion Supplier selection practices were strongly associated with essential medicines availability in the sampled private pharmacies. Quality standards and supplier capacity showed statistically significant regression coefficients, while the reliability coefficient should be interpreted cautiously because of multicollinearity. Strengthening supplier quality assurance, capacity assessment, and collaborative replenishment planning may support medicine availability.